allelochemicals world congress

5th World Congress on Allelopathy “Growing Awareness of the Role of Allelopathy in

Ecological, Agricultural, and Environmental Processes”

September 21- 25, 2008 The Saratoga Hilton, Saratoga Springs, New York, USA

http://www-iascongress5.org

5th WCA │September 21-25, 2008 │Saratoga Springs, NY, USA --------------------------------------------------------------------------------------------------------------

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Schedule at a glance

Morning Breaks and Luncheons Afternoon

Evening

Sunday September 21

Registration 2:00 – 7:00 pm

Reception 7:00 pm –

Monday September 22


Opening ceremony 8 am – 9:15 MT 9 & 12 9:20 –

Breaks10:35 & 15:30 Lunch and posters 12:15 –

MT 8 & 13 13:45 – Odd numbered posters 17:00 –

Dinner on your own

Tuesday September 23


MT 2 & 78:00 –

Break10:00 Lunch – 11:30

Conference tour departs 1300

18:00 Dinner cruise on Lake George

Wednesday September 24

Registration 8 – 5 pm

MT 1, 3 & 58:00 –

Breaks10:00 & 15:00 Lunch and posters 11:45 –

MT 4 & 10 13:00 – Evern numbered posters – 16:30

Congress Banquet 18:30 –

Thursday Sept ember 25

Registration 8:00 – 11:00 am

MT 6 & 118:00 –

Break10:00 Lunch on your own

12:15 – Closing ceremony and IAS business meeting

Prasanta C. Bhowmik, Editor University of Massachusetts

Amherst, MA 01003


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Welcome from the Conference Chairs We welcome you to the 5th World Congress of Allelopathy. The continuing success of this triennial congress series reflects the continued interest of scientists throughout the world in the intriguing science of allelopathy. In fact, we have scientists from almost forty countries on the program for this 5th iteration of the congress. We have been impressed by the breadth of scientific areas covered by the thirteen Main Topics. We thank the Main Topic Organizers for helping to attract such a varied and highly interesting assemblage of papers. Please join us for the Opening Reception on Sunday evening and take the opportunity to renew friendships and meet new colleagues. The congress technical program will begin with the plenary address by Dr. Norman Lewis on Monday morning, followed by several days of oral and poster presentations. Lunches will be provided for registered delegates on Monday through Weds. We have an excursion to beautiful natural areas on Tuesday afternoon, followed by a dinner cruise on Lake George. Our congress banquet will be on Wednesday evening. Finally, we hope that all of you can stay for the closing ceremony and International Allelopathy Society business meeting and awards ceremony on Thursday afternoon. At this meeting, we will decide the venue for the 6th World Congress of Allelopathy in 2011 and announce winners or the awards. We hope that all of you will take advantage of the opportunities for learning and networking throughout the events of the conference. We wish you a rewarding and enjoyable stay in Saratoga Springs.

Prasanta Bhowmik Stephen Duke Leslie Weston


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Contents Schedule at a glance 1 Welcome from the Conference Chairs 2 Congress Organizers 4 Program Committee 5 General Information 6 Program 8 Abstracts 28 Author Index 105


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Conference Organizers Conference Chair

Leslie Weston Charles Sturt University, Wagga Wagga, Australia Program Chairs

Prasanta Bhowmik University of Massachusetts, Amherst, MA, USA Stephen Duke USDA, ARS, Oxford, MS, USA Leslie Weston

Charles Sturt University, Wagga Wagga, Australia

Organizing Committee

Prasanta Bhowmik University of Massachusetts, Amherst, MA, USA

Stephen Duke USDA, ARS, Oxford, MS, USA Leslie Weston

Charles Sturt University, Wagga Wagga, Australia Jeffrey Weidenhamer Ashland University, Ashland, OH, USA


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Program Committee Prasanta Bhowmik, Co-Chair University of Massachusetts, Amherst, MA, USA Stephen Duke, Co-Chair USDA, ARS, Oxford, MS, USA Leslie Weston, Co-Chair Charles Sturt University, Wagga Wagga, Australia Scott Baerson USDA, ARS, Oxford, MS, USA Regina Belz University of Hohenheim, Hohenheim, Germany Nils-Ove Bertholdson Swedish University of Agricultural Sciences, Alnarp, Sweden Ray Callaway University of Montana, Missoula, MT, USA Frank Dayan USDA, ARS, Oxford, MS, USA Gary Ervin Mississippi State University, Starkville, MS, USA Marina Della Greca Università degli Studi di Napoli Federico II, Naples Italy Inge Fomsgaard University of Aarhus, Slagelse, Denmark Ines Fritz Universität für Bodenkultur Wien, Tulln, Austria David Gealy USDA, ARS, Stuttgart, AR, USA Inderjit Univeristy of Delhi, Delhi, Inda

Shibu Jose University of Florida, Gainesville, FL, USA Chuihua Kong Chinese Academy of Sciences, Shenyang, China Y. Fujii National Institute for Agro-Environmental Sciences, Tsukuba, Japna Francisco Macias Univeristy of Cadiz, Cadiz, Spain Azim Mallik Lakehead Univeristy, Thunder Bay, Canada Tsutomu Ohno University of Maine, Orono, ME, USA Ann Osbourn John Innes Centre, Norwich, UK Jim Pratley Charles Sturt University, Wagga Wagga, Australia Agnes Rimando USDA, ARS, Oxford, MS, USA Margo Schulz University of Bonn, Bonn, Germany Jeffrey Weidenhamer Ashland University, Ashland, OH, USA Ren-sen Zeng South China Agricultural University, Guangzhou 510642, P.R. China


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General Information Registration Hours Registration will be located in the Gallery near the Saratoga Hilton lobby. Participants can pickup registration materials during the registration hours below: Sunday, September 2:00 PM – 7:00 PM Monday, September 22 8:00 AM – 5:00 PM Tuesday, September 23 8:00 AM – 12:30 PM Wednesday, September 24 8:00 AM – 5:00 PM Thursday, September 25 8:00 AM – 11:00 AM Poster Session Gallery We would like all posters to be mounted on boards in the Gallery near the hotel lobby from Sunday at 3:00 PM until Thursday at 10:00 AM. Poster presentations of odd numbered posters (consult program abstract number for number) will be on Monday and even-numbered posters will be on Wednesday. See the program for further details. Posters left after 10:00 AM on Thursday will be disposed of. Reception Welcoming Reception will take place in the Foyer/Pavilion area on Sunday, September 21 7:00 – 8:30 PM and will feature regional wines and cocktails as well as finger foods. Conference Tour Tour will take place from 12:45 PM until 9:45 PM on Tuesday September 23. Tour will depart from the hotel on air conditioned buses and stop at several sites of interest to view local points of interest with respect to invasive species, and succession and regional history. Lunch will be completed before departure. Refreshments and dinner will be provided on the tour and lake cruise on Lake George. We will not be returning to the hotel during the tour, so please bring along any necessary items. Banquet Wednesday, September 24 6:00 – 6:45 Cash bar in the Atrium across from the Ballroom 6:45 – 9:00 Banquet and awards presentations, with comments from President Stephen O. Duke Saratoga Ballroom IAS Closing Ceremony and Business Meeting Thursday, September 25 12:30 – close Saratoga Ballroom 1 & 2 There will be a short Closing Ceremony and an International Allelopathy Society business meeting will be conducted by the Executive Committee of IAS and will be held following the regular program. The meeting is open to all members and we encourage attendance at this important event where we will choose the meeting site for the 6th World Congress on Allelopathy (2011) and new members of the executive committee and board of directors, and entertain any new business presented by the membership.


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Accompanying Persons’ Program: Although there is no formal program for accompanying persons each day, we have many local activities and sites of interest that can be arranged by the hotel and interested parties. For example, local spas have numerous day packages to enjoy mineral baths and massages, the harness track is running daily, excursions can be easily arranged to Lake George for tours and shopping, and the historic art district and local gardens and museums can be accessed by foot from the hotel. If you have a particular interest in exploring a regional location, please let Leslie Weston know and she would be happy to help organize a visit for all interested. Most venues are easily accessible by foot or by hotel van or limo service. Local limo service can be accessed in the lobby of the Saratoga Hilton. Lists of local restaurants and locations of interest are found at the concierge desk in the hotel lobby. Please google search Saratoga Springs and you will readily find sites of interest to visit, listed by the local chamber of commerce website.


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Program Sunday, Sept. 21, 2008 Registration begins at 2:00 PM Gallery Reception at 7:00 PM Foyer/Pavilion Monday, September 22, 2008 08:00 to 09:15 Opening ceremony Saratoga Ballroom 3 Phytochemical Diversity and Its Implications Norman G. Lewis Eisig-Tode Distinguished Professor and Director, Institute of Biological Chemistry Washington State University, USA (1.) 09:20 to 12:30 Concurrent sessions: MTs 9 and 12 Main Topic 9. Allelopathy methodologies Travers/Alabama Organizer: Jeffrey Weidenhamer Co-organizer: Regina Belz 9:20 The Conundrum of Allelopathic Agents in Soils: Soil Extractions and Dose Response Studies Udo Blum Department of Plant Biology, North Carolina State University, USA (151) 9:35 Measurement of Allelochemical Dynamics and Movement with Polydimethylsiloxane Sorbents Jeffrey D. Weidenhamer Department of Chemistry, Ashland University, USA (152) 9:50 Hormesis in Allelopathy Research – Modelling and Characteristic Features Regina G. Belz University of Hohenheim, Institute of Phytomedicine, Germany (153) 10:05 On Density-Dependence of Plant Growth Response to Toxic Compounds Aki Sinkkonen, Minna Vesterinen, Mari Hansi, Rauni Strömmer University of Helsinki, Dept. Ecol. Environmental Sciences, FInland (154) 10:20 Allelopathy: From Field Observation to Laboratory and Glasshouse Experiments J.R. Qasem Faculty of Agriculture, University of Jordan, Jordan (155) 10:35 Break 11:00 Parasitic Plants as a New Target Plant for Bioassay Method of Evaluating or Screening Rice Allelopathic Potential Yiqing Guo1, 2, Donghyun Shin1, Kil-Ung Kim1

1College of Agriculture & Life Science, Kyungpook National University 2Yunnan Academy of Agricultural Sciences, Korea (156) 11:15 Can Marigold Root Exudates Suppress Weed Growth? Shobha Sondhia, Jay G. Varshney National Research Centre for Weed Science, India (157) 11:30 Allelopathy of Polish Winter Wheat Cultivars


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Helena Gawronska, Dorota Ciarka, Dariusz Ruszkowski, Stanislaw Gawronski* Laboratory of Basic Research in Horticulture, Warsaw University of Life Sciences, Poland (158) 11:45 Current Allelopathic Research in Pakistan-Some Implications Zahid Ata Cheema*, Abdul Khaliq and M. Naeem Mushtaq Weed Science-Allelopathy Laboratory, University of Agriculture, Pakistan (159) 12:00 Effect of UV-B (280-320 nm) on the Enhancement of Allelochemicals (phenols) in Catharanthus roseus Plants V. Selvakumar, P. Periyakaruppiah, K. Rajarathinam, M. Jayakumar Research Department of Botany, VHNSN College, India (160) Main Topic 12. Allelopathy in aquatic environments Broadway 1 & 2 Organizer: Gary Ervin Co-organizer: Marina Della Greca 9:20 Impact of Allelopathy on the Periphyton of Submersed Freshwater Macrophytes D. Erhard Limnological Station, Technical University of Munich, Germany (199) 9:35 Chemical Warfare in the Marine Plankton J. Kubanek1, E. Prince1, T. Myers1, and J. Naar2 1School of Biology, Georgia Institute of Technology 2Center for Marine Science, University of North Carolina at Wilmington, USA (200) 9:50 Can Allelopathic Interactions Explain Plankton Blooms? P. Jonsson, G. Toth, and H. Pavia Tjärnö Marine Biological Laboratory, Göteborg University, Sweden (201) 10:05 Allelopathic Effects of Plant Growth Regulators on Growth Promotion of Marine Photosynthetic Bacteria L. Li, X. Wang, Y. Liu, J. Almeira, F. Li, and X. Hu Department of Environmental Studies and Environmental Engineering, Ocean University of China, China (202) 10:20 Chlorellin Production by Chlorella vulgaris: Qualitative and Quantitative Changes Influenced by Chemical and Biological Factors M. DellaGreca1, P. Fergola2, M. Cerasuolo2, A. Pollio3, G. Pinto3, and A. Zarrelli1 1Dipartimento di Chimica Organica e Biochimica 2Dipartimento di Matematica e Applicazioni “R. Caccioppoli 3Dipartimento delle Scienze Biologiche, Sezione di Biologia Vegetale. Università degli Studi di Napoli Federico II, Italy (203) 10:35 Break 11:00 Allelopathic Activities of Ceratophyllum demersum on Microcystis aeruginosa in Co-cultivation Q. Xian1, X. Li1, J. Xu1, S. Gao1, D. Yin2, and H. Zou1 1State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University 2Key Laboratory of Yangtze River Water Environment, Tongji University, China (204) 11:15 QTL Mapping and Identification of Candidate Compounds Associated with Allelopathic Effect of Rice Kazutoshi O.1, K. Ebana2, and M. M. Y. Hegab3

1Graduate School of Life and Environmental Sciences, University of Tsukuba, Japan 2 National Institute of Agrobiological Sciences, Japan 3 Faculty of Science, Beni-Suef University, Egypt (205) 11:30 Response of A Native Insect to Allelochemicals from A Native and Invasive Watermilfoil M. D. Marko1,2,3, R. M. Newman1, and F. K. Gleason2 1Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota 2Department of Plant Biology, University of Minnesota 3The Connecticut Agricultural Experiment Station, Department of Soil and Water, USA (206) 11:45 Utilization of Allelopathic Plant Water Extracts in Combination with Reduced Rate of Atrazine for Weed Management in Maize (Zea mays L.) Azhar Mahmood, Zahid Ata Cheema, Abdul Khaliq and M. Naeem Mushtaq Weed Science & Allelopathy Laboratory, University of Agriculture, Pakistan (207)


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12:00 Influence of Plant Population, Allelopathic Water Leachates and a Post-Emergence Herbicide on Weeds in Transplanted Rice (Oryza sativa L.) Arif Rehman, Zahid Ata Cheema, Abdul Khaliq and M. Naeem Mushtaq Weed Science & Allelopathy Laboratory, University of Agriculture, Pakistan (208) 12:15-13:45 Lunch provided and odd numbered posters Saratoga Ballroom 1 & 2 13:45-17:00 Concurrent sessions: MTs 8 and 13 Main Topic 8. Interactions in the rhizosphere Travers/Alabama Organizer: Chuihua Kong Co-organizer: Ines Fritz 13:45 The Rhizosphere – The Hidden Half of The Hidden Half Markus Puschenreiter and Walter W. Wenzel University of Natural Resources and Applied Life Sciences - BOKU, Department of Forest and Soil Sciences, Austria (138) 14:00 Rhizosphere Processes and Interactions in Cropping Systems in China F. S. Zhang, J. G. Wang, C. H Kong, J. B. Shen, X. J. Liu and L. Li College of Resources and Environmental sciences, China Agricultural University, China (139) 14:15 Fate of Phytotoxic Allelochemicals Produced by Cyperus rotundus in Environment and Change of Their Phytotoxicity Masanori Morimoto Dept. of Applied Chemistry, Kinki University, Japan (140) 14:30 The Role of Soil Microorganisms in Transformation and Activity Change of Allelochemicals from Selected Plants Ines Fritz, Denise Schneider, Dominic Funk, Marcus Pruckner, Michaela Bauer, Rudolf Braun Universität für Bodenkultur Wien, Department IFA-Tulln, Austria (14.) 14:45 Role of Root-mediated Allelopathy in the Rhizosphere of Ageratum conyzoides Daizy R. Batish1, Shalinder Kaur1, H.P.Singh2 and R.K.Kohli2 1Department of Botany, Panjab University 2Centre for Environment and Vocational Studies, Panjab University, India (142) 15:00 Allelochemical Interactions in the Rhizoshpere C. H. Kong Institute of Applied Ecology, China Agricultural University, China (143) 15:30 Break 16:00 Studies on Composition of Amino Acids in Watermelon Root Exudates and Their Effects on Growth and Development of Fusarium oxysporum f.sp.nevium Bo Liu, Fengzhi Wu, Yang Yang, and Xuezheng Wang Horticulture College, Northeast Agricultural University, China (144) 16:15 Analysis of the Structure and Its Function of Microbial Flora in the Rhizospheric Soil Mediated by Allelopathic and Non-allelopathic Rice Accessions Long Qiu1,2, Jun Xiong1,2, Yue e Zhuang2, Kaihui Hu2, Wenxiong Lin1,2

1Fujian Agriculture and Forestry University (FAFU), China; 2Institute of Agroecology, FAFU, China (145) 16:30 Rice Root Exudates Induced by UV-irradiation in Rhizosphere Soil Khalid Mahmood1, 2 and Ren Sen Zeng1, 2 1Research Center for Chemical Ecology 2Institute of Tropical and Sub-tropical Ecology, South China Agricultural University, China (146) 16:45 Fate of Glucosinolates and Isothiocyanates in Soil A. L. Gimsing and H. C. B. Hansen Department of Natural Sciences, University of Copenhagen, Denmark (147)


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Main Topic 13. Genetics and Biochemistry Broadway 1 & 2 Organizer: Scott Baerson Co-organizer: Anne Osbourn 13:45 Exploitation of Allelopathic Interactions in Cereal Crops R. Gordon-Weeks and J. Pickett Biological and Ecological Chemistry Department, Rothamsted Research, UK (210) 14:00 Strigolactones: A cry for help results in fatal attraction C. Ruyter-Spira1, J. A. Lopez-Raez1, C. Cardoso1, T. Charnikhova1, R. Matusova1, W. Kohlen1, F. Verstappen1,2, and H. Bouwmeester1,2 1Laboratory for Plant Physiology 2 Plant Research International, The Netherlands (211) 14:15 Biosynthesis and Allelopathic Activity of Diterpenoid Phytoalexins in Rice H. Yamane1, A. Okada1, K. Okada1, and T. Toyomasu2 1Biotechnology Research Center, The University of Tokyo 2Department of Bioresource Engineering, Yamagata University, Japan (212) 14:30 Glucosinolates in Brassica Species: Weed Suppression, Biosynthesis and Engineering H. Wu, E. Koetz, and D. Lemerle EH Graham Centre for Agricultural Innovation, Wagga Wagga Agricultural Institute, Australia (213) 14:45 Investigating the Function of OsCYC1 and OsAOS Genes in Rice Allelopathy by RNA Interference S. Luo, H. Bi, and R. Zeng Institute of Tropical and Sub tropical Ecology, South China Agricultural University, China (214) 15:00 Evolution of Benzoxazinone Biosynthesis M. Frey, R. Dick, K. Schullehner, and A. Gierl Lehrstuhl für Genetik, Technische Universität München, Germany (215) 15:15 Molecular Characterization of Enzymes Involved in the Biosynthesis of the Allelochemical Sorgoleone Z. Pan, S. R. Baerson, F. E. Dayan, A. M. Rimando, and S. O. Duke USDA, ARS, Natural Products Utilization Research Unit, USA (216) 15:30 Break 16:00 Allelopathic Compounds Produced by Oat A. Osbourn and S. Mugford Department of Metabolic Biology, John Innes Centre, UK (217) 16:15 Identification and Analysis of meta-Tyrosine Resistance in Arabidopsis thaliana G. Jander Boyce Thompson Institute for Plant Research, USA (218) 16:30 Breeding Rye Cover Crops for Increased Allelopathic Potential C. Reberg-Horton, A. Brooks, D. Danehower, M. Burton, J. Burton, G. Ma, and P. Murph Depts. of Crop Science and Horticultural Science, North Carolina State University, USA (219) 16:45 Development of Weed-Suppressing Rice Variety, Weed-Suppressing No.1, via a Specific Secondary Metabolite Marker Shao-chuan Zhou, De-cheng Lu, Hong Li, and Dao-Qiang Huang Rice Research Institute, Guangdong Acamemy of Agricultural Sciences, China (220) 17:00 – 18:30 Odd numbered Posters Gallery Dinner on your own


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Tuesday, September 23, 2008 08:00-11:30 Concurrent sessions; MTs 2 and 7 Main Topic 2. Allelochemicals: Fate in soil and water Travers/Alabama Organizer: Inge Fomsgaard Co-organizer: Tsutomu Ohno 08:00 Transformation of Benzoxazinoids in Soil - Kinetics and Pathways Inge S. Fomsgaard1, Per Kudsk1, Solvejg K. Mathiassen1, Sandra Carlsen1, Stine Krogh Steffensen1,2 1:Department of Integrated Pest Management,Faculty of Agricultural Sciences, University of Aarhus 2:Department of Chemistry, University of Copenhagen, Denmark (28) 08:15 Evaluation of The Effectiveness of Allelochemicals in Soils S. Hiradate, K. Ohse, A. Furubayashi, and Y. Fujii National Institute for Agro-Environmental Sciences (NIAES), Japan (29) 08:30 Behavior and Phytotoxic Activity of Allelochemical in Soil K. Kobayashi Graduate School of Life and Environmental Sciences, University of Tsukuba, Japan (30) 08:45 Mineralization of Sorgoleone, An Allelochemical Produced by Sorghum, in Soil A. L Gimsing1, F. Dayan2, J. Bælum3, and C. S. Jacobsen3

1Department of Natural Sciences, University of Copenhagen, Denmark 2United States Department of Agriculture, Natural Products Utilization Research Unit, USA 3Geological Survey of Denmark and Greenland, Department of Geochemistry, Denmark (31) 09:00 The Fate and Impact on Microorganism of Rice Allelochemical in Paddy Soil C. H. Kong1, 2, P. Wang1, and X. H. Xu2 1Institute of Applied Ecology, Chinese Academy of Sciences 2State Key Laboratory of Elemento-organic Chemistry, Nankai University, China (32) 09:15 Presence that Belies The Persistence: A Perspective on Mediation of Allelopathy by Soils N. Tharayil1 and P. C. Bhowmik2. 1Entomology, Soil and Plant Sciences, Clemson University 2Plant, Soil, and Insect Sciences, University of Massachusetts, USA (33) 09:30 The Biodegradation and Sorption of Flavonoids in Soil L. Shaw1 and J. Hooker2

1Department of Soil Science, The University of Reading 2School of Applied Sciences, Auckland University of Technology, New Zealand (34) 09:45 Fate of Benzoxazinoids in Soil Following Application of Rye (Secale cereale L.) as a Cover Crop and Their Possible Link to Allelopathic Activity C. P. Rice1, J. R. Teasdale1, I. A. Zasada2, and K. Bialek-Kalinski1 1USDA-ARS Sustainable Agricultural Systems Lab 2USDA-ARS Nematology Lab, USA (35) 10:00 Break 10:30 Chemical Interaction in Spear-grass (Imperata cylindrica) T. D. Xuan, T. D. Khanh, and S. Tawata Department of Bioscience and Biotechnology, University of the Ryukyus, Japan (36) 10:45 Impact of Allelopathic Rice Seedlings on Rhizospheric Microflora Functional Diversity and Soil Enzyme Activities L. Rui-yu, Y. Cui-ping, R. Hong, X. Qing-tie, and L. Wen-xiong Institute of Agro-ecology, Fujian Agriculture & Forestry University, PR China (37) 11:00 Biomedicine: Degradation and Ecotoxicity of Artemisinin in Soil Karina Knudsmark Jessing1, Nina Cedergreen2, John Jensen3 and Hans Christian Bruun Hansen1

1University of Copenhagen, Department of Natural Sciences 2University of Copenhagen, Department of Agricultural Sciences 3Aarhus University, National Environmental Research Institute, Denmark (38)


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11:15 Allelopathic Effect of Continuously Cropping Soils under Chinese Medicinal Achyranthes bidentata Blume and its Molecular Mechanism Zhenfang, Li1,2, Zhongyi Zhang1,3, Jun Xiong1,2, Hui Chen1,2, Wenxiong Lin1,2*

1Key Laboratory of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University 2. Institute of Agroecology, School of Life Sciences 3. Institute of Chinses medicinal plants, Henan Agriculture University, China (39) Main Topic 7. Invasion ecology and allelopathy 1 Saratoga Ballroom 3 Organizer: Y. Fujii Co-organizer: L. A. Weston, 08:00 Integrated Invasive Plant Management in the Adirondack Park, New York, USA Hilary A. Oles1, Steven M. Flint1 and Daniel M. Spada2 1The Nature Conservancy – Adirondack Chapter 2New York State Adirondack Park Agency, USA (122) 08:15 The Invasive Swallow-worts: What Do We Know About Their Biology and Management? Kristine M. Averill1, Antonio DiTommaso1, Charles L. Mohler1, and Lindsey R. Milbrath2 1Dept. of Crop and Soil Sciences, Cornell University 2 USDA-ARS Robert W. Holley Center for Agriculture and Health, USA (123) 08:30 Studies on The Ecology and Allelopathic Potential of Black and Pale Swallow-worts (Vincetoxicum nigrum and rossicum) in New York State, USA Cameron Douglass1, Leslie A. Weston2 and Antonio DiTommaso1 1Cornell University College of Agriculture and Life Sciences, USA 2E. H. Graham Centre for Agricultural Innovation, Charles Sturt University, Australia (124) 08:45 The Curse of Paterson’s Curse J. E. Pratley and A. N. Seal E.H. Graham Centre for Agricultural Innovation, Charles Sturt University, Australia (125) 09:00 Parthenium hysterophorus L Invasion and Allelopathy in Nepal P. K. Jha, B. B. Shrestha, S. Maharjan, S. Joshi and B. Timsina Central Department of Botany, Tribhuvan University, Nepal (126) 09:15 Allelopathic Potential as an Interference Strategy of the Invader Weed Rottboellia cochinchinensis (Itchgrass) Silvia M. Contreras-Ramos1, Luc Dendooven2, and Ana Luisa Anaya1. 1Laboratorio de Alelopatía, Instituto, Universidad Nacional Autónoma de México 2Laboratorio de Ecología de Suelos, Centro de Investigación y Estudios Avanzados del IPN, Mexico (127) 09:30 Density-dependent Crop Allelopathy: Effectiveness for Weed Control, Associated Root Interaction and Morphology Changes M. An1, C.J. Li2, and J. Pratley1 1E.H. Graham Centre for Agricultural Innovation, Australia 2College of Resources and Environmental Sciences, China Agricultural University, China (128) 09:45 Is the Allelochemical Parthenin Responsible for the Invasiveness of Parthenium hysterophorus L.? Carl Reinhardt1, Regina Belz2 and Karl Hurle2 1Department of Plant Production and Soil Science, University of Pretoria 2University of Hohenheim, Institute of Phytomedicine, South Africa (129) 10:00 Break 10:30 Comparison of Allelopathy Potential between an Exotic Invasive Weed Alternanthera philoxeroides and a Local Weed A. sessilis Yong-jun, Zhou1, Yoshiharu Fujii2, Liu-qing Lu1, Jian-ping Zhang1, Yong-liang Lu1, Song-nan Xuan1 1State Key Laboratory of Rice Biology China National Rice Research Institute 2National Institute for Agro-Environmental Science, Japan (130) 10:45 Allelopathic Effects of an Invasive Species Solidago canadensis on Soil-borne Pathogens: Implication of an Alternative Explanation for Plant Invasion Shanshan Zhang, Guodong Yu, Jianjun Tang, Xin Chen College of Life Sciences, Zhejiang University, China (131) 11:00 Evaluation of Invasive Alien Plants by Modified FAO-WRA (2005): Importance of Allelopathy in Weed Risk Assessment


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Yoshiharu Fujii, Syunji Kurokawa, and Syuntaro Hiradate

National Institute for Agro-Environmental Science, Japan (132) 11:30-13:00 - Lunch provided 13:00 - Conference tour departs Fieldtrip to view invasive weed ecology/lakes/forest ecosystems, followed by dinner cruise on Lake George 18:00 Dinner cruise on Lake George

Wednesday, September 24, 2008 08:00-11:45 Concurrent sessions: MTs 1, 3 & 5 Main Topic 1. Allelopathic interactions including plant pathogens, endophytes, mycorrhizal associations, and insect impacts Travers/Alabama Organizer: Marina Della Greca. Co-organizer: Nils-Ove Bertholdson 08:00 Fungal Endophyte Metabolism and Allelopathic Interactions with Host Plants A. E. Glenn, N. C. Zitomer, and R. T. Riley USDA, ARS, Russell Research Center, Toxicology & Mycotoxin Research Unit, USA (2) 08:15 Specific Interactions between AM-fungi, PGPR and Plant Pathogens with Regard to Plant Growth Promotion U. Granhall, V. Arthurson, and L. Jäderlund Dept. of Microbiology, Swedish Univ. of Agric. Sciences (SLU), Sweden (3) 08 :30 Endophytic Fungi: New Perspectives in Allelopathy A. L. Anaya1, M. C. González2, A. E. Glenn3, A. Saucedo-García1, M. L. Macías-Rubalcava1, B. E. Hernández-Bautista1, and R. T. Hanlin4 1Departamento de Ecología Funcional, Instituto de Ecología 2Departamento de Botánica, Instituto de Biología. Universidad Nacional Autónoma de México, Mexico 3USDA, ARS, Toxicology & Mycotoxin Research Unit, USA

4University of Georgia, Museum of Natural History Annex, USA (4)

08:45 Bioprospecting for Allelopathic Endophytes from Native Australian Flora with Mycofumigation Potential S. Mattner, R. Mann, D. Allen, I. Porter, and J. Edwards BioSciences Research Division, Department of Primary Industries, Australia (5) 09:00 Research Progress of Compounds Isolated from Fungus for Weed Control in China L. Yu, G. Duan, R. Geng, J. Zhang, Y. Lu and Y. Zhou State Key Laboratory of Rice Biology, China National Rice Research Institute, China (6) 09:15 Plant Allelochemicals Mediate Tritrophic Interactions among Crops, Pathogens, and Insects via Induction of Insect Cytochrome P450 Monooxygenases R. S. Zeng1,2, Z. Wen3, G. Niu2, M. A. Schuler3, M. R. Berenbaum2 1Institute of Tropical & Subtropical Ecology, South China Agricultural University, China 2Department of Entomology, University of Illinois 3Department of Cell and Developmental Biology, University of Illinois, USA (7) 09:30 Bioprotective Functions of Ergot Alkaloids in an Endophytic Fungus-Grass Symbiosis D. G. Panaccione1, J. R. Cipoletti 1, C. L. Schardl 2, and D. A. Potter2 1West Virginia University 2University of Kentucky, USA (8) 09:45 Amending Soil with Artemisinin-Rich Dry Leaf Tissue of Artemisia annua Improves A. annua’s Competitive Ability N. Delabays Swiss Agricultural Research Station, Switzerland (9) 10:00 Break 10:15 Plant-Plant Interaction – A Multitrophic Phenomenon? Studies in a Barley Crop System


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V. Ninkovic Swedish University of Agricultural Sciences, Sweden (10) 10:30 Effect of Phenolic Compounds on Spring Host Plant Alternation by the Bird Cherry-oat Aphid (Rhopalosiphum padi L.) P. Czerniewicz and B. Leszczyński University of Podlasie, Department of Biochemistry and Molecular Biology, Poland (11) 10:45 Differential Responses of Withania somnifera (L.) Dun. in VAM Soil Containing Glomus fasciculatum on Vegetative Growth, Nitrogen, and Phosphorus Uptake M. B. Ray and S. Halder 1Department of Botany, Burdwan University 2Department of Botany, Burdwan Raj College, India (12) 11:00 Reaction of Oncomelania hugpensis to the Allelopathic Cardiac Glycosides of Nerium indicum W.–X. Wang1, Y. Yang1, W.–P. Tang 2, Q.-X. Sun3, X.-D. Zhang 3, X.-Y. Hu2, W. Chen 1, H.-D. Jiang 1, W.-L. Yun1, J. Wu 1 1Institute of Biology and Science, Hubei University 2Hubei Provincial Academy of Forestry 3Research Institute of Forestry, Chinese Academy of Forestry, China (13) 11:15 Rice Allelopathy for Control of Phytophathogenic Fungi R. Bajwa and A. Javaid Institute of Mycology and Plant Pathology, University of the Punjab, Pakistan (14) 11:30 Allelopathic Compound Production Influences Fungal Endophyte Community Assembly and Establishment of a Seed-borne Primary Colonizer in Maize M. Saunders, A. E. Glenn and L. M. Kohn Dept. of Ecology and Evolutionary Biology, University of Toronto, Canada (15) MT 3 Allelochemical identification, localization and applications Broadway 3 & 4 Organizer: Agnes Rimando Co-organizer: Francisco Macias 08:00 Developing New Herbicides from Gramineae Allelochemicals Francisco A. Macías, Elena Arroyo, Nuria Chinchilla, Rosa M. Varela and Jose M.G. Molinillo Dept. of Organic Chemistry, University of Cadiz, Spain (44) 08:15 Momilactone A and B as Rice Allelochemicals Hisashi Kato-Noguchi Department of Applied Biological Science, Kagawa University, Japan (45) 08:30 Biological Activity of Phytotoxins Isolated from Fungal Pathogens of Cirsium arvense and Sonchus arvensis. Alexander Berestetskiy1, Andrey Dmitriev1, Galina Mitina1, Oleg Yuzikhin1, Alessio Cimmino2, Anna Andolfi2, Antonio Evidente2 1All-Russian Institute of Plant Protection, Russian Academy of Agricultural Sciences, Russia 2Dipartimento di Scienze del Suolo, Università di Napoli Federico II, Italy (46) 08:45 Bioactivity-guided Chemical Isolation of Secondary Metabolites from Plants that Interact and Inhibit Photosynthesis Blas Lotina-Hennsen, Maria Isabel Aguilar and Beatriz King-Díaz Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico (47) 09:00 Potential Allelopathic Interferences in Mediterranean Macchia Antonio Fiorentino, Assunta Esposito, Brigida D’Abrosca, Angelina Izzo, and Pietro Monaco Dipartimento di Scienze della Vita, Second University of Naples, Italy (48) 09:15 Why Orobanche cumana is a Specific Parasite of Sunflower: Some Chemical Clues Francisco A. Macías, María D. García-Díaz, Pablo Sánchez-Gómez and Juan C. G. Galindo Cadiz Allelopathy Group, University of Cadiz, Spain (49) 09:30 Inhibitors of Acetylcholinesterase as Allelochemicals Rajendra Gupta Department of Botany, University of Delhi, India (50) 09:45 Cyanamide as a Natural Product


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Tsunashi Kamo, Syuntaro Hiradate and Yoshiharu Fujii National Institute for Agro-Environmental Sciences (NIAES), Japan (51) 10:00 Break 10:15 Allelopathic Studies on Teak (Tectona grandis): New Active Naphthoquinones Francisco A. Macías, José M. G. Molinillo, Rosa M. Varela, Rodney R. Lacret, Clara Nogueira and Carlos K. Z. Andrade Dept. of Organic Chemistry, University of Cadiz, Spain (52) 10:30 Trichothecene chemotype is Thought to Play a Key Role in the Phytopathogenicity of Individual Fusarium Strains Takumi Nishiuchi Advanced Science Research Center, Kanazawa University, Japan (53) 10:45 Physiological Activity of Allelochemicals from Germinating Plant Seeds: Recent Progress and Future Prospects Kosumi Yamada1, Katsutoshi Hirose2, Hideyuki Shigemori1 and Koji Hasegawa1,2 1Graduate School of Life and Environmental Sciences, University of Tsukuba 2KNC Laboratories Co., Ltd., Japan (54) 11:00 Allelochemicals Involved in Rice Allelopathy C. H. Kong1,2 and X. H. Xu2 1Institute of Applied Ecology, Chinese Academy of Sciences 2State Key Laboratory of Elemento-organic Chemistry, Nankai University, China (55) 11:15 New Potential Allelochemical from Acacia leucophloea Willd. Raj Nath Yadava Natural Products Laboratory, Dr. Hari Singh Gour University, India (56) 11:30 Effect of Essential Oils on the Germination of Solanum nigrum and Physalis angulat Ilhan Uremis, Mehmet Arslan and Ahmet Uludag Plant Protection Department, Aegean University, Turkey (57) Main Topic 5. Allelopathy in agricultural settings High Rock Organizer: Jim Pratley Co-organizer: David Gealy 08:00 Developments in Rice Allelopathy: Searching for the Balance between Allelopathic Activity, Agronomic Viability and Commercial Acceptability David Gealy1, Karen Moldenhauer2, John Mattice3, and Wengui Yan1

1USDA-ARS, Dale Bumpers National Rice Research Center 2University of Arkansas Rice Research and Extension Center 3University of Arkansas, Department of Crop, Soil, and Environmental Sciences, USA (82) 08:15 Allelopathy in Agroecosystems of Northwestern India and its Practical Utility Daizy R. Batish1, H.P.Singh2 and R.K.Kohli2

1Department of Botany, Panjab University 2Centre for Environment and Vocational Studies, Panjab University, India (83) 08:30 Role of Allelopathy in the Stimulatory and Inhibitory Effects of Hairy Vetch Cover Crop Residue in No-Tillage Sustainable Production Systems John R. Teasdale USDA-ARS Sustainable Agricultural Systems Lab, USA (84) 08:45 Green Manures in Organic Farming Systems: Multiple Stresses Affect Seedbank Dynamics E. R. Gallandta, H. M. Kruidhofb, E. R. Haramotoc and L. Bastiaansd

aUniversity of Maine bUniversity of California, Riverside cMount Holyoke College, USA dWageningen University, The Netherlands (85) 09:00 Alternative Weed Management in Cotton Field by Employing Allelopathy Principles: A Case Study in Pakistan Javaid Iqbal1 and Zahid A. Cheema2

1College of Agriculture 2 University of Agriculture, Pakistan (86) 09:15 The Use of Mustard Cover Crops in Potato Rotations


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Rick Boydston USDA-ARS, USA (87) 09:30 The Allelopathic Potential of Rice Cultivars to Control Multiple Australian Rice Weeds A. N. Seal and J. E. Pratley E.H. Graham Centre for Agricultural Innovation, Charles Sturt University, Australia (88) 09:45 Allelochemically-Enhanced-Competition: Theoretical Framework, Experimental Approach, and Ecological Significance M. An1, Y.H. Liu2, M. Saeed3 and J. Pratley1 1E.H. Graham Centre for Agricultural Innovation, Australia 2Institute of Tropical & Subtropical Ecology, College of Sciences, South China Agricultural University, China 3Directorate of Agronomy, Ayub Agricultural Research Institute, Pakistan (89) 10:00 Break 10:15 Breeding for Improved Allelopathic Activity in Swedish Spring Wheat Nils-Ove Bertholdsson Dept. of Plant Breeding and Biotechnology, Swedish University of Agricultural Sciences, Sweden (90) 10:30 Terpenoids: Better Candidates for the Development of Natural Herbicides HaiBin He, HaiBin Wang and Wen Xiong Lin Key Laboratory of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University, China (91) 10:45 Effect of Continuous Cropping of Chinese Medicinal Plant Rehmannia glutinosa on Rhizospheric Microorganisms Zhongyi Zhang1,3, ZhenfangLi1,2 Jun Xiong1,2,Hui Chen1,2 and Wenxiong Lin1,2*

1Key Laboratory of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University (FAFU), China 2Institute of Agroecology, FAFU 3Institute of Chinese Medicinal Plants, Henan Agriculture University, China (92) 11:00 Modelling Autotoxicity in Continuous Cropping and the Dynamics of Autoxins Y.H. Liu1, Y. L. Fu1 and M. An2

1College of Sciences, South China Agricultural University, China 2E.H. Graham Centre for Agricultural Innovation, Australia (93) 11:15 Weed Management in Wheat (Triticum aestivum l) through applying Allelopathic Plant Water Extracts in Combination with Reduced Herbicide Doses Muhammad Saeed *1, Muhammad Rafiq2, Min An3 and Aamer Sattar4 1Directorate of Agronomy, Ayub Agricultural Research Institute & University of Agriculture, Pakistan 2Technical Branch, Ayub Agricultural Research Institute, Pakistan 3E.H. Graham Centre for Agricultural Innovation, Australia 4Ayub Agricultural Research Institute, Pakistan (94) 11:30 The Influence of Tea Saponins and Caffeine on the Growth of Tea Plant in Vitro P. Okinda Owuor1, and Francis N. Wachira2 1Department of Chemistry, Maseno University, Kenya 2Department of Biochemistry and Biotechnology, Egerton University, Kenya (95) 11:45-13:00 - Lunch provided with even numbered posters Saratoga Ballroom 1 & 2 13:00 – 16:30 - Concurrent sessions MTs 4 & 10 MT 4 Allelopathy in forest ecosystems Broadway 3 & 4 Organizer: Azim Mallik Co-organizer: Shibu Jose 13:00 Allelopathy by Empetrum hermaphroditum in the Boreal Forest – A Summary of Research Conducted Marie-Charlotte Nilsson Swedish University of Agricultural Sciences, Department of Forest Ecology and Management, Sweden (69) 13:15 Kalmia – Conifer Interactions in Eastern Canada: From Allelopathy to Satellite Imagery Nelson Thiffault


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Direction de la recherche forestière, Ministère des Ressources naturelles et de la Faune du Québec, Canada (70) 13:30 Belowground Competition and Chemical Interference between Kalmia and Black Spruce Azim U. Mallik, Shekhar R. Biswas and Laura C. Siegwart Department of Biology, Lakehead University, Canada (71) 13:45 Allelopathic Influence of Imperata cylindria (L.) Beauv.) on Recruitment and Establishment of Understory Plants of Southeastern U.S. Forests Shibu Jose and E. Corrie Pieterson School of Forest Resources and Conservation, University of Florida, USA (72) 14:00 Describing Phytotoxic Effects of Blackwood (Acacia melanoxylon L.) on Cumulative Germination M. Iftikhar Hussain, l. González Rodriguez and M. J. Reigosa Roger Laboratory of Plant Ecophysiology, University of Vigo, Spain (73) 14:15 Changes in Eucalyptus camaldulensis Essential Oils with Water Stress Silvia Leicach1, A. Garau2, A.B. Guarnaschelli2 , N Sztarker1 and A. Dato1 1Cátedra de Química Orgánica 2Cátedra de Dasonomía. Facultad de Agronomía. Universidad de Buenos Aires, Argentina (74) 14:30 A process-based Approach for Predicting the Toxicity of Juglone (5-hydroxy-1,4-napthoquinone) and other Phytochemicals in Soils beneath Black Walnut (Juglans nigra L.) Trees Guntram von Kiparski University of California – Riverside, Department of Environmental Sciences, USA (75) 14:45 Plant-plant Interference in Mediterranean Forest Dynamic: Consequences of Resource Competition and Allelopathy on Aleppo pine (Pinus halepensis Mill.) and a Deciduous Oak (Quercus pubescens Willd.) Growth Yogan Monnier, Bruno Vila, Catherine Fernandez Institut Méditerranéen d’Ecologie et Paléoécologie IMEP Equipe Ecologie Fonctionnelle, Aix-Marseille Université, France (76) 15:00 Break 15:15 76. Opportunities for Allelopathy Research in the Management of Vegetation in Power Line Rights-of-way Timothy A. Chick Div. of Forestry, Natural Resources and Recreation, Paul Smith’s College, USA (77) 15:30 Allelopathy of a Sacred Grove Tree Species, Aglaia elaegnoidea on Green Gram, Vigna radiata M. P. Ramanujam, P. Suganthi, M. Sathya and D. Kadamban Botany Laboratory, Centre for Post Graduate Studies, India (78) 15:45 Allelopathic Potential of Mangrove Plants on Growth and Development of Pearl Millet (Pennisetum typhoides St. and Hub.) K. Arumugam Department of Botany – DDEAnnamalai University, India (79) 16:00 Using Plant Extracts in Control of Canary Grass (Phalaris minor Retz.) Masoumeh Younesabadi, Habib Ollah Kashiri, Ali Reza Savari Nejad and Leila Torbati Dept. of Plant Protection, Agricultural research center, Iran (80) 16:15 Tropical Trees Leaves Used as Mulches: Effects on Crop Plants Growth, Weeds, Microbiota, and Soil Properties M. Flores-Carmona, R. Cruz-Ortega, and A. L. Anaya Laboratorio de Alelopatía, Universidad Nacional Autónoma de México, Mexico (81) MT 10 Invasion ecology and allelopathy 2 Travers/Alabama Organizer: Inderjit Co-organizer: Ray Callaway 13:00 Biogeographical Approaches to Allelopathy Helps to Evaluate the Impact of Exotic Invaders R. M. Callaway and Inderjit Division of Biological Sciences, The University of Montana, USA 1Centre for Environmental Management of Degraded Ecosystems (CEMDE), University of Delhi, India (163) 13:15 Invasion Success: Are Mode of Actions of Root and Exudate Chemicals Useful Indicators?


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F. Hadacek and Chobot University of Vienna, Austria (164) 13:30 Allelpathic Interference of Cyperus rotundus L. with Some Crops Alsaadawi and Salih Office of Agricultural Researches, Ministry of Science and Technology, Iran (165) 13:45 Significance of Algal Allelochemicals in Natural and Agroecosystem A. S. Ahluwalia Department of Botany, Panjab University, India (166) 14:15 Conditional Effects of an Allelopathic Root Exudate: The Toxicity of (±)-catechin is Affected by Interactions with Different Metals Jarrod Pollock, Ragan M Callaway, Inderjit and William E. Holben Division of Biological Sciences, The University of Montana, USA (167) 14:30 Allelopathy Contributes to The Invasion Success by Creating a Negative Feedback for Native Residents Inderjit1 and R. M. Callaway2 1Centre for Environmental Management of Degraded Ecosystems (CEMDE), University of Delhi, India 2Division of Biological Sciences, The University of Montana, USA (168) 14:45 Allelopathy of Acacia dealbata Link in Invaded Areas in North West of Spain Paula Lorenzo, Eva Pazos, Luís González, Manuel J. Reigosa Departamento de Química Orgánica, Universidad de Alicante, Spain (169) 15:00 Break 15:15 Allelopathic Interaction Between Two Co-occurring Ruderal Invasive Plant Species in The Kashmir Himalaya, India Reshi Z. and Rashid University of Kashmir, India (170) 15:30 Allelopathy as a Mechanism for Invasion by Non-indigenous Species Robin Svensson Department of Marine Ecology, Gothenburg University, Sweden (171) 15:45 Seed Germination, Growth and Root Vessel Elements of Sesame Seedlings as Affected by Leaves, Stem and Root Extracts of Aristolochia esperanzae 1Alfredo G. Ferreira, 2Ana B. Gatti and 3Sonia C.J.G.A.Perez 1Botany Department, Rio Grande do Sul Federal University, Brazil 2Ecological and Natural Course at São Carlos University, Brazil 3Botany Department, São Carlos University, São Paulo State, Brazil (172) 16:00 Allelopathic Effects of Black Locust (Robinia pseudoacacia L.) Litter on Soil Microbial Activity F. Esposito1*, A. De Marco1, A. Zarrelli2 and A. Virzo1 1Dipartmento di Biologia Strutturale e Funzionale 2Dipartimento di Chimica Organica e Biochimica, Università degli Studi di Napoli ”FEDERICO II”, Complesso Universitario Monte S. Angelo via Cinthia, Italy (173) 16:15 The Bittersweet Paradox: Toxic Allelochemicals also Facilitate Nutrient Acquisition Nishanth Tharayil1, Prasanta Bhowmik2 and Peter Alpert3

1Entomology Soil & Plant Sciences, Clemson University 2Plant Soil & Insect Sciences, Univ. of Massachusetts Amherst 3Biology Department, Univ. of Massachusetts Amherst, USA (174) 16:30 – 18:30 Even numbered posters Gallery 18:30 Banquet at hotel (with presidential address) Saratoga Ballroom Thursday, September 25, 2008


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08:00-12:00 Concurrent sessions: MTs 6 & 11 Main Topic 6. Biosynthesis, mode of action, and detoxification of phytotoxins from plant Saratoga Ballroom 1 Organizer: Franck Dayan Co-organizer: Margo Schulz

08:00 The Allelochemical Benzoxazolinone – Molecular Backgrounds of Its Detoxification and Degradation M. Schulz, S. Kant, M. Knop, D. Sicker1, T. Colby2, A. Harzen2 and J. Schmidt2 IMBIO (Institut für Molekulare Physiologie und Biotechnology der Pflanzen 1Institut für Organische Chemie, Universität Leipzig 2Max-Planck-Institut für Züchtungsforschung, Germany (101) 08:15 Momilactone B Accumulation in Rice and Rice Rhizosphere by Environmental Stresses H. Kato-Noguchi, H. Kujime and T. Ino Department of Applied Biological Science, Kagawa University Miki, Japan (102) 08:30 Cytotoxic Effects of Cyanamide on Tomato (Lycopersicon esculentum L.) Root Growth D. Sołtys1, A. Rudzińska-Langwald2, W. Kurek2, A. Gniazdowska1 and R. Bogatek1 1Department of Plant Physiology, Warsaw University of Life Science-SGGW 2Department of Botany, Warsaw University of Life Science-SGGW, Poland (103) 08:45 Phytotoxicity Caused by Sicyos deppei (Cucurbitaceae): Metabolic Targets in Lycopersicon esculentum A. Lara-Nuñez, A. L. Anaya and R. Cruz-Ortega Laboratorio de Alelopatía, Universidad Nacional Autónoma de México, Mexico (104) 09:00 In planta Mechanism of Action of the Allelochemical Sorgoleone F. E. Dayan Natural Products Utilization Research Unit, USDA-ARS, USA (105) 09:15 Elucidation of the Final Reactions of DIMBOA-Glucoside Biosynthesis in Maize M. Frey1, R. Jonczyk1, E. Glawischnig1, D. Sicker2, and A. Gierl1 1Lehrstuhl für Genetik, Technische Universitaet Muenchen 2Institut für Organische Chemie, Universitaet Leipzig, Germany (106) 09:30 Allelopathic Potential of Sunflower Plants (Helianthus annus L.) on Soil Texture and its Root Extract on Physiology of Wheat (Triticum aestivum L.) Seedlings J. Kamal and Asghari Bano Department of Plant Sciences, Quaid-I-Azam University Islamabad, Pakistan (107) 09:45 Root Inhibitory Effect of Caffeic Acid: Role of Reactive Oxygen Species (ROS) S. Kaur1, H. P. Singh2, D. R. Batish1 and R. K. Kohli1 1Department of Botany 2Centre for Environment and Vocational Studies, Panjab University, India (108) 10:00 Break 10:30 Allelopathic Potential and Molecular Analysis of Some Rice Cultivars (Oryza sativa L.) Cultivated in Kurdistan Region – Iraq Z. M. Al-Asaadee, J. M. S. Jubrael and H. A. M. Mezori University of Dohuk, Iraq (109) 10:45 Changes of Allelopathic and Autotoxic Potentials of Zanthoxylum bungeanum Under Enhanced Ultraviolet-B Radiation K. Pan, H. Li, J. Wang and Y. Wang Chengdu Institute of Biology, Chinese Academy of Sciences, China (110) 11:00 Understanding the Mode of Action of BOA (2-benzoxazolinone) and PCA (Protocatechualdehyde) on Arabidopsis Plants M. J. Reigosa Roger, A. Martínez-Peñalver and A. M. Sanchez Moreiras Laboratory of Plant Ecophysiology, Universidade de Vigo, Spain (111) 11:15 Protein Profiles From Lettuce Plants: Testing the Stress Hypothesis A. M. Sanchez Moreiras and M. J. Reigosa Roger Laboratory of Plant Ecophysiology, Universidade de Vigo, Spain (112)


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11:30 Allelopathic Potential of Caesulia axillaries on Physiology and Yield of Wheat Devendra Singh, Mrintunjay Kumar, Nawalesh K. Sinha and S. S. Mandal Department of Agronomy, Rajendra Agricultural University, India (113) 11:45 The Comparative Study of Allelopathic Effects of Acroptilon repens L. on Some of Physiological Properties of Brassica napus L. and Accompanying Weeds 1F. Abbassi, 2M. R. Rusta Nejad, 3R. Ghorbani and 4M. Bazubandi 1Biology Department of Islamic Azad University of Mashhad 2Agriculturi Department of Islamic Azad University of Mashhad 3Agronomy Plant Breeding Department of Agriculture Faculty of Ferdowsi University Mashhad 4Research Center of Khorasan-e-Razavi, Plant Pests & Diseases Research Institute, Iran (114) Main Topic 11. Allelopathy in crop settings for weed suppression Saratoga Ballroom 2 Organizer: Prasanta Bhowmik Co-organizer: Ren-sen Zeng 08:00 The Challenge of Annual Ryegrass (Lolium rigidum) – Will Allelopathy be Part of the Solution? J. E. Pratley E. H. Graham Centre for Agricultural Innovation, Charles Sturt University, Australia (175) 08:15 Role and Persistence of Rye Allelopathic Activity in Soil John R. Teasdale1, Clifford P. Rice1 and Inga A. Zasada2 1USDA-ARS Sustainable Agricultural Systems Lab 2USDA_ARS Nematology Lab, USA (176) 08:30 Rye Cover Crop Management to Enhance Allelopathic Weed Suppression James Burton, Christophe LaHovary, Christine Sickler, David Danehower, Chris Reberg-Horton, Michael Burton, and Paul Murphy Depts. of Horticultural Science and Crop Science, North Carolina State University, USA (177) 08:45 Open Paper moved to Poster Session 09:00 Allelopathic Rice: From Theory to Practice in China H. Fei, *C. Kong and X. Chen Laboratory of Weed Science, South China Agricultural University, China (179) 09:15 Molecular Physiological Properties of Different Allelopathic Potential Rice Accessions in Responses to Nutrition Deficiency W.X. Lin 1, 2, J. Xiong1, 2, H.B. He1, 2, H.B Lin1 , 2 and L. Qiu1,

1Key Laboratory of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University (FAFU) 2Institute of Agroecology, FAFU, China (180) 09:30 FQ-PCR Analysis on Key Enzymatic Genes Related with Phenolic Acid Metabolism in Rice Accessions (Oryza Sativa L.) Exposed to Nitrogen Stress J. Xiong1, H.B. Wang1, L. Qiu1, H. Wu2, H.B. He1, R.Y. Lin1 and W.X. Lin1 1Key Laboratory of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University (FAFU) 2Institute of Agroecology, FAFU, China (181) 09:45 Exploiting Rice Allelopathy for Management of Parthenium hysterophorus L. Arshad Javaid, Sobiya Shafique, Shazia Shafique and Tariq Riaz Institute of Mycology and Plant Pathology, University of the Punjab, Pakistan (182) 10:00 Break 10:30 Effect of Different Allelopathic Crop Residues Applied as Surface Mulch for Weed Management in Maize (Zea mays L.) Azhar Mahmood, Zahid Ata Cheema, Abdul Khaliq and M. Naeem Mushtaq Weed Science & Allelopathy Laboratory, University of Agriculture, Pakistan (183) 10:45 Allelopathic Potentials of a Non-Leguminous Cover Crop, Nelsonia canescens (Lam) Spreng, Family Acanthaceae A. G. N. Fongod1, D. A. Focho2, A. M. Mih1, Nukuna B. N.3 and V. P. K. Titanji1 1Department of Plant and Animal Sciences, University of Buea, Cameroon 2Department of Plant Biology, University of Dschang, Cameroon 3Lerner Research Institute, Cleaveland, Ohio, USA (184)


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11:00 Control of Weeds in Wheat Field by Applying Allelopathic Concept in Bangladesh P. K. Biswas1, M. M. Morshed1 and P. C. Bhowmik2 1Dept. of Agronomy, Sher-e-Bangla Agricultural University, Bangladesh 2University of Massachusetts, Amherst, USA (185) 11:15 Phyto-toxicity of Wheat Straw on Selected Weed Species in Respect to Germination and Growth G.P.Satsangi, Garima Bartariya, and Anjali Saxena Department of Botany, Dayalbagh Educational Institute (Deemed University, India (186) 11:30 Allelopathic Effect of Jatropha curcus Oil Cakes after Biodiesel Recovery on Zea mays and Sorghum vulgare. M. Jayakumar and P. Meena Research Department of Botany, VHNSN College, India (187) 11:45 Weed Suppression in Organic Gardening and Farming: Is Allelopathy the Answer? Gerald R. Leather West Virginia University Agriculture Extension Service, USA (188) 12:15 – Closing ceremony and IAS business meeting Saratoga Ballroom 1 & 2 Posters listed by their abstract number Odd numbered posters presented on Monday, even numbered poster on Wednesday (see schedule). All posters remain throughout the meeting. Gallery Main Topic 1. Allelopathic interactions including plant pathogens, endophytes, mycorrhizal associations, and insect impacts 16. Evaluation and Nematocide Effect of Capparis spinosa L. on Germination and Early Growth of Cumcumber (Cucumis sativus L.) Under Laboratory Conditions M. Rafieiolhossaini1, 2, H. Sodaeizadeh1, 3 and P. Van Damme1 1Laboratory of Tropical and Subtropical Agronomy and Ethnobotany, Coupure links 653, B-9000 Gent, Belgium; 2Department of Agronomy, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran; 3Faculty of Natural Resource and Desert Study, Yazd University, Yazd, Iran 17. Effect of the Fungal Endophyte Epichloë festucae on the Allelopathic Potential of Festuca rubra Grass M. Romo, B. García-Criado, A. García-Ciudad, B. R. Vázquez de Aldana Instituto de Recursos Naturales y Agrobiología – Consejo Superior de Investigaciones Científicas (IRNASA-CSIC), P.O. Box 257, 37071 Salamanca, Spain 18. Characterization of Fusarium verticillioides Genes Necessary for Benzoxazolinone Biotransformation A. E. Glenn and C. W. Bacon USDA, ARS, Russell Research Center, Toxicology & Mycotoxin Research Unit, 950 College Station Road, Athens, GA 30604, USA. 19. Bacillus mojavensis Transforms BOA Into Fungitoxic APO in the Presence of Fusarium verticillioides C. W. Bacon1, D. M. Hinton1, A. E. Glenn1, F. A. Macias2, and D. Marin2 1USDA, ARS, Toxicology and Mycotoxin Research Unit, Athens, Georgia 30604, USA; 2Department of Organic Chemistry, University of Cadiz, Cadiz, Spain. 20. Allelopathic Actions of Camptotheca acuminata Decne. Against Pest Spodoptera exigua Hubner H. Jiang Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 110094, China 21. Peroxidase and Polyphenol Oxidase as Bioindicators of Grain Aphid Adaptations towards Walnut Phenolics G. Chrzanowski, B. Leszczynski, H. Matok, and K. Milewska Department of Biochemistry and Molecular Biology, University of Podlasie 12 B. Prusa St., 08 110 Siedlce, Poland. 22. Studies on the Allelopathy of the Triterpene Sapogenin from Nerium indicum to


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Oncomelania hugpensis W. –X. Wang1, Y. Yang1, W. –P. Tang2, Q.-X. Sun3, X.-D. Zhang3, X.-Y. Hu2, W. Chen1, H. –D. Jiang1, W.-L. Yun1 and J. Wu1 1Institute of Biology and Science, Hubei University, Wuhan 430062; 2Hubei Provincial Academy of Forestry, Wuhan 430079; 3Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091.

23. Introducing Neotyphodium occultans in Australian Annual Ryegrass Populations K. A. Kirkby 1, J. Pratley1, D.E. Hume 2, A. Seal1, M. An1, and H. Wu3 1 EH Graham Centre for Agricultural Innovation Charles Sturt University, Wagga Wagga, NSW, 2678; 2 Grasslands Research Centre, AgResearch, Palmerston North, New Zealand, 4442 3 EH Graham Centre for Agricultural Innovation, NSW Department of Primary Industries, Wagga Wagga, NSW 2650 24. Effect of Plant Extracts on Grain Aphid (Sitobion avenae F.) G. Chrzanowski and B. Leszczyński Department of Biochemistry and Molecular Biology, University of Podlasie 12 B. Prusa St., 08-110 Siedlce, Poland. 25. Induction of DIMBOA and Phenolic Acids by Arbuscular Mycorrhizal Fungus Glomus mosseae Confers Increased Corn Resistance to Rhizoctonia solani R. S. Zeng1,2, M. Cao2, J. H. Huang2 and S. M. Luo1,2 1Research Center for Chemical Ecolog 2Institute of Tropical and Sub-tropical Ecology, South China Agricultural University, Wushan, Guangzhou, 510642 P.R. China 26. Effect of Bird Cherry Volatiles on Host Plant Selection by Bird Cherry-oat Aphid During Autumn R. Krzyżanowski and B. Leszczyński University of Podlasie, Department of Biochemistry and Molecular Biology, B. Prusa 12 St., 08-110 Siedlce, Poland. 27. Allelopathy Impact of Two Resistant Tomato Rootstocks on the Population Dynamics and Diversity of Rhizosphere Free-living Nematodes Z. Cao and L. Han College of Resources and Environmental Science, China Agricultural University, Beijing, China, 100094 Main Topic 2. Allelochemicals: Fate in soil and water 40. Allelopathic Potential of Barnyardgrass (Echinochloa crus-galli)-infested Soil Extract and its Phytotoxic Compounds Tran Dang Khanh, Tran Dang Xuan, and Sinshichi Tawata Department of Bioscience and Biotechnology, Faculty of Agriculture, University of the Ryukyu, Okinawa 902-0213, Japan 41. Fate of Toxic Potato Glycoalkaloids in a Potato Field P. H. Jensen1,2, O. S. Jacobsen1, R. B. Pedersen2, B. W. Strobel2, and H. C. B. Hansen2

Department of Natural Sciences, Faculty of Life Sciences, University of Copenhagen , Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark. 1Geological Survey of Denmark and Greenland (GEUS), Department of Geochemistry, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark; 2University of Copenhagen, Department of Natural Sciences, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark 42. Content and Distribution of the Carcinogen Ptaquiloside in Soil and Groundwater P. H. Jensen1, 2, O. S. Jacobsen1, R. K. Juhler1, A. L. Gimsing2, and H. C. B. Hansen2

1Geological Survey of Denmark and Greenland (GEUS), Department of Geochemistry, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark; 2Department of Natural Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark 43. Allelopathic Activity of Camphor Tree (Cinnamomum camphora Sieb) Leaf Powder Yumi Okamoto, Keiko Yamaji, and Katsuichiro Kobayashi Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan Main Topic 3. Allelochemical identification, localization and applications 58. Potential Allelopathic Interferences of Melilotus neapolitana Metabolites Assunta Esposito, D’Errico Elena, Severina Pacifico, Annunziata Golino, Maria Teresa Pascarella, Brigida D’Abroca, Antonio Fiorentino Dipartimento di Scienze della Vita, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy. 59. Autotoxic Compounds from Fibrous Roots of Panax quinquefolium L. Weiwei Gao1, Chunnian He1, Jiaxue Yang1, Wu Bi1, Xuesong Zhang2 and Yangjing Zhao1


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1Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 151 Malianwa North Road, Haidian District, Beijing 100094, P. R. China; 2Beijing Tianhui Ginseng Industrial CO., LTD, Beijing 101400, P. R. China. 60. Isolation and Identification of Allelothathic Substance in Cucumber Plants Hisashi Kato-Noguchi1, Ho Le Thi1, Teruya Toshiaki2 and Suenaga Kiyotake2 1Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan; 2Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama 223-8522, Japan. 61. Biotechnological Production of Benzoxazinones Domingo Cantero1, Gema Cabrera1, Jose M. Gómez1, Antonio Valle 1, José M.G. Molinillo2 and Francisco A. Macías2* 1Dept. of Chemical Engineering; 2Organic Chemistry, Faculty of Sciences, University of Cadiz, c/ República Saharaui s/n, 11.510 Puerto Real, Spain. 62. Allelopathic Activity of Root Extracts of Aristolochia esperanzae from Brazil’s Cerrado Ana Beatriz Gatti1, Sonia Cristina J. Gualtieri de A. Perez1, Rosa M. Varela2, José M. G. Molinillo2 and Francisco A. Macíasb* 1P.O. Box 676, Dept. of Botany, Federal University of S. Carlos, CEP13565-905, S Carlos SP, Brazil; 2Dept. of Organic Chemistry, Faculty of Sciences, University of Cadiz, c/ República Saharaui s/n, 11.510 Puerto Real, Spain. 63. Novel Preussomerins and Palmarumycins with Allelochemical Activity from the Tropical Endophytic Fungus Edenia gomezpompae Martha L. Macías-Rubalcava1, Blanca E. Hernández-Bautista1, Manuel Jiménez-Estrada2, María C. González3, Anthony E. Glenn4, Richard T. Hanlin5, Simón Hernández-Ortega2, Aurora Saucedo-García1, Jordi M. Muria-González1, Claudio Meléndez-González1 and Ana Luisa Anaya1* 1Laboratorio de Alelopatía, Departamento de Ecología Funcional, Instituto de Ecología; 2Instituto de Química; 3Instituto de Biología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, 04510, México, D.F.; 4USDA, ARS, Toxicology & Mycotoxin Research Unit, Russell Research Center, Athens, Georgia 30604, USA; 5University of Georgia, Museum of Natural History Annex, 4435 Atlanta Highway, Bogart, Georgia 30622, USA. 64. Potential Allelopathic Effects of Mediterranean Shrubs Metabolites on Coexisting Species and on Weed Seedling Growth Piera Uzzo, Angelina Izzo, Angela Natale, Marianna Letizia, Brigida D’Abrosca, Assunta Esposito and Antonio Fiorentino Dipartimento di Scienze della Vita - Second University of Naples – via Vivaldi 43, 81100 Caserta, Italy. 65. Searching for Allelopathic Activity of Guazuma ulmifolia: Inhibition Effect on Photosynthesis Alonso Zavaleta-Fernandez de Cordova, Beatriz King-Diaz, and Blas Lotina-Henssen C.P. 04510 Departamento de Bioquímica; Facultad de Química, Universidad Autónoma de México, México, D.F., México. 66. Characterization of Secondary Metabolites from Stereocaulon antarctica Collected from Caleta Cierva, Antarctica: A pilot International Research Experience for Undergraduates (NSF REU) Adrianna Pavia1, Ascensión Torres Martínez2, Juan Carlos García Galindo2 and Joanne G. Romagni1 1St. Edward's University, Dept. of Chemistry, Austin, TX 78704 USA; 2University of Cadiz, Dept. of Organic Chemistry, Puerto Real, Spain. 67. Resistance of Grafted Eggplants to Verticillium (Verticillium dahllae) Wilt and Identification of Allelochemicals from Its Root Exudates Na Liu, Baoli Zhou, Yixiu Li, Jing Hao and Bo Lu College of Horticulture, Shenyang Agricultural University, Shenyang 110161, China 68. Characterization of Secondary Metabolites from Cladina rangiferina collected from Caleta Cierva, Antarctica: a Pilot International Research Experience for Undergraduates (NSF REU) Alicia Jones1*, Ascensión Torres Martínez2, Juan Carlos García Galindo2, and Joanne G. Romagni1 1St. Edward's University, Dept. of Chemistry, Austin, TX 78704 USA; 2University of Cadiz, Dept. of Organic Chemistry, Puerto Real, Spain Main Topic 5. Allelopathy in agricultural settings 96. Allelopathic Effect of Cleavers (Galium aparine) on Germination and Early Growth of Wheat A.Aziz*, A. Tanveer, A. Ali, M. Yasin*, B.H. Babar and M.A. Nadeem Department of Agronomy, University of Agriculture, Faisalabad, Pakistan *Institute of Soil and Environmental Sciences University of Agriculture, Faisalabad, Pakistan 97. Potential Phytotoxic Effects of Achillea santolina L. on two Economically Important Field Crops in Egypt S.M. El-Darier and A.A. Tammam Botany Department, Faculty of Science, Alexandria University, Alexandria, Egypt 98. Management of Allelopathy in Closed-Ecosystem for Space Agriculture


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Kaori Tomita-Yokotani1, Hiroko Iwasawa1, Kanae Hiraishi1, Maki Asano1,2, Yoshiharu Fujii3, Hirofumi Hashimoto4, and Masamichi Yamashita4

1University of Tsukuba, 2Keio University, ３National Institute for Agro-Environmental Sciences, Jaxa 99. Brassica Allelopathy against Soilborne Pathogens and Weeds of Strawberry Scott Mattner, Ian Porter, Rajendra Gounder, and David Allen Private Bag 15, BioSciences Research Division, Department of Primary Industries, Ferntree Gully DC, Vic 3156, Australia 100. Allelopathy in Bangladesh Rice Cultivars Hisashi Kato-Noguchi and Md. Abdus Salam Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan 101. Assessment of Phytotoxic Properties of Peganum harmala on Growth of Redroot Amaranth (Amaranthus retroflexus) in Greenhouse Conditions Hamid SodaeiZadeh*1,2 and Patrick Van Damme1

1Laboratory of Tropical and Subtropical Agronomy and Ethnobotany, Coupure links 653, B-9000 Gent, Belgium; ²Faculty of natural Resources & Desert Studies, Yazd University, Yazd, Iran. Main Topic 6. Biosynthesis, mode of action, and detoxification of phytotoxins from plant 116. Inhibition of Maize (Zea mays) Root Growth by m-Tyrosine Results From Cell Cycle Disruption R. Bogatek1, A. Rudzińska-Langwald2, W. Kurek2, Z. Kostrzewa1 and A. Gniazdowska1 1Department of Plant Physiology, Warsaw University of Life Science-SGGW, Nowoursynowska 159, 02-776 Warszawa, Poland; 2Department of Botany, Warsaw University of Life Science-SGGW, Nowoursynowska 159, 02-776 Warszawa, Poland. 117. Allelopathic Effect of Zingiber officinale on Seed Germination and Seedling Growth of Soybean and Chive C. Han, K. Pan, J. Wang, Y. Wang Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China 118. Camphor and Menthol Affect Plant Growth, Polarity, and Cytoarchitecture Via Their Effects on the Actin Cytoskeleton O. Šamajová, M. Schlicht, B. Kriegs1, Margot Schulz1 and F. Baluška IZMB (Institut für Zelluläre und Molekulare Botanik) Universität Bonn Kirschallee 1, 53115 Bonn, Germany 1IMBIO (Institut für Molekulare Physiologie und Biotechnology der Pflanzen, Universität Bonn Karlrober Kreiten Str. 13, 53115 Bonn, Germany. 119. Approaching Molecular Backgrounds of Stomata Response to Monoterpenes B. Kriegs, H. Peisker, A. Ulbrich1 and M. Schulz IMBIO (Institut für Molekulare Physiologie und Biotechnologie der Pflanzen) Universität Bonn Karlrobert-Kreiten-Str. 13, 53115 Bonn, Germany 1Forschungszentrum Jülich ICG.3:Phytosphäre, D-52425 Jülich, Germany. 120. Allelopathic Effects of Phenolic Extracts of Canola (Brassica napus L.) on Growth and Physiological Responses of Soybean (Glycine max L.) Seedlings Z. Gerivani1, Gh. R. Haddadchi1 and M.Gerivani2 1Department of Biology, College of Science, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan.Iran; 2Department of Plant Breeding, College of Agriculture, Zabol University, Zabol, Iran. 121. In vivo Effects of Cercocarpus macrophyllus Organic Extracts on Trifolium alexandrinum and Lolium perenne and Bioactivity-guided Isolation of 3β, 28-dihydroxyolean-12-ene and its Effect as a Hill Reaction Inhibitor on Photosynthesis C.J. Meixueiro-Galán1, B. King-Díaz1, M.I. Aguilar-Laurents2 and B. Lotina-Hennsen1 1Departamento de Bioquímica, 2Departamento de Farmacia, Fac.de Química, Universidad Nacional Autónoma de México, México D.F., C. P. 04510. México Main Topic 7. Invasion ecology and allelopathy 1 133. Phillyrea angustifolia as a source of potentially phytotoxic compounds Marina Della Greca, Lucio Previtera, Raffaella Purcaro, and Armando Zarrelli Università degli Studi di Napoli Federico II, Dip. di Chimica Organica e Biochimica, Via Cinthia 4 80126 Napoli, Italy. 134. Allelopathic Assessment of Annual Ryegrass (Lolium rigidum) by Root Exudate Bioassay R. Amini1, M. An2 and J. Pratley2

1Department of Agronomy, College of Agriculture, University of Tehran, Karaj, Iran,; 2E.H. Graham Centre for Agricultural Innovation (a collaborative alliance between Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga, NSW 2650, Australia. 135. Rosmarinic Acid as Potent Allelochemical from Comfrey (Symphytum officinale L) Yoshiharu Fujii 1*, Zahida Iqbal 1, 2, Habib Nasir1, 2, Akihoro Furubayashi1, and Syuntaro Hiradate1


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1National Institute for Agro-Environmental Science, Tsukuba 305-8604, Japan; 2University of Arid Agriculture Rawalpindi, Rawalpindi, Pakistan 136. Demonstration of Allelopathy in Tissue Culture of Coffee and Guarana: Plant Cells Communicate through Production of Caffeine as an Autotoxic Allelochemical in Mixed Culture George R. Waller1, Zahida Iqbal2, and Yoshiharu Fujii 2* 1 Oklahoma State University, Stillwater, Oklahoma 74078 USA; 2 National Institute for Agro-Environmental Science, Tsukuba 305-8604, Japan 137. An Investigation into The Allelopathic Potential of Two Invasive Alien Species of Balsam (Impatiens) Found in The UK, Using the Plant Box and Dish Pack Methods. Owen Smith 1 and Yoshiharu Fujii 2

1School of Biological Sciences, University of Plymouth, UK; 2National Institute of Agro-Environmental Sciences, Tsukuba, Ibaraki, Japan Main Topic 8. Interactions in the rhizosphere 148. Root Associated Microorganisms Perform Degradation of Caffeine Absorbed by Salvia officinalis Margot Schulz, Mona Knop, Maritta Kunert● and Carmen Müllenborn IMBIO (Institut für Molekulare Physiologie und Biotechnology der Pflanzen, Universität Bonn, Karlrober Kreiten Str. 13, D-53115 Bonn, Germany; ●Max-Planck-Institut für chemische Ökologie, Beutenberg Campus, Hans-Knöll-Str. 8, D-07745 Jena, Germany 149. Analyses of the Components from the Root Exudates of the Cucumber Cultivars with the Different Resistance to Fusarium Wilt Pan Kai, Wu Fengzhi Horticulture College, Northeast Agricultural University, Harbin 150030, China 150. Biological Induction of DIMBOA in Wheat Seedlings by Weeds Yongquan Zheng, Jianlei Yu, Xingang Liu and Fengshou Dong

Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100094, P. R. China Main Topic 9. Allelopathy methodologies 161. Allelopathic Effect of Floral Volatile Chemicals on Behavioural and Electrophysiological Responses of a Female Predator Insect Mourad Shonouda1, Sergio Angeli2, Stefan Schuetz2 and Stefan Vidal3

1Zoology Department, Faculty of Science, 21511 Mharam Bey, Alexandria University, Egypt; 2Institute for Forestzoology and Conservation, University of Göttingen, Germany; 3AgroEntomology Section, Crop Sciences Department, University of Göttingen, Germany. 162. Methods for Analysis of the Distribution of Allelochemicals in Selected Plants Denise Schneider, Ines Fritz1, Dominic Funk, Marcus Pruckner, Michaela Bauer, Rudolf Braun Universität für Bodenkultur Wien, Department IFA-Tulln, Konrad Lorenz Str. 20, A-3430 Tulln, Austria. Main Topic 10. Invasion ecology and allelopathy 2 123. In Vitro Comparisons of Root Allelopathy among Native and Invasive Asteraceae Guangyan Ni1, 2, Shaolin Peng2 and Ragan Callaway1 1Division of Biological Sciences, The University of Montana, Missoula, MT, 59812 USA 2State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, Guangdong, 5I10275 China Main Topic 11. Allelopathy in crop settings for weed suppression 178. Argentinean Rice Cultivars: Their Allelopathic Potential for Weed Control Florencia Urteaga Omar, Hugo D. Chludil1 and Silvia R. Leicach 1Organic Chemistry, Agronomy School, Buenos Aires University, Argentina 189. Bio-control of Parthenium hysterophorus L. by Using Extracts of Selected Plant Species G.P.Satsangi, Anjali Saxena and Garima Bartariy Department of Botany, Faculty of Science, Dayalbagh Educational Institute (Deemed University), Dayalbagh, Agra 282005, India.


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190. The Effects of Common Lambsquarters (Chenopodium album) Extracts on Sugar Beet (Beta vulgaris) and its Important Weeds Mohammad Armin and mosareza Hookmabadi Department of Agriculture, Islamic Azad University of Sabzeva, Iran Email: 191. Exploring the Possibility for Canarygrass (Phalaris minor Ritz.) Control through Allelopathy Khawar Jabran, Muhammad Farooq, Hafeez-ur-Rehman and Mubashir Hussain Department of Agronomy, University of Agriculture, Faisalabad-38040, Pakistan 192. DIBOA and BOA Production by Eight Rye Cultivars and Allelopathic Effect of the Mulch on Four Warm Season Weeds Vincenzo Tabaglio1, Carolina Gavazzi1, Margot Schulz2 and Adriano Marocco1

1Istituto di Agronomia Generale e Coltivazioni Erbacee, Facoltà di Agraria, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29100 Piacenza, Italy; 2IMBIO, University of Bonn, Karlrobert Kreiten Str. 13, 53115 Bonn, Germany. 193. Allelopathic Effects of Circium arvensis (L.) Scop. on Germination and Growth of Some Crops and Weeds Masoumeh Younesabadi, Habib Ollah Kashiri, Leila Habibian and Ali Kian Poor Dept. of Plant Protection, Agricultural Research Center, Beheshti Avenue, Gorgan, Golestan 49156-77555, Iran 194. Use of Plant Extract in Control of Avena ludoviciana Durieu Masoumeh Younesabadi, Habib Ollah Kashiri and Koorosh Ghaderi Dept. of Plant Protection, Agricultural Research Center, Beheshti Avenue, Gorgan, Golestan 49156-77555, Iran 195. Herbicidal Potential of Nettle Leaf Goosefoot (Chenopodium murale L.) Masoumeh Younesabadi Dept. of Plant Protection, Agricultural Research Center, Beheshti Avenue, Gorgan, Golestan 49156-77555, Iran 196. Allelopathic Activity of Cauliflower (Brassica oleracea var. botrytis) on Certain Common Weed Species N. N. Issa and J. R Qasem Department of Plant Protection, Faculty of Agriculture, University of Jordan, Amman, Jordan. 197. Allelopathy in Cultivated Amaranth Varieties Solvejg K. Mathiassen, Per Kudsk and Inge S. Fomsgaard Department of Integrated Pest Management, Faculty of Agricultural Sciences, University of Aarhus, Forsøgsvej 1, DK-4200 Slagelse, Denmark 198. Effect of Walnut Phenolics on Germination of Dandelion Seeds Henryk Matok, Bogumil Leszczynski and Grzegorz Chrzanowski Department of Biochemistry and Molecular Biology, University of Podlasie 12 B. Prusa Str., PL-08110, Siedlce, Poland Main Topic 12. Allelopathy in aquatic environments 209. A Preliminary Study on Allelopathic Effect of three Compositae Plants on Microcystis aeruginosa Weihao Zhang School of Resource and Environmental Science, Wuhan University, Wuhan 430079, China Main Topic 13. Genetics and Biochemistry 221. Selection for Allelopathy in Rye (Secale cereale) A. Brooks Dept. of Crop Science, North Carolina State University, Raleigh, NC 27695, USA 222. Overcoming Plant Biotic Stresses Through Allelopathy and Induced Resistance Ren Sen Zeng1,2* and Shi Ming Luo1,2 1Research Center for Chemical Ecology 2Institute of Tropical and Sub-tropical Ecology, South China Agricultural University, Wushan, Guangzhou, 510642, China


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ABSTRACTS

Main Topic 1: Allelopathic interactions including plant pathogens, endophytes, mycorrhizal associations, and insect impacts 1. Manipulating Phytochemical Diversity: Unintended Causes and Effects? Norman G. Lewis Institute of Biological Chemistry, Washington State University, Pullman, WA, USA 99164-6340 Email: [email protected] The fantastic diversity of phytochemicals found in nature profoundly influences the interactions of all forms of plant life with all other living (biological) organisms. This phytochemical diversity, in turn, serves to underscore the remarkable metabolic complexity that has evolved and been fine-tuned over the passage of time. Today, the recent advances in plant genetics/plant biochemical pathway manipulations now affords new insights into such processes, as well as the severe limitations of our knowledge of factors controlling metabolism in general. This presentation summarizes, in a general sense, the breadth of phytochemical diversity, as it relates to allelopathy. More specifically, a focus is placed upon some of the consequences of altering phenylpropanoid pathway metabolism and the unintended/unexpected physiological consequences that can result as regards growth, development and metabolism of manipulated plant lines. These, in turn, have many downstream consequences, including those affecting rhizosphere and allelopathic processes. 2. Fungal Endophyte Metabolism and Allelopathic Interactions with Host Plants Anthony E. Glenn, Nicholas C. Zitomer, Ronald T. Riley USDA, ARS, Russell Research Center, Toxicology & Mycotoxin Research Unit, 950 College Station Road, Athens, GA 30604, USA Email: [email protected] The maize endophyte Fusarium verticillioides produces the fumonisin mycotoxins, which are of significant concern for their animal toxicity caused by inhibition of ceramide synthase and disruption of sphingolipid metabolism. Fumonisin-producing strains associated with maize cause leaf lesions, developmental abnormalities, stunting, and sometimes death of susceptible corn seedlings. Leaf lesion incidence and severity of effects on root and stalk growth were significantly correlated with fumonisin accumulation and disruption of sphingolipid metabolism in roots. Fumonisins were also detected in leaf tissues, with fumonisin B1 (FB1) preferentially accumulated in leaves over fumonisin B2 and fumonisin B3. Levels of FB1 accumulation in the 1st leaf paralleled the susceptibility of maize lines to F. verticillioides-induced leaf lesions, and the levels of FB1 in all leaves of a susceptible sweet corn were significantly (p<0.001) greater than in the resistant dent corn. For all leaves, plants inoculated with a fumonisin-producing strain had significantly elevated sphingoid bases and their 1-phosphates, indicating disruption of sphingolipid metabolism.

Interestingly, a unique population of F. verticillioides pathogenic on banana does not produce fumonisins. Fumonisin-nonproducing banana strains form asymptomatic infections in maize without disruption of sphingolipid metabolism. Molecular analysis of the fumonisin biosynthetic gene cluster showed that essentially the entire cluster was deleted in the banana-associated strains. To further evaluate the impact of fumonisin production on maize seedling disease, a banana strain was cotransformed with two overlapping cosmids containing the full gene cluster. Fumonisin-producing cotransformants were recovered and were pathogenic on sweet corn seedlings, thus supporting the hypothesis that fumonisin production is required for development of foliar disease symptoms. The mechanism of action involves accumulation of FB1 and disruption of sphingolipid metabolism in plant tissues. The significance of maize genotype effects on disease development is being investigated in greater detail, including assessing impacts of fumonisin sensitivity on other maize-associated microbes and metabolic activities. 3. Specific Interactions between AM-fungi, PGPR and Plant Pathogens with Regard to Plant Growth Promotion Ulf Granhall, Veronica. Arthurson, L. Jäderlund P.O. Box 7025, Dept. of Microbiology, Swedish Univ. of Agric. Sciences (SLU), Uppsala, SE- 75007, Sweden Email: [email protected] A series of green-house experiments were conducted with winter wheat (Triticum aestivum), arbuscular mycorrhizal fungi (AMF; Glomus mosseae and G. intraradices), plant growth promoting rhizobacteria (PGPR; Paenibacillus and Pseudomonas strains isolated from different plant hosts) and a plant pathogen (snow mould; Michrodochium nivale). Mycorrhizal root colonisation, plant growth and in some cases plant uptake of phosphorous were analyzed. Bacterial antagonism against the plant pathogen and phosphate solubilisation was tested separately in vitro. The most interesting observations about the interactions were: ¤ The plant host origin affected the compatibility of the rhizobacteria with regard to plant-microbe-interactions. High inoculation levels of less compatible strains could interfere negatively with plant emergence. ¤ Certain bacterial strains had direct plant growth stimulating effects possibly by production of phytohormones. P. polymyxa strains alone (isolated from wheat) had dramatic effects on root growth, whereas only certain bacterial combinations with AMF stimulated shoot growth. ¤ All paenibacillii solubilised inorganic phosphates in vitro but not all stimulated plant P-uptake. The AM-fungi alone did not increase P-uptake. ¤ AMF root colonisation level above a threshold value influenced plant P-levels positively, but only in the presence of bacterial strains isolated from the


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same plant host. ¤ The different bacteria affected root colonisation levels of the two AM-fungi variously. Some acted as mycorrhiza-helper-bacteria (MHB). The colonisation level, however, was not directly related to plant growth. The specificity of the interactions determined the efficiency rather than colonisation rate per se. ¤ All paenibacillii but not the pseudomonas were antagonistic against M. nivale in vitro. In vivo, however, only G. intraradices alone or in combination with the biocontrol strain of Pseudomonas clearly counteracted the negative effects on plant growth caused by the plant pathogen. In conclusion, most PGPR studied showed specificity with regard to interaction with the plant host, the AMF (invasion and efficiency in P-transfer) and the plant pathogen. 4. Endophytic Fungi: New Perspectives in Allelopathy Ana Luisa Anaya1, Maria C. González2, Anthony E. Glenn3, Aurora Saucedo-García1, Martha L. Macías-Rubalcava1, Blanca E. Hernández-Bautista1, Richard T. Hanlin4 1Departamento de Ecología Funcional, Instituto de Ecología, 2Departamento de Botánica, Instituto de Biología. Universidad Nacional Autónoma de México, Apartado Postal 275, 04510 México, D.F. USDA, ARS, Toxicology & Mycotoxin Research Unit, Russell Research Center, Athens, Georgia 30604, USA

4University of

Georgia, Museum of Natural History Annex, 4435 Atlanta Highway, Bogart, Georgia 30622, USA Email: [email protected] Tropical forests contain a great diversity of plants that suggests a great diversity of fungi species associated with plants since millions of years ago. Endophytic fungi studies are important to know the variety of interactions among plants and microorganisms in natural conditions, and to emphasize the significance of these relations in the plant history. Experiments of in vitro competence between endophytic fungi show that most of them inhibited the growth of other endophytic and phytopathogenic species. We performed an investigation on the endophytic fungi isolated from the leaves of four plant species of the dry forest of the Ecological Reserve El Eden, Quintana Roo, Mexico. Antagonism bioassays showed the type of interactions between fungi by means of percentages of growth inhibition and antagonism indexes. Four endophytic fungi with the higher antagonism indexes and the lower percentages of inhibition of their growth were selected to perform additional antagonism bioassays against seven species of phytopathogenic fungi. At the same time, fermentations at low scale of the four fungi were made to obtain organic extracts and to evaluate their bioactivity on phytopathogenic fungi and plants. The endophytic fungus with the higher antagonism index was identified as a new genus and species: Edenia gomezpompae (Pleosporaceae). This fungus was isolated from the leaves of Callicarpa acuminata (Verbenaceae). Chemical investigation of the mycelium of this novel fungus resulted in the isolation of various novel naphthoquinone spiroketals and palmarumycin CP2. Their bioactivity was tested on endophytic fungi and phytopathogenic microorganisms. We conclude that investigations on endophytic fungi could help to elucidate complexity, variety and importance of relationships that establish with their biotic surrounding. Moreover, they contribute to the knowledge of biodiversity and to find novel

compounds for the discovering of new potential agrochemicals and drugs of natural origin. 5. Bioprospecting for Allelopathic Endophytes from Native Australian Flora with Mycofumigation Potential Scott Mattner, Ross Mann, David Allen, Ian Porter, Jacky Edwards Private Bag 15, BioSciences Research Division, Department of Primary Industries, Ferntree Gully DC, Vic 3156, Australia Email: [email protected] Soil mycofumigation is the process of using volatile allelochemicals produced by fungi to control soilborne phytopathogenic fungi, bacteria, nematodes, weeds and insect pests. Endophytic fungi inhabit plant tissues without causing disease, and many have formed symbiotic relationships with their hosts. For example, some endophytes protect their hosts from pest and pathogen infection through the production of allelochemicals. Our preliminary research aimed at bioprospecting for endophytic fungi from native Australian flora that produce volatile allelochemicals, with potential for use as mycofumigants against soilborne pathogens of horticultural crops. By direct culturing, a total of 66 endophytic fungi were isolated from 12 Australian native plants in a cool temperate rainforest in Victoria (Sherbrooke Forest, Dandenong Ranges). In vitro bioassays showed that two isolates, from Lomatia fraseri and Olearia argophylla, produced volatile allelochemicals that suppressed the growth of the fungal pathogens Rhizoctonia fragariae, Fusarium oxysporum, Sclerotium rolfsii, Verticillium dahliae, and Colletotrichum acutatum by between 50 – 100%. Molecular (amplification and sequencing of the ITS region of the rRNA) and morphological identification placed the two isolates in the same undescribed species of Nodulisporium (teleomorph Hypoxylon, Xylariaceae). The volatile compounds (characterised by SPME GC/MS) produced by the two isolates varied, but mostly included of a range of terpenes and alcohols. We hypothesise that some of these compounds are allelochemicals with potential for use as mycofumigants. Our future research aims to: (1) screen the individual volatile compounds produced by the Nodulisporium isolates for their activity against phytopathogens, weeds and pests; (2) determine the potential of the isolates for soil mycofumigation against pathogens of vegetable crops, and (3) determine the potential of integrating mycofumigation with other treatments (eg allelopathic green manure crops, biological control, solarisation) to offer growers more sustainable soil disinfestation systems than the use of synthetic pesticides. This is the first report of volatile allelochemicals from Nodulisporium spp. having antifungal activity against phytopathogens. 6. Research Progress of Compounds Isolated from Fungus for Weed Control in China Liuqing Yu, Guifang Duan, Ruimei Geng, Jianping Zhang, Yongliang Lu, Yongjun Zhou State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China Email: [email protected]


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There are seven phytotoxic compounds that were isolated from four fungus species in China. A mycotoxin compound, α, β-dehydrocurvularin was isolated from a fungus Curvularia eragrostidis. This compound was effective control the troublesome weed Digitaria sanguinalis, interfered upland crops. The mode of action of this compound might be the damage of PSII reaction center and inhibition of the reoxidation of the primary electron acceptor (QA), which resulted in the inhibition in electron transport between PSII reaction center and QA or between QA and the second electron acceptor (QB). Another toxin compound, helminthosporin was isolated from the same strain C. eragrostidis. There were 18 out of the 28 species tested on their selective were susceptible to the toxin. Chenopodium serotinum is the most susceptive, and D. sanguinalis, Polygonum aviculare and Alopecurus japonicus took second place. Soybean, cotton and tomato were resistant to the toxin at 500 µg/mL concentration. However, maize and wheat were susceptible to this compound. Brefeldin was isolated, purified and identified from the filtering liquid of fermentation of Alternaria zinniae. Brefedin gave excellent control to Eupatorium adenophorum Spreng., the most troublesome invasive weed in South-west part of China. Vulculic acid was isolated and identified from liquid fermentation of the fungus Nimbya alternantherae. Vulculic acid had good control to the invasive weed Alternanthera philoxeroides in China. Four compounds, 3-anhydroophiobolin B, ophiobolin A, 3-anhydro-6-epiophiobolin A and 3-anhydro-6-epiophiobolin B were isolated from mycelia and culture filtrate of Heminthosporium gramineum Rabenh., a fungus phytopathogenic to barnyardgrass (Echinochloa crus-galli (L.) Beauv). Ophiobolin A with the molecular weight of 400 and the molecular formula of C25H36O4 had the most activity to control barnyardgrass with the IC50 of 7.5µM among these four compounds. 7. Plant Allelochemicals Mediate Tritrophic Interactions among Crops, Pathogens and Insects via Induction of Insect Cytochrome P450 Monooxygenases Ren Sen Zeng1,2, Zhimou Wen3, Guodong Niu2, Mary A. Schuler3, May R. Berenbaum2 1Institute of Tropical & Subtropical Ecology, South China Agricultural University, Guangzhou 510642, P.R. China 2Department of Entomology, University of Illinois, Urbana, IL, 61801 3Department of Cell and Developmental Biology, University of Illinois, Urbana, IL, 61801 Email: [email protected] The polyphagous corn earworm Helicoverpa zea is a major pest throughout the United States of corn and a number of other crops. H. zea encounters a diversity of plant allelochemicals in its many host plants and, as well, can encounter aflatoxins, the mycotoxins produced by Aspergillus flavus and A. parasiticus, two closely related fungal species that can infect multiple hostplants of H. zea. Aflatoxins are among the most active natural carcinogens known. Aspergillus fungal infections and aflatoxin contamination are often exacerbated by Helicoverpa zea feeding. This study elucidates the impact of plant allelochemicals on detoxification responses of Helicoverpa zea to aflatoxin B1 (AFB1) and synthetic insecticides. Our investigations have

demonstrated that aflatoxin B1 is in fact extremely toxic to H. zea and that toxicity results from bioactivation via cytochrome P450 monooxygenase-mediated metabolism; this bioactivation parallels that which occurs with certain classes of insecticides, such as organophosphates. However, dietary supplementation of plant allelochemicals that are frequently (coumarin, flavone), occasionally (indole-3-carbinol) or rarely (xanthotoxin, visnagin) encountered by H. zea larvae substantially reduced the toxicity of AFB1 and insecticides (diazinon, α-cypermethrin and carbaryl) to H. zea. Diets containing coumarin and xanthotoxin significantly increased CYP6B8 transcripts; CYP321A1 transcripts increased 20.7, 8.3 and 10.6-fold in response to coumarin, indole-3-carbinol and xanthotoxin, respectively. These indicate that tritrophic interactions among crops, pathogens and herbivorous insects are mediated by plant allelochemicals, consumption of allelochemicals in host plants can ameliorate toxicity of natural mycotoxins and synthetic insecticides encountered by insects and suggest that cytochrome P450 monooxygenases induced by these allelochemicals contribute to detoxification of these chemicals in H. zea. 8. Bioprotective Functions of Ergot Alkaloids in an Endophytic Fungus-grass Symbiosis Daniel G. Panaccione1, Jessica R. Cipoletti 1, Christopher L. Schardl 2, Daniel A. Potter2 1West Virginia University, Morgantown, WV 26506 USA 2University of Kentucky, Lexington, KY 40546 USA Email: [email protected] Ergot alkaloids are indole-derived mycotoxins produced by several fungi, including species of Neotyphodium that grow as endophytic symbionts in pasture and turf grasses. Neotyphodium sp. Lp1 in perennial ryegrass (Lolium perenne) produces the ergot pathway end product, ergovaline, but also accumulates pathway intermediates and spur products (clavine ergot alkaloids) to relatively high concentrations. I hypothesize that inefficiency in the pathway has been selected for because the intermediates and spur products provide benefits that differ from benefits conferred by pathway end products. Ergot mutants generated by gene knockout truncation of the pathway at the first step (producing no ergot alkaloids) or the penultimate step (accumulating clavine intermediates and spur products but not ergovaline or other lysergic acid derivatives) were tested for activity against vertebrate and invertebrate herbivores. Clavine alkaloids were sufficient to deter feeding by rabbits (Oryctolagus cuniculus), whereas lysergic acid derivatives were either ineffective or redundant with clavine alkaloids. In alternate feeding trials ergovaline but not clavine alkaloids affected satiety of rabbits. In experiments with black cutworm (Agrotis ipsilon), only lysergic acid derivatives (products of the finals stages of the pathway) affected feeding or survival of neonates. The data indicate that intermediates and end products of the ergot alkaloid pathway have different activities and confer different benefits to the producing fungi and the grasses that harbor them.


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9. Amending Soil with Artemisinin-rich Dry Leaf Tissue of Artemisia annua Improves A. annua’s Competitive Ability Nicolas Delabays Swiss Agricultural Research Station, Agroscope Changins-Wädenswil, P.O. Box 1012, CH-1260 Nyon, Switzerland Email: [email protected] Several strains of annual wormwood (Artemisia annua) accumulate in their glandular trichomes high quantities of artemisinin, a sesquiterpene lactone that, besides an antimalarial activity, exhibits also phytotoxic properties. It has been shown that the incorporation into the soil of dry leaf tissue from artemisinin-rich plants inhibits weed development in the field. Moreover, artemisinin, when brought into the soil with the leaves, is quite stable. It has also been reported that leaves left on the ground after harvest still produce and accumulate artemisinin for several weeks while drying. Although the mode of action of artemisinin as a phytotoxin remains unknown, the strong allelopathic effects of the molecule under field conditions raise questions about a possible ecological role for the species. One hypothesis is that the molecule produced in the leaves of the plant contributes to clean the ground for the next generation. Studies have being carried out in order to evaluate this hypothesis. Seeds of Artemsisia annua and of two weeds, Chenopodium album and Rumex obtusifolim, were sowed, alone or in mixture, in soil amended with 1% artemisinin-rich dry leaf tissue or in non-amended soil. The incorporation of the leaves of A. annua inhibited the growth of the three species sown alone, but C. album and R. obtusifolium were more strongly affected. When sown together with A. annua in non-amended soil, the biomass production of both weeds was much higher than that of A. annua. In the presence of the A. annua debris into the substrate, the growth of the two weeds was reduced, while the biomass production of A. annua plants was significantly higher, indicating that its competitive ability was improved. Similar trials carried out with leaves of a artemisinin-poor strain of A. annua suggest that artemisinin contributes to the positive effect of A. annua debris on the competitive ability of the species. 10. Plant-plant interaction - A Multitrophic Phenomenon? Studies in a Barley Crop System Velemir Ninkovic P.O. Box 7044, Dept. of Ecology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden Email: [email protected] Emission of volatile compounds as a natural consequence of plant life may have profound effects on neighbouring plant individuals. Volatiles produced by damaged plants have been shown as signals that initiate defensive responses in neighbouring plants making them less attractive for herbivores and more attractive for their natural enemies. However plant interactions by volatiles emitted from foliage between undamaged plants have not previously been considered an important factor for induced resistance to herbivores. Results from experiments with a barley cropping system as model, show that allelopathic interactions occur not only between weeds and barley but also between different genotypes of Hordeum. These chemical interactions are

expressed via volatile substances and have affects across three trophic levels; they affect barley biomass allocation, aphid settling response and searching behavior of predatory ladybirds. The results stimulate discussion on plant responses to their environment, not only in terms of ‘chemical warfare’ and allelopathy as a means for plant competition, but as an advanced capacity of a plant to adapt to current conditions. It may be hypothesized that herbivores closely adapted to plant physiology are more sensitive to plant allelopathic responses, and that the third trophic level (predators of herbivores) respond to traits in the host plant that are shared with stress conditions. 11. Effect of Phenolic Compounds on Spring Host Plant Alternation by the Bird Cherry-oat Aphid (Rhopalosiphum padi L.) Paweł Czerniewicz, Bogumił Leszczyński University of Podlasie, Department of Biochemistry and Molecular Biology, B. Prusa 12 St., 08-110 Siedlce, Poland Email: [email protected] Bird cherry-oat aphid, Rhopalosiphum padi L. is a heteroecious species that alternates between woody primary host (Prunus padus L.) and herbaceous secondary hosts (Poaceae). The aphid life cycle is quite well known, but there is little information on chemical interactions between R. padi and its host plants. One of the most active group of allelochemicals, that affect aphid’s behaviour are phenolics. The present paper reports on changes in content of plant phenolics within leaves of bird cherry and selected secondary hosts while the insect occurrence on them. Host plant alternation of the bird cherry-oat aphid was monitored in central-eastern Poland on bird cherry and two species of secondary hosts: orchard grass (Dactylis glomerata L.) and winter triticale (Marko cv.). Content of free phenolic compounds within tissues of the tested plants was determined by high performance liquid chromatography (HPLC). While the aphid population developed on the primary host the highest concentration of the phenolics was noted in mature leaves of bird cherry and was followed by R. padi migration onto secondary hosts. At that time the orchard grass and winter triticale contained lower level of the phenols in comparison to P. padus. In particular, chlorogenic acid, (+)-catechin and p-hydroxybenzoic acid occurred in higher concentration in bird cherry leaves, whereas coumarin was detected only within tissues of the secondary hosts. Obtained results suggest that host plant alternation allows the bird cherry-oat aphid to avoid accumulation of high level of the phenolics within wooden primary host and on the other hand coumarin might be important in the secondary host plant selection. 12. Differential Responses of Withania somnifera (L.) Dun. in VAM Soil Containing Glomus fasciculatum on Vegetative Growth, Nitrogen and Phosphorus Uptake Manjubilas B. Ray1 and S. Halder2

1Plant Physiology and Biochemistry Section , Department of Botany, Burdwan University, Burdwan, West Bengal, India 2Department of Botany, Burdwan Raj College, Burdwan, West Bengal, India Email: [email protected]


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Withania somnifera (vern. Ashwagandha) belonging to the family Solanaceae is an important medicinal and endangered plant grows in dry and arid soil of subtropical regions. It is mainly cultivated for its medicinal roots containing heterogeneous alkaloids. Plants were grown in plastic pots under aseptic conditions. The VAM soil containing Glomus fasciculatum was applied once after 30 days of transplanting in one set of plants and twice after 30 days and 75 days of transplanting in another set of experiment. In this investigation, attempt has been made to establish Glomus fasciculatum with the root system of W. somnifera and to analyze the effectiveness of this mycorrhiza on plant growth and absorption of nutrients from the soil. The establishment of the fungus within the root in the form of vesicle was observed. Formation of vesicles within the root indicated the affinity of the fungus with the plant. It was noted that mycorrhizal treatment showed better vegetative growth including root in comparison to non-mycorrhizal treatment, particularly when VAM soil was applied twice. Significant increase in root, height of the plant, number of branches and number of leaves over non-treated plants were found. Observation also showed the increase of fresh weight and dry weight of stem, leaf and root. Glomus fasciculatum also enhanced the levels of phosphorus in different parts of treated plants. But nitrogen levels were higher in different parts of the plant when VAM soil applied once. This result indicates that Glomus fasciculatum has an effective role as biofertilizer on Withania somnifera. 13. Reaction of Oncomelania hupensis to the Allelopathic Cardiac Glycosides of Nerium indicum Wan-Xian Wang 1, Yi Yang 1, Wan-Peng Tang2, Qi-Xiang Sun3, Xu-Dong Zhang3, Xin-Yi Hu2, Wen Chen1, Hui-Dong

Jiang 1, Wei-Lin Yun1, Jun Wu1 1Institute of Biology and Science, Hubei University, Wuhan 430062 2Hubei Provincial Academy of Forestry, Wuhan 430079 3Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091 Email: [email protected] Cardiac glycosides from the fresh leaves of Nerium indicum were used in experiments. The fresh leaves were cleaned and smashed by grinder, immersed in 70-80% ethanol (10 times the weight of fresh leaves) at 70° C for 12 h, drew, filtrated and solvent removed under vacuum. The concentrate was dissolved in water extracted with ether, added of saturated solution of lead acetate, and filtrated. The filtrate was passed through with the H2S, filtrated and the settlement crystallized. After qualitative analysis by chromatography, mass spectrum, NMR, etc., crystallizations gave mainly Oleandrin, Neriantin, Adynerin, Deacetyloeandrin. They are called total glycosides of N. indicum. From 118.2 g fresh leaves, 0.9815 g of cardiac glycosides were obtained. The mortality of Oncomelania hupensis treated with 20 mg/L cardiac glycosides for 3-4 d was similar to that treated with 1 mg/L niclosamidum for 2-3 d. The LD50 and LD90 values for the cardiac glycosides were 4.05 mg/L and 22.25 mg/L, respectively. The treated samples displayed higher activities of EST isozyme in early stage, and lower that in middle stage and late stage and lesser the glycogen content (ranged from 9.9 % to 32.6 %) than control,

however, the protein contents were not affected. This paper analyzed the molluscicidal activity of cardiac glucosides and elucidated the mechanisms underlying the allelopathic effects of the cardiac glucosides on morphological pathology, metabolisms of sugar and protein of O. hupensis. We have obtained chemiecological evidence that N. indicum is capable of killing O. hupensis and plant molluscacide can control O. hupensis. We have published several papers about the molluscicidal activities of plants. The activity of N. indicum extracts were stronger than other plants, while the activity of the cardiac glycosides of N. indicum were lower than synthetic molluscicides, plant moluscicides are much safer to human beings and environment. 14. Rice Alelopathy for Control of Phytophathogenic Fungi Rukhsana Bajwa, Arshad Javaid Institute of Mycology and Plant Pathology, University of the Punjab, Quaid-e-Azam Campus Lahore, Pakistan Email: [email protected] The study was designed to evaluate the in vitro antifungal activity of aqueous, methanol and n-hexane shoot extracts of 0, 1, 3 and 5% of three rice varieties viz. Basmati-385, Basmati-386 and Basmati Super against two phytopathogenic fungi viz. Ascochyta rabiei (Pass.) Lab. and Macrophomina phaseolina (Tassi) G. Goid. Aqueous and n-hexane extracts of the three test varieties significantly suppressed the in vitro growth of M. phaseolina resulting 21–52 % and 18–60% reduction in growth of M. phaseolina due to aqueous and n-hexane extracts of different rice varieties, respectively. Effect of ethanol extracts on this phytopathogenic fungus was insignificant. A. rabiei was found to be less susceptible to employed extracts as compared to M. phaseolina. Only 1% aqueous extracts of Basmati 385 and Basmati 386, and 3% that of Bamati Super significantly inhibited the growth of this fungus while all other extracts either exhibited insignificant effect or stimulated the fungal growth. 15. Allelopathic Compound Production Influences Fungal Endophyte Community Assembly and Establishment of a Seed-borne Primary Colonizer in Maize. Megane Saunders, Anthony E. Glenn, Linda M. Kohn Dept. of Ecology and Evolutionary Biology, University of Toronto, 3359 Mississauga Road, Mississauga, ON, Canada L5L 1C6 Email: [email protected] Maize was used to assess the influence of three biotic factors on fungal endophyte community assembly: production of host allelopathic compounds, proximity of a host to a neighboring plant producing allelopathic compounds, and presence of a primary colonizer tolerant to these compounds. Maize has been selectively bred to produce high concentrations of benzoxazinoids (BXs), some byproducts of which are toxic to fungi, bacteria, arthropods and plants. To determine the influence of BX production on endophyte communities, fields were planted with maize genotypes differing in their ability to produce


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BXs. Fungal endophyte community members were identified and tested for tolerance to a toxic BX-byproduct, 2-benzoxazolinone (BOA). Species diversity and distribution of BOA tolerance levels in communities was determined. In seedling roots and mature leaves, the community proportion with low tolerance to BOA was significantly greater in BX non-producers (BX-) than in producers (BX+). Mean abundance of Fusarium species, including agents of animal toxicosis and corn diseases, was up to 35 times higher in mature leaves of BX+ than in BX- plants. Next, we compared communities from BX- plants that were either planted in plots with two BX+ genotypes, or in a BX- monoculture. Mean endophyte abundance and species diversity were greater in monoculture than in triculture. Finally, the effect of a seed-borne endophyte on communities was investigated. Fields were planted with BX+ and BX- genotypes that were sterilized or inoculated with Fusarium verticillioides, a maize endophyte able to detoxify BOA. Results indicate that F. verticillioides facilitates colonization by closely related species in BX+, but not BX- plants. Collectively, results suggest that increased colonization of maize by Fusarium may be an outcome of selective breeding for BX production. Production of BXs, spatial proximity of BX- hosts to BX+ plants, and presence of F. verticillioides as a primary colonizer in seed significantly altered endophyte community assembly. 16. Evaluation of Allelopathic and Nematodicide Effect of Capparis spinosa L. on Germination and Early Growth of Cucumber (Cucumis sativus L.) under Laboratory Conditions Mohammad Rafieiolhossaini1, 2, Hamid Sodaeizadeh1, 3 and Patrick Van Damme1 1 Laboratory of Tropical and Subtropical Agronomy and Ethnobotany, Coupure links 653, B-9000 Gent, Belgium 2

Department of Agronomy, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran 3 Faculty of Natural Resource and Desert Study, Yazd University, Yazd, Iran Email: [email protected] In recent years, there has been an increasing focus on exploiting allelopathy not only for weed management, but also for pest control. Capparis spinosa L. (Capparaceae) is a common perennial shrub in the Mediterranean regions, growing both wild and cultivated, with medicinal and aromatic properties. It has been documented that this plant has allelopathic and nematodicide effects. The aim of the present investigation was to evaluate the allelopathic and nematodicidal effects of C. spinosa on Cucumis sativus L. as a test plant. Five g of powder of shade-dried material was soaked in a flask containing 100 ml distilled water for 24 hours. The extract was diluted with sterile water to yield desirable concentrations. Treatments consisted of 5 concentrations of aqueous extract of C. spinosa (5 – 10 – 25 – 50 – 100% (w/v)) and distilled water as a control in combination with 2 parts of C. spinosa plant materials (above-ground and under-ground) replicated thrice in a completely randomized design. Based on the results of this experiment, the aqueous extract concentration for eavaluation the nematodicide effect was modified to 5 – 10 – 25 percent. Results indicate that an aqueous extract of C. spinosa especially at 50 and 100 percent concentration has strong

allelopathic effect on germination and growth of cucumber. Between the evaluated traits, plant materials had only significant effect on germination percentage. With Regard to nematodicidal effect, results indicate that the 10 percent aqueous extract concentration and above can kill about 100 percent of the parasitoide nematodes. On the other hand, for all of the concentrations, the allelopathic and nematodicidal effects of above-ground parts displayed stronger suppression than under-ground part. We can conclude that C. spinosa and more especifically its above-ground parts of it has allelopathic and nematodicidal effects on cucumber at laboratory conditions whereas the effect was concentration-dependent.

17. Effect of the Fungal Endophyte Epichloë festucae on the Allelopathic Potential of Festuca rubra Grass María Romo, Balbino García-Criado, Antonia García-Ciudad, Beatriz R. Vázquez de Aldana Instituto de Recursos Naturales y Agrobiología – Consejo Superior de Investigaciones Científicas (IRNASA-CSIC), P.O. Box 257, 37071 Salamanca, Spain Email: [email protected] In Mediterranean grasslands from the ‘dehesa’ ecosystem (Spain), a 70% of Festuca rubra plants are systemically and asymptomatically infected by the fungal endophyte Epichloë festucae. Endophyte-infected grasses are characterized by increased resistance to herbivores and abiotic stresses, as compared to non-infected grasses. The objective of this work was to determine whether allelopathic potential of Festuca rubra is affected by the presence of the fungal endophyte Epichloë festucae. For this purpose, experiments in Petri dishes were carried out to evaluate the effect of extracts from infected (E+) and non-infected (E-) Festuca rubra plants on the germination and seedling growth of several legume species: Trifolium pratense, T. repens, T. subterraneum, Anthyllis vulneraria and Lotus corniculatus. Leaf and root plant tissues were used to prepare aqueous extracts. All extracts inhibited radicle growth over control and extracts of leaves caused more inhibition than root extracts. The effects of root extracts of E+ plants on the radicle growth of T. repens and T. pratense were more pronounced than extracts of E- plants. Thus, the percentage of radicle inhibition (over control) of T. repens was 45% with E+ and 29% with E- root extracts, and that of T. pratense was 50% with E+ and 0% with E- extracts. The effect in Anthyllis vulneraria was the opposite and root extracts of E- plants inhibited radicle growth in a greater extent than E+ extracts. The effect of the endophyte in T. subterraneum and Lotus corniculatus was not significant. The effect of F. rubra extracts on germination was lower. Only concentrate leaf extract decreased percentage of germination over control, and it was independent of fungus. We found a greater content of total phenolics in extracts of roots of E+ plants than in those of E- plants. These results suggest that fungal endophyte can affect allelopathic potential of F. rubra plants.

18. Characterization of Fusarium verticillioides Genes Necessary for Benzoxazolinone Biotransformation


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Anthony E. Glenn, Charles W. Bacon USDA, ARS, Russell Research Center, Toxicology & Mycotoxin Research Unit, 950 College Station Road, Athens, GA 30604, USA Email: [email protected] Maize produces the benzoxazinones DIMBOA and DIBOA, which naturally transform into the more stable benzoxazolinones MBOA and BOA, respectively. These weed-suppressive allelopathic compounds are also implicated in resistance to microbial diseases and insect feeding. Fusarium verticillioides, the most common fungal pathogen associated with maize, has the physiological capacity to detoxify MBOA and BOA. The biotransformation pathway is suggested to involve hydrolysis of BOA (encoded by the FDB1 locus) to produce 2-aminophenol (2-AP), which is subsequently acylated (encoded by the FDB2 locus) to produce N-(2-hydroxyphenyl) malonamic acid (HPMA). Fungal growth is inhibited on BOA-amended medium if either gene is mutated. An fdb2 mutant can produce low levels of an acetylated 2-AP branch metabolite, N-(2-hydroxyphenyl) acetamide (HPAA). In order to molecularly characterize genes involved in biotransformation, suppression subtractive hybridization was used to identify genes up-regulated in response to BOA. Two gene clusters were identified that functionally correspond to the FDB1 and FDB2 loci. Genes at both loci are being evaluated. At the FDB2 locus a putative N-acetyltransferase (NAT) was of particular interest due to the postulated role of the FDB2 locus. This gene was subcloned from an identified cosmid that complemented an fdb2 mutant. The subcloned gene also complemented an fdb2 mutation. Deletion of the gene eliminated the ability of F. verticillioides to metabolize BOA, and the mutants did not grow. We therefore functionally associate FDB2 as the gene encoding this putative NAT activity. The branch metabolite HPAA was produced at low concentrations in ∆fdb2 mutants suggesting acetylation of the intermediate 2-aminophenol occurred independently from the putative N-acyltransferase activity of FDB2, which is proposed to involve malonylation of 2-aminophenol. Thus, we have provided further evidence for the genetics and biochemical nature of benzoxazolinone biotransformation, a metabolic process that may enhance the ecological fitness of F. verticillioides in the maize field environment. 19. Bacillus mojavensis Transforms BOA into Fungitoxic APO in the Presence of Fusarium verticillioides Charles W. Bacon1, Dorothy M. Hinton1, Anthony E. Glenn1, Francisco A. Macias2, and D. Marin2 1USDA, ARS, Toxicology and Mycotoxin Research Unit, Athens, Georgia 30604, USA 2Department of Organic Chemistry, University of Cadiz, Cadiz, Spain Email: [email protected] Benzoxazolin-2(3H)-one (BOA) is an important transformation product of cyclic hydroxamic acids of maize. This natural product has the potential of providing resistance to maize from Fusarium verticillioides, a major pathogen of maize. However, it has been demonstrated that this maize pathogen and others are capable of detoxifying the benzoxazolinones, producing less toxic N-(2-hydroxyphenyl)

malonamic acid (HPMA) and 2-acetamidophenol via the intermediate 2-aminophenol (AP). A potential biocontrol bacterium for this pathogen on maize is Bacillus mojavensis, an endophytic species that confers growth enhancements and disease protection. Since, the benzoxazolinones are known to be toxic to both Gram negative and positive bacteria, an in vitro study of the effects of BOA on this endophytic species was examined. The study illustrated a curious interaction of BOA and its decomposition products in the presence of the bacterium and F. verticillioides. The results showed that apparently the bacterium is tolerant to BOA, and that there was an increased production of a red pigment on BOA amended media when wild type and specific genetic crosses of F. verticillioides were co-cultured with this bacterium. The red pigment was identified as 2-amino-3H-phenoxazin-3-one (APO), which is a highly toxic and stable product of AP. The results indicate that the bacterium directly or indirectly interacts with the fungus preventing it from transforming BOA to the non-toxic HPMA, resulting in an accumulation of APO, which is very toxic to F. verticillioides and other organisms, but nontoxic to B. mojavensis. Thus, an enhanced biocontrol is suggested from this in vitro study. 20. Allelopathic Actions of Camptotheca acuminata Decne. Against Pest Spodoptera exigua Hubner Hongyun Jiang Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 110094, China Email: [email protected] There are chemical interactions mediated by plant secondary metabolites between plant and pests, which act as plant chemical defense on pests in agro-ecosystems. Clarification of the chemical interactions and compounds can develop new strategy for pest management. Camptotheca acuminata Decne may produce the several compounds to impact on economically destructive pest Spodoptera exigua Hubner. In this study, the effects of various extracts from C. acuminata against S. exigua were investigated. As a result, ethyl alcohol, chloroform and aqueous extracts from C. acuminata seeds showed strong effects of anti-growth and breed-inhibition on the new-hatching larvae of S. exigua. Particularly, the development stage for larvae was delayed 1.16 days by ethyl alcohol extracts. Furthermore, pupal weight of S. exigua was obviously reduced by the extracts of C. acuminate seeds. Similarly, the adult longevity was shortened by the extracts. Female adult longevity of S. exigua decreased 3.4, 5.3 and 4.6 days while 2.8, 4.6 and 3.6 days for male adult longevity, respectively. There are significant differences in average egg production per day by S. exigua among three extracts, but their ranges were relatively wide. The average overall egg production was only 364.5 grain for those female adults that feed on ethyl alcohol extract, 411.7 grain for chloroform extract and 648.5 for aqueous extract. The results suggested that C. acuminate seeds contained active compounds against S. exigua.


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21. Peroxidase and Polyphenol Oxidase as Bioindicators of Grain Aphid Adaptations towards Walnut Phenolics Grzegorz Chrzanowski, Bogumil Leszczynski, Henryk Matok, Katarzyna Milewska Department of Biochemistry and Molecular Biology, University of Podlasie 12 B. Prusa St., 08-110 Siedlce, Poland Email: [email protected] Peroxidase (PX) and polyphenol oxidase (PPO) play an important role in metabolism of plant phenolics by herbivorous insects. Both enzymes protect herbivores from the phenolic compounds and convert them into less toxic metabolites. The aim of this paper was to investigate effect of the phenolic extracts from walnut (Juglans regia L.) on activity of the polyphenol oxidase and peroxidase within tissues of the grain aphid (Sitobion avenae F.). Extraction of the phenolics from walnut leaves and green-brown shells was carried out with 80% methanol and the crude extracts were diluted with distilled water to obtain 4% methanol solutions. The bioassays were performed by spraying the grain aphid populations reared on winter wheat seedlings with the 4% methanol solutions of the crude walnut extracts or 4% methanol solution in case of the control aphids. Aphids from treated and control populations were collected after 24, 48 and 168h and activity of the peroxidase and polyphenol oxidase within their tissues was examined. The walnut extracts reduced activity of the polyphenol oxidase within the grain aphid tissues with exception of insects sprayed with the walnut leaf extract that were collected 24h after treatment. Higher reduction in activity of the PPO was observed when the grain aphids were treated with extracts from the green-brown shells. Activity of the aphid peroxidise showed a great variation and was clearly modified under the walnut extract treatments. Obtained results suggest that the walnut phenolics possess an allelopathic activity towards the grain aphid and might be useful as a natural allelochemicals in biocontrol of the aphid pest. 22. Studies on the Allelopathy of the Triterpene Sapogenin from Nerium indicum to Oncomelania hupensis Wan-Xian Wang1, Yi Yang1, Wan-Peng Tang2, Qi-Xiang Sun3, Xu-Dong Zhang3, Xin-Yi Hu2, Wen Chen1, Hui-Dong

Jiang 1, Wei-Lin Yun1, Jun Wu1 1Institute of Biology and Science, Hubei University, Wuhan 430062 2Hubei Provincial Academy of Forestry, Wuhan 430079 3Research Institute of Forestry, Chinese Academy of Forestry, Beijing 10009 Email: [email protected] This paper has analyzed the reaction of Oncomelania hupensis to molluscicidal activity of the sapogenins from Nerium indicum. Five concentrations of the triterpene sapogenins from N. indicum were used to treat O. hupensis, and treatments of O. hupensis with niclosamidum and dechlorided water were set as control. The result of probit analysis showed that the LD50 of triterpenoid saponins from N. indicum were 78.31, 30.26, 20.50, 14.19 mg/L, respectively. The result of variance analysis showed that the concentration and the time of treatment as well as their

interaction had significant effect on the mortality of O. hupensis. The result of scanning electron microscope proved that the samples of O. hupensis treated by 40mg/L of the concentrations lixivium of the triterpene sapogenins from N. indicum could cause apparent damage to the soft tissues. The changes in liver and intestines structure were observed under transmission electron microscope: After treated for 24h, the nuclear was swollen up, nucleolus decomposed, nucleoplasm reduced; rough endoplasmic reticulum (rER) was destroyed and vesiculated, mitochomdrias in it were more than that in normal liver cell, and the microvilli arrange of intestines was out of order. After treated for 48h, the damage was more severe than ever; rER became many small saccules; some of nucleus and mitochondrias ruptured, the microvilli arrange deteriorate, lots of vacuoles could be seen, some nucleolus was dissociated, and cell organ in cytoplast had vacuole of different sizes. The esterase (EST) isozyme electrophoresis in liver of O. hupensis was analyzed. The activity of enzyme was higher than control group after been treated for 24-48h, lowered and disappeared after 72h. We have obtained ultrastructure evidence in killing snails in the microscopic field for the morphologic pathology of O. hupensis caused by allelopathy. This result has provided the foundation for constructing plant community with strong allelopathy to kill O. hupensis.

23. Introducing Neotyphodium occultans in Australian Annual Ryegrass Populations K.A Kirkby1, Jim Pratley1, D.E Hume2, A. Seal1, Min An1, H. Wu3 1EH Graham Centre for Agricultural Innovation Charles Sturt University, Wagga Wagga, NSW, 2678 2Grasslands Research Centre, AgResearch, Palmerston North, New Zealand, 4442 3EH Graham Centre for Agricultural Innovation, NSW Department of Primary Industries, Wagga Wagga, NSW 2650 Email: [email protected] Annual ryegrass (Lolium rigidum Gaudin) is a major weed of economic importance in winter crops in southern Australia. Changes in farming practices have led to the development of herbicide resistant populations (Gill, 1996, Heap and Knight, 1982, Powles et al., 1997, Broster and Pratley, 2006). Authors (Moon et al., 2000) found annual ryegrass is infected with the cool season grass endophyte Neotyphodium occultans. Whilst there is an abundance of research on perennial ryegrass (Lolium perenne L.) and its symbiotic relationship with the endophyte Neotyphodium lolii, little is known about the relationship of annual ryegrass and N. occultans. During the course of my PhD the focus of research will be to address the following research questions:

• What is the effect of storing seed on endophyte viability?

• What is the incidence/frequency of N. occultans infection in annual ryegrass in Australia?

• What is the extent of genetic variation in both host and endophyte?


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• Is there a fitness benefit/penalty (competitive advantage) associated with this symbiotic relationship?

• What allelochemicals are exuded by annual ryegrass infected with N. occultans?

• Is there any link between herbicide resistance and endophyte infection?

24. Effect of Plant extracts on Grain Aphid (Sitobion avenae F.) Grzegorz Chrzanowski, Bogumil Leszczyński Department of Biochemistry and Molecular Biology, University of Podlasie 12 B. Prusa St., 08-110 Siedlce, Poland Email: [email protected] The grain aphid is known as serious pest of cereals across Europe. The rising costs of pesticides, environmental contamination and reduction of natural enemies caused a searching for natural biopesticides, e.g. plant phenolics. The aim of the conducted research was to examine an influence of several plant extracts containing phenolics on fecundity and development of the grain aphid. The active compounds were extracted from leaves of sour cherry (Cerasus vulgaris Mill.), black currant (Ribes nigrum L.) and walnut (Juglans regia L.) with 80% methanol. After purification with petroleum ether the phenolic fraction (a crude extract) was dissolved with distilled water to obtain 1% and 5% solutions. The grain aphid population was sprayed with the obtained solutions and control population was treated with 1% or 5% methanol. Effect of the studied plant extracts on the grain aphid growth and development was monitored daily. All examined extracts showed a negative influence on growth and development of the grain aphid population. They prolonged length of the prereproductive period (time from birth till maturity) about 2.5 – 4.5 days and decreased daily fecundity even about 2.5 larva’s per female. The value of intrinsic rate of natural increase (rm) of treated aphids was about 30% lower and net reproductive period significantly shorter in comparison to control aphids. Among the studied plants the walnut extract showed the strongest effect on the grain aphid growth and development. Obtained results suggest that the phenolic extracts of the studied plants might be used as a source of biopesticides highly active towards the grain aphid. 25. Induction of DIMBOA and Phenolic Acids by Arbuscular Mycorrhizal Fungus Glomus mosseae Confers Increased Corn Resistance to Rhizoctonia solani Ren Sen Zeng1,2, Man Cao2, Jing Hua Huang2 and Shi Ming Luo1,2 1Research Center for Chemical Ecology, 2Institute of Tropical and Sub-tropical Ecology, South China Agricultural University, Wushan, Guangzhou, 510642 P.R. China Email: rszeng @scau.edu.cn Arbuscular mycorrhizas are most important symbioses in terrestrial ecosystems and they enhance the plant defense against numerous soil-borne pathogenic fungi and nematodes. Two varieties Gaoyou 115 and Yuenong 9 of corn were used for mycorrhizal inoculation in this study. The disease resistance of corn to Rhizoctonia solani was greatly increased after inoculated with arbuscular mycorrhizal fungus (AMF)

Glomus mosseae. The disease incidence and disease index were reduced by 50-67.7% and 25-57.0%, respectively. HPLC analysis showed that AMF inoculation led to significant increase in 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) and p-hydroxycinnamic, caffeic and ferulic acids in corn leaves and roots. R. solani inoculation resulted in more accumulation of DIMBOA in corn after mycorrhization. Ten days after inoculation with R. solani DIMBOA concentrations in roots of Gaoyou 115 and Yuenong 9 pre-inoculated with AMF increased 3.0-fold and 2.4-fold compared with these of non-mycorrhizal control, respectively. DIMBOA inhibited mycelial growth in vitro by 18.5% and 69.4% at concentrations of 50 and 500 µg/mL, respectively. Ferulic, p-hydroxycinnamic and caffeic acids inhibited mycelial growth by 20.3%, 8.5% and 6.3% at 250 µg/mL, respectively. BX9 gene is one of the key genes in DIMBOA biosynthesis pathway. RT-PCR analysis showed that the transcripts of BX9 and other three defense related genes PR2a, PAL and AOS in leaves of maize significantly increased in response to mycorrhizal infection, especially when the plants were challenged by R. solani pathogen. These results indicate that allelochemicals induced by mycorrhizal infection play a vital role in mycorrhizal induced defense in host plants. 26. Effect of Bird Cherry Volatiles on Host Plant Selection by Bird Cherry-oat Aphid during Autumn Robert Krzyżanowski, Bogumił Leszczyński University of Podlasie, Department of Biochemistry and Molecular Biology, B. Prusa 12 St., 08-110 Siedlce, Poland Email: [email protected] Overwintering of the bird cherry-oat aphid, Rhopalosiphum padi /L./ in form of eggs takes place on bushes of bird cherry, Prunus padus /L./. Thus in the end of summer winged forms of the aphid migrate onto primary (winter) host plant. The phenomenon is well known, however not much information on chemical interactions between these organisms at this stage of season is available. The present paper reports on volatile allelochemicals that may attract the winged migrants to recolonize the primary host-plant. The autumn migration of the bird cherry-oat aphid was monitored in Aleksandria Park at Siedlce during September and October. The volatile compounds emitted by the bird cherry trees were trapped using the HS-SPME method. The samples were separated with help of gas chromatography combined with mass spectrometry (GC-MS). Volatile compounds were identified by their mass spectra and on base of their retention times confirmed with internal standards. Obtained results demonstrated that attraction of the bird cherry-oat aphid to its primary host during autumn was mostly conditioned by benzaldehyde. Moreover, at this period of growing season the bird cherry did not show any emission of the green leaf volatile compounds. Role of the volatiles in allelopathic interactions between the bird cherry and the bird cherry-oat aphid is discussed. 27. Allelopathy Impact of Two Resistant Tomato Rootstocks on the Population Dynamics and Diversity of Rhizosphere Free-living Nematodes Zhiping Cao Lifang Han


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College of Resources and Environmental Science, China Agricultural University, Beijing, China, 100094 Email: [email protected] In Shandong province, eastern China, root-knot nematode (Meloidogyne incognita, RKN) is a serious soil born disease in greenhouse for vegetable production. Two resistant tomato rootstocks, Energy F1 (L.esuclentum x L.esculentum and He-man F1 (L. lycopersicum x L. hirsutum), were selected to grafted with RKN-susceptible commercial scion FA189 as a biological approach to combat the RKN diseases, and the field experiment results showed that they are very efficient to reduce root-knot nematode infection and prevent tomato fruit yield loss. But what is their soil ecological impact? Will the resistant rootstocks influence the rhizosphere organisms? The objective of this study is to investigate the possible allelopathy effect of rootstocks to soil free-living nematodes. A 3-year filed experiment was designed with 3 treatments as following (1) FA189 (control); (2) FA189/Energy (Energy

grafted with susceptible scion FA189); (3) FA189/He-man (He-man grafted with susceptible scion FA189), a blank plot without any tomato planting was also included. Soil samples were collected twice a year in each three years, before planting (September 2005, 2006, 2007) and at harvest (March 2005, 2006, 2007) of tomato. Soil nematodes populations were classified into four trophic groups: bacterivores, fungivores, plant-parasites and omnivore-predators. Bacterivore nematodes were always the most abundant trophic group in the consecutive 3 years. Compared with blank control, the density of free-living nematode increased from 230 to 3556 individuals/100g dry soil, with low diversity and evenness and high dominance with tomato planting, and this trend is clearer with the increase of consecutive tomato planting times from 2005 to 2007. The nematode trophic diversities of Energy and He-man were 1.29 and 1.35 respectively, while of FA189 was 2.32.

Main Topic 2: Allelochemicals: Fate in soil and water 28. Transformation of Benzoxazinoids in Soil - Kinetics and Pathways Inge S. Fomsgaard, Per Kudsk, Solvejg K. Mathiassen Department of Integrated Pest Management, University of Aarhus, Forsøgsvej 1, DK-4200 Slagelse, Denmark Email: [email protected] Benzoxazinoids are allelochemicals found in plants (for instance wheat, maize, rye) of the monocotyledonous family Poaceae but their occurrence in some dicotyledonous species was also reported. The occurrence and allelopathic effects of benzoxazinoids have been studied for decades. The exploitation of the suppressive effects of benzoxazinoids on weeds and soil-borne diseases requires substantial knowledge of their transformation in soil to be able to evaluate both target and non-target effects. A substantial part of the EU-financed FATEALLCHEM project was dedicated to such studies. When young rye plants were incorporated into soil as a simulation of the use of rye as green mulch, LC-MS analysis of the soil revealed the appearance of 6-methoxybenzoxazolin-2-one (MBOA), 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA), 2-hydroxy-1,4-benzoxazin-3-one (HBOA), 2-hydroxy-7-methoxy-1,4-benzoxazin-3-one (HMBOA), benzoxazolin-2-one (BOA) and the benzoxazinoid derivate 2-amino-3H-phenoxazin-3-one (APO). The profiling of the benzoxazinoids in soil was dynamic and time dependent. The highest concentrations of most of the compounds were seen at day 1 after incorporation. A maximum concentration was reached at day 4 for a few of the compounds. Field studies are currently being undertaken, in which a total of 20 allelochemicals (phenolic acids, benzoxazinoids and their derivatives) are quantified continuously in soil after incorporation of rye. Preliminary results of these studies will be presented. In other experiments the pure compounds 6-methoxybenzoxazolin-2-one (MBOA) and benzoxazolin-2-one (BOA) and their synthesized isotopomers were incorporated into soil with the purpose of elucidating transformation kinetics and pathways. Half-lives

varied according to initial concentrations of the compounds. Transformation of BOA to APO was significantly faster than the transformation of MBOA to 2-amino-7-methoxy-3H-phenoxazin-3-one (AMPO). A complex pattern of further hydroxylated and acetylated transformation products was seen. Chemical characterization and quantification of allelochemicals and their transformation products in soil are thus necessary tools in the exploitation of allelopathic properties for suppressing weeds and soil-borne diseases. 29. Evaluation of the Effectiveness of Allelochemicals in Soils Syuntaro Hiradate, Kenji Ohse, Akihiro Furubayashi, Yoshiharu Fujii National Institute for Agro-Environmental Sciences (NIAES), 3-1-3 Kan-nondai, Tsukuba, Ibaraki 305-8604, Japan Email: [email protected] The authors have proposed the use of the terms “specific activity” and “total activity” for evaluating biological activity of a compound and a plant material, respectively. The specific activity is expressed as a concentration showing the half-maximum biological effect, which is EC50. The total activity is expressed by the following equation: (total activity) = (concentration of the biologically active compound in the plant material) / EC50 which means the number of times the biologically active compound is concentrated against the specific activity (EC50) in the plant material. An allelopathic potential of a plant material should be evaluated by the total activity, but many allelochemicals are assumed active in soil environments, where the concentration of the biologically active compound may be decreased by adsorption, transformation, biodegradation, etc. We evaluated the overall changes of the biological activity of several allelochemicals in soils (overall soil factor) by using a


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soil-based bioassay system, and an allelopathic potential in soil (total activity in soil) was evaluated by taking into account both the overall soil factor and the total activity in plant as follows: (total activity in soil) = (total activity in plant) × (overall soil factor) L-Mimosine shows a high total activity of 130 in Leucaena leucocephala but its total activity in soil is substantially decreased to < 3 in volcanic ash soil, alluvial soil, and calcareous soil because of the very low values of the overall soil factors (< 0.02). Similar trend was observed for L-DOPA and (+)-catechin. This result indicates that the allelopathic activity of these allelochemicals would be substantially reduced in these soils. On the other hand, the overall soil factors of juglone and coumarin were higher and in the range between 0.5 and 0.1. These parameters would be useful for evaluating allelopathic potential in various soil environments. 30. Behavior and Phytotoxic Activity of Allelochemical in Soil Katsuichiro Kobayashi Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 306-8572, Japan Email: [email protected] Allelopathy in soil is plant-plant interaction mediated by the chemical released from the donor plant into soil and the chemical reaches the receiver plant in various ways. The behavior of allelochemicals released from a donor plant is an important factor affecting the phytotoxic activity of the receiver plant in soil. In soil, the allelochemical is released by leaching from the foliage, exudation from the roots and decomposition of the dead residues of the donor plant. Consequently, the allelochemical is present in soil water, adsorbed on soil solids, desorbed from the solids, moved with water, and metabolized by chemical and biological processes. When an allelochemical is released into soil, its behavior is dominated by various soil factors such as soil moisture, soil texture, soil organic and inorganic matters as well as the organisms. In our various studies on phytotoxic activity of allelochemicals in soil, it was revealed that the concentration of allelochemical in soil water is a dominant factor directly determining its phytotoxic activity in soil and the concentration is controlled by the behavior of allelochemical such as adsorption, desorption and degradation in soil. It is suggested that the phytotoxic activity of allelochemicals in soil is a function of the complex interactions among the behavior of allelochemicals and the physiological and ecological properties of both donor and receiver plants. 31. Mineralization of Sorgoleone, an Allelochemical Produced by Sorgum, in Soil Anne Louise Gimsing1, Franck Dayan2, Jacob Bælum3, Carsten Suhr Jacobsen3

1Department of Natural Sciences, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark. 2United States Department of Agriculture, Natural Products Utilization Research Unit, P.O. Box 8048, University of Mississippi, Oxford 38677, USA 3Geological Survey of Denmark and Greenland, Department of Geochemistry, Ø. Voldgade 10, DK-1310 Copenhagen K,

Denmark Email: [email protected] Sorghum is known for its weed suppressive activity. It has been discovered that the basis of the weed suppressive activity is the compound sorgoleone found in sorghum root exudates. Sorgoleone (2-hydroxy-5-methoxy-3-[(8'Z,11'Z)-8',11',14'-pentadecatriene]-p-benzoquinone) is phytotoxic because it inhibits photosynthesis by blocking photosystem II electron transport in a way similar to herbicides such as s-triazines, phenyl urea and uracil. Several studies have confirmed that growing sorghum plants inhibits the growth of other plants. At present the biosynthetic pathway of sorgoleone, its mode of action and excretion by root hairs is known, but virtually no knowledge exists about sorgoleone’s behavior and fate in the soil environment. As sorgoleone is released into soil from the roots of sorghum, knowledge of its fate in soil will be of importance to understand and optimize the use of sorghum’s weed suppressive properties for weed management and for making a risk assessment for sorgoleone. Results from a study of the mineralization of sorgoleone will be presented. The experiments were performed with 14C-labeled sorgoleone labeled in three different ways. The labeled sorgoleone was produced by germinating sorghum seeds in the presence of the labeled precursors. These experiments showed that the methoxy group of sorgoleone is easily mineralized, whereas the pentadecatriene chain is very hard to mineralize, possibly because of sorption to soil. Both Danish and American soils were used in the experiments and it was shown that soils differ in their ability to mineralize sorgoleone. 32. The Fate and Impact on Microorganisms of Rice Allelochemicals in Paddy Soil C. H. Kong a, b, P. Wang a, X. H. Xu b

aInstitute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China b State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin 300071, China Email: [email protected] Allelopathic rice varieties can release allelochemicals into soil to inhibit neighboring weeds, but little is currently known about their fate and impact on microorganisms in paddy soil. This study showed that allelopathic rice PI312777 released much higher concentrations of 5,4′-dihydroxy-3′,5′-dimethoxy-7-O-β-glucopyranosylflavone than non-allelopathic rice Liaojing-9. Once released the flavone O-glycoside immediately hydrolyzed glucose with stimulation on soil bacteria and aglycone 5,7,4′-trihydroxy-3′,5′-dimethoxyflavone with inhibition on soil fungi. When quantitative 5,7,4′-trihydroxy-3′,5′-dimethoxyflavone was incubated into soil, the flavone gave a short half-life of 18.27±2.32 h (r2 0.94) and could easily be degraded into benzoic acid by soil interactions. Benzoic acid with a half-life of 29.99±2.19 h (r2 0.96) was more resistant toward degradation in paddy soil. The results implied that the flavone would be responsible for the dynamics of soil microorganisms during an early period of release, and any observed effect during a late period of release would very likely be due to its


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degradation products particularly benzoic acid rather than the flavone itself. Both the culturable microbial population and the entire microbial community structure of soil incubated with the flavone and benzoic acid were evaluated using the soil dilution plate method and phospholipid fatty acid (PLFA) analysis, respectively. It appeared from the results that the flavone could reduce microorganisms especially for fungi present in paddy soil, while benzoic acid could induce a higher response for soil microorganisms especially for bacteria. These results suggested that allelopathic rice varieties could modify soil microorganisms to their advantage through release of allelochemicals. The concentration and fate of discriminating allelochemicals between allelopathic and non-allelopathic varieties tested in rice soil would result in the different pattern of microbial population and community structure in the paddy ecosystem. 33. Presence that Belies the Persistence: A Perspective on Mediation of Allelopathy by Soils Nishanth Tharayil1 and P. C. Bhowmik2 1304 Long Hall, Entomology Soil & Plant Sciences, Clemson University, Clemson, SC 29634, USA 2Plant Soil & Insect Sciences, Univ. of Massachusetts Amherst, MA 01003, USA Email: [email protected] In spite of competent research efforts, the occurrence and significance of allelopathy at ecosystem levels is still highly debated, primarily due to the fact that the purported allelochemicals are rarely found at phytotoxic concentrations under field conditions. In most pant-plant interactions the medium of transportation of allelochemicals is soil, and soil matrix is capable of altering the bioavailability of allelochemicals by various processes including sorption, and chemical and microbial degradation. Since allelochemicals are secreted in quantities far smaller than needed to overwhelm the soil processes at the field level by moderating its bioavailability, the soil matrix becomes the governing factor in the allelochemical phytotoxicity. Consequently, the phytotoxicity predictions based on the plant tissue allelochemical concentration and release often have lower ecological significance. Since the allelochemicals are exuded in mixtures, we investigated the role of co-solutes in increasing persistence of allelochemicals in soil matrices through competitive sorption and preferential microbial degradation. In axenic environments, in equilibrated systems, the phenolic acids exhibited competition for sorption sites, displacing the more hydrophilic compounds to soil solution, and thus increasing their effective concentration. In the presence of ferulic acid, more than 90% of the initially added vanillic acid remained in the soil solution, as opposed to 10% in the absence of ferulic acid. We further investigated the role of phenolic acids, produced during the litter decomposition of Centaurea maculosa, in stabilizing its allelochemical catechin in a soil-microbial system. Compared to a single-solute system the persistence of individual allelochemicals significantly increased in a multi-solute system. Oxidation was primarily involved in the initial rapid degradation of allelochemicals as observed by the corresponding soil Fe and Mn reduction. In single-solute systems, catechin rapidly underwent polymerization to form procyanidin dimmer and tannins both in soil and bioassay medium, resulting in reduced persistence

and phytotoxicity. The presence of phenolic co-solutes resulted in a four times increased persistence of catechin in a sandy soil; however, this persistence was less significant in silt loam soil. This indicates catechin could persist in some soils under the right set of conditions. The results underline a need to have a shift in allelopathic research ‘from identification of phytotoxins in the plants to the elucidation of mechanisms of persistence of allelochemicals in soil matrices that facilitate the proposed phytotoxic effect’.

34. The Biodegradation and Sorption of Flavonoids in Soil Liz Shaw1, John Hooker2 1Department of Soil Science, the University of Reading, Whiteknights, P. O. Box 233, Reading, RG6 6DW, U.K. 2School of Applied Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand Email: [email protected] Flavonoids are a diverse family of secondary metabolites produced by higher plants. It is thought that flavonoid structures enter the soil and rhizosphere as a result of above-ground litter inputs, root exudation and root senescence. Once present in soil, it is thought that flavonoids play a multi-functional role in plant-microbe, plant-soil and plant-plant interactions. However, little is known about their fate and bioavailability in the soil system. Therefore, the aim of this research was to conduct experiments to estimate the bioavailability of flavonoids in soil through quantification of their sorption to soil constituents and to quantify flavonoid biodegradation potential when subject to the catabolic activities of the soil microbial community. Three flavonoids were chosen for study: naringenin, a flavanone central to the flavonoid biosynthetic pathway; formononetin, an isoflavanone produced almost exclusively by legumes and ononin the glucoside conjugate of formononetin. Construction of sorption isotherms and estimation of log(Koc) (the organic carbon-normalized partition coefficient) for comparison to compounds whose soil behavior is better known revealed that naringenin and formononetin had a log(Koc) similar to that of naphthalene (3.1-3.2), indicating a ‘moderate’ bioavailability. Indeed, tests indicated that both naringenin and formononetin (spiked at 50 µg g-1) were sufficiently bioavailable to allow rapid biodegradation in soil. The log (Koc) for ononin was lower (2.18) than that of naringenin and formononetin, suggesting less interaction with the soil solid phase and therefore potentially greater bioavailability and mobility. These results are discussed with reference to what is known regarding total and bioavailable concentrations of flavonoids experienced by microbes in soil. Information is currently lacking regarding the spatial influence of flavonoids in the rhizosphere; approaches which could be used to address this knowledge gap will be outlined. 35. Fate of Benzoxazinoids in Soil following Application of Rye (Secale cereale L.) as a Cover Crop and their Possible Link to Allelopathic Activity


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Clifford P. Rice1, John R. Teasdale1, Inga A. Zasada2, Krystyna Bialek-Kalinski1 USDA-ARS Sustainable Agricultural Systems Lab1 and Nematology Lab2, Beltsville, MD 20705, USA Email: [email protected] Few investigators have attempted to measure benzoxazinoids in field soils after the incorporation of a rye (Secale cereale L.) cover crop. Verifying the presence and availability of these secondary plant defense compounds in soil is important to linking their presence to observed allelopathic effects. An experiment was conducted to determine the allelopathic activity and persistence of rye after cover crop termination in 2006 and 2007 at two sites near Beltsville, MD. Rye in a late vegetative stage was killed by an application of paraquat and residue either shallowly incorporated or retained on the soil surface without tillage. This study was part of a larger study evaluating the effect of rye on weed emergence. The major goal of this study was to follow the persistence and fate of selected allelopathic compounds arising from the cover crop residues. The rye biomass was collected at cover crop termination to determine initial benzoxazinoid concentrations available for each treatment. Soil samples were collected at the initiation of the treatments and at approximately weekly intervals up to the time when allelopathic activity became minimal (about five weeks after cover crop termination). All samples were stored frozen for subsequent analysis with triple quadrupole LC/MS-MS to determine benzoxazinoid concentrations. Methods were tested for efficient extraction of the benzoxazinoids likely to occur in these samples. This was especially challenging with the soil samples, since effective spike recoveries did not appear to be a precise indicator of recoveries of some of the more tightly bound benzoxazinoids, especially DIBOA and BOA. The list of monitored compounds included glucose-DIBOA, DIBOA, HBOA, BOA, APO, AAPO, glucose-DIMBOA, DIMBOA, HMBOA, MBOA, and AMPO. Early results show that levels of DIBOA were higher when rye was incorporated into soil versus retained on the soil surface without tillage. 36. Chemical Interaction in Spear-grass (Imperata cylindrical L) Tran Dang Xuan, Tran Dang Khanh, Shinkichi Tawata

Department of Bioscience and Biotechnology, Faculty of Agriculture, University of the Ryukyus, Okinawa, 902-0213, Japan Email: [email protected] Spear-grass (Imperata cylindrical L) is an invasive species, distributed widely worldwide. This weed is causing trouble for agricultural production and plant ecosystems. Its strong and deep rhizome plays an important role in the weed’s invasion as well as results in much difficulty in spear-grass control, compared to other weeds. Our results showed that the rhizome of spear-grass contained numerous growth inhibitors, of which 29 compounds were identified for the first time, belonging to phenolic acids, phenols, lactones, fatty acids, and steroids. iso-Ferulic was the major compound in the rhizome of the weed, followed by trans-p-coumaric acid, and linoleic acid. Although many allelochemicals were detected in the roots, only 9 and 5 (major are phenolic acid and long chain fatty acid) compounds were found in the roots’ leachate and in

spear-grass soil, respectively. Contents of the plant growth inhibitors in the rhizome were 0.76-166.2 mg/g, whereas they were 0.01-0.07 mg/g in the leachate and 0.02-0.4 mg/g in the weed’s soil. The inhibitive strength against barnyardgrass growth was maximum for iso-eugenol (IC50=63.6 µg), followed by 2,4-bis-(1,1) dimethylethyl phenol (IC50=139.8 µg) and hydrocinnamic acid (IC50=207.7 µg). Stearic acid was the least inhibitive (IC50=6.2 mg), followed by ferulic acid (IC50=3.6 mg), linoleic acid (IC50=2.6 mg), palmitic acid (IC50=1.9 mg), and iso-ferulic (IC50=1.6 mg). Evidences from our study suggest that the detected chemicals from spear-grass are involved in the invasiveness of the weed in the plant ecosystem. 37. Impact of Allelopathic Rice Seedlings on Rhizospheric Microflora Functional Diversity and Soil Enzyme Activities Lin Rui-yu, Yu Cui-ping, Rong Hong, Xiao Qing-tie, Lin Wen-xiong Institute of Agro-ecology, School of Life Sciences, Fujian Agriculture & Forestry University, Fuzhou, PR China, 350002 Email: [email protected] Rice allelopathic potential is indirectly regulated by the microflora in the rhizosphere. Four rice cultivars with varied allelopathic activity, PI312777, IAC47, Iguape and Lemont, were used to investigate the functional diversities and soil enzyme activities in the seedling rhizospheres of rice by employing BIOLOG and enzyme activities analysis. The microbial flora in the rhizospheric soil of different rice cultivars was dominated by bacteria (58.4%~65.6%), followed by actinomycete (32.2%~39.4%) and fungi (2.2%~2.8%). BIOLOG analysis showed that the value of Average Well Color Development (AWCD) was always highest in the rhizospheric soil of the strongly allelopathic rice cv. PI312777 and lowest in the poorly allelopathic rice cv. Lemont. Three principal component factors in relation to carbon sources were identified, accounting for 70.1%, 11.3% and 7.0% of the variation respectively. Phenolic acids, carbohydrates, amino acids and amides were significantly related to the principal component 1, phenolic acids, carbohydrates and fatty acids to the principal component 2, and carbohydrates and hydroxylic acids to the principal component 3. Amino acids and amides were the two main carbon sources separating the 3 principal component factors. The analysis of soil enzyme activities showed that allelopathic rice suppressed the activities of dehydrogenase, peroxide, ployphenol oxidase, urease, and cellulose, while acid phosphatase, alkaline-phosphatase, ucrase, and catalase were enhanced in its rhizospheric soils. This will be beneficial to the accumulation of allelopathic substances, promote the soil carbon cycles and phosphorus cycles in the rhizosphere, implying that these changes might play a role in governing the rice allelopathic activity in the field. 38. Biomedicine: Degradation and Ecotoxicity of Artemisinin in soil Karina Knudsmark Jessing1, Nina Cedergreen2, John Jensen3, Hans Christian Bruun Hansen1


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1University of Copenhagen, Department of Natural Sciences, Thorvaldsensvej 40, 1870 Frederiksberg C, Denmark 2University of Copenhagen, Department of Agricultural Sciences, Højbakkegård Allé 13, 2630 Taastrup, Denmark 3University of Aarhus, National Environmental Research Institute, Vejlsøvej 25, 8600 Silkeborg, Denmark Email: [email protected] To commercially use the effect of an allelopathic compound in the field, knowledge of the active compounds’ degradation kinetics, leaching potential and effect toward both target and non-target organisms is pivotal. This is also the case when cultivating plants producing active compounds for medical purposes. Artemisia annua, wormwood, is a vigorous weedy annual and highly aromatic plant belonging to the Asteraceae family. A. annua is a widely dispersed invasive species and the plant has potential allelopathic properties. In addition A. annua is cropped on large scale in many countries for medicinal purposes, as the plant synthesizes and accumulates the secondary metabolite artemisinin. Artemisinin, a sesquiterpene lactone with an endoperoxide bridge is an efficient drug against drug-resistant strains of the malaria parasite. Also, artemisinin has documented phytotoxicity as well as toxicity toward insects. It has therefore been proposed as a “green pesticide”. To gain knowledge on the fate of artemisinin in the field, the degradation kinetics of artemisinin and its effects on seedling emergence and growth of salad, duckweed and algae and effect on soil living organisms have been studied. Degradation experiments showed a two-phase exponential decay with half lives of 4.2 and 0.9 days in sandy and loamy soil, respectively, and complete disappearance after 43 and 63 days. Artemisinin did not affect seedling emergence but EC50 for salad, Latuca sativa L., growth was 2.48 mg/kg. EC50 for earthworm, Eisenia fetida, avoidance was 21.6 mg/kg whereas springtails, Folsomia candida, were not significantly affected, <50 mg/kg. The measured water solubility was 49.7 mg/l and medium mobility of artemisinin in soil was indicated as Koc was estimated to 324 kg/l. In water artemisinin gave an EC50 of 0.19 mg/l for duckweed, Lemna minor, and of 0.24 mg/l for the algae, Pseudokirchneriella subcapitata. These values are comparable to the effects of commercial pesticides. 39. Allelopathic Effect of Continuously Cropped? Soils under the Chinese Medicinal Plant Achyranthes bidentata Blume and its Molecular Mechanism ZhenfangLi1,2, Zhongyi Zhang1,3, Jun Xiong1,2,Hui Chen1,2, Wenxiong Lin1,2

1Key Laboratory of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University (FAFU), C/O Ministry of Education China 2Institute of Agroecology C/O School of Life Sciences, FAFU, Fuzhou 350002, China 3Institute of Chinese Medicinal Plants, Henan Agricultural University, Zhengzhou, 450002, China Email: [email protected] Based on the investigation of a positive allelopathic effect of Achyranthes bidentata Blume in a continuous cropping system in the Henan province, an experiment was conducted to study the promotion of continuously cropped soils under Achyranthes bidentata Blume.

The allelochemicals in the rhizospheric soil sampled from the field of continuously cropped A. bidentata Blume plants were extracted by water and organic solvent. The results from the bioassay in Petri dishes showed that the promotion effect of the extracts on the growth of Lactuca sativa was significant, implying that the allelochemicals especially from the water extracts might contain plant activators to promote the growth of L. sativa. To further understand the mechanism of the growth promotion by the extracts, subtractive hybridization suppression (SSH) was used to investigate gene expression profiles of A. bidentata Blume treated with the extracts. Ten up-regulated genes from the SSH-cDNA library were sequenced and assigned. According to the function category, the identified genes were related to the elementary metabolism, flavonoids and phytosterol synthesis.The results indicated that flavonoids and phytosterol might play an important role in the promotion of continuously cropped A. bidentata Blume. Proteomics were employed to confirm the molecular mechanism of growth promotion by the extracts. The result showed that 25 proteins changed in the expression abundances in the treated plants compared with control, of which 15 were up-regulated and 10 down-regulated. Based on the functions of the identified proteins, the results confirmed that the extracts from continuously cropped soils under the Chinese medicinal plant A.bidentata Blume activated the genes encoding the key enzyme involved in terpenes and flavonoids synthesis, in turn leading to promoted growth of A. bidentata Blume. 40. Allelopathic Potential of Barnyardgrass (Echinochloa crus-galli)-infested Soil Extract and its Phytotoxic Compounds Tran Dang Khanh, Tran Dang Xuan, Sinshichi Tawata

Department of Bioscience and Biotechnology, Faculty of Agriculture, University of the Ryukyu, Okinawa 902-0213, Japan Email: [email protected] Barnyardgrass is one of the most competitive annual grasses, has been ranked as the world’s worst rice weed and causes problems in at least 61 countries and in 36 different food crops. The objectives of this experiment were to examine the allelopathic potential of barnyardgrass-infested soil extract and identify its phytotoxic compounds by GC-MS. In a bioassay, an aqueous extract exhibited strong inhibition on the growth of its major competitive species, germination of monochoria was inhibited most. The IC50 values of the other tested crops were 1.71-2.77 mg ml-1; of these, inhibition of carrot and radish was shown to be greater than rice and lettuce. Germination of rice growth was also significantly reduced by 1.96, 0.45 and 1.01 mg ml-1 for shoot and root length of rice. However, the barnyardgrass-infested soil extract exhibited less phytotoxic action against non-competitive species such as lettuce, radish and carrot, and showed least influence on the growth of barnyardgrass itself. In general, the emergence of all indicator plants was stunted, but the growth of rice and monochoria showed most influence. Eighteen compounds, which are potentially involved in the phytotoxic activity of


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barnyardgrass released in paddy soil, were identified by GC-MS; most of them belong to the terpenoids, the derivatives of cinnamic acid and ferulic acid, and long-chain fatty acids. Four compounds were quantified and tested for their herbicidal activity on the growth of radish. Linalool, methyl phenethyl ketone and methyl ester cinnamic acid revealed inhibition from 14.0 to 36.2%, respectively, whereas 4-tepineol and coumaran exhibited promotion to the growth of radish by 20.1 to 31.7%. Følgende kan jeg ikke få til at give meningThe obtained data noted that barnyardgrass contains strong phytotoxic substances which can be released into paddy soil to compete with rice and other paddy weeds in its vicinity by chemical pathways. 41. Fate of Toxic Potato Glycoalkaloids in a Potato Field Pia H. Jensen1,2, Ole S. Jacobsen1, Rasmus B. Pedersen2, Bjarne W. Strobel2, Hans Christian B. Hansen2 1Geological Survey of Denmark and Greenland (GEUS), Department of Geochemistry, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark 2University of Copenhagen, Department of Natural Sciences, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark Email: [email protected] The glycoalkaloids α-solanine and α-chaconine are plant toxins produced in all parts of the potato plant. The compounds are believed to be a part of the plant defensive system, and they are known to be toxic toward fungi, insects, snails, and humans. The glycoalkaloids may be released to the terrestrial environment due to leaching from the plant parts and due to release from plant debris left on the soil after harvest. In this study, we investigated the load of glycoalkaloids from potato plants to the field during the growth season and the fate of the glycoalkaloids in soil. Soil and plant samples were collected in the field during the growth season and were analyzed for glycoalkaloids and metabolites. There was a potentially high load of glycoalkaloids in the soil; the highest content in the plants was found in July (~25 kg ha-1), while it declined during the autumn (~800 g ha-1). A substantial amount was still detected in the plant debris on the soil surface in September-October. The highest concentrations in the soil samples were found in September and October, where preliminary results showed a total glycoalkaloid concentration of up to 1.5 kg/ha. In January detectable amounts were still found. In general, the concentrations varied widely between the individual samples, showing the distribution of glycoalkaloids in the soil to be rather heterogeneous. Laboratory incubation studies at 15ºC showed a dissipation time (DT50) of about 2 days, while 5% of the added glycoalkaloids were still present in the soil after 42 days. Only a limited effect of whether the degradation was taking place in top- or subsoil was observed. As the glycoalkaloids were shown to be present in the soil for a long period of time, a possible effect toward soil microorganisms may last for several months.

42. Content and Distribution of the Carcinogen Ptaquiloside in Soil and Groundwater Pia H. Jensen 1 2, Ole S. Jacobsen1, René K. Juhler1, Anne Louise Gimsing2, Hans Christian B. Hansen2

1 Geological Survey of Denmark and Greenland (GEUS), Department of Geochemistry, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark 2 University of Copenhagen, Department of Natural Sciences, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark Email: [email protected] The invasive and cosmopolitan plant, bracken fern (Pteridium aquilinum (L.) Kuhn) produces a number of toxic compounds. The carcinogenic norsesquiterpene glucoside ptaquiloside (PTA) is one of these natural toxins. Bracken fern contains PTA in all plant parts, and the concentration varies with the season. Also, the content varies widely between locations. Part of the produced PTA is transferred to soil, where the mobility may be high due to little sorption. In this work, the seasonal variation of the content of PTA and the transformation product pterosin B (PTB) in soil and groundwater was investigated. Soil, groundwater, and plant samples were collected from three Danish bracken-covered field locations during a growth season. Soil samples were taken from the litter layer and from the two subsequent soil layers. Groundwater samples were sampled from the uppermost groundwater. All plant, soil and groundwater samples were analyzed for PTA and PTB by HPLC-UV or a newly developed LC-MS/MS method. The highest amount of PTA in the plants was found in the period June-September (up to 160-630 mg/m2 or 700-2200 mg/kg dry weight), whereas almost no PTA was present after withering in November-December. In the soil samples PTA as well as PTB were present in almost all samples during the whole season. Concentrations up to 3.2 mg PTA/kg dry soil and 8.5 mg/kg PTB dry soil were found. Preliminary analyses of the groundwater samples showed both compounds to be present in some samples (up to approx 0.2-0.5 µg/L). Exact concentrations are to be determined. The presence of PTA and PTB in as well soil samples as in some of the groundwater samples indicates a serious risk of groundwater contamination. In comparison, the maximum tolerable concentration of PTA in drinking water was estimated to 0.5-0.16 ng/L 43. Allelopathic Activity of Camphor Tree (Cinnamomum camphora Sieb) Leaf Powder Yumi Okamoto, Keiko Yamaji, Katsuichiro Kobayashi Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan Email: [email protected] The allelopathic activity of Camphor tree (Cinnamomum camphora Sieb.) leaf powder on the growth of rice (Oryza sativa L.) seedlings was investigated. The growth of rice seedlings, as a test plant, was inhibited in the soil incorporated with Camphor tree leaf powder. Growth reduction of rice seedlings was also found in the sea sand applied with soil water separated from the soil previously incorporated with the leaf powder. The results suggested that the phytotoxic activity of Camphor tree leaf powder incorporated into soil depends on the concentration of some compound(s) in soil-water. The growth of rice seedlings in sea sand culture was inhibited by the leaf


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powder placed in a small glass vial in a large glass bottle tightly sealed. It is suggested that the volatile compound(s) in the leaf shows the phytotoxic activity. Camphor tree leaf extract was analyzed by GC-MS and camphor was identified as a phytotoxic compound. These results suggested that the

allelopathic activity of Camphor tree leaf is induced by two different absorption ways: the receiver plants directly absorb camphor from the air through its stomata and camphor and/or the other phytotoxic compound(s) in soil-water released from Camphor tree into soil.

Main Topic 3: Allelochemical Identification and localization 44. Developing New Herbicides from Gramineae Allelochemicals Francisco A. Macías, Elena Arroyo, Nuria Chinchilla, Rosa M. Varela, Jose M.G. Molinillo Dept. of Organic Chemistry, Faculty of Sciences, University of Cadiz, c/ República Saharaui s/n, 11.510 Puerto Real, Spain Email: [email protected] DIMBOA and DIBOA have been described as important allelochemicals from Gramineae. Several bioactivities have been described and evaluated for these compounds and their degradation products, especially APO. 2-Deoxy derivatives of benzoxazinones have been proposed as useful candidates for natural herbicide models development. A second generation of chemicals, which include structural modifications to enhance their phytotoxicity and selectivity, have been synthesized and tested on rice, the Standard Target Species (Lepidium sativum L., Lycopersicon esculentum Mill., Allium cepa L., and Triticum aestivum L.) and common weeds (Lollium rigidum, Avena fatua and Echinochloa crus-galli). Quantitative structure-activity relationship studies (QSAR) constitute the key for a systematic analysis of structure and bioactivity properties. QSAR methodology was extensively employed for drug discovery, and its applications on new agrochemicals’ design are starting to rise. The barriers that a crop protection agent must cross to reach its molecular target site may vary. Systemic transportation would be favored by a higher aqueous solubility, but some lipophilicity will be necessary to cross cell membranes and to reach the target site of action. We have studied the structural requirements for this activity, and some molecular properties that can be related with the results were obtained. These modifications include the introduction of halogenated substituents that modify the electronic properties and the introduction of side-chains to regulate their lipophilicity. Results showed that higher activities were found in those compounds halogenated at C-6, whereas halogenation at C-8 enhanced selectivity. Following the same methodology, preliminary studies are being performed using APO as a model for the development of new herbicides. D-DIBOA degradation experiments were performed in wheat crop soil. The results permitted to estimate its half-life in this environment, being longer than that for the natural allelochemical DIBOA, which is too short. This could be an advantage for its use as herbicide. 45. Momilactone A and B as Rice Allelochemicals Hisashi Kato-Noguchi Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan Email: [email protected]

Momilactone A and B were first isolated from rice (Oryza sativa) husks as growth inhibitors involved in seed dormancy, and later confirmed in rice plants as phytoalexins. Recently, both momilactones were found in rice root exudates as potent rice allelochemicals. Momilactone A and B, respectively, inhibited the growth of Echinochloa crus-galli, E. colonum and Arabidopsis thaliana at concentrations greater than 10 and 1 mM. However, momilactone A and B inhibited the growth of rice seedlings at concentrations greater than 100 and 300 mM, respectively. The effectiveness of momilactone A and B on the growth inhibition of rice seedlings were 1% of those on the growth inhibition of E. crus-galli, E. colonum and A. thaliana, suggesting that the toxicities of momilactone A and B to rice seedlings are probably much less than to E. crus-galli, E. colonum and A. thaliana. When A. thaliana seedlings were incubated in medium containing 10 µM of momilactone A and B, endogenous concentrations of momilactone A and B in A. thaliana were 14.8 and 11.6 pmol plant-1, respectively. It was confirmed that A. thaliana itself did not produce momilactone A and B. Therefore, very small amounts of momilactone A and B were absorbed by A. thaliana and induced growth inhibitory effects on A. thaliana, which suggests that momilactone A and B may be involved in the early events of growth inhibiting process in A. thaliana. In addition, novel proteins were found in momilactone A- and B- treated A. thaliana seedlings by SDS-polyacrylamide gel electrophoresis. Rice plants were grown hydroponically and concentrations of momilactone A and B in the culture solutions were determined. The concentrations of momilactone A and B in the culture solution increased rapidly from day 30 until day 80 when flowering started, and then decreased, which indicates the secretion of momilactone A and B by rice plants occur throughout the life cycle. These results suggest that rice plants may be able to inhibit the growth of their neighboring plants due to the secretion of momilactone A and B into their rhizosphere without serious toxicity to the source rice plants. Thus, momilactone A and B may play an important role in rice defense mechanism in the rhizosphere for competition with invading root systems of neighboring plants. 46. Biological Activity of Phytotoxins Isolated from Fungal Pathogens of Cirsium arvense and Sonchus arvensis Alexander Berestetskiy1, Andrey Dmitriev1, Galina Mitina1, Oleg Yuzikhin1, Alessio Cimmino2, Anna Andolfi2, Antonio Evidente2 1All-Russian Institute of Plant Protection, Russian Academy of Agricultural Sciences, Pushkin, Saint-Petersburg, 196608 Russia;


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2Dipartimento di Scienze del Suolo, della Pianta, dell’Ambiente e delle Produzioni Animali, Università di Napoli Federico II, Portici, Italy Email: [email protected] The perennial Asteraceae weeds Cirsium arvense (L.) Scop. and Sonchus arvensis L. infest different crops worldwide in regions of temperate climate. A number of fungal pathogens of these weeds were identified and proposed as potential biocontrol agents. Some of these fungi can also be sources of phytotoxins, metabolites with herbicidal properties, which could be used as templates for the development of novel agrochemicals against weeds. Two species, Stagonospora cirsii Davis and Phoma exigua Desm. var. exigua, were found to be common pathogens of both weeds and were used for the isolation and characterizations of phytotoxic compounds. New nonenolides named stagonolide and stagonolides B-F were recently isolated from the culture filtrate and the solid culture of S. cirsii, respectively. Stagonolide was found to be the most potent phytotoxin. A number of well-known and new phytotoxic cytochalasins together with p-hydroxybenzaldehyde were isolated from the liquid and solid cultures of two strains of P. exigua var. exigua. Several phytotoxic nonenolides and cytochalasins from different phytopathogenic fungi were used for structure-activity relationship study. Stagonolide was shown to be the most toxic to C. arvense leaves, whereas deoxaphomin was highly active against S. arvensis. The effect of selected cytochalasins and nonenolides on light absorption and membrane permeability of leaf tissues of C. arvense was studied. It was hypothesized that stagonolide acted on C. arvense leaves in different way than known photosynthesis inhibitors and the cytochalasins. At present, Alternaria spp. infecting both perennial weeds is targeted for the isolation phytotoxic compounds. Zinniol was identified first in the culture filtrate of A. cirsinoxiae Simmons et Mortensen; its activity on leaves of C. arvense was demonstrated. Isolation and characterization of other phytotoxins are in progress. Research was supported in part by European Commission (FP 6, contract NFOOD-CT-2003-001687) and International Science and Technology Center (Project N2939). 47. Bioactivity-guided Chemical Isolation of Secondary Metabolites from Plants that Interact and Inhibit Photosynthesis Blas Lotina-Hennsen, Maria Isabel Aguilar, Beatriz King-Díaz C. P 04510 Universidad Nacional Autónoma de México, Facultad de Química, Ciudad Universitaria, México D. F., México Email: [email protected] The photosynthetic machinery of chloroplasts is a preferred target for allelochemicals. Interruption of the electron transport chain in photosynthesis is detected by polarography and chlorophyll a fluorescence induction curves. Secondary metabolites that transform the regular O-J-I-P sequence into an O-J curve have similar site of inhibition as those of the phenylurea type herbicides. Secondary metabolites like sorgoleone, tricolorin A, trachyloban-19-oic acid, flindersine and N-methyl-flindersine behave like Diuron, blocking the electron transfer at QB site. N-methyl-flindersine has another site of inhibition located at PQH2 oxidation. Odoratol,

Annonaceous acetogenins such as squamocin, bullatacin and motrillin, and bis-tetrahydrofuran affect the J-I phase of fluorescence in a similar way as Tris does, indicating that the inhibition site of these compounds is at the water-splitting enzyme. Air-dried leaves of Croton ciliatoglanduliferus were ground and extracted at room temperature with n-hexane. The solvent was evaporated in vacuo to give a crude extract that inhibited ATP synthesis (I50 = 42 ppm). The n-hexane extract was fractionated by column chromatography, then by thin-layer chromatography. Two compounds were isolated and characterized as the flavonoids retusin (5-hydroxy-3,7,3´,4´-tetramethoxyflavone) and pachypodol (5,4´-dihydroxy-3,7,3´-trimethoxyflavone). These compounds were separated by repeated preparative thin-layer chromatography runs (hexane:ethyl acetate, 80:20 v/v); their structures were confirmed by comparison of physical (melting point) and spectroscopic (UV, 1HNMR, 13CNMR, HMQC, HMBC, NOESY) properties with those reported in the literature. Pachypodol was the most active inhibitor of ATP synthesis. Its inhibition site was located at OEC level. Bioactivity-guided fractionation of the dried stems of Croton ciliatoglanduliferus led to the isolation of labdanes [labdane-8a,15-diol (1) and its acetyl derivative (2)]. The inhibition site for 1 was located at OEC level, and for 2, at OEC and at P680 in PSII, and at the span of P700 to FX in PSI. (Acknowledgements to DGAPA-UNAM for the financial support on the project PAPIIT IN205806)

48. Potential Allelopathic Interferences in Mediterranean Macchia Antonio Fiorentino, Assunta Esposito, Brigida D’Abrosca, Angelina Izzo, Pietro Monaco Dipartimento di Scienze della Vita, Second University of Naples, via Vivaldi 43, 81100 Caserta, Italy Email: [email protected] Plant performance can be influenced by several factors (e.g. environmental conditions, disturbance type, plant species interference) specially when these are rigorous, complex and specialized. Therefore the complexity and the variability of an ecosystem can be understood as the result of intra- and inter-specific interactions among species and between species and their environment. It is known that Mediterranean macchia ecosystems are characterized by high level of spatial variability and structural complexity, depending mainly on its environmental conditions and disturbance history. As a consequence it is hypothesized that Mediterranean plant species have evolved and activated allelopathic mechanisms as life strategies to survive in this environment. In order to investigate the potential allelopathic interferences among plant species of the Mediterranean area, we carried out work on herbaceous and shrub plant communities of “Castel Volturno” Nature Reserve, a flat coastal area north of Naples (Southern Italy). Several approaches were utilized: field sampling vegetation, phytochemical study of selected species, bioassays, phytotoxicity of decomposed plant material, analysis of allelochemical in soil samples. In particular, analysis of allelochemicals was performed on selected


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species such as Carex distachya, Melilotus neapolitana, Lobularia maritima, Arbutus unedo, Teucrium chamaedrys. Plant metabolites were isolated, purified by HPLC, and identified by spectroscopic methods. Results showed that each plant species is characterized by specific bioactive metabolites belonging to different classes of natural products. These compounds were present in high quantities both in the leaves and roots, are released in the environment by decomposition processes, and are persistent in the soil even after a year from the release. The metabolites were tested on coexisting species showing a species-specific inhibiting or stimulating response, suggesting a probable competitive co-evolution phenomenon. 49. Why Orobanche cumana is a Specific Parasite of Sunflower: Some Chemical Clues Francisco A. Macías, María D. García-Díaz, Pablo Sánchez-Gómez, Juan C. G. Galindo Cadiz Allelopathy Group, Dept. of Organic Chemistry, Faculty of Sciencies, University of Cadiz, c/ República Saharui s/n, Apdo. 40, 11520 – Puerto Real, Cádiz, Spain Email: [email protected] Parasitic plants have a very specific tight relationship with their hosts. The chemical relationship between host and parasite is complex and not fully understood as yet. However, one thing is known: the parasitic seeds need a specific chemical exuded by their hosts to induce germination. The seeds recognize the chemical as a signal that there is a host in the vicinity. Detection of the chemical cue triggers seed germination. Among the natural chemical inducers isolated from host and non-host plants the bisnorsesquiterpenes called strigolactones are the ones most often reported. These compounds induce germination of parasitic seeds of the genera Striga (witchweeds) and Orobanche (broomrapes). Orobanche cumana parasitizes sunflower; however, no seed germination inducer has been isolated from Helianthus spp. so far. Sunflower is a rich source of sesquiterpenes, and sesquiterpene lactones (SLs) constitute an important part of the plant’s chemical pool. Whether these compounds are exuded into the environment is a question that remains to be addressed. We have previously shown that SLs have the capacity to induce germination of Orobanche cumana seeds but not other Orobanche species. SLs have also been previously reported to induce germination of Striga asiatica and Striga hermonthica. Here we present results on structure-activity relantionship (SAR) studies and a QSAR study that addresses the question of host specificity of O. cumana. To investigate host specificity, we synthesized and tested as germination inducers a series of strigolactone-like guaianolides (which we named guaianostrigolactones) that mimics the ABC-D enol-γ-lactone system typical of strigolactones. These compounds were tested on O. cumana and O. ramosa (tobacco broomrape) as model systems. Influence of lipophilicity on germination activity was also taken into consideration in the QSAR study. Results are explained in terms of the specificity of O. cumana towards sunflower. 50. Inhibitors of Acetylcholinesterase as Allelochemicals Rajendra Gupta

Department of Botany, University of Delhi, Delhi-110007, India Email: [email protected] One of the most important factors for the ecological success of weeds is the presence of chemicals that are (a) strong deterrents against herbivory and, (b) harmful to the growth of other plants. Several phytochemicals found in weeds affect animals by interfering in the working of the workhorse neurotransmitter acetylcholine. Interestingly, some of these phytochemicals that are toxic to animals’ acetylcholine system are also known allelochemicals. In recent years, there has been increasing realization that all the components of the neuronal acetylcholine system are also present in plants and that some phytochemicals that severely hit important enzymes in animals’ nerves may also target some crucial enzymes in plants. This work explores an interesting possibility that some weeds may utilize inhibitors of acetylcholine metabolism as a weapon against other plants to win ecological competition. Extracts of 45 weeds not only inhibited acetylcholinesterase in animals but also inhibited the same enzyme in crop plants, besides inhibiting germinating and seedling growth. Weeds that are invasive in India were found to have extremely high concentrations of anticholinesterases. Results from experiments with anticholinesterases from native and invasive species against native and introduced crop plant support the chemical weapon hypothesis, that the native species are adapted to chemicals present in each other but they are susceptible to chemicals in the introduced species. Levels of anticholinesterases in weeds may be used as a marker of aggressiveness and to predict potential invasiveness in a new environment. Anticholinesterases, physostigmine from Physostigma venenosum and its synthetic analogue neostigmine, were found to inhibit induction of gibberellic acid–induced α–amylase activity in germinating seeds of barley and wheat, thereby suggesting a crosstalk between gibberellins and acetylcholine systems in allelopathy. A tissue culture based study led to the confirmation of the involvement of acetylcholine system in allelopathy. 51. Cyanamide as a Natural Product Tsunashi Kamo, Syuntaro Hiradate, Yoshiharu Fujii National Institute for Agro-Environmental Sciences (NIAES), 3-1-3 Kan-nondai, Tsukuba, Ibaraki 305-8604, Japan Email: [email protected] Cyanamide is contained in hairy vetch (Vicia villosa subsp. varia), a potentially allelopathic crop which strongly inhibits the growth of weeds. Cyanamide has been considered to not occur in nature until it was isolated from this legume as a major plant growth inhibitory compound. This finding led us to confirm the natural occurrence of cyanamide, establish a useful method for its quantification, and survey its distribution in the plant kingdom. By feeding experiments to confirm that cyanamide is a natural product, [15N]nitrate and [15N]ammonium were used and were successfully incorporated into cyanamide molecules. We also established a stable isotope dilution gas chromatographic


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mass spectrometry (SID-GCMS) method in which [15N2]cyanamide was used as an internal standard. The leaves of 553 species of higher plants were analyzed by using the SID-GCMS method. Among the nine Vicia species tested, only V. villosa subsp. varia (449 mg/kg fresh wt.) and V. cracca (3526 mg/kg fresh wt.) contained detectable cyanamide. Although all the other species in the higher plants tested contained no detectable cyanamide (<1 mg/kg fresh wt.), a leguminous tree, Robinia pseudo-acacia (442 mg/kg fresh wt.), was a remarkable exception. These results indicate that the distribution of cyanamide in the plant kingdom was highly limited. To discuss the role of cyanamide in plants, the localization of cyanamide was investigated. In a seedling of V. villosa subsp. varia, more than 95% of cyanamide was contained in the leaves (629 mg/kg fresh wt.) and the stems (256 mg/kg fresh wt.), while the cyanamide concentration in the roots was lower than the detectable level (<20 mg/kg fresh wt.). The accumulation of the majority of cyanamide in the aerial parts suggests that this compound might function against herbivores and insects. 52. AllelopathicStudies on Teak (Tectona grandis): New Active Naphthoquinones Francisco A. Macías, José M. G. Molinillo, Rosa M. Varela, Rodney R. Lacret, Clara Nogueira, Carlos K. Z. Andrade Dept. of Organic Chemistry, Faculty of Sciences, University of Cadiz, c/ República Saharaui s/n, 11.510 Puerto Real, Spain Email: [email protected] The forest species Tectona grandis is of interest from chemical and biological point of view. This is based on its etnobotanical uses, the biological activity shown by its extracts, the success in agroforestry systems and the durability of its wood. The bioactive fractions of Tectona grandis have yielded seven apocarotenoids, two were isolated for the first time as natural products (tectoionol A and B), as well as 21 terpenes (4 sesquiterpenes, 8 diterpenes and 9 triterpenes). Of the terpenes, abeograndinoic acid has been isolated as natural product for the first time and presents a new skeleton. A biogenetic hypothesis for this compound is proposed. Together with these compounds, two new naphthoquinones (naphthotectone A and B) have been isolated, naphthotectone A being one of the most abundant in the extract. The general bioactivity of the compounds isolated was studied using the etiolated wheat coleoptiles bioassay. Those compounds that presented higher levels of activity were assayed on Standard Target Species (Lactuca sativa, Lycopersicum esculentum, Lepidium sativum and Allium cepa). The compound that showed higher phytotoxic activity was naphthotectone A, followed by the diterpenes 2-oxokovalenic acid and 19-hydroxyferruginol, and the bisnorsesquiterpene 3β,9-dihydroxy-7,8-dihydro-β-ionol. Naphthotectone A is the compound that showed the highest activity from those evaluated and its level of activity, as well as the quantity in which it is present in the plant, suggest that it contributes clearly to the allelopathic potential of Tectona grandis. These results allowed proposing this new quinone as model for subsequent structure-activity relationship studies for the possible development of natural product based herbicides. Additionally, we present studies on the synthesis of this compound and some analogues that will allow us to perform

QSAR studies and the enhancement and modulation of this activity. 53. Trichothecene Chemotype is thought to Play a Key Role in the Phytopathogenicity of Individual Fusarium Strains Takumi Nishiuchi Advanced Science Research Center, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa, Japan Email: [email protected] Phytopathogenic fungi such as Fusarium species synthesize the trichothecene family of phytotoxins. Trichothecenes are classified into four major groups based on their chemical structures. Type A (T-2 toxin, HT-2 toxin, and diacetoxyscirpenol [DAS]) and type B (nivalenol and deoxynivalenol [DON]) are often detected in certain agricultural commodities and commercial foods. These compounds are distinguishable by the absence or presence of a carbonyl group at the C8 position. Trichothecenes are thought to be a virulence factor allowing infection of plants by the producing Fusarium species. Trichothecenes inhibit protein synthesis in eukaryotic cells, therefore considered to be the suppressors of defense response in host plants. Effects of various trichothecenes on defense response were investigated in Fusarium-susceptible Arabidopsis thaliana (Nishiuchi et al., MPMI, 19: 512-520, 2006). Type A trichothecenes trigger cell death by activation of an elicitor-like signaling pathway in Arabidopsis. It is likely that type A trichothecene-induced cell death is contributing directly to the virulence of their-producing necrotrophic fungi. Although DON did not have such an activity even at 10 µM, translational inhibition by DON was observed at concentrations above 5 µM. These results suggested that Fusarium species utilize DON as a non-defense-inducing translational inhibitor during disease spread in host plants. Trichothecene-producing Fusarium species have strain-specific trichothecene metabolite profiles. It is thought that trichothecene chemotype play a role in the phytopathogenicity of individual Fusarium strains. Recently, the AtNFXL1 gene was reported as type A trichothecene-inducible gene (Masuda et al., JXB, 58: 1617-1626). The atnfxl1 mutant exhibited hypersensitivity phenotype to type A trichothecenes (Asano et al., Plant J., 53: 450-464). In contrast, such a phenotype was not observed in DON-treated atnfx1 mutant. Thus, the AtNFXL1 gene functions as a signaling component of the type A trichothecene-dependent response in Arabidopsis. 54. Physiological Activity of Allelochemicals from Germinating Plant Seeds: Recent Progress and Future Prospects Kosumi Yamada1, Katsutoshi Hirose2, Hideyuki Shigemori1, Koji Hasegawa1, 2 1Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan 2KNC Laboratories Co., Ltd., Hyogo 651-2271, Japan Email: [email protected] The term "allelopathy" has been defined as both detrimental and beneficial biochemical interactions among


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all classes of plants (including microorganisms) through the production of chemical compounds that are released into the environment. Previously, it was shown that the hypocotyl growth of cockscomb seedlings was significantly promoted when various plant species were cultured together with cockscomb seeds in a Petri dish. This phenomenon led to the finding of stimulatory allelopathy in which germinating plant seeds secrete growth-promoting substance(s) to their environment as allelopathic factors. Candidates for stimulatory allelopathic factors include lepidimoide and lepidimoic acid from the mucilage of germinating cress seeds (Hasegawa et al., 1992, Plant Physiol.), vanillic acid from the exudate of germinating watermelon seeds (Kushima et al., 1998, Plant Growth Regul.) and arctigenin and arctigenic acid from the exudate of germinating burdock seeds (Higashinakasu et al., 2005, Heterocycles). During the past decade, many significant advances concerning the biological activities of lepidimoide in several developmental stages of plants have been made and a convenient method for the synthesis of lepidimoide from okra (Hibiscus esculentus) mucilage has been developed. Lepidimoide promotes chlorophyll accumulation in sunflower and cucumber cotyledons by affecting the level of 5-aminolevulinic acid, leaf development, flowering and seed production in Arabidopsis thaliana as well as shoot growth in seedlings of various plant species, and inhibits the loss of total chlorophyll in oat leaf segments and the formation of abscission in bean petiole explants. On the basis of this information, lepidimoide appears to be a novel plant growth regulator with multiple physiological functions for the regulation of growth and development in plants. A summary of this work as well as the possible application of these allelochemicals in agriculture will be presented. 55. Allelochemicals Involved in Rice Allelopathy C. H. Kong1,2, X. H. Xu2 1Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China 2State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin 300071, China Email: [email protected] A few rice (Oryza sativa L.) varieties or rice straw can produce and release allelochemicals participating in its defense against paddy weeds. However, it remains obscure which allelochemicals are predominantly involved in rice allelopathy. In this presentation, more than 100 compounds were systematically isolated and identified from an allelopathic rice variety, PI312777. Among the compounds, alkaloids, alkylresorcinols, cyclohexenone, urea derivatives, flavonoids and their glucosides, diterpenoids and triterpenes had inhibitory activity on the growth of paddy weeds. However, the presence of these compounds in allelopathic rice plants does not necessarily mean that they can be released into the environment to fulfill their allelopathic effects under natural field conditions. Accordingly, allelochemicals released from selected rice seedlings or straw into soil were determined and analyzed by LC/MS and HPLC. Phenolic acids, flavonoids, diterpenoids, cyclohexenone and urea derivatives were found in the soil. Particularly, 3-isopropyl-5-acetoxy-cyclohexene-2-one-1, momilactone B and 5,7,4′-trihydroxy-3,5-dimethoxyflavone occurred in the soil at day 15 after rice seedling emergence, and reached the

concentration for initiation of inhibition of associated weeds at day 30 after seedling emergence. The other compounds were not detected, or were only in trace amounts in the soil. Results indicated that allelopathic rice seedlings can establish weed defense mechanism through the production and release of 3-isopropyl-5-acetoxycyclohexene-2-one-1, momilactone B and 5,7,4′-trihydroxy-3,5-dimethoxyflavone. However, either allelopathic or non-allelopathic rice straw released momilactone B and lignin-related phenolic acids (p-hydroxybenzoic, p-coumaric, ferulic, syringic and vanillic acids) into the soil during decomposition to inhibit successive plants. These results suggested that allelochemicals involved in rice allelopathy from living and dead plants are substantially different. 56. New Potential Allelochemical from Acacia leucophloea Willd. R. N. Yadava Natural Products Laboratory, Department of Chemistry, Dr. Hari Singh Gour University, Sagar (M.P.) 470 003, India Email: [email protected] Acacia leucophloea Willd. (Family Leguminosae), commonly known as “Safed Kikkar” in Hindi, is an ornamental tree found throughout India. It is an important dry season fodder and pasture tree. Its pods are eagerly eaten by goats, sheep and cattle. Its stems are used as dyes. Fiber from its inner bark is used to make fish nets and rough rope. Its bark cures inflammation, bronchitis, leprosy; is useful in biliousness, vomiting and burning sensation. Its leaves are used in the treatment of syphilis. The present paper deals with the isolation and structural elucidation of a new isoflavone glycoside [melting point 265-266°C, molecular formula C33H40O19, [M]+ 740 (FABMS)] from the methanolic extract of the defatted seeds of this plant. Its structure was characterized as 7,2'-dihydroxy-4',5'-dimethoxy-isoflavone-7-O-α-L-arabinopyranosyl(1→3)O-β-D-xylopyranosyl(1→4)O-β-D-glucopyranoside by various chemical degradations and spectral analysis. This new compound showed activity against various plant pathogenic bacteria and fungi. 57. Effect of Essential Oils on the Germination of Solanum nigrum and Physalis angulata Ilhan Uremis, Mehmet Arslan, Ahmet Uludag Plant Protection Department, Faculty of Agriculture, Aegean University, Bornova, Izmir 35100, Turkey Email: [email protected] Trends in agriculture, such as organic and sustainable agriculture, and caring attitude of human being on the environment and health require new methods to combat pests. Weeds are among the main pests which limit agricultural production and interfere with the environment. Solanum nigrum L. and Physalis angulata L. are important weeds in summer crops such as corn, cotton and soybean in Turkey. Studies with allelopathic chemicals to control weeds have been receiving more attention. In this study, the possible use of essential oils of Ocimum basilicum L., Salvia officinalis L., Thymus vulgaris L.,


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Lavandula angustifolia Mill., Satureja hortensis L., and Origanum majorana L. were researched to determine their effect on germination of S. nigrum and P. angulata. Oil extracted from all the species inhibited germination of both weeds, but the effective rate was significantly different. T. vulgaris and S. hortensis oil inhibited S. nigrum germination at the lowest rate applied, 2 ml per petri dish. O. basilicum at 8 ml, and L. angustifolia and O. majorana at 16 ml reached 90 % inhibition while S. officinalis inhibited less than 90 % at the highest application rate of 32 ml per petri dish. S. hortensis again was the most inhibitory species for P. angulata germination. Little inhibition was detected with S. officinalis treatments. Inhibition of over 90 % occurred for T. vulgaris at 8 ml, O. basilicum and O. majorana at 16 ml, and L. angustifolia at essential oil application of 32 ml per Petri dish. 58. Potential Allelopathic Interferences of Melilotus neapolitana Metabolites Assunta Esposito, D’Errico Elena, Severina Pacifico, Annunziata Golino, Maria Teresa Pascarella, Brigida D’Abroca, Antonio Fiorentino Dipartimento di Scienze della Vita, Second University of Naples, via Vivaldi 43, 81100 Caserta, Italy Email: [email protected] As part of our research to evaluate the allelopathic potential of Mediterranean plants, Melilotus neapolitana L., an annual stenomediterranean species that frequently occurs in the herbaceous plant community of the Mediterranean macchia was investigated. This vegetation type shows a characteristic spatial pattern with spotted areas as virtual monocultures mainly covered by Melilotus neapolitana and areas with small scale species richness and a co-dominance of grasses, forbs and other nitrogen fixing legumes. Analysis of M. neapolitana extracts led to the isolation of eleven secondary metabolites: the coumarin and their glycoside precursors cis- and trans-melilotoside, and dihydromelilotoside; seven flavone glycosides, as well as the β-sitosterol, a C13-norterpene glucoside and a polyphenol. All the structures were elucidated on the basis of their spectroscopic features. The organic extracts and all the pure compounds were assayed for their allelopathic activity on three coexisting species, Petrorhagia velutina (Guss.) Ball. et Heyw., Dactylis hispanica Roth., and Phleum subulatum (Savi) Asch. et Gr. Cluster analysis showed a clear structure-activity relationship as evidenced from four main groups of compounds with specific effect patterns. Coumarin, the most abundant compound both in the plant extracts and soil, was found to be highly phytotoxic on all the test species. As for the flavone glycosides, it was shown that aglycones play an important role due to their bioactivity. 59. Autotoxic Compounds from Fibrous Roots of Panax quinquefolium L. Weiwei Gao1, Chunnian He1, Jiaxue Yang1, Wu Bi1, Xuesong Zhang2, Yangjing Zhao1 1Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 151 Malianwa North Road, Haidian District, Beijing 100094, P. R. China 2Beijing Tianhui Ginseng Industrial CO., LTD, Beijing 101400, P. R. China

Email: [email protected] Panax quinquefolium (American ginseng) is a perennial understory herb that has been wildly used as a medicinal plant in China and other countries. Autotoxicity has been reported to be one of the major problems hindering the consecutive cultivation of American ginseng. Here, we reported the isolation and characterization of a group of autotoxic compounds from the aqueous extracts of the fibrous roots of American ginseng, and elucidated their allelopathic effect on American ginseng. Forty-four compounds were identified that can be sorted into 7 major chemical groups. Of these compounds, the existence of five compounds was further confirmed by column chromatography isolation followed by NMR and mass spectrometry analyses. To determine which compounds contributed to the autotoxicity, we examined the functional effect of 14 individual compounds found in the bioactive fraction. Results revealed that 9 phenolic compounds significantly reduced the growth of seedlings in a concentration-dependent manner while 5 aliphatic compounds showed modest inhibition at all three concentrations tested. Furthermore, we verified the existence of the autotoxic compounds in the plow layer soil of 3-year-old and 4-year-old American ginseng commercially cultivated fields, and the concentration of some compounds as determined by HPLC was inline with the concentration tested to be bioactive. Taken together, our study has established a functional link between the compounds produced by American Ginseng and their autotoxic effect. 60. Isolation and Identification of Allelopathic Substance in Cucumber Plants Hisashi Kato-Noguchi1, Ho Le Thi1, Teruya Toshiaki2, Suenaga Kiyotake2 1Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan; 2Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama 223-8522, Japan Email: [email protected] Cucumber (Cucumis sativus) is one of the important crop plants in the gourd family Cucurbitaceae and currently widely cultivated. After crop harvesting, however, cucumber plants are mostly dumped as waste at a huge expense. Manipulation of wastes is now becoming a serious environmental issue. Extract of cucumber plants after harvest have been reported to inhibit the germination and growth of Echinochloa crus-galli under laboratory and greenhouse conditions. These findings suggest that cucumber plants may have substances with allelopathic activity, and may be potentially useful for weed management in some agricultural field settings. However, the chemical basis for cucumber allelopathy is not fully understood. Thus, the allelopathic activity of cucumber plants was determined and a growth inhibitor causing the allelopathic effect was isolated and characterized. Aqueous methanol extracts of the cucumber plants inhibited the growth of roots and shoots of cress, lettuce, alfalfa, ryegrass, timothy, crabgrass, E. crus-galli (L.) and


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E. colonum, and increasing the extract concentration increased the inhibition. The aqueous methanol extract of cucumber plants was divided into ethyl acetate and aqueous fractions, and the growth inhibitory activity of ethyl acetate fraction was greater than that of aqueous fraction. Thus, ethyl acetate fraction was further purified and a main allelopathically active substance in the fraction was isolated and determined as (S)-2-benzoyloxy-3-phenyl-1-propanol by spectral data. This substance inhibited root and shoot growth of cress seedlings at concentrations greater than 10 mM, and the concentration required for 50% inhibition of root and shoot growth was 21 and 23 mM, respectively. These results suggest that (S)-2-benzoyloxy-3-phenyl-1-propanol may contribute to the growth inhibitory effect of cucumber plants and may play an important role in cucumber allelopathy. Thus, cucumber plants may be potentially useful for weed management in a field setting. 61. Biotechnological Production of Benzoxazinones Domingo Cantero1, Gema Cabrera1, Jose M. Gómez1, Antonio Valle 1, José M.G. Molinillo2, Francisco A. Macías2

1Dept. of Chemical Engineering; 2Organic Chemistry, Faculty of Sciences, University of Cadiz, c/ República Saharaui s/n, 11.510 Puerto Real, Spain Email: [email protected] Benzohydroxamic acids, such as DIBOA and DIMBOA, have demonstrated an important bioactivity as phytotoxic agent. The synthesis of 2-deoxy derivatives of this class of compounds has been developed in laboratory scale from different precursors in three steps. From commercial and economic point of view, substitution of the second step of the synthesis; i.e., the reduction of nitro group of the precursor, with a microorganism-mediated process is of interest. This work studied the viability of reduction of the nitro aromatic compound intermediate to the corresponding hydroxylamine derivative (D-DIBOA, benzohydroxamic acid) by the biological action of two different bacteria. Microorganisms were selected according to their capacity to reduce the nitro groups of trinitrotoluene (TNT) via hydroxylamine intermediates. Escherichia coli JM109 (ATCC 53323) and Pseudomonas aeruginosa (ATCC 700310) were chosen. Both bacteria were adapted to the corresponding culture medium and 30°C temperature, to facilitate a subsequent scale-up of the process. Experiments to determine tolerance of the two bacteria to solvents (dimethyl sulfoxide, methanol, water) and precursor concentration (0.1-0.4 mg/ml) were carried out. Notable changes were not seen in the kinetic growth of both bacteria. Analysis of metabolites by HPLC showed the disappearance of the precursor and the formation of hydroxylamine intermediate and others byproducts (amine compounds). The best results, hydroxylamine intermediate production, were obtained with E. coli. In order to improve the bioprocess it is necessary to increase the concentration of the nitroaromatic compound and optimize the operating conditions (such as culture medium, pH, temperature, fermentation time) of the reaction. 62. Allelopathic Activity of Root Extracts of Aristolochia esperanzae from Brazil’s Cerrado Ana Beatriz Gatti1, Sonia Cristina J. Gualtieri de A. Perez1, Rosa M. Varela2, José M. G. Molinillo2, Francisco A. Macías2

1P.O. Box 676, Dept. of Botany, Federal University of S. Carlos, CEP13565-905, S Carlos SP, Brazil 2Dept. of Organic Chemistry, Faculty of Sciences, University of Cadiz, c/ República Saharaui s/n, 11.510 Puerto Real, Spain Email: [email protected]

Aristolochia esperanzae is one of the most abundant pioneer species in the dense vegetation of São Paulo state, Brazil that presented allelopathic potential as determined in previous works. A. esperanzae roots were extracted two different methods. In method 1, 200g of root powder was extracted with 600mL each of hexane, dichloromethane, ethyl acetate, acetone and methanol. The extraction was carried out with ultrasound during one hour then the extracts were filtered with a vacuum pump and evaporated. Method 2 was a liquid - liquid extraction; 200 g of root powder was extracted with 300 mL distilled water, left in an ultrasound during one hour. The aqueous extract was filtered and fractionated with dichloromethane and ethyl acetate. The dichloromethane fraction obtained from method 1 extraction was subjected to chromatographic partition having silica gel as stationary phase. A mixture of hexane + acetate 20, 30, 40 and 60%; ethyl acetate 100%; ethyl acetate + acetone 20, 30; 40, 50%; and methanol were employed as mobile phases. This procedure produced 14 sub-fractions, obtained from combining fractions with similar thin layer chromatography profiles. The phytotoxic activity of fractions from method 1 extraction and Method 2 liquid - liquid extraction (dichloromethane, ethyl acetate and aqueous fractions) were investigated. Different bioassays were performed using seeds or wheat coleoptile. Germination and growth inhibition of the roots and aerial part of tomato, lettuce, cress and onion were recorded. The dichloromethane and ethyl acetate fractions from the two methods of extractions presented the highest inhibitory activity. In the wheat coleoptile bioassay, the dichloromethane fraction obtained from liquid - liquid extraction was the most toxic, and in general, was more toxic than Logran®, an herbicide with known activity.

63. Novel Preussomerins and Palmarumycins with Allelochemical Activity from the Topical Endophytic Fungus Edenia gomezpompae Martha L. Macías-Rubalcava1, Blanca E. Hernández-Bautista1, Manuel Jiménez-Estrada2, María C. González3, Anthony E. Glenn4, Richard T. Hanlin5, Simón Hernández-Ortega2, Aurora Saucedo-García1, Jordi M. Muria-González1, Claudio Meléndez-González1, Ana Luisa Anaya*1 1Laboratorio de Alelopatía, Departamento de Ecología Funcional, Instituto de Ecología; 2Instituto de Química; 3Instituto de Biología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, 04510, México, D.F.; 4USDA, ARS, Toxicology & Mycotoxin Research Unit, Russell Research Center, Athens, Georgia 30604, USA; 5University of Georgia, Museum of Natural History Annex, 4435 Atlanta Highway, Bogart, Georgia 30622, USA Email: [email protected]


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Bioassay-guided fractionation of the mycelial extract from E. gomezpompae, a newly discovered endophytic fungus isolated from the leaves of Callicarpa acuminata (Verbenaceae) collected from the ecological reserve El Eden, Quintana Roo, Mexico, resulted in the isolation of eight naphthoquinone spiroketals, including seven novel compounds and palmarumycin CP2. We elucidated the structures of the new metabolites by extensive NMR studies, including DEPT, COSY, NOESY, HSQC, HMBC, and chiroptical methods. The trivial names proposed for the new spiroketals are preussomerins EG1 (1), EG2 (2), EG3 (3) EG4 (4), and palmarumycins EG1 (5), EG2 (6), and EG3 (7). In addition, the X-ray data of 5, 6 and 8 were obtained. The bioactivity of the mycelial organic extracts and the pure compounds was tested against three endophytic fungi (Colletotrichum sp., Phomopsis sp., and Guignardia manguifera) also isolated from C. acuminata, and against four economically important phytopathogenic microorganisms (two fungoid oomycetes, Phythophtora capsici and P. parasitica, and the fungi Fusarium oxysporum and Alternaria solani). In general, the spiroketals displayed significant growth inhibition against all the phytopathogens. Preussomerin EG1 (1) showed the strongest bioactivity. The acetylated derivatives of 1, 1a and 1b, were obtained and their biological activity was tested on endophytes and phytopathogens. Preussomerins 1, 1a, and 1b exhibited significant bioactivity against all microorganisms tested with the exception of Alternaria solani. Study of relationship between plants and endophytic fungi constitutes a promising field to study chemical relationships among organisms living in intimate contact, and to discover novel secondary bioactive metabolites. 64. Potential Allelopathic Effects of Mediterranean Shrubs Metabolites on Coexisting Species and on Weed Seedling Growth Piera Uzzo, Angelina Izzo, Angela Natale, Marianna Letizia, Brigida D’Abrosca, Assunta Esposito, Antonio Fiorentino Dipartimento di Scienze della Vita, Second University of Naples, via Vivaldi 43, 81100 Caserta, Italy Email: [email protected] In the ecosystem, plants communicate with other organisms (animals or other plants) through characteristic chemical signals. In fact, they produce a great variety of chemical substances known as secondary metabolites. These natural products are specific for a species or genus, and are responsible for a wide range of biological activities. It is widely demonstrated that secondary metabolites interfere with the development of other organisms present in the same habitat. The interference also concerns other vegetal species and, in this case, the phenomenon is known as allelopathy. Many natural products from plants (allelochemicals) have been proven to have stimulating or inhibitory effects on the growth of other coexisting species. In the study of natural products’ allelopathic role we recently reported the potential allelopathic role of bioactive compounds isolated from plant species in the Mediterranean area. In this communication we report the chemical characterization and the bioactivity of secondary metabolites from several plants of the shrub community of the Mediterranean area. The metabolites were identified on the basis of their spectroscopic features, tested

for their effect on germination and seedling growth of three coexisting herbaceous species. The effects of these metabolites on weeds were also investigated. 65. Searching for Allelopathic Activity of Guazuma ulmifolia: Inhibition Effect on Photosynthesis Alonso Zavaleta-Fernandez de Cordova, Beatriz King-Diaz, Blas Lotina-Henssen C.P. 04510 Departamento de Bioquímica; Facultad de Química, Universidad Autónoma de México, México, D.F., México Email: [email protected] Guazuma ulmifolia is an arboreal plant native of the American continent. It has wide distribution and great adaptability, which may be due to its allelopathic property. We have been studying this plant for this activity. We tested in vitro the effect of the chloroform extract of the dry leaves on isolated spinach (Spinacia oleracea) chloroplasts. We found that the extract inhibited ATP synthesis (I50 = 17 ppm). In addition, the chloroform extract was sprayed on leaves of Trifolium alexandrinum (a dicot) seedlings and Echinocloa crus-galli (a monocot weed). After 24 hours, direct chlorophyll a (Chl a) fluorescence in photosystem II (PSII) was measured, and fluorescence transients were analyzed through the O-J-I-P test. T. alexandrinum and E.crus-galli plants showed alterations in several values; specifically the Photosynthetic Performance Indexes (calculated on absorption basis) were decreased by 40% and 80%, respectively. The PIABS performance index combines three parameters favorable to photosynthetic activity: (1) the density of reaction centers (expressed on absorption basis RC/ABS); (2) the quantum yield of primary photochemistry jPo =TRo/RC, and (3) the ability to feed electrons into the electron chain between PSII and PSI, designated as Y0. All data suggested the presence of allelochemicals in G. ulmifolia that affect chloroplasts PS II. In addition, the organic extract inhibited biomass accumulation of Trifolium alexandrinum by 35%. The allelochemical(s) will be isolated from the chloroform extract through bioactivity-guided fractionation. (The authors gratefully acknowledge the financial support from grants DGAPA-UNAM, IN 205806)

66. Characterization of Secondary Metabolites from Stereocaulon antarctica Collected from Caleta Cierva, Antarctica: A Pilot International Research Experience for Undergraduates (NSF REU) Adrianna Pavia1*, Ascensión Torres Martínez2, Juan Carlos García Galindo2, and Joanne G. Romagni1 1St. Edward's University, Dept. of Chemistry, Austin, TX 78704 USA 2University of Cadiz, Dept. of Organic Chemistry, Puerto Real, Spain Email: [email protected] The characterization of secondary metabolites from an Antarctic lichen species, Stereocaulon antarctica, was studied. Lichens are symbiotic relationship resulting from a partnership between a fungus and algae (or cyanobacteria). S. antarctica is unique to the Antarctic


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peninsula and the surrounding islands. It contains a cyanobacterial photobiont in addition to the mycobiont. The objective of this study was to extract, isolate and identify the secondary metabolites. Standard methods were used. Following Soxhlet extraction, fractions from the hexane and acetone extractions were used. Characterization of total proteins, lipids, carbohydrates, fatty acids and simple sugars were also done. We used 2 mg from each concentrated extraction to determine the biological activity of the lichen through in coleoptile bioassays. Preliminary results indicate high levels of bioactivity in the acetone fractions. NMR analysis has identified several compounds within this fraction. Future research includes analysis of the remaining three extractions through column chromatography as well as HPLC separations. Isolation and identification of the secondary metabolites in this lichen is necessary to better understand the allelopathy of this organism. Upon purification of the bioassay-directed fractions, elucidation of mechanism of action will be done for all bioactive compounds. 67. Resistance of Grafted Eggplants to Verticillium (Verticillium dahllae) Wilt and Identification of Allelochemicals from its Root Exudates Liu Na, Zhou Baoli, Li Yixiu, Hao Jing, Lu Bo College of Horticulture, Shenyang Agricultural University, Shenyang 110161, China Email: [email protected] Eggplant (Solanum melongena L.) is a popular vegetable worldwide. Eggplant Verticillium wilt is a soil-borne disease, which causes great reduction in eggplant yield annually due to continuous cropping. Rootstock replacement through grafting is considered the most effective method to prevent this disease. Specially, eggplants grafted with tomatoes as rootstocks have better resistance to Verticillium wilt than those grafted with wild eggplant. In this study, resistance of grafted eggplants to Verticillium (Verticillium dahllae) wilt and the allelochemicals in root exudates of eggplant grafted with tomatoes as rootstocks are presented. Results showed that disease incidence and disease index of grafted eggplants were markedly lower than those of non-grafted eggplants. Five days after artificial introduction of V. dahllae into the rhizosphere, the disease incidence and disease index of grafted eggplants were 0, but were 66.7% and 36.25%, respectively, for the non-grafted eggplants. Until 25 days after inoculation, disease incidence and disease index of grafted eggplants were only 9.53% and 2.5%, respectively; however, for the non-grafted eggplants these values sharply increased to 100% and 81.48%, respectively. Mycelium growth was inhibited by root exudates of grafted eggplants (RI value = -0.155). In contrast, root exudates of non-grafted eggplant enhanced mycelium growth (RI value = 0.090). GC-MS analysis revealed eleven chemical classes in the root exudates of grafted eggplants. The class and the relative contents of compounds in root

exudates of grafted eggplants were different from those of the non-grafted eggplants. Carbazoles, azulenes, amines, fluorene and indenol were detected only in the root exudates of grafted eggplants. The relative contents of hydrocarbon and ester were higher in the grafted as compared to non-grafted eggplants. Derivatives of benzene and indene were correspondingly lower. The enhanced disease resistance of tomato-grafted eggplant to Verticillium wilt may be due to the changes in classes and contents of allelochemicals. 68. Characterization of Secondary Metabolites from Cladina rangiferina collected from Caleta Cierva, Antarctica: a Pilot International Research Experience for Undergraduates (NSF REU) Alicia Jones1*, Ascensión Torres Martínez2, Juan Carlos García Galindo2, and Joanne G. Romagni1 1St. Edward's University, Dept. of Chemistry, Austin, TX 78704 USA 2University of Cadiz, Dept. of Organic Chemistry, Puerto Real, Spain Email: [email protected] When compared to many regions of the globe, the terrestrial biodiversity initially appears low in Antarctica. However, it is spatially complex and the changes, particularly on the Antarctic Peninsula, are happening much faster than on any other place on the globe. Most of the terrestrial flora is either moss or lichens. With the rapid climate changes occurring globally, we wish to monitor the effects of these changes on lichens with particular attention paid to their ecological chemistry. Cladina rangiferina is a global lichen species containing a green algal photobiont. Due to the unique enviornmental conditions, we expect to find distinctive metabolites produced. The objectives were to characterize, isolate and identify lichen secondary metabolites. Standard methods were conducted at the University of Cadiz in Spain, including Soxhelt extraction, TLC, column chromatography, HPLC and NMR. Separate 2 mg samples were prepared for coleoptile bioassays to determine bioactivity. The acetone extraction containing the majority of secondary metabolites was fractionated using column chromatography. Results indicated that one fraction contained several products. Characterization of the lichen also included total protein, total lipids, fatty acids, total carbohydrates and simple sugars. Future studies continue with the isolation and identification of other secondary metabolites from other fractions. Three extractions still need to be fractionated and the products further analyzed with the same techniques. Following identification of bioactive compounds, elucidation of mechanism of action will be done.

Main Topic 4: Allelopathy in forest ecosystems 69. Allelopathy by Empetrum Hermaphroditum in the Boreal Forest – A Summary of Research Conducted Marie-Charlotte Nilsson

Swedish University of Agricultural Sciences, Faculty of Forest Sciences, Department of Forest Ecology and Management, SE- 901 83 Umeå, Sweden. Email: [email protected]


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In the prolonged absence of fire in the boreal forest of Scandinavia, the clonal long-lived evergreen dwarf shrub Empetrum hermaphroditum commonly dominates the ground vegetation where it suppresses surrounding vegetation to form low productive sites. Several earlier experimental field- and glass house studies have shown that Empetrum inhibits tree seed germination and growth by both resource competition and allelopathy, and that increasing densities of Empetrum are frequently associated with lower levels of decomposer microbes and reduced forest tree stand productivity. In the longer term Empetrum is also affects belowground processes such as decomposition rates, soil microbial activity, availability of soil N, soil C sequestration and buildup of soil humus. This is likely to be the result of allelopathic rather than competitive effects of Empetrum as Empetrum produces high concentrations of dihydrostilbene Batatasin-III (3-methoxy-5,3'-dihydroxy-dihydrostilbene). This phenolic substance constitutes as much as up to 11% of the shrub’s leaf dry mass and is released from glandular trichomes on the green leaf surfaces when the leaves are in contact with rain, drizzle and snowmelt. Stable levels of Batatasin-III have been quantified in Empetrum throughfall, litter and soil humus suggesting that Batatasin-III does not easily undergo transformations in soil nor is completely degraded by soil microbes. The negative effects of Empetrum on tree seedlings are largely mitigated in field plots when activated carbon is added as an adsorbent of Batatasin-III in soil. Charcoal produced during wildfires, which operates as a form of activated carbon, may also minimize the effects of Batatasin-III on ecosystem processes. In vitro studies have shown that Batatasin-III inhibits both photosynthesis and ammonium uptake in birch seedlings, further supporting the hypothesis that Batatasin-III is involved in the chemical interference exerted by the shrub. The mechanisms by which Batatasin-III operates at the cellular level is not fully known, but Batatasin-III strongly inhibits proton pumping in isolated plant plasma membrane vesicles, suggesting that it disturbs membrane integrity and fundamental processes such as ion uptake in target plants. We have also shown in short-term studies that Batatasin-III is carried by runoff into streams and lakes during the snowmelt period and is a potential harzard to aquatic fauna (eg. brown trout and water fleas). As no apparent effects were shown when exposing brown trout alevins and seeds to simple phenols, our studies suggest a specific toxic component in the bibenzyl structure of Batatasin-III. 70. Kalmia – Conifer Interactions in Eastern Canada: From Allelopathy to Satellite Imagery Nelson Thiffault Direction de la recherche forestière, Ministère des Ressources naturelles et de la Faune du Québec, 2700 Einstein, Québec, QC, G1P 3W8, Canada Email: [email protected] In eastern Canada, the ericaceous shrub Kalmia angustifolia is recognized to rapidly invade fotest sites following harvesting or wildfire. On some sites, such invasion can induce ecosystem retrogression, as the species induces a “growth check” of naturally established or planted conifers. This shift from once productive forest stands to Kalmia heaths has important effects on forest productivity and biodiversity. The direct and indirect effects of ericaceous shrubs on conifers are

mainly related to severe competition for nutrients, allelopathic interactions, and the production of recalcitrant humus. However, our understanding of the interactions among Kalmia, conifers, and site ecological characteristics is not complete. We demonstrated how the extensive root system of Kalmia ensures that the species dominates the nutrient uptake processes. We also confirmed that the recalcitrant ericaceous humus has striking effects on soil temperature, reducing the energy absorbed by the rooting zone. However, Kalmia does not seem to directly influence soil temperature and moisture, or induce water stress to planted seedlings. In boreal Québec, we verified if slow-released fertilizers can alleviate the nutrient status of Kalmia sites. We measured increased early growth responses following fertilization, compared to unfertilized conditions. We also confirmed the efficacy of mechanical scarification to stimulate planted seedling growth. Site preparation favoured the establishment of early-succession species that were absent from control plots. We carried further research to explain the distribution and dynamics of ericaceous shrubs at various scales, from the site to the national level by using ecological data from forest inventories. We are developing cartographical tools based on satellite imagery to assess ericaceous heath expansion over time. We will use this new knowledge to elaborate succession models that take into account the ‘ericaceous effect’ on forest regeneration. Such models are essential to assess forest productivity. A better understanding of mechanisms of ericaceous interferences is needed to develop ecosystem-based silviculture. 71. Belowground Competition and Chemical Interference between Kalmia and Black Spruce Azim U. Mallik, Shekhar R. Biswas and Laura C. Siegwart Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada P7B 5E1 Email: [email protected] Empirical evidence suggests that ericaceous plants interfere with conifer germination, establishment and growth through competitive and allelopathic interactions. However, the relative roles of these processes are unclear. We tested the importance of course and fine root competition and root allelochemicals between a common ericaceous plant, Kalmia angustifolia and a widely distributed boreal conifer, black spruce (Picea mariana) in a replicated (n=9) greenhouse experiment with a 3 x 2 factorial design (N=72). Kalmia and black spruce seedlings were planted in pairs in rectangular (28 x 20 x 22 cm deep) plastic pots containing non-Kalmia mineral soil and 3:1 peat vermiculite mixture with the following treatments: i) removal of course root competition, by placing a 20µm wire mesh separating the rooting zone of the two species but allowing fine root penetration, ii) suppression of ericoid mycorrhiza, by applying 1 ppm benomyl fungicide while allowing coarse root competition, iii) combined effect of competition, allelopathy and ericoid mycorrhiza, by allowing roots of Kalmia and black spruce free to grow in each plants rooting zone, iv) removal of root exudation by treating half of the pots with activated charcoal while the rest


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received no charcoal and v) control established by planting pairs of only Kalmia and only black spruce seedlings in each plot with and without charcoal. Preliminary results after 6 months indicate that removal of coarse root competition in the absence of charcoal significantly increased black spruce height and diameter compared to the other treatments. There was no significant difference in height or diameter growth among species receiving benomyl application or treatment allowing root competition. However, charcoal treatment caused significantly greater relative height and diameter growth in Kalmia than black spruce with and without competition. Charcoal and benomyl treatment had significant interaction effect facilitating greater height and diameter increase in black spruce than Kalmia. These results suggest that Kalmia coarse root competition inhibits black spruce growth more than fine root competition and Kalmia root exudation, and that phenolics secreted from Kalmia roots may have autotoxic effect on Kalmia. 72. Allelopathic Influence of Imperata cylindria (L.) Beauv.) on Recruitment and Establishment of Understory Plants of Southeastern U.S. Forests Shibu Jose and E. Corrie Pieterson School of Forest Resources and Conservation, University of Florida, 351 Newins-Ziegler Hall, Gainesville, FL 32611. Email: [email protected] Recent literature has focused extensively on the potential role of allelochemicals for increased competitive ability of invasive plants. The “novel weapons hypothesis” hypothesizes that exotic plants may increase their likelihood of invasion success through allelochemicals and novel allelopathic agents in the soil. These allelopathic agents can either affect the invaded community plants directly or affect the soil biota to inhibit or cause harm to native plant growth and development. Plants in the invaded community, following this hypothesis, will be more vulnerable to allelochemicals because they will lack the co evolutionary relationship that existed between the exotic and the plants in the native range. Imperata cylindria, one of the most troublesome weed species in the world has been spreading in the U.S. Southeast at an alarming rate in the recent past. Changes in species diversity and productivity loss have been reported in infested forests. However, the underlying mechanisms of invasion success have not been explored completely. I. cylidrica has known allelopathic properties, which may add to its ability to outcompete other species. We tested the allelopathic effects of I. cylindrica on germination and growth of 10 common understory plants of the longleaf pine (Pinus palustris) ecosystem in the southeastern U.S. The understory of the longleaf pine ecosystem is considered having the highest species diversity outside the tropics. The plants tested included three functional groups; grasses, forbs and shrubs. The results indicated that allelopathy could be partially responsible for the reduction in species richness and diversity in infested stands. I. cylindrica poses a serious threat to the ecological sustainability of the longleaf pine understory communities. 73. Describing Phytotoxic Effects of Blackwood (Acacia melanoxylon L.) on Cumulative Germination M. Iftikhar Hussein, I. Gonzalez Rodriguez, and M. .J. Reigosa Roger

Laboratory of Plant Ecophysiology, Faculty of Biology, University of Vigo, Lagoas-Marcosende, 36200 Vigo, Spain Email: [email protected] Plants may favorably or adversely affect other plants through allelochemicals which may be released directly or indirectly into surrounding environment. Acacia melanoxylon L. is an invader in Galician forests with well-documented allelopathic tendencies that have generally been ascribed to its most abundant secondary metabolites present in flowers, leaves and other plant parts. Laboratory bioassays were conducted to test the herbicidal potential of aqueous extract of A. melanoxylon flowers and leaves on germination, seedling growth and radicle length of four test species (Rumex acetosa, Lolium perenne, Lactuca sativa and Dactylis glomerata). We compared four common germination indices (GT, S, AS, and CRG) calculated with same data in order to discuss their physiological meaning. Each index led to a different interpretation of allelochemicals effect on germination. All four indices of germination (GT, S, AS, CRG) are sensitive enough to establish the allelopathic activity. Inhibition of seed germination of test species showed a species-specific and dose-dependent response with highest inhibition occurring at concentration of 100% flowers and leaves aqueous extract. The L. perenne, L. sativa and D. glomerata seeds are most sensitive, whereas those of R. acetosa are least sensitive. The aqueous extract of A. melanoxylon flowers is more phytotoxic as compared to leaves even at lowest concentration (25%). The extracts were selective in their herbicidal activity and did not significantly affect germination in R. acetosa while A. melanoxylon flowers significantly inhibited radicle length of all target species at all concentration as compared to A. melanoxylon leaves and control. A. melanoxylon flowers and leaves significantly inhibited radicle length of D. glomerata at all concentration. The limitations of any index to adequately reflect the effect of allelochemicals on germination is evident from the present studies, and the use of multiple indices seems necessary

74. Changes in Eucalyptus camaldulensis Essential Oils with Water Stress Silvia Leicach1, A. Garau2, A.B. Guarnaschelli2 , N Sztarker1 and A. Dato1 1Cátedra de Química Orgánica. 2Cátedra de Dasonomía. Facultad de Agronomía. Universidad de Buenos Aires. Avda. San Martín 4453. Buenos Aires (1417), Argentina Email: [email protected] Eucalyptus camaldulensis seedlings are planted in Argentina during spring, when drought events causing increased seedling susceptibility to herbivory and disease and compromise their survivorship and growth. Water stress, a common problem in forestry during planting due to poor initial contact between seedling roots and soil, has proved to modify eucalypts seedling quality through physiological and morphological changes. Seedlings subjected to drought conditions at nursery stage increased their tolerance to water stress performing better during early establishment. Changes in essential oil composition


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could also contribute to avoid herbivory. The aim of this work was to evaluate changes in essential oil production and composition in Eucalyptus camaldulensis seedlings subjected to drought conditions. Water restriction was applied during 4 weeks at the last stage of the nursery period (20 weeks). Control seedlings (C) were irrigated daily and water stressed seedling (S) received irrigation in every three days. Treatments were applied with 11 replicates. Changes in seedlings leaves essential oil composition as a response to water deficiency were evaluated by GC ad GC-MS. We found no significant changes due to water-stress in oil yield (0.79 mg g-1 fr. wt.), but there were significant changes in essential oil relative composition. Non-oxygenated terpenes lowered 44% their total relative abundance under drought conditions. Cineole content was enhanced 28.3%, and sesquiterpenes globulol, epiglobulol and ledol (among other oxygenated terpenes) contents almost doubled. It was demonstrated that higher 1,8-cineole content in Eucalyptus essential oils lowered herbivory damages (3). 75. A process-based Approach for Predicting the Toxicity of Juglone (5-hydroxy-1,4-napthoquinone) and other Phytochemicals in Soils Beneath Black Walnut (Juglans nigra L.) Trees Guntram von Kiparski University of California – RiversidE, Department of Environmental Sciences, 2208 Geology Buildign, Riverside, CA 92521, USA Email: [email protected] Although there is considerable evidence for the presence of juglone in soils beneath black walnut trees, determining the ecological significance of any of juglone and related compounds in soils has been elusive. This is because many competing source and sink mechanisms and rates interact to determine the availability and activity of these and other phytochemicals as potential toxins in soils. Factors determining juglone’s release, accumulation, and decline in soils will be discussed using data from soils beneath black walnut trees, greenhouse studies, and laboratory sorption/degradation studies. The significance of this data in describing the distribution behavior and toxicity of juglone in soils will be discussed together with a process-based approach for predicting the accumulation and fate of juglone and other potential allelochemical agents in soils. 76. Plant-plant Interference in Mediterranean Forest Dynamic: Consequences of Resource Competition and Allelopathy on Aleppo Pine (Pinus halepensis Mill.) and a Deciduous Oak (Quercus pubescens Willd.) Growth Yogan Monnier, Bruno Vila, Catherine Fernandez Institut Méditerranéen d’Ecologie et Paléoécologie IMEP, UMR CNRS 6116, Equipe Ecologie Fonctionnelle, Aix-Marseille Université, Campus de St. Jérôme, Case 421, 13397 Marseille, Cedex 20, France. Email: [email protected] Vegetation succession dynamics greatly depend on species colonization and establishment and plant-plant interferences (resources competition and allelopathy) could play a central role during this process. In Mediterranean region, Aleppo pine forms dense tree stands with low regeneration rate contrary to

Quercus pubescens, a late successional species. Aleppo pine is known to produce secondary compounds that may influence early recruitment. The purpose of this study was to distinguish and quantify resource competition and allelopathic effects on Pinus halepensis and Quercus pubescens in early vegetation development stage. In a nursery experiment, four factors were tested on tree growth: (i) competition (pine, oak, and pine with oak), (ii) allelopathy (with or without pinus leaf leachates), (iii) light (natural or shading conditions) and (iv) resource availability (low or high nutrient rates) in order to understand their interactions. Results show no effect of allelopathic compounds on oak growth which is limited by shading conditions, competition and low nutrient availability. As expected pine growth is also limited by competition and low resources availability. But for this last species, P. halepensis leaf leachates strongly inhibited its height growth, indicating autotoxic effect. This experiment highlights the importance of pine-oak interactions in early regeneration stages throgh autotoxicity, and resources competition. 77. Opportunities for Allelopathy Research in the Management of Vegetation in Power line Rights-of-way Timothy A. Chick Div. of Forestry, Natural Resources and Recreation, Paul Smith’s College, 51 Juniper Circle Lake Placid, NY 12946, USA. Email: [email protected] There are over 2 million acres of land in the United States that are occupied by high voltage transmission power lines. In order for utility companies to supply energy to customers in a safe and reliable manner, it is necessary to keep tall growing trees and shrubs from interfering with power lines. Traditional methods for managing vegetation on power line rights-of-way (ROWs) include manual cutting, mowing with large machines and spraying with herbicides. In 1953, researchers found that specific cutting and spraying techniques produced stable low-growing herbaceous and shrub communities that limited the germination and growth of trees. This ecological approach for controlling undesirable vegetation, which is commonly used today, presumed that competition for light was the regulator of these communities. Allelopathy wasn’t mentioned in the literature as a possible consideration in the management of ROWs until the early 1980s. During the mid-1990s, a handful of ROW managers and researchers initiated projects related to allelopathy but there seemed to be little interest within the utility industry to accept allelopathy as an interference element in plant community dynamics or in recognizing its potential for use in the management of ROW vegetation. In spite of the lack of research about allelopathy within the utility industry, there is information from allied disciplines that can be incorporated into present ROW management practices. Forest regeneration and soils studies along with research in ecology and agriculture provide knowledge that is relevant to ROW mgmt. Bioherbicide research in agriculture might provide a model for the development of pesticides for use in ROW management that are more


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socially acceptable than currently used herbicides. It appears that allelopathy may not become an integral part of ROW management until public and legislative pressures prohibit current herbicides from being used. In the meantime, there are ample opportunities for researchers to explore the allelopathic potential of numerous herbaceous and woody shrub species for resistance to tree invasion and to develop bioherbicdes using new modes of action for controlling tall woody species. 78. Allelopathy of a Sacred Grove Tree Species, Aglaia elaegnoidea, on Green Gram, Vigna radiata M. P. Ramanujam., P. Suganthi., M. Sathya and D. Kadamban Botany Laboratory, Centre for Post Graduate Studies, Pondicherry-605008, India Email: [email protected] Aglaia elaegnoidea (A. Juss.) Benth. is a dominant tree species of sacred groves of Pondicherry region. Green gram, Vigna radiata (L.) Wilczek, is a grain legume commonly cultivated in the adjoining fields. The allelopathic influence of this tree was investigated by exposing green gram seeds and seedlings to 0, 1.0, 2.5 and 5% concentrations of the aqueous leaf extract. While the seeds were presoaked in the test solutions and germinated in Petri plate moist chambers, the seedlings were raised in pot-culture and irrigated with the test solutions on alternate days and with tap water on other days. Germination and seedling growth (length, and biomass of shoot, root and plant) lateral root development and nodulation were adversely affected by the leaf extracts. Besides nodule number and size, the activity of nitrate reductase was inhibited too. Of the cellular metabolites, the levels of starch and total soluble sugars decreased in proportion to the concentration of the extract. The photosynthetic pigments viz. chlorophylls and carotenoids levels were also decreased. Concomitantly, the photosynthetic performance was also suppressed as indicated fluorescence transient measurements (Fv/Fm and Fo/Fv). The structural and functional integrity of the plasma membrane seem to have been disrupted significantly since the leakage of electrolytes and malondialdehyde levels were more in the treatments than in control. However, the antioxidative enzymes, Super oxide dismutase (SOD), polyphenol oxidase (PPO) and ascorbate peroxidase (APO) were increased. Of these, PO and SOD were stimulated significantly while polyphenol oxidase was increased only mildly. 79. Allelopathic Potential of Some Mangrove Plants on Growth and Development of Pearl Millet (Pennisetum typhoides St. and Hub.) K. Arumugam Department of Botany – DDE, Annamalai University, Annamalai Nagar – 608 002, India Email: [email protected] The six mangrove plants were selected from Pitchavaram mangrove forest, Tamil Nadu, South India to study their allelopathic potential against the growth and development of Pearl millet (Pennisetum typhoides St. and Hub.). Different concentrations (5, 10, 15, 25, 50, 75 and 100%) of aqueous and methanol leaf extracts prepared from six mangrove plants ie. Rhizophora apiculata Bl, Avicennia officinalis L, Acanthus ilicifolius L, Bruguiera cylindrica (L) Bl, Sesuvium portulacastrum L and Excocaria agallocha L. The laboratory

and pot experiment results revealed that the lower concentrations (5 and 10%) of both aqueous and methanol extracts of all the mangrove plants except Excocaria agollocha L increased the percentage of seed germination, morphological parameters and Biochemical constituents of test crop seedlings. But in higher concentrations retarding effects were observed. Among the six mangrove plants the aqueous and methanol extracts of Excocaria agollocha L showed an adverse inhibitory effect in all the parameters studied in the Pearl millet seedlings even in the lower concentrations (5 and 10%) of the extracts. 80. Using Plant Extracts in Control of Canary Grass (Phalaris minor Retz.) Masoumeh Younesabadi, Habib Ollah Kashiri, Ali Reza Savari Nejad, Leila Torbati Postal Code: 49156-77555, Dept. of Plant Protection, Agricultural research center, Beheshti Avenue, Gorgan, Golestan, Iran Email: [email protected] Canary grass (Phalaris minor Retz.) is one of the most important weeds in winter crops in Iran. Successive and excessive using of chemical herbicides against P.minor caused its resistance to common herbicides. Searching natural compounds that can be replaced with chemical herbicides is a useful method to solve this problem. In this experiment, herbicidal effects of 6 plant species water extract (Camel thorn (Alhgi camelorum fisch), Canada thistle Silybum marianum (L.) Gaertn. Horse mint (Mentha longifolia L.), Dwarf mallow (Malva neglecta Wallr.), Elder berry (Sambucus nigra L.)and Nettle leaf goose foot( Chenopodium murale L.)) were tested on germination and growth of P. minor. All extracts were prepared from above ground organs, at vegetative phase except M.longifolia extract that prepared in flowering stage. The result showed that P. minor germination was inhibited by all extracts especially at 75% and 100% (1:10 w/v) concentration. Root length of P.minor had no change by treatments, although a little decrease was observed in generally. 75% and 100% concentration of all extracts had significant reduction on stem length of P. minor but lower doses had no effects on stem length. A little increase of P.minor stem length was observed at 25% extracts of S.nigra and A.camelorum but this increase was not different from control treatment significantly. 81. Tropical Trees Leaves Used as Mulches: Effects on Crop Plants Growth, Weeds, Microbiota, and Soil Properties María del Carmen Flores-Carmona, R. Cruz-Ortega, Ana Luisa Anaya Laboratorio de Alelopatía. Departamento de Ecología Funcional. Instituto de Ecología. Universidad Nacional Autónoma de México. Apartado Postal 275, 04510 México, D.F. Email: [email protected] The use of organic fertilizers, particularly plant mulches, among Maya people to improve soil is a very ancient agricultural practice. Plant mulches decomposition


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releases allelochemicals that affect, positively or negatively, soil microbiota, nutrients dynamics, and plant growth. We performed a greenhouse experiment incorporating dry leaves of two trees from the dry tropical forest of Quintana Roo, Mexico: Sebastiania adenophora (Euphorbiaceae) and Zuelania guidonia (Flacourtiaceae) into the soil of pots. Both trees produce bioactive allelochemicals; the leachates of their leaves inhibited in in vitro bioassays, the germination and root growth of tomato. In this greenhouse experiment we determined: 1) the effects of both plant mulches on the emergence and dry weight of weeds; 2) the relative growth of tomato, maize and cowpea; 3) the colonization of arbuscular mycorrhizal (AM) fungi in roots of the three crop plants, and of Rhizobium in cowpea roots; 4) and the effects of these

mulches on some chemical and physical characteristics of soil. Results showed that weeds increased in pots with Zuelania leaves. Both mulches, Zuelania and Sebastiania leaves, had negative effects on tomato, maize, and cowpea relative growth. On the other hand, they increased the number of Rhizobium nodules in cowpea roots, the colonization of AM fungi in the three crop roots, and improve the stability of soil aggregates. We conclude that the decomposition of Sebastiania and Zuelania leaves in the soil release mixtures of allelochemicals modifying its conditions, altering the dynamic of biotic interactions, chemical and physical factors, and therefore the emergence of weeds and plant growth.

Main Topic 5: Allelopathy in Agricultural Settings 82. Developments in Rice Allelopathy: Searching for the Balance between Allelopathic Activity, Agronomic Viability and Commercial Acceptability David Gealy1, Karen Moldenhauer2, John Mattice3, and Wengui Yan1 1USDA-ARS, Dale Bumpers National Rice Research Center, 2890 Hwy 130 East, Stuttgart, AR 72160 USA 2University of Arkansas Rice Research and Extension Center, 2900 Hwy 130 East, Stuttgart, AR 72160, USA, and 3University of Arkansas, 1366 W. Altheimer Drive, Department of Crop, Soil, and Environmental Sciences, Fayetteville, AR 72704, USA Email: [email protected] Sustainable weed control is an ongoing challenge in rice production. Indica rice lines that suppress troublesome C4 grass weeds such as Echinochloa crus-galli and Leptochloa fusca ssp. fascicularis have been evaluated extensively in Arkansas. Earlier findings suggested that suppression likely included both competition and allelopathic components. These indicas often reduced growth of the weed roots (determined using 13C depletion) and aboveground parts more than did commercial cultivars. In an ongoing breeding/selection program we attempt to combine desirable quality and yield characteristics of southern long grain cultivars with highly weed-suppressive rice lines. One such selection (RU0701087; from pedigree PI 338046 / KATY // PI 312777) was evaluated in the five-state Uniform Regional Rice Nursery (URRN) in 2007. In this test, its yield and quality were acceptable, but in other tests, weed suppression was less than that of the PI 338046 and PI 312777 parents. Additional selections that suppressed E. crus-galli in bioassays were not effective in the field. Chinese indicas such as ‘4484’ (PI 615022) and its irradiated mutant selection, ‘4484-1693’ (RU0603075), also have been evaluated in field tests including the URRN. Typically, weed suppression by these indica lines was greater than that of commercial standards, and yield and disease tolerance were as high or higher than in standards. Commercial, high-tillering hybrids have also suppressed weeds effectively in the field. High-yielding indica lines such as 4484-1693 are now being used in limited commercial production of organic rice, in part because of their weed-suppressive characteristics. A challenge for

reduced-input systems is that environmental conditions and weed pressure vary from year-to-year. Thus, weed-suppressive rice cultivars in systems permitting herbicides (i.e. not organic) could benefit substantially from herbicide application at reduced rates or on a ‘wait-and-see’ basis. Using such an approach, weed suppressive cultivars could be a viable component of major U.S. rice systems.

83. Allelopathy in Agroecosystems of Northwestern India and Its Practical Utility Daizy R. Batish1, H.P.Singh2 and R.K.Kohli2

1Department of Botany, Panjab University, Chandigarh – 160014, India 2Centre for Environment and Vocational Studies, Department of Botany, Panjab University, Chandigarh – 160014, India Email: [email protected] Allelopathic interactions are known to have occurred in the complex environment of agroecosystems since antiquity. This is evidenced by the observations and experimental work of renowned philosophers and scientists. A number of crops, weeds and agroforestry trees are known to be allelopathic by reducing the growth, development and yield of crops and thus adversely affecting agricultural productivity. India, being primarily an agriculture-based country, is no exception in this regard. Several reports from India indicate a decline in crop productivity owing to the chemical interference of weeds. In northwestern India where rice and wheat are the major crops and grown in rotation, several weeds like Ageratum conyzoides, Chenopodium murale, C. album, Parthenium hysterophorus, Echinochloa crus-galli and Phalaris minor interfere with the growth and development of crops and cause enormous crop losses thus putting economic burden on the farmers. To control these weeds farmers use huge amounts of synthetic herbicides that not only reduce soil quality but also increase the risks of environmental pollution and human health effects. Allelopathy, if suitably manipulated, can help control harmful weeds in an eco-friendly way and thus maintain soil sustainability since the allelochemicals (being natural


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plant products) are biodegradable and provide several other advantages. Some of the approaches for practical use of allelopathy include use of allelopathic plant residues and allelochemicals that selectively control weed species of rice and wheat – the major crops of Northern India. The present paper discusses these aspects of allelopathy that help in enhancing crop productivity and restoring sustainability of agroecosystems in this region. 84. Role of Allelopathy in the Stimulatory and Inhibitory Effects of Hairy Vetch Cover Crop Residue in No-Tillage Sustainable Production System John R. Teasdale USDA-ARS Sustainable Agricultural Systems Lab, Building 001 Room 245, Beltsville, MD 20705, USA Email: [email protected] Cover crops can provide multiple benefits to sustainable cropping systems including building soil organic matter, controlling soil and nutrient losses from fields, moderating radiation and moisture exchange, releasing nutrients for subsequent crops, and suppressing weed and pest populations. Many of these benefits are particularly important for no-tillage systems where cover crop residue interacts directly with nutrient, moisture, and weed/pest dynamics at the soil surface. Hairy vetch (Vicia villosa Roth) is a winter annual legume cover crop that has been the subject of extensive research on its capacity for providing nitrogen to subsequent crops. The potential of hairy vetch for promoting crop growth also can result in the promotion of germination and emergence of selected weed species responsive to inorganic nitrogenous compounds. In addition, surface vetch residue can create “safe sites” for both crops and weeds by maintaining more uniform soil moisture and moderate temperature under hot, dry conditions. However, high levels of hairy vetch residue also can inhibit weed emergence by attenuating environmental cues required for germination, by physically interfering with the upward movement of the emerging seedling and the downward penetration of light, and by releasing phytotoxic allelochemicals. Allelopathic compounds appear to be released into soil only during the initial phases of residue decomposition, primarily from leaf tissue, and appear to only contribute to weed suppression for a couple of weeks. Research has shown that phytotoxins may be more effective at suppressing weeds when combined synergistically with the etiolating influence of a surface mulch; this is a potentially important area for future investigation. As a result of these multiple stimulatory and inhibitory effects, it may be difficult to predict weed suppression by a leguminous cover crop such as hairy vetch. Clearly, more research is needed to optimize management of these complex interactions to selectively promote crop production and limit weed interference. 85. Green Manures in Organic Farming Systems: Multiple Stresses Affect Seedbank Dynamics E.R. Gallandt1, H.M. Kruidhof2, E.R. Haramoto3 and L. Bastiaans4

1University of Maine, Orono, ME, U.S.A 2Wageningen University, Wageningen, The Netherlands, currently, University of California, Riverside, CA, U.S.A. 3Mount Holyoke College, South Hadley, MA, U.S.A 4Wageningen University, Wageningen, The Netherlands. ‘

Email; [email protected] Green manures—crops grown and incorporated into the soil primarily for soil-improvement—have the potential to contribute multiple stresses in the life cycle of annual weeds. Such system-level effects are of particular importance to organic farmers who typically rely heavily on cultivation for weed management. These farmers often work in the context of an abundant weed seedbank that can overwhelm even effective cultivation practices. Central to improving weed management on such farms are strategies that target the seedbank, reducing seed inputs and increasing seed losses. During their growth, competitive effects of green manure crops decrease seed inputs, particularly when compared to “fallow” controls. However, this effect is probably less important than the opportunity for preemption of seed inputs by careful timing of green manure incorporation. There are several mechanisms through which green manures may increase weed seed losses. Most importantly, incorporated residues effectively reduce the “effective” weed seedbank by reducing the probability of seedling establishment. Field bioassays conducted with a wide range of species sown into one leguminous and several non-leguminous green manures show that establishment may be reduced 23 to 34% compared to bare fallow controls. Thus, all else equal, greater seed inputs the preceding year could thus be tolerated. Green manures may also reduce seedling performance, evidenced by an average 2 day delay in emergence, but these effects on the individual become more difficult to detect later in the season. Although other reports had indicated that seed mass was positively correlated with the ability to withstand the various stresses related to incorporated residues, our first analyses of these data failed to show this effect. However, re-analysis of these data demonstrated that the magnitude of residue-mediated effects was affected foremost by timing of seedling emergence relative to inhibitory potential of the residues, after which seed mass was an important factor. Improved understanding of green manure contributions to organic farming systems will require mechanistic advances, particularly with greater focus on variation attributed to environmental conditions, and greater system-level understanding that will come from cropping systems experiments and simulation models that permit exploration of the many cropping scenarios possible with long- and short-season green manures. 86. Alternative Weed Management in Cotton Field by Employing Allelopathy Principles: A Case Study in Pakistan. Javaid Iqbal1 and Zahid A. Cheema2

1College of Agriculture, Dera Ghazi Khan 32200 Pakistan, 2 University of Agriculture, Faisalabad 38040 Pakistan Email: [email protected] Twoyear field investigations were carried out during 2003-2004 to establish alternative purple nutsedge (Cyperus rotundus L.) management strategies in cotton by employing allelopathy principles. In the first study, crop water extracts (sorghum, sunflower and brassica) @ 12


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and 15 L ha-1 in different combinations were tank mixed with reduced rates of glyphosate at 67% (767 g a.e. ha-1) of label rate (2.3 kg a.e. ha-1) and sprayed as directed post emergence at 40 days after sowing (DAS). Purple nutsedge density was decreased by 59-99% and dry weight by 66-99% as compared to control. The high rate of crop water extracts (15 L ha-1) significantly reduced the growth of purple nutsedge more than the lower rates (12 L ha-1). Seed cotton yield in these treatments was comparable to herbicide applied at recommended rates. The second study was conducted to determine the effectiveness of intercropping single and double rows of sorghum, soybean and sesame in a cotton crop on the suppression of purple nutsedge. Results revealed that all these intercrops were effective in inhibiting purple nutsedge density (70-96%) and dry matter production (71-97%) during both years of experimentation. Control in the second year was more effective than in the first year. The seed cotton yield was also depressed by the intercrops but its suppression (8-23%) was far less severe than that of purple nutsedge and its loss was compensated by greater total economic returns. Intercropping of sorghum and sesame produced greater than 20% net benefits (up to 60%) in comparison with control (cotton alone). The sesame two rows intercrop treatment was the most profitable with net benefits of 51-59% with good purple nutsedge control (73-92% density suppression, 77-95% dry weight suppression) during both years of experimentation. 87. The Use of Mustard Cover Crops in Potato Rotations Rick Boydston USDA-ARS, Prosser, WA, (509) 786-9267 Email:[email protected] The use of Brassicaceae cover crops has increased recently as a result of benefits including nematode, weed, and disease suppression, soil conservation, nutrient cycling, and increasing soil quality. Brassicaceae cover crops suppress weeds due to fast emergence and vigorous competitive growth during fall establishment and allelopathic substances released during degradation of the cover crop residues. Early season weed emergence is often suppressed following fall-planted S. alba or B. napus cover crops. The mechanisms of weed suppression with Brassicaceae cover crops are not completely understood, but breakdown products of glucosinolates, such as isothiocyanates and ionic thiocyanate (SCN¯) are believed to contribute to weed suppression. Preventing weeds from producing seed in fall-planted cover crops contributes to reduced weed emergence in the succeeding spring-planted crop. White mustard (Sinapis alba), rapeseed (Brassica napus), brown mustard (B. juncea), and oilseed radish (Raphanus sativus) have been utilized as fall-planted cover crops preceding potatoes. White mustard (S. alba) or rapeseed (B. napus) produced the greatest amount of biomass if planted from August 15 to September 1 in the Pacific Northwest. Seed meal, a by-product of mustard grown for biofuel, can contain high levels of glucosinolates that produce compounds that suppress weeds. S. alba seed meal at rates above 1 MT/ha suppressed early season weeds in peppermint and potato with little or no injury to the deeper-planted crop.

88. The Allelopathic Potential of Rice Cultivars to Control Multiple Australian Rice Weeds A. N. Seal & J. E. Pratley

E.H. Graham Centre for Agricultural Innovation, Charles Sturt University, Wagga Wagga, NSW, Australia 2678 Email: [email protected] In Australia, researchers are detecting increasing levels of resistance to the major herbicide available for weed control in rice. The objective of the current research was to determine if those cultivars previously shown to be suppressive towards arrowhead also inhibited the growth of several currently and potentially important aquatic rice weeds in Australia. Several rice weed species belonging to the Alismataceae were tested to ascertain whether the allelopathic potential of rice cultivars extended beyond a single weed if the weed species were related. Rice cultivars were screened in the laboratory for allelopathic potential using the Equal Compartment Agar Method (ECAM). Significant differences existed between rice cultivars in their ability to suppress the root growth of each weed studied. Correlation analysis between root inhibition values for various combinations of all five tested weeds was undertaken. All correlations were significant. A. lanceolatum and S. graminea both correlated very highly with the overall ranking having r values of 0.96 and 0.97, respectively. This information would be useful for breeders who want to breed for more than one weed at the same time. In this case, screening rice cultivars for their allelopathic effect using either of the aforementioned weeds as test species would be a good indication of their allelopathic potential against the whole range of rice weeds tested here. Breeders are also interested in how certain traits are inherited. When cluster analysis was performed on the pedigree information available for these rice cultivars, it was observed that several cultivars with high allelopathic potential were grouped in one cluster, whereas many of the cultivars with lower allelopathic potential formed clusters of their own on the resulting dendrogram. This information along with the overall ranking, correlations and cluster analysis may be useful for breeders attempting to understand the specificity of allelopathic potential. 89. Allelochemically-Enhanced-Competition: Theoretical Framework, Experimental Approach, and Ecological Significance M. An1, Y.H. Liu2, M. Saeed3, and J. Pratley1 1E.H. Graham Centre for Agricultural Innovation (a collaborative alliance between Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga, NSW 2650, Australia 2Institute of Tropical & Subtropical Ecology, College of Sciences, South China Agricultural University, Wushan, Guangzhou -510642, China 3Directorate of Agronomy, Ayub Agricultural Research Institute, Faisalabad, Pakistan Email; [email protected] Competition is one of the foundations for the science of ecology. However, the mechanism for competition still remains largely unknown and unexplored. Allelopathy and its relationship with competition have been long ignored and underestimated even though allelopathy has been a long-recognized phenomenon. Increasing density of crop


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plants can increase crop competitiveness, effectively controlling weed growth by reducing weed biomass and seed production. By employing such a density-dependent crop/weed interaction as a model system, the concept of allelochemically-enhanced competition, and an associated theoretical framework, is proposed for exploring the relationship between allelopathy and competition. This concept proposes that a density-dependent two species interaction consists of three phases, and both inter- and intraspecific competition, which coexist and evolve from one to another as density increases. Mechanism for such alternation is the increased allelochemical production as density increases. In a density-dependent crop/weed interaction, the observed increased crop competitiveness is largely a result of its increased allelochemical production as density increases. Therefore, allelopathy and competition may not be two distinct processes as commonly perceived but inherently related. Allelopathy may be one of the internal motivating forces of a plant species for defending and maintaining a favourable growth environment, while competition may be an external expression of such operation. A laboratory experiment involving wheat and annual ryegrass (Lolium rigidum) has demonstrated the concept of allelochemically-enhanced competition and further quantified the enhancement portion of allelopathy in species competition. Full understanding of the competition mechanism will enable management practices, such as high crop density for controlling weeds, to be utilised as part of an integrated weed management program while avoiding the disadvantages of crop autotoxicity and the associated yield decline. 90. Breeding for Improved Allelopathic Activity in Swedish Spring Wheat Nils-Ove Bertholdsson P.O. Box 101, Dept. of Plant Breeding and Biotechnology, Swedish University of Agricultural Sciences (SLU), SE-230 53 Alnarp, Sweden Email: [email protected] Spring wheat is less competitive against weeds than is rye, oat or barley. This is probably an effect of less vigorous growth early in spring, but allelopathy may also be involved. In a screening of more than 800 different genotypes from a world collection, Swedish cultivars both, old and new, showed low allelopathic activity against perennial ryegrass (Lolium perenne L.) if compared with e.g. barley or most of the foreign wheat cultivars. Two foreign wheat cultivars were identified to be as allelopathic as the most allelopathic Swedish barleys and are now used in a breeding program. Since the cultivars are not adapted to Swedish conditions several steps, involving crossings and back-crossings followed by repeatedly allelopathy selections, are therefore needed to recover the originally high quality wheat but with higher allelopathic properties. From a breeding point of view it is important, at an early stage, to evaluate how important allelopathy is for the weed competitive ability. Therefore, in 2007, four breeding lines (not completely stable and only back-crossed once) were studied in an organic yield trial together with the Swedish parent and other advanced normal breeding lines. As in most studies including weeds, standard errors are high, but genotypic differences in weed biomass were still observed. Interestingly, the only single trait found to be correlated with

the differences in weed biomass was the allelopathic activity measured as the root growth inhibition of ryegrass. Neither early biomass growth nor early plant height or straw length was correlated with weed biomass. These first field data indicate that it is feasible to breed for improved weed suppression by selecting allelopathic activity. Hopefully new field trials in the spring of 2008 will confirm this statement. The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas) is acknowledged for funding this research 91. Terpenoids: Better Candidates for the Development of Natural Herbicides HaiBin He, HaiBin Wang & Wen Xiong Lin Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education; Agroecological Institute, Fujian Agriculture and Forestry University, Fuzhou 350002, China Email: [email protected] Because terpenes are nonpolar compounds and have negligible water solubility, research on their ecological roles has been focused on their volatile characters in chemical defenses against herbivores, feeding attraction or repellence, pollination attraction and fighting disease or antimicrobial activity. Weidenhamer et al. suggested that many monoterpenes are phytotoxic in concentration under 100 ppm, well below the saturated aqueous concentrations of oxygenated monoterpenes. The oxygenic terpenes, even diluted in soil solutions, may act allelopathically on paddy weeds. Some oxygenic monoterpenes and sesquiterpenes were detected in root exudates from the allelopathic rice variety PI312777 cultured in paddy soil and sand media, and the inhibitory effect of 5 oxygenic monoterpenes on BYG were validated as previously described. Based on the results of our previous study, 5 oxygenic terpenoids, namely (–)-carveol, (+)-carvone, (–)-menthone, (–)-carvyl acetate, and (+)-cedrol, were subjected to an interaction test. The optimum combination of the abovementioned 5 terpenoids was determined by orthogonal rotatable central composite design for 5 variables and 5 concentration levels. In a petri dish test, barnyard grass (Echinochloa crus-galli; BYG) was unable to regrow in the solution containing a mixture of the optimum combination of the 5 terpenoids. In hydroponic experiments, this mixture significantly inhibited the root length, plant height, plant dry weight, and root activity of BYG, causing a considerable decline in the superoxide dismutase, peroxidase, and catalase activities in the root and leaves of BYG. In a field test, the mixture was highly effective in suppressing BYG development in both monocultures and co-cultures of BYG with 2 rice accessions. However, the mixture was not harmful to the 2 rice accessions. Further, this mixture inhibited the growth of most paddy weeds in the field test. Oxygenic terpenoids that show high inhibitory effects at low concentrations may be promising herbicides candidates. 92. Effect of Continuous Cropping of Chinese Medicinal Plant Rehmannia glutinosa on Rhizospheric Microorganisms


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Zhongyi Zhang1,3, ZhenfangLi1,2 Jun Xiong1,2,Hui Chen1,2, Wenxiong Lin1,2* 1Key Laboratory of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University (FAFU), C/O Ministry of Education China 2Institute of Agroecology C/O School of Life Sciences, FAFU, Fuzhou 350002, China 3Institute of Chinese medicinal plants, Henan Agriculture University, Zhengzhou, 450002, China: Email: [email protected] An experiment was conducted to determine microbe quantity, microbial population and soil enzyme activity in the rhizospheric soils under successively cropped Rehmanniae.glutinosa for one and two years respectively. Successive cropping of R.glutinosa significantly affected the microbial flora and enzyme activity in the rhizospheric soil. With successive cropping years increasing, the number of bacteria and fungi decreased but not significantly in the rihzospheric soil. The reverse was true for the number of actinomycetes, which in the soil successively cropped for two years was about four times as many as in the soil successively cropped for one year. The result also showed that ammonifier, aerobic azotobacter, sulphate reducer, denitrifier and anaerobic cellulosede-composer were increased by 25.99, 45.39, 11.43, 1.36 and 1.43 folds, while aerobic cellulose-decomposer was reduced by 86.74 % in the soil respectively. In addition, It was also found that the root exudates of successively cropping R.glutinosa markedly promoted the activities of urease, polyhphenol oxidase, sucrase, protease and cellulase glucose, showing their increases by 62.87%, 9.43%, 47.91%, 139.62% and 31.33% respectively, but inhibited the activity of catelase. The findings suggested that continuously cropping R.glutinosa would result in a destroyed balance of rhizospheric microbial flora, and provided an insight into the mechanism of the obstacle in successively cropping R.glutinosa. 93. Modelling Autotoxicity in Continuous Cropping and the Dynamics of Autoxins Y.H. Liu1, Y. L. Fu1 and M. An2 1College of Sciences, South China Agricultural University, Wushan, Guangzhou -510642, China 2E.H. Graham Centre for Agricultural Innovation (a collaborative alliance between Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga, NSW 2650, Australia. Email: [email protected] Continuous monocropping and intensive culture systems often result in poor growth and yield decline of the crops, a phenomenon often referred to as autotoxicity, and contribute to the autoxins produced and accumulated by crop plants in that soil. Mathematical approaches have been undertaken to model this important phenomenon in order to increase understanding of autotoxicity and to guide cropping practices to avoid its negative impacts. Theoretical analysis demonstrates that the biological responses of crop plants to autotoxicity follow the prediction of the An_Hormesis model. Autotoxicity is dose-dependent and may only occur when the autotoxin levels accumulated in the soil reaches a high threshold. The amount of autoxins present in the soil varies

and is governed by biotic and abiotic factors, the results of which variously affect the growth of the next crop.. The identified factors include length of cropping, seedling density of the crop, rate of autoxins released from the previous crop, and rate of transfer of autoxins in the soil. Modelling outcomes of autoxicity and the dynamics of autoxins under various conditions are presented, and their agronomic implications are discussed. 94. Weed Management in Wheat (triticum aestivum l) through Applying Allelopathic Plant Water Extracts in Combination with Reduced Herbicide Doses Muhammad Saeed1, Muhammad Rafiq2, Min An3 and Aamer Sattar4

1Directorate of Agronomy, Ayub Agricultural Research Institute, Faisalabad (Pakistan) & University of Agriculture, Faisalabad, Pakistan 2Technical Branch, Ayub Agricultural Research Institute, Faisalabad, Pakistan 3E.H. Graham Centre for Agricultural Innovation (a collaborative alliance between Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga, NSW 2650, Australia 4Ayub Agricultural Research Institute, Faisalabad, Pakistan Email: [email protected]

In order to find alternatives for minimizing the total reliance on synthetic herbicides for weed management in wheat, a field experiment was conducted to assess the efficacy of water extract of allelopathic crops, sorghum and sunflower, in combination with reduced doses of some post emergence herbicides, such as mesosulfuron, idosulfuron, metribuzin, phenoxaprop, and bensulfuron, on weed control during the winter seasons of 2005-06 and 2006-07. It was found that sorghum and sunflower extracts in combination with reduced herbicide doses of all herbicides effectively controlled the weeds of wheat and at the same time 20-36% increase in grain yield was obtained, which was equal to the grain yield achieved with application of recommended doses of herbicides. The economic analysis showed that sorghum and sunflower extracts each at 18 L ha-1 in combination with 70% reduced dose of metribuzin + phenoxaprop gave the maximum net benefits. Those field results demonstrated the feasibility of reducing reliance on synthetic herbicides for weed control by utilizing allelopathic principles, which can contribute significantly to the agricultural and environmental sustainability as well as to the savings of farming costs. 95. The Influence of Tea Saponins and Caffeine on the Growth of Tea Plant in Vitro P. Okinda Owuor1, and Francis N. Wachira2 1Department of Chemistry, Maseno University, P. O. Box 333 -40105, Maseno Kenya 2Department of Biochemistry and Biotechnology, Egerton University, P. O. Box 536, Njoro Kenya. Email: [email protected] The tea plantations can have life spans of over 100 years, reaching a maximum production potential after 20 to 40 years beyond which yields decline or stagnate, making it


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mandatory to uproot and replace old plants. However, replanted germplasm perform poorly, compared to the same cultivars cultivated on virgin lands. Rehabilitation of such lands by fallowing or using alternative crops does not improve their productivity. These problems suggest these soils may be suffering from long-term deposition of allelochemicals, possibly metabolites of the plant. Caffeine in coffee and saponins in mungbeans exhibited allelopathic activities. Tea leaves contain up to 4% caffeine while tea roots, tea seeds and tea leaves contain saponins. In tea cultivation, large amounts of leaves are returned to the soil via prunings and leaf fall, while the tea roots are usually not disturbed and formed tea seeds also drop in the tea fields. Over long period, the metabolites can accumulate in the tea soils. Leachates from tea leaves inhibited seed germination and subsequent growth of lettuce, indicating possible allelopathic potential. Tea roots and seeds saponins were tested on seed germination, root and stem growth of various vegetables. The saponins did not affect the germination of the vegetables, but inhibited the roots and stems elongation, demonstrating allelopathic potential. The inhibition of root growth was higher than that of stem growth. Tea seed saponins were more potent than the tea roots saponins. Further experiments assessed in vitro growth response of young tea plants to tea seed saponins and caffeine. Caffeine reduced root and stem growth of the young tea plants while saponins promoted their growth. The poor re-growth on the old tea soils maybe associated with accumulation of caffeine in these soils. However, accumulation of saponins in the soils may promote the growth of the tea plants. 96. Allelopathic Effect of Cleavers (Galium aparine) on Germination and Early Growth of Wheat A.Aziz, A. Tanveer, A. Ali, M. Yasin2, B.H. Babar and M.A. Nadeem Department of Agronomy, University of Agriculture, Faisalabad, Pakistan, 2Institute of Soil and Environmental Sciences University of Agriculture, Faisalabad, Pakistan. Email: [email protected] Aqueous extracts obtained from roots, stem, leaves and fruit of cleavers (Galium aparine) harvested at maturity, and soil taken from a G. aparine field were used to determine their phytotoxic effects on germination and seedling growth of wheat (Triticum aestivum L.) in the laboratory at 15 and 20oC. Maximum time taken for 50% germination and mean germination were recorded for stem and fruit extracts. Time taken for 50% germination and reduction in germination index were greater at 20oC whereas highest mean germination time was recorded at 15oC. Reduction in root and shoot length, and biomass of wheat seedlings due to different extracts over control was 34.0 to 67.9%, 10.4 to 61.6% and 16.5 to 38.0%, respectively. Greatest reduction in root and shoot length, their dry weights and seedling biomass of wheat was caused by the fruit extract of G. aparine. Root extract showed 32.4% increase in shoot dry weight and 11.4% in seedling biomass over control. Soil beneath G. aparine plants significantly reduced the shoot length, dry weight and seedling biomass but increased root dry weight of wheat seedlings. These findings suggest that soil incorporated plant residues of this weed may have broad implications for the growth of a succeeding crop.

97. Potential Phytotoxic Effects of Achillea santolina L. on Two Economically Important Field Crops in Egypt S.M. El-Darier and A.A. Tammam Botany Department, Faculty of Science, Alexandria, University, Alexandria, Egypt Email: [email protected] The aim of this study was to investigate the phytotoxic effect of Achillea santolina L. on some growth parameters physiological and biochemical processes during germination of mustard seeds (Sinapis alba L. cv. Nakielska). To exclude the involvement of osmotic stress in seed reaction to phytotoxic compounds, we compared the effect of 10% (w/v) water extract from sunflower (Helianthus annuus L. cv. Ogrodowy) leaves and 28.4% (w/v) polyethylene glycol (PEG) 8000 solution characterized by an equal Ψ = −1 MPa. We evaluated (1) the amount of hydrogen peroxide (H2O2); (2) activities of antioxidant enzymes: superoxide dismutase, catalase, and glutathione reductase; (3) membrane permeability; and (4) level of malondialdehyde (MDA). Both, sunflower compounds and PEG solutions inhibited mustard seed germination, but only phytotoxins caused an increase in the cell membrane permeability, MDA level, H2O2 concentration, and alterations in activities of antioxidant enzymes. Our results demonstrate that despite the activation of the antioxidant system by sunflower phytotoxins, reactive oxygen species accumulation caused cellular damage, which resulted in the decrease of germinability and gradual loss of seed vigor. It seems that the negative effect of sunflower on germination of mustard seeds is mostly because of its toxicity and not to its contribution to osmotic potential. 98. Management of Allelopathy in Closed-Ecosystem for Space Agriculture Kaori Tomita-Yokotani1, Hiroko Iwasawa1, Kanae Hiraishi1, Maki Asano1,2, Yoshiharu Fujii3, Hirofumi Hashimoto4, Masamichi Yamashita4 1University of Tsukuba 2Keio University, ３National Institute for Agro-Environmental Sciences, ４Jaxa Email: [email protected] Habitation in outer space becomes reality in these day. We start our study on space agriculture to provide foods for space living people. Inter-organisms and -species interactions have long been known as allelopathy. However, little is known about whether such interaction (allelopathy) may, or may not, differ under space environment, exposed on the space station or in the closed-ecosystem on extraterrestrial bodies. We have examined allelopathy under altered gravitational environment, in order to answer those questions. Gravitational effects on allelopathy among a plant-plant system were surveyed by applying them pseudo-microgravity, generated by a 3D-clinostat. The candidate substances related to allelopathy, which are affected by gravity, were found in some plant species, velvet bean (Mucuna pruriens L.), broccoli (Brassica coleracea var.


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italica) and sunflower (Helianthus annuus L.). In addition to those allelopathic plant species, we chose buckwheat (Fagopyrum esculentum Moench ) and Lotus japonicus in this study to analyze allelopathic action. Some of flavonoids are responsible for the allelopathic function. The production of total flavonoid was affected by gravity. Some enzyme related to flavonoids synthesis would relate to the reduction of flavonoid production. We also study on the relationship between the gravity and each allelochemical synthesis. If biosynthesis, emission, transport and sensing process of allelopathic substances would be affected by gravity, member organisms in a closed-ecological system might exhibit different behaviors, when they are exposed to micro- or hypo-gravity in space. To synthesize a robust ecosystem for space agriculture, we have to consider the principle of allelopathy under the various environments. 99. Brassica Allelopathy against Soilborne Pathogens and Weeds of Strawberry Scott Mattner, Ian Porter, Rajendra Gounder, and David Allen Private Bag 15, BioSciences Research Division, Department of Primary Industries, Ferntree Gully DC, Vic 3156, Australia Email: [email protected] This research aimed at identifying factors that improve / limit the efficacy of allelopathy by brassica green manures for soil disinfestation against strawberry pathogens and weeds. In bioassays, the volatiles released from macerated roots of a Brassica rapa / B. napus mixture were six times more effective at suppressing the growth of the strawberry pathogen Rhizoctonia fragariae than shoots. The toxicity of the volatiles increased as brassica developmental stage progressed. These results related to the release of higher quantities and a greater diversity of isothiocyanates (ITCs) from the roots of mature brassica plants than from their shoots. Separate bioassays showed the volatiles from the brassica crop suppressed the growth of six soil-borne pathogens of strawberry and seven clover weed species. Suppression of clovers did not relate to their seed size, but might relate to their hard-seededness or genotype. Freeze dried root meal of the brassica crop (8 tonnes/ha) released 10 molar equivalents less of ITCs into soil (64 mol/ha) than the commercial soil fumigant, metam sodium (736 mol/ha, applied at 106 kg ai/ha). Currently, the relatively low amounts of ITCs released by brassica crops into soils are important limitations to their ability to control soilborne pests to the levels of synthetic fumigants. In the field, rotary incorporation of the brassica crop did not produce detectable levels of ITCs in soil; reduce the survival of the strawberry pathogens, Phytophthora cactorum and Cylindrocarpon destructans; or affect populations of culturable soil microflora. Yet, it suppressed the growth of emerging weeds (mostly Poa annua) by 40% and the growth of Phytophthora cactorum by 20%. We hypothesise that allelochemicals other than ITCs, such as nitriles, or other biological mechanisms might also play a role in brassica allelopathy. A key to improving the efficacy of brassica allelopathy in the field seems to lie in the development of application technologies that can macerate and incorporate plant tissues evenly in soils, in addition to incorporating brassicas under optimal edaphic conditions for release of ITCs.

100. Allelopathy in Bangladesh Rice Cultivars Hisashi Kato-Noguchi and Md. Abdus Salam Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan Email: [email protected] Rice crop productivity of Bangladesh is low in comparison to other rice-producing countries, although rice is one of the main foods in the country. Severe weed infestation is one of the major reasons for such low yield in Bangladesh andand weeding is the most widely used weed control method. Weed control is often imperfect and/or delayed because several constraints limit the effective use of hand weeding. Rice allelopathy has received much attention, and may be an alternative to the chemical and mechanical control of weeds. The allelopathic effect of rice on weeds could be applied to reduce use of chemical herbicides, which might results in improved water quality and less environmental contamination and also reduce labor for hand weeding. It was therefore of interest to assess the allelopathic potential of Bangladesh rice cultivars for weed control purposes. The allelopathic potential of 102 Bangladesh rice (42 high yielding and 60 traditional cultivars) was determined against the seedling growth of cress, lettuce, Echinochloa crus-galli and E. colonum. Some high yielding and some traditional rice cultivars were found to have allelopathic effect against these test plant species. High yielding rice cultivars, BRRI dhan37, BRRI dhan30 and BRRI dhan38, respectively, had the most significant inhibiting effect on the growth of cress, lettuce and E. colonum, and traditional rice cultivar, Kartikshail had the most significant inhibiting effect on barnyard grass. The high yielding rice cultivar, BR17 marked the greatest inhibitory activity with an average of 39.5% of the growth inhibition on roots and hypocotyls/shoots of cress, lettuce, barnyard grass and E. colonum. The present research suggests that BR17 is the most allelopathic in 102 Bangladesh rice cultivars and may be one of the candidates for a research programme in Bangladesh rice allelopathy for isolation and identification of allelochemicals. 101. Assessment of Phytotoxic Properties of Peganum harmala on Growth of Redroot Amaranth (Amaranthus retroflexus) in Greenhouse Conditions Hamid SodaeiZadeh*1, 2 and Patrick Van Damme1 1Laboratory of Tropical and Subtropical Agronomy and Ethnobotany, Coupure links 653, B-9000 Gent, Belgium ²Faculty of natural Resources & Desert Studies, Yazd University, Yazd, Iran Email: [email protected] Wild plant species usually contain much higher levels of secondary chemicals than cultivated crops. Peganum harmala (Zygophyllaceae) is a common species in arid Middle East areas. The objectives of the present study were to investigate the effect of P. harmala residues on seedling growth of redroot amaranth (Amaranthus retroflexus) as a weed species and the role of activated charcoal in mitigating the allelopathic interference of P.


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harmala. Ten redroot amaranth seeds were sown in plastic pots containing 300 g of sandy loam soil mixed with three amounts of shade-dried powder of above- ground P. harmala material (4, 8 and 12 g dry weight per 1000 g dry soil). By mixing 4 g activated charcoal into the soil in half of the pots we established an experimental environment to check the role of allelopathy and release of organic molecules from residues. Untreated soil with and without activated carbon served as control. Treatments were arranged in a randomized complete block design with three replicates. Results indicate that addition of 12 g P. harmala residues to 1000 g soil reduced leaf area and root length of redroot amaranth by 79 and 65 %, respectively, when compared to non-amended soil.

Amendment of 4, 8 and 12 g per kg soil reduced dry weight of redroot amaranth by 31, 85 and 92 %, respectively. Addition of activated charcoal ameliorated the inhibitory effect of P. harmala plant materials at all residue amounts. At 12g concentration, activated charcoal increased leaf area, root length, plant height and dry weight by 46, 38, 24 and 75 % respectively, when compared to amended soil without charcoal. In conclusion, the present study indicates the phytotoxic nature of P. harmala residues and the possible involvement of organic molecules in growth inhibition of redroot amaranth.

Main Topic 6: Biosynthesis, mode of action, and detoxification of phytotoxins from plant 102. The Allelochemical Benzoxazolinone – Molecular Backgrounds of Its Detoxification and Degradation M. Schulz, S. Kant, M. Knop, D. Sicker1, T. Colby2, A. Harzen2 and J. Schmidt2 IMBIO (Institut für Molekulare Physiologie und Biotechnology der Pflanzen, Universität Bonn Karlrober Kreiten Str. 13, 53115 Bonn, Germany 1Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, Leipzig, Germany 2Max-Planck-Institut für Züchtungsforschung, Carl von Linné Weg 10, 50829 Köln, Germany. Email: [email protected] Benzoxazolinones are bioactive compounds that can suppress certain weeds such as crabgrass or redroot pigweed. However, numerous European weeds and cereals are able to detoxify the compounds and to release a certain portion of the detoxification products again by root exudation. At present eight higher plant detoxification products have been identified. All investigated species are able to detoxify BOA via BOA-6-OH and subsequent O-glucosylation, Poaceae mainly perform BOA-N-glucosylation, the resulting BOA-N-glucoside is rearranged to glucoside carbamate. In Zea mays, this product is further modified by malonylation or transformed to gentiobioside carbamate, both of which are generated late in the detoxification process steps. Detoxification of MBOA results in BOA-6-O-glucoside or in glucoside methoxy carbamate. Enzymes supposedly involved in the detoxification reactions include monooxygenases, glucosyltransferases and malonyl-transferases. The maize glucosyltransferase catalysing BOA-6-O- and BOA-N-glucosylation was purified, biochemically characterized and identified as constitutive BX9. The well known natural function of the enzyme is DIMBOA detoxification, for instance, in maize roots. BX9 is posttranslationally modified by redox mechanisms that enable the protein to catalyse either BOA-6-OH or BOA-N-glucosylation. Carbamate production is closely coupled to oxidative stress reduction. The BX9 gene is not induced during the BOA incubation period. When exposure to BOA is combined with additional stress situations (herbicide application and sulfur deficiency), both glucosylation mechanisms break down. Exuded carbamates and other detoxification products can be degraded by microorganisms.

Carbamate degradation is initiated by the production of carbamic acid, from which BOA is reconstituted. The uptake and detoxification cycle can start again or soil microorganisms degrade BOA via 2-aminophenol and phenoxazinone is produced. Phenoxazinones can be degraded by oxidative mechanisms which require fungal activities. 103. Momilactone B Accumulation in Rice and Rice Rhizosphere by Environmental Stresses H. Kato-Noguchi, H. Kujime and T. Ino Department of Applied Biological Science, Faculty of Agriculture, Kagawa University Miki, Kagawa 761-0795, Japan Email: [email protected] Rice seedlings were hydroponically grown and subjected to injury, heavy metal, UV-irradiation stresses, and the changes in the concentration of momilactone B in the seedlings and secretion level of momilactone B into the medium were determined. The injury stress was made by cutting the first leaves of rice seedlings. The concentration of momilactone B was 3.1-fold greater in the medium of the injury stressed seedlings than that of the non-stressed seedlings. Rice seedlings were grown in 1 mM CuCl2 solution. The concentration of momilactone B was 3.7-fold greater in the medium containing CuCl2 than that in control medium. These results indicate that injury and heavy metal stresses may increase momilactone B secretion from rice seedlings into the medium. UV-irradiation increased the concentration of momilactone B in shoots and roots of rice seedlings. The concentration in UV-irradiated shoots and roots, respectively, was 31.8- and 3.6-fold greater than that of non-irradiated shoots and roots. Accumulation of momilactone B occurred in medium in which UV-irradiated seedlings were grown. UV-irradiation increased not only production of momilactone B in rice seedlings but secretion of momilactone B. These results suggest that injury, heavy metal and UV-irradiation stresses may increase momilactone B secretion from rice roots into rice rhizosphere. The plant rhizosphere is a densely populated area in which plant roots must compete with invading root


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systems of neighboring plants for space, water, and mineral nutrients, and with other soil-bore organism, including bacteria and fungi. Momilactone B exhibits antimicrobial properties and are synthesized as a part of defensive response to the bacterial and antifungal activities. Momilactone B also acts as an allelochemical. Therefore, secretion of momilactone B into the rhizosphere may provide a competitive advantage for root establishment through local suppression of soil microorganism and inhibition of the growth of competing plant species. 104. Cytotoxic Effects of Cyanamide on Tomato (Lycopersicon esculentum L.) Root Growth D. Sołtys1, A. Rudzińska-Langwald2, W. Kurek2, A. Gniazdowska1, R. Bogatek1 1Department of Plant Physiology, Warsaw University of Life Science-SGGW, Nowoursynowska 159, 02-776 Warszawa, Poland 2Department of Botany, Warsaw University of Life Science-SGGW, Nowoursynowska 159, 02-776 Warszawa, Poland Email: [email protected] Cyanamide, a well-known synthetic fertilizer and herbicide synthesized about 100 years ago, was reported as a natural product of hairy vetch (Vicia villosa). Hairy vetch is now cultivated as organic weed control in orchards and fallow of rice fields in Japan, but mode of action of cyanamide in allelopathic interaction is still unknown. We investigated phytotoxic effect of cyanamide on the root growth of young tomato (Lycopersicon esculentum) seedlings. Tomato seeds were germinated in water for 3 days. After radicule protrusion seeds were transferred to cyanamide water solution. It was demonstrated that cyanamide (used in different concentrations: 0.2 - 2 mM) inhibited tomato root growth in a dose-dependent manner. The strongest inhibition in root growth was detected after exposure of the seedlings to 1.2 mM solution of cyanamide. The inhibition of root growth was accompanied by disturbances in cell division of root tips. Cyanamide suppressed mitoses and no mitotic figures were observed. The lower concentration induced aberrant mitotic figures with highly condensed chromosomes randomly spread over the entire cell. No other stages of mitosis were observed. We also studied cell cycle in root tip cells using a flow cytometric analyses of the nuclear DNA content and immunodetection of α-tubulin. Upon cyanamide treatment formation of mitotic spindles was impaired leading to inhibition of cell division. Finally, it resulted in root growth arresting. Inhibition in root growth was not accompanied by induction of oxidative stress in tomato root cells, since ROS concentration in roots of cyamanide treated plants was similar to that observed in control plants. On the other hand, the inhibiting effect of cyanamide on tomato root growth was accompanied by 2-fold increase in ethylene emission after 24 hr of exposure. The interaction between phytohormones in regulation of cell cycle of cyanamide stressed plants will be discussed. 105. Phytotoxicity Caused by Sicyos deppei (Cucurbitaceae): Metabolic Targets in Lycopersicon esculentum A. Lara-Nuñez, A. L. Anaya and R. Cruz-Ortega

Laboratorio de Alelopatía Departamento de Ecología Funcional, Instituto de Ecología, Universidad Nacional Autónoma de México. Apartado Postal 275, 04510 Mexico Sicyos deppei is an endemic noxious weed of Mexico that grows extensively in crop fields and covers open areas. The physiological mechanism of action of the soluble phytotoxic compounds released by S. deppei was investigated using Lycopersicon esculentum (Solanaceae) as the receptor plant. Tomato seed were exposed to S. deppei aqueous leachate (0.5%) for different hours of imbibition until germination, and several metabolic targets were investigated. S. deppei causes a delay in the germination process, resulting in an inhibition of radicle growth. Tomato seeds exposed to S. deppei aqueous leachate show oxidative damage, evidenced by an unbalance of the activity of enzymes of the antioxidant system, an increase in H2O2, and membrane lipid peroxidation that is correlated with the inhibition of membrane enzymes such as H+-ATPase and NADPH oxidase. Carbohydrate metabolism is also affected; there is a delay in starch degradation as well as in sucrose hydrolysis reflected in less fructose and glucose content; being lower the activity of sucrose phosphate synthase, cell wall invertase and α-amylase. Additionally, activity of cell wall enzymes involved in endosperm weakening for radicle protusion, such as endo β-mannanase, β-1, 3-glucanase, α-glucosidase and exo-polygalacturonase, are significantly lower in treated seeds. The activity of enzymes of primary metabolism, i.e. phosphofructokinase, citrate synthase, malic dehydrogenase, isocitrate lyase, and fructose 1,6-bisphosphatase, was lower in treated seeds than in control. In addition, treated seeds had higher ABA content through imbibition times. To test if ABA is regulating cell cycle, the expression of the cycline genes, cycD3;1, cycB2;1, and the CDKB2;1 was analyzed; finding both cyclins and CDKB2;1 down regulated. These results were related with flow cytometry analysis that showed that most cells in treated seeds are in G2 phase. Finally, phytotoxic activity of S. deppei aqueous leachate might be related with the presence of protease inhibitors. 106. In planta Mechanism of Action of the Allelochemical Sorgoleone F. E. Dayan Natural Products Utilization Research Unit, USDA-ARS, P.O. Box 8048, University, MS 38677 USA Email: [email protected] Injury to crops grown in rotation with sorghum (Sorghum bicolor L.) suggested that this species was allelopathic. This phytotoxicity is associated with a group of lipid benzoquinones called sorgoleone that exude from the root hairs of sorghum. The amount produced does not differ during the early stages of development, but varies with temperature and responds to the presence of other plants. Sorgoleone is released directly in the soil and acts like a pre-plant incorporated herbicide. One factor expanding the apparent persistence of sorgoleone in soil is the fact that it is continually released from the roots of sorghum, which sustains its concentration in soil over a long period of time. Sorgoleone inhibits photosynthetic and


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mitochondrial electron transports and the activity enzyme p-hydroxyphenylpyruvate dioxygenase in in vitro assays. However, the in vivo mode(s) of action of sorgoleone is unclear. Root or foliar exposure to sorgoleone has no effect on photosynthesis of 7 days-old velvetleaf. Radiolabeled sorgoleone is not translocated beyond the point of application. However, sorgoleone disrupts photosynthesis in young cotyledonary tissues; therefore, this allelochemical may still act as a PSII inhibitor in emerging seedlings. Sorgoleone is also known to inhibit root H+-ATPase activity and water uptake. We demonstrate that 40 µg mL-1 of sorgoleone causes a significant disruption of membrane integrity in the dark, and that the growth of 3 days-old velvetleaf seedlings was reduced by half with 30 µg sorgoleone per plant. This loss of vigor may results in an even higher rate of weed suppression. Therefore, the allelopathic effect of sorgoleone is strong on young developing plants, which may take up sufficient amount of sorgoleone through their cotyledonary tissues to exert a phytotoxic response by light-independent disruption of membrane integrity, direct inhibition of photosynthesis, or a combination of these mechanisms of action with yet unknown ones. 107. Elucidation of the Final Reactions of DIMBOA-Glucoside Biosynthesis in Maize M. Frey, R. Jonczyk, E. Glawischnig, D. Sicker1, A. Gierl Lehrstuhl für Genetik, Technische Universitaet Muenchen, Am Hochanger 8, 85 350 Freising 1Institut für Organische Chemie, Universitaet Leipzig, Johannisallee 29, 04103 Leipzig Email: [email protected] Benzoxazinoids have been identified in the early 1960s as secondary metabolites of the grasses that function as natural pesticides and exhibit allelopathic properties. Benzoxazinoids are synthesized in maize seedlings and stored as glucosides, the main aglucone moieties are DIBOA (2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one) and DIMBOA (2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one). Genes of DIBOA-glucoside biosynthesis, Bx1 to Bx5 and Bx8, Bx9 have previously been isolated and the enzymatic functions characterized. Recently, the enzymes for conversion of DIBOA-glc to DIMBOA-glc were identified and will be described in detail. DIBOA-glc is the substrate of the dioxygenase BX6, the produced TRIBOA-glc is metabolized by the methyltransferase BX7 to yield DIMBOA-glc. Both enzymes exhibit moderate Km values (below 0.4 mM) and kcat values of 2.10 s-1 and 0.25 s-1, respectively. Although BX6 uses a glucosylated substrate, the enzyme is localized in the cytoplasm. Bx6 and Bx7 are highest expressed in seedling tissue, a feature shared with the other Bx-genes. Bx6 and Bx7 are unique and specific genes that at present have no close relatives among the members of their respective gene families. In maize, all Bx-genes are located on the short arm of chromosome 4, all genes for the synthesis of DIBOA-glc map within 4 cM. 108. Allelopathic Potential of Sunflower Plants (Helianthus annus L.) on Soil Texture and its Root Extract on Physiology of Wheat (Triticum aestivum L.) Seedlings J. Kamal and Asghari Bano

Department of Plant Sciences Quaid-I-Azam University Islamabad, Pakistan Email: [email protected] . The allelopathic potential of root extract from sunflower cv- Hysun 38 (Helianthus annus L.) was studied and its effect on texture of soil and root extract of sunflower at different concentrations were applied to determine their effect on wheat two varieties cv-Margalla 99 and cv- Chakwall 97 seed germination rate, fresh weight, dry weight, shoot length, hormonal analysis (IAA, GA and ABA) and quantification of DNA under labortary conditions in Petridishes were conducted. Water extract of sunflower root significantly inhibited germination rate, seedling growth, Fresh weight, dry weight, root length, shoot length, IAA, GA, DNA while increased ABA contents of wheat in petridishes as compared to control. In pots sunflower plant affected on soil change soil texture from sandy soil to sandy loam soil. 109. Root Inhibitory Effect of Caffeic Acid: Role of Reactive Oxygen Species (ROS) S. Kaur1, H. P. Singh2, D. R. Batish1 and R. K. Kohli1 1Department of Botany 2Centre for Environment and Vocational Studies, Panjab University, Chandigarh 160 014, India Email: [email protected] Caffeic acid (CA), a well known phenolic acid ubiquitously present in plants, is widely implicated in allelopathic interactions among plants. The present study investigated the effect of CA on adventitious root formation in mung bean (Phaseolus aureus) hypocotyls and whether it involved an induction of oxidative stress via generation of reactive oxygen species (ROS). CA significantly reduced the de novo root formation as depicted by decrease in number of rooted hypocotyls, and reduction in number and length of adventitious roots. We further explored the role of conventional stress-response to CA exposure in terms of oxidative stress markers (malondialdehyde, MDA and hydrogen peroxide, H2O2) and alterations in antioxidant enzymes. In CA treated mung bean hypocotyls, a sharp increase in H2O2 and oxidizing ability observed indicating a possible cellular damage. Further, CA significantly enhanced solute leakage and increased levels of MDA content thus indicating lipid peroxidation and negative impact on membrane stability. To counter the CA-induced stress in hypocotyls, there occurred an upregulation of scavenging enzymes’ viz. SOD (superoxide dismutase), APX (ascorbate peroxidase), and CAT (catalase) activities. Increased activities of enzymatic antioxidants indicated their role in protecting from cellular damage induced by enhanced MDA and H2O2 (ROS) generated upon CA treatment. The study concludes that CA inhibits root formation in mung bean hypocotyls by inducing ROS-generated oxidative stress and altering activities of scavenging enzymes. 110. Allelopathic Potential and Molecular Analysis of Some Rice Cultivars (Oryza sativa L.) Cultivated in Kurdistan Region – Iraq


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Z. M. Al-Asaadee, J. M. S. Jubrael, H. A. M. Mezori University of Dohuk, Iraq Email: [email protected] Several experiments were conducted to determine the allelopathic potential variation among six rice cultivars locally cultivated in Kurdistan Region. This was performed to study the effect of aqueous extract of rice cultivars on seed germination, seedling growth, and some physiological and possible genetic malformation of lettuce plant. Aqueous extracts of different rice cultivars significantly inhibited seed germination, the highest reduction was noticed in the cultivar shash-mah (80%).Seedling growth was found to be more sensitive to the water soluble extracts than seed germination, the inhibition was (92%).the aqueous extracts of all rice cultivars significantly reduced chlorophyll a,b, total chlorophyll content, ion uptake such as nitrogen , phosphorus, calcium , Magnesium, potassium , and sodium of lettuce leaves , the reduction in chlorophyll and ion uptake appeared to be paralleled to the reduction in growth of lettuce plant. Generally, shash-mah cultivar showed the highest allelopathic potential among other rice cultivars used. To investigate any possible genetic malformation, genomic DNA of lettuce as the model plant was isolated and quantified. After optimization of RAPD reactions conditions, ten different decamer primers of arbitrary sequences were used to scan for DNA polymorphisms. Results of repeated experiments revealed no genetic changes had occurred within primers annealing sites, thus, most probably, it may be suggested that allelochemicals released did not have any genotoxicitical effects on lettuce plant. 111. Changes of Allelopathic and Autotoxic Potentials of Zanthoxylum bungeanum Under Enhanced Ultraviolet-B Radiation K. Pan, H. Li, J. Wang, Y. Wang Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China Email: [email protected] Chinese prickly ash (Zanthoxylum bungeanum Maxim.), an important commercial crop growing in Asia, is widely planted in the mountain areas of the eastern Qinghai-Tibetan Plateau. Continuous cropping problem of Chinese prickly ash occur at this region and could be incurred by autotoxic effects. Meanwhile, increases in solar ultraviolet-B radiation (UV between 280 and 320 nm) due to continuing depletion of stratospheric ozone have been well documented over the past several decades. However, Effect of enhanced ultraviolet-B on allelopathic and autotoxic potential of Chinese Prickly Ash has seldom been reported. The objectives of the study were to determine: (1) change of autotoxic potential of Chinese Prickly Ash for the seedlings using green house experiments, and (2) change of allelopathic potential of Chinese Prickly Ash using alfalfa, lettuce as target organism exposure to leaves aqueous extracts. Results indicated that increases in solar ultraviolet-B radiation significantly alter Chinese prickly ash autotoxic and allelopathic potentials. A significant inhibitory effect on germination rate was observed at all concentrations of extracts of Zanthoxylum leaf both treated with enhanced ultraviolet-B and untreated control except on radish (Raphanus sativus) under 12.5g L-1 concentration. To

alfalfa (Medicago sativa) and lettuce (Lactuca sativa), significant differences in inhibitory effects of Zanthoxylum leaf extracts of 50 g L-1 and 25 g L-1 were observed positively in response to enhanced ultraviolet-B, and so did on Medicago sativa under 12.5 g L-1, but to radish there was no significant differences in all concentration under bioassay. Content of UV-B absorbing compounds in Zanthoxylum seedlings responded positively to increases in UV-B radiation. 112. Understanding the Mode of Action of BOA (2-benzoxazolinone) and PCA (Protocatechualdehyde) on Arabidopsis Plants M. J. Reigosa Roger, A. Martínez-Peñalver, A. M. Sanchez Moreiras Lab. of Plant Ecophysiology. Facultade de Ciencias. Universidade de Vigo. Campus Lagoas-Marcosende s/n. 36200-Vigo (Spain) Email: [email protected] Plants alter gene expression pattern for coping with stress-imposing changes in the environment. When an environmental change takes place, common and linked signal transduction pathways are activated, which can be implicated in stress acclimation or cell death depending on the degree of the stress situation. Measurement of changes in gene expression can help in understanding the global cellular responses concerning consecutive changes in the expression patterns of numerous genes and gene-gene interactions after biotic and/or abiotic stress. Analysis of proteomic patterns, with emphasis on stress-related proteins, appears as a new approach in the gene expression studies. Comparative analyses for control and treated plants give qualitative and quantitative information about the changes at protein expression level, which is used for understanding gene function or correlating cell responses in front of biotic or abiotic stress. This study is focused on understanding the mode of action of the secondary metabolites 2-3H-benzoxazolinone and protocatechualdehyde. Some previous studies have shown already that plant derived natural compounds (hydroxamic acid derived compounds, phenolic acids, terpenoids, etc.) with a role in plant-plant interactions can be decisive because of their high potential as possible natural herbicides with a very short half-life and a benign toxicological profile. However, we need to know in detail the mode of action of these compounds for a realistic use of such molecules on pest control techniques, knowing where, when, and how they affect plant metabolism, characterizing their primary and secondary effects, and understanding their molecular mechanisms of action. The current experiment is based on this characterization by obtaining proteomic profiles from treated Arabidopsis plants and comparing them with untreated plants. To establish the right harvesting time, 5 weeks old Col-0 Arabidopsis plants were treated once with the bioactive compounds 1 mM 2-benzoxazolinone (BOA) and 1 mM Protocatechualdehyde (PCA) and chlorophyll a emission measurements were recorded for each plant at 1, 3, 6, 12, 24 and 30 h after allelochemical watering. Maximal PS II quantum yield, quantum yield of nonregulated energy dissipation, effective PS II quantum yield, and the


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coefficient of nonphotochemical quenching were recorded for each measuring time with an IMAGING-PAM M-Series Fluorometer (Chlorophyll Fluorescence System) from Walz. With this record we get not only measure images of chlorophyll fluorescence but provide also all relevant chlorophyll fluorescence parameters using the Saturation Pulse method. Information about photosynthetic activity and its spatiotemporal variations were obtained. Plants were harvested for RNA extraction when the first changes on photosynthetic yield and fluorescence appeared and 24 h later, a new harvest was done for two-dimensional electrophoresis proteome studies. The two allelochemical compounds showed fast effects on Arabidopsis treated plants, which were confirmed by two-dimensional electrophoresis. Not only reduced amount but also different protein profile was detected on treated plants. 113. Protein Profiles from Lettuce Plants: Testing the Stress Hypothesis A. M. Sanchez Moreiras, M. J. Reigosa Roger Lab. of Plant Ecophysiology. Facultade de Ciencias. Universidade de Vigo. Campus Lagoas-Marcosende s/n. 36200-Vigo Spain Email: [email protected] The classical Gramineae compound 2-benzoxazolinone (BOA) has been associated with dose-dependent germination inhibition and growth reductions, as well as with more in-depth effects on energy metabolism in higher plants. In the same way, different measurements related to oxidative damage on plant metabolism were significantly affected by the allelochemical BOA. Our interest and main objective in the second phase of this experiment was to know if the presence of another stress in the medium could enhance the previously found effects of BOA on plant metabolism. As secondary objective we want to know also if the response from plants treated with the combined stress treatment is similar to those from BOA or from salt-treated plants. The stress hypothesis is considered to be a second possible paradigm in allelopathy. The first would be the Rabotnov’s hypothesis. “It means that in special situations where plants are under stress, allelopathy could become important”. As reviewed by several authors, some works have suggested that temperature, irradiance, salt, nutrient, and moisture stresses can intensify the negative effects of an allelochemical, appearing additive germination or growth inhibitions in combined experiments. In our lab, previous studies demonstrated that using two single-stress treatments (BOA and Salt) and a parallel analysis of the combined stress (BOA+Salt), plant responses to abiotic stress were very different depending on the presence of the allelopathic compound. BOA+Salt led to greater inhibition of plant growth, vigor, and viability than either treatment alone. BOA treatment alone induced mechanisms of tolerance to salt stress, while the combined BOA+Salt treatment increased salt sensitivity. In that way our results morphological and physiological results validated the stress hypothesis previously proposed. We propose with this experiment to compare the protein patterns from lettuce leaves during such induced BOA phytotoxicity (allelochemical action) and Salt treatment (abiotic stress) by using two-dimensional gel electrophoresis. Two-dimensional electrophoretic patterns were obtained from BOA and BOA+Salt treated plants to be a complement of

previously published metabolic analyses. It can help us in the understanding of the molecular basis of BOA mode of action, its implication with environmental stresses, and its correlation with the results obtained previously by functional genomics. The protocol used in this work was sensitive enough for the solubilization and separation of proteins from the very large lettuce genome. We got reproducible gels with high levels of quantified spots for a proteome never analyzed by two-dimensional electrophoresis: the lettuce leaf proteome. With only 7 µg protein we got an equitable representation between acidic and basic as well as high and low molecular mass in these gels. This work confirmed also the different protein content on plant metabolism under biotic and abiotic stress, which resulted in significant inhibition on protein number for plants treated only with BOA. Like so, plants exposed only to BOA showed less protein content, less global intensity, and less specific new proteins for this treatment. We propose the identification in of the previously showed spots for validating the nature of these spots as ‘stress proteins’ and their role in the whole plants stress response induced after BOA or BOA+Salt treatments. 114. Allelopathic Potential of Caesulia axillaries on Physiology and Yield of Wheat Devendra Singh1, Mrintunjay Kumar2, Nawalesh K. Sinha3 and S.S. Mandal* Department of Agronomy, Rajendra Agricultural University, Bihar, Pusa, Samastipur-848 125 (India) Email: [email protected], An experiment was conducted during rabi season of 2005-2006 and 2006-2007, to study the allelopathic potential of Caesulia axillaries, a predominant weed of rice showed an allelopathic effect in succeeding crop, wheat under rice-wheat cropping system which is most adopted cropping system of the state Bihar. Application of dried plant part of Caesulia axillaris @ 1.0, 2.0, 3.0, 4.0 and 5.0 t/ha was used as treatment. Control plot were run without application of Caesulia axillaries. The plot treated with 1.0 and 2.0 t/ha dried Caesulia axillaries observed significantly higher test weight (1000-grain weight) and grain yield. All physiological yield attributes viz. root weight, root volume, leaf area and specific leaf weight showed an increasing trend but significantly higher at the application of 1.0 and 2.0 t/ha of dried Caesulia axillaries per plot. Chlorophyll-a, -b and total Chlorophyll were also observed in increasing order up to the treatment 4.0 t/ha of dried Caesulia axillaries. Enzymatic activities viz. Nitrate reductase activity and total dehydrogenase activity in terms of root activity were also observed in increasing order. A significant increase and then decrease in Morpho-physio-biochemical yield attributes and yield by the application of Caesulia axillaries dried plant part indicating the synergistic and antagonistic effect at lower and higher concentrations, respectively. 115. The Comparative Study of Allelopathic Effects of Acroptilon repens L. on Some of Physiological Properties of Brassica napus L. and Accompanying Weeds


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1F. Abbassi, 2M. R. Rusta Nejad, 3R. Ghorbani and 4M. Bazubandi 1Biology Department of Islamic Azad University of Mashhad, Iiran 2Agriculturi Department of Islamic Azad University of Mashhad, Iiran 3Agronomy Plant Breeding Department of Agriculture Faculty of Ferdowsi University Mashhad,Iran 4Research Center of Khorasan-e-Razavi, Plant Pests & Diseases Research Institute, khorasan, Iran. Email: [email protected] In order to investigation of allelophatic effects of different sections of russian knapweed (Acroptilon repens L.) on germination and vegetative growth of canola (Brassica napus L.), wild mustard (Sinappis arvensis L.) and wild barley (Hordeum spontaneum) two separate examinations in a factorial design with completely randomized arrangement and four replications were conducted. In the first examination (germination) treatments were combinations of two different sections of russian knapweed (shoot and root), ten different levels of water extracts (0, 15, 25,30,35,40,45,50,75 and 100 %) and three different plants (canola, wild mustard and wild barley). In the other examination that was performed in pots, treatments were two different sections of russian knapweed (shoot and root), three levels of dried powder (0, 0.25, 0.75, 1 and 1.25 % w/w soil) and different plants (canola, wild mustard and wild barley). Results indicated intense allelopathic effects but the magnitude on each species and different criteria of germination and vegetative stages were different. Generally germination criteria significantly affected more than vegetative growth. The effects of shoot section of russian knapweed was more intense than the root section and wild mustard was the most sensitive plant, although wild barley was the lest sensitive plant to russian knapweed. 116. Inhibition of Maize (Zea mays) Root Growth by m-Tyrosine Results from Cell Cycle Disruption R. Bogatek1, A. Rudzińska-Langwald2, W. Kurek2, Z. Kostrzewa1, A. Gniazdowska1 1Department of Plant Physiology, Warsaw University of Life Science-SGGW, Nowoursynowska 159, 02-776 Warszawa, Poland 2Department of Botany, Warsaw University of Life Science-SGGW, Nowoursynowska 159, 02-776 Warszawa, Poland. Email: [email protected] The non protein amino acid, m-tyrosine, was identified as a major active allelopathic component of fescue grasses root exudates. In order to study the phytotoxic activity of m-tyrosine, its inhibitory effect was investigated using young seedlings of maize (Zea mays). We demonstrated that m-tyrosine applied in concentrations 250-1000 µg ml-1 strongly inhibits root growth of maize in a dose-dependent manner. Observations of mitoses in squashed root tips revealed strong suppression of cell divisions after 24 hour treatment with m-tyrosine. There were cells with aberrant metaphases and anaphases. In the majority of cells in metaphase, chromosomes arranged in a metaphase plate could not be identified. The pattern of mitotic microtubular assemblies in meristematic cells was also studied by means of α-tubulin immunodetection. m-Tyrosine treatment resulted in

impairment of mitotic spindle formation. We have also studied cell cycle during imbibition in m-tyrosine solution using a flow cytometric analyses of the nuclear DNA content. m-Tyrosine-induced disturbance in cell cycle of meristematic root cells is probably the reason of the observed root growth suppression. The inhibiting effect of m-tyrosine on maize root growth was expressed also by strong decrease in ethylene production by the tissue. The regulatory role of phytohormones in plant-plant allelopathic interaction will be discussed. 117. Allelopathic Effect of Zingiber officinale on Seed Germination and Seedling Growth of Soybean and Chive C. Han, K. Pan, J. Wang, Y. Wang Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China Email: [email protected] Zingiber officinale (ginger) produces a pungent, aromatic rhizome that is valuable all over the world either as a spice or herbal medicine, being an important horticultural crop in tropical Southeast Asia. However, ginger plant is easily infected by Pseudomonas solanacearum, and thus ginger yield dramatically decreased. Crop systems of ginger intercropped with soybean and chive are traditionally considered as an effective ways to reduce frequency and intensity of ginger blast in Leshan City, Sichuan Province, China. Nevertheless, whether ginger has significantly allelopathic effect on seed germination and early seedling growth of soybean and chive is still unknown. In the paper, the rhizome, stem and leaf aqueous extracts of ginger were assayed at 10, 20, 40, and 80 g l-1 for their effects on seed germination and early seedling growth of soybean and chive. All aqueous extracts at all concentrations inhibited seed germination, seedling growth, water uptake and lipase activity of soybean and chive compared with the control, and the degree of inhibition increased with the incremental extracts concentration. The degree of toxicity of different ginger plant parts can be classified in order of decreasing inhibition as stem > leaf > rhizome. The results of this study suggest that rhizome, stem and leaf of ginger contain water soluble allelochemicals which could inhibit seed germination and seedling growth of soybean and chive. The rhizome is the main harvested part of ginger. The residue (mainly stems and leaves) of the ginger plant should be removed from the field so as to diminish its inhibitory effect. Further work is needed to specify and verify the allelochemicals produced by this plant. The results of this study suggest that ginger allelochemicals are heterotoxic, and thus intercropping should not be practiced using ginger if the potential production of the system is soybean and chive. 118. Camphor and Menthol Affect Plant Growth, Polarity, and Cytoarchitecture via Their Effects on the Actin Cytoskeleton O. Šamajová, M. Schlicht, B. Kriegs1, Margot Schulz1 and F. Baluška IZMB (Institut für Zelluläre und Molekulare Botanik) Universität Bonn Kirschallee 1, 53115 Bonn, Germany


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1IMBIO (Institut für Molekulare Physiologie und Biotechnology der Pflanzen, Universität Bonn Karlrober Kreiten Str. 13, 53115 Bonn, Germany Email: [email protected] The volatiles camphor and menthol are allelochemicals with high biological activity. Both of them affected growth of Zea mays L. and Arabidopsis thaliana seedlings in a dose-dependent manner. At higher concentrations, both monoterpenes inhibited growth of primary and adventitious roots and coleoptyles, but hypocotyls growth was unaffected. At lower concentrations moderate growth stimulation of seedlings was observed. Treatment with camphor for 24 hours caused anatomical changes in the root apex of both tested plants. Root apex was regularly swollen. Abnormalities in the growth of shoots and swollen root tips are already known effects of the monoterpene 1,8-cineole. Camphor and menthol were additionally tested for their effects on plant cytoarchitecture. Both monoterpenes caused reorganisation and partial disruption of F-actin filaments consistent with their influence on cellular growth. Effects on actin filaments seem to be a common mode of action of several monoterpenes as it was also observed with osteoclasts from rats. 119. Approaching Molecular Backgrounds of Stomata Response to Monoterpenes B. Kriegs, H. Peisker, A. Ulbrich1 and M. Schulz IMBIO (Institut für Molekulare Physiologie und Biotechnologie der Pflanzen) Universität Bonn Karlrobert-Kreiten-Str. 13, 53115 Bonn, Germany 1Forschungszentrum Jülich ICG.3:Phytosphäre, D-52425 Jülich, Germany Email: [email protected] The lipophilic layers of Arabidopsis thaliana leaf surface and the stomata are primary targets of monoterpene allelopathic attack. Exposure to the monoterpenes camphor and menthol or to the volatiles of the aromatic plants Mentha piperita, Lavandula latifolia and Artemisia camphorata resulted in a dramatic increase of stomata aperture and enhanced transpiration. Long term exposure to the two monoterpenes killed Arabidopsis plants by desiccation. On the other hand, short term fumigations with low amounts of the monoterpenes could also stimulate the growth of Arabidopsis plants under phytotron conditions. To get deeper insights into molecular events that trigger damage or growth stimulation we investigated gene inductions, malate dialdehyde (MDA) production and PEPCase activity in Arabidopsis leaves exposed to camphor and menthol. By means of real time PCR, we found alterations in the expression of numerous genes, some of them are involved in stress (drought) response, such as strongly induced RD29B, AREB1 and AREB2. MAP kinase 3 gene (MPK3), involved in stomata closure, was induced, whereas PEPC was down regulated. PEPCase activity was as well reduced, the MDA content showed no alterations. Although the machinery for stomatal closure was activated, closing of the stomatal aperture failed after long term exposure to the monoterpenes. The reasons for the failure are currently under investigation. High concentrations of monoterpenes and long term treatments are phytotoxic due to uncontrolled transpiration ending up in plant death. Short term exposures are supposed to increase plant fitness which can induce in growth stimulations.

120. Allelopathic Effects of Phenolic Extracts of Canola (Brassica napus L.) on Growth and Physiological Responses of Soybean (Glycine max L.) Seedlings Z. Gerivani1, Gh. R. Haddadchi1 and M.Gerivani2 1Department of Biology, College of Science, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan.Iran 2Department of Plant Breeding, College of Agriculture, Zabol University, Zabol, Iran. Email: [email protected] Allelopathy, the production and release of toxic chemicals produced by one species that affect receiving susceptible species, has been the subject of diverse degrees of scientific enquiry. In this study soybean seedling were grown in sand culture containing root and shoot extracts. Phenolic extracts of canola shoot (including leaves, stem, and flower) and root plant part were made by methanol 70%, to determine their effects on seedling growth, hill reaction, chlorophyll content, and antioxidant enzymes. In the 3-leaf stage, increasing the phenolic extract concentration of separated canola plant parts decreased soybean seedling length and weight, specially reduced the root hair density compared with control. In higher concentration of root and shoot extracts severely reduced hill reaction, chlorophyll a and total chlorophyll. There were no significant difference in chlorophyll b under root extracts but was reduced by shoot extract. In compared with control, root SOD activity was enhanced by 26.2% and 36.4% leaf SOD enhanced by 15.6% and 12.6%, root CAT activity was enhanced by 972% and 975%, leaf CAT activity was enhanced by 205% and 183% by root and shoot phenolic extracts respectively. The result showed that there were no significant difference in root peroxidase activity, but leaf POD activity increase significant by root and shoot extracts. Membrane lipid peroxidation, in root cells, also was enhanced by root and shoot extracts. Synthesis of SOD and CAT as an adaptive response to oxidative stress has been reported. In the present study, the activities of CAT and SOD were also induced in agent dose-dependent manner, suggesting that the oxidative stress condition led to an increased antioxidant capability of root and leaf cells. Root was more sensitive to extract source than leaf. 121. In vivo Effects of Cercocarpus macrophyllus Organic Extracts on Trifolium alexandrinum and Lolium perenne and Bioactivity-guided Isolation of 3β,28-dihydroxyolean-12-ene and its Effect as a Hill Reaction Inhibitor on Photosynthesis C.J. Meixueiro-Galán1, B. King-Díaz1, M.I. Aguilar-Laurents2, B. Lotina-Hennsen1. 1Departamento de Bioquímica 2Departamento de Farmacia, Fac. de Química, Universidad Nacional Autónoma de México, México D.F., C. P. 04510. México Email: [email protected] Hexane, chloroform and methanol extracts obtained from eight different plants collected from Guerrero State,


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Mexico; were sprayed at 10 and 50 µM on Trifolium alexandrinum (a monocot plant) and Lolium perenne (an eudicot plant) after 20 days of emergence. Chlorophyll a fluorescence of PSII determination was performed after 24, 48 and 72 hrs for control plants and plants sprayed; dry biomass was measured after 15 days of treatment. Of all organic extracts assayed, those obtained from Cercocarpus macrophyllus plant were the most active affecting these activities, therefore this plant was chosen for bioactivity-guided chemical study. Cercocarpus macrophyllus belongs to the family Rosaceae. It is found through north of Mexico and west of United States. The n-hexane extract from the C. macrophyllus leaves was fractionated by bioactivity-guided, led to the isolation of the triterpene 3β,28-dihydroxyolean-12-

ene, erythrodiol, this is the first molecule isolated from this plant. This compound inhibited ATP synthesis, the I50 value was 120 µM. Erythrodiol behaved as a Hill reaction inhibitor. It inhibited the uncoupled electron flow on photosystem II and the partial reactions from H2O to silicomolybdate and from DPC (diphenyl carbazide) to DCPIP (dichlorophenol indophenol). These results suggested that erythrodiol inhibits the span of electron transport chain from P680 to QA. The fluorescence decay data indicated the formation of silent reaction centers, inactive reaction centers can neither reduce QA nor back transfer their excitation energy to the antenna, instead they transfer the energy to heat.

Main Topic 7: Invasion ecology and allelopathy 1 122. Integrated Invasive Plant Management in the Adirondack Park, New York, USA Hilary A. Oles1, Steven M. Flint1 and Daniel M. Spada2 1P.O. Box 65, The Nature Conservancy – Adirondack Chapter, Keene Valley, New York 12943, USA 2P.O. Box 99, New York State Adirondack Park Agency, Ray Brook, New York 12977, USA Email: [email protected] The Adirondack Park Invasive Plant Program (APIPP) is a two-time, national award-winning program that provides the expertise and framework through area-wide partnerships for invasive plant monitoring, management, and community outreach in the 2.4 million hectare Adirondack Park. Initiated in 1998 and formalized through a Memorandum of Understanding in 2003, the Program is a partnership of state agencies, not for profit organizations, and resident groups. Partners developed an integrated management plan to expand partnerships with communities across the region and inventory, map, monitor, and eradicate infestations to prevent the spread of certain targeted invasive species in the Adirondacks. Examples of target species include Alliaria petiolata, Fallopia japonica, Phragmites australis, Lythrum salicaria, Cynanchum spp., Myriophyllum spicatum, Potamogeton crispus, and Trapa natans. Program successes include developing a regional volunteer monitoring program to detect aquatic invasive plants; recruiting and training 300 staff and citizen volunteers to survey 205 lakes and ponds; engaging 100 volunteers to inventory, map, and control hundreds of terrestrial plant sites Park-wide; managing terrestrial invasive plants using best management practices including biological, physical, and chemical control techniques; identifying research needs and pursuing projects to meet those needs; developing educational materials to increase public awareness and a website www.adkinvasives.com to facilitate information exchange; reaching more than 10,000 individuals through presentations since 2004; and, leveraging $1,100,000 since the program’s inception. Invasive species management is most effective when addressed at the landscape level with the synergy of diverse partnerships. The APIPP has successfully incorporated this strategy by utilizing the strengths of each Partner, organizing hundreds of volunteers and approaching the daunting issue of invasive

plant management in a comprehensive, systematic, and cooperative manner that has produced real on-the-ground results. 123. The Invasive Swallow-worts: What Do We Know About Their Biology and Management? Kristine M. Averill1, Antonio DiTommaso1, Charles L. Mohler1, and Lindsey R. Milbrath2

1Dept. of Crop and Soil Sciences, Cornell University, Ithaca, NY 14853, USA 2USDA-ARS Robert W. Holley Center for Agriculture and Health, Ithaca, NY 14853 USA Email: [email protected] The swallow-worts [Vincetoxicum rossicum (Kleopow) Barbar. and V. nigrum (L.) Moench] are nonnative, perennial, herbaceous vines in the Apocynaceae that are invading natural areas in the northeastern U.S.A. and southeastern Canada. A classical biological control program was initiated by the USDA-ARS in 2005 with the goal of providing sustainable and economical long-term suppression of these two aggressive species. This long-term management approach will complement the search for effective short-term strategies, such as chemical and mechanical control. The success of this biological control effort is dependent on the availability of plant demographic data that can be modeled to determine which swallow-wort life stage(s) may be most susceptible to control efforts. Thus, we initiated several field studies in Central New York State that focused on gathering such data, including assessing (a) the degree and rate of swallow-wort vegetative expansion of the in old-field and/or forest environments and (b) seedling establishment success in habitats subjected to different disturbance regimes. In the vegetative expansion study, the number of stems per plant did not change during two growing seasons in the forested sites, but increased by 30% from July 2005 to July 2007 in the old-field sites. First-year (2007) results from the seedling establishment study varied by site and type of disturbance. At the Hanshaw site, total seedling emergence was greater on mowed plots (21%) than plots of other treatments: glyphosate + tilled (4%), glyphosate only (7 %), and control (11%). Control


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plots had greater emergence than glyphosate + tilled plots. At the Mt. Pleasant site, total emergence in May 2007 was 18% and did not differ between treatments. In September 2007, at Mt. Pleasant, a better drained site located at a higher elevation than the Hanshaw site, survival was 73 and 88% of May and June 2007 cohorts, respectively. At the Hanshaw site however, survival to September was 40 and 43% of May and June 2007, respectively. Additional research on these two swallow-worts is focused on determining (a) resource allocation patterns following the removal of aboveground tissue at different intensities and frequencies, (b) the duration of the juvenile phase in habitats varying in light availability, and (c) seed survival at different soil depths. 124. Studies on the Ecology and Allelopathic Potential of Black and Pale Swallow-worts (Vincetoxicum nigrum and rossicum) in New York State USA Cameron Douglass1, Leslie A. Weston2 and Antonio DiTommaso1 1Cornell University College of Agriculture and Life Sciences, Ithaca NY, 14853 USA 2Charles Sturt University, E H Graham Research Centre, Wagga Wagga NSW Australia. Email: [email protected] Black and pale swallow-wort are invasive perennial vines that were introduced to estates and botanical gardens in North America as novel plants of interest in the 19th century. Recently, these species have become invasive throughout New York, Ontario, Quebec and New England states. Our research sought to: 1) develop an empirical basis for the role that allelopathy might play in the competitive ability of these species, and 2) evaluate both morphological and genetic diversity of swallow-wort populations collected from across New York. We collected swallow-wort seeds and studied populations from numerous habitats across New York, including open fields and forest understory. Significant variation in swallow-wort growth and morphology was observed in both species, and range of infestation was broad but different for both species and nearly converged in several locations. Results from laboratory agar and Petri dish assays showed that while swallow-wort root exudates, particularly those of the pale species, were capable of causing significant root length reductions and germination inhibition in both ’introduced’ and ‘natural’ bioassay indicator species, swallow-wort species did not exhibit comparatively greater allelopathic abilities than the closely related milkweed. Allelopathic toxicity by swallow-wort root exudates and tissue leachates may not play a substantive role in competitive plant-plant interactions in which the invasive swallow-wort species are clearly superior in field settings. Molecular marker-based comparison among local populations of both species showed consistent and significant interspecies variation but very little intraspecies variation among populations across New York. Our preliminary results from molecular marker-based studies suggest that genetic diversity levels among invasive swallow-wort populations in New York are lower than might be expected given the multiple introductions of swallow-worts in North America over an extended period of time. Principal components analysis of morphology, soil and climate factors indicated that variation in mean plant height between sites was strongly correlated with soil pH and Mg levels at the site, and

precipitation levels were highly correlated with variation in swallow-wort leaf size. 125. The Curse of Paterson’s Curse J. E. Pratley and A. N. Seal E.H. Graham Centre for Agricultural Innovation, Charles Sturt University, Wagga Wagga, NSW, Australia 2678 Email: [email protected] Paterson’s curse (Echium plantagineum) was introduced into Australia from Europe as a garden plant. It escaped from a garden near Albury in southern NSW because the garden was adjacent to a travelling stock reserve and now covers a large part of the temperate (southern) part of the continent. It often occurs as a totally dominating plant community and is considered one of Australia’s worst pasture weeds. It is an enigma in that its pollen produces the finest quality honey yet it is toxic to grazing livestock, particularly in their second year of grazing. This is due to its content of pyrrolizidine alkaloids which accumulate progressively in the livers of affected animals. Preliminary tests suggest that Paterson’s curse exudes allelochemicals, most likely alkaloids, which interfere with the growth and development of neighbouring plants and give this weed a competitive advantage for its invasion of pastures and rangelands. We will briefly discuss the biology and ecology of Paterson’s curse in southern Australia and possible strategies for management of this invasive pasture weed. 126. Parthenium hysterophorus L Invasion and Allelopathy in Nepal PK Jha, BB Shrestha, S Maharjan, S Joshi and B Timsina Central Department of Botany, Tribhuvan University, Kathmandu Nepal Email: [email protected] Parthenium hysterophorus L was first reported in Nepal in 1967 but it remained unnoticed until the end of twentieth century. In the last decade, it has spread extensively in mid hills and terai plains, particularly in urban cities such as Kathmandu, Pokhara, Hetaunda and Butwal, posing a serious threat to native species, livestock and human health. Currently, this species has invaded around 30% of fallow lands (grasslands and roadside areas) in the Kathmandu valley, indicating its high rate of spread. To understand its invasive ecology, its distribution, reproductive biology, phenology, leaf attributes and allelopathic effects have been studied in Kathmandu (location: 85۫ 10’ to 85۫ 32’ E, 27۫ 28’ to 27۫ 34’ N, alt. 1350 – 1500 m). The vegetative phase exists for about four weeks and reproductive phase for about 12-16 weeks in each individual plant. Monsoon is the main growing season (May to September) but the plant could germinate, flower and produce seed throughout the year at moist localities. The remaining plants were found in the flowering stage in most months during the year. Seed production was prolific (12-16 weeks) and seed output of individual plants collected in August ranged from 1392 to 3864 seeds/plant. The plant has replaced native palatable species such as Acrachne racemosa (Heyne) Ohwi., Trifolium repens L., Imperata sp., Chrysopogan


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aciculatus (Retz.) Trin., Sporobolus sp. and Dactyloctenium aegypticum (L.) P. Beauv. Among the bioassay test species, crucifers appeared to be more sensitive to allelopathic inhibition of P. hysterophorus to seed germination. Negative impact to human and livestock health (e.g. allergy, bittering of milk products) has been already noticed in some urban cities such as Hetauda. Currently, none of the proposed control measures has been implemented by government authorities to mitigate the impact of invasion of P. hysterophorus. 127. Allelopathic Potential as an Interference Strategy of the Invader Weed Rottboellia cochinchinensis (Itchgrass) Silvia M. Contreras-Ramos1, Luc Dendooven2, and Ana Luisa Anaya1 1Laboratorio de Alelopatía. Departamento de Ecología Funcional. Instituto de Ecología. Universidad Nacional Autónoma de México, Apartado Postal 70-275, 04510 México, D.F. 2Laboratorio de Ecología de Suelos, Departamento de Biotecnología y Bioingeniería. Centro de Investigación y Estudios Avanzados del IPN (Cinvestav-IPN), Av. Instituto Politécnico Nacional No. 2508, 07360 México Email: [email protected] Rottboellia cochinchinensis (Lour.) (itchgrass) is an annual tropical weed grass very competitive that invades agricultural fields in different countries. Itchgrass is aggressive causing serious problems in the different crop fields that invade and it is considered one of the 12 worst weeds in the world. However, there is little information about its allelopathic potential and the effects of decomposition of its organic matter (leaves and roots) on microbial soil processes such as nitrification. We investigated the allelopathic potential of R. cochinchinensis that invades maize and sugar cane fields along the coast of the Gulf of Mexico. This weed was collected in an Experimental Agricultural Field in Cotaxtla, Veracruz, Mexico. In vitro bioassays with leachates (1%) from fresh and dry entire leaves, primary and secondary roots were performed to test their effects on the root growth of five test plants using non-germinated and pre-germinated seeds. Results showed in general that Echinochloa crus-galli was the most sensitive test plant to the phytotoxicity of all leachates of Rottboellia. Leachates of leaves and secondary roots (both fresh and dry) produced the strongest root growth inhibition on the three maize varieties. Amaranthus root growth was more inhibited by fresh Rottboellia material. In addition, we performed an aerobic incubation with soil moistened with leachates (2%) from dry entire leaves or dry secondary roots, and amended with dry leaves or dry roots (2%) to evaluate their effect on nitrification. We evaluated ammonium, nitrite and nitrate concentrations and microbial respiration during 56 days. Our study is a contribution to the knowledge of the allelopathic potential of invasive itchgrass as a more advantageous interference strategy of this grass weed in Mexican crop fields. 128. Density-dependent Crop Allelopathy: Effectiveness for Weed Control, Associated Root Interaction and Morphology Changes M. An1, C.J. Li2, and J. Pratley1

1E.H. Graham Centre for Agricultural Innovation (a collaborative alliance between Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga, NSW 2650, Australia. 2College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100094, China Email: [email protected] Australia is facing severe challenges related to chemical options for effective control of certain crop weeds. Alternative means are urgently required to address this issue. Laboratory experiments were conducted to assess the effectiveness of density-dependent crop allelopathy in weed control and to examine associated root mechanisms by using wheat-annual ryegrass (Lolium rigidum) interaction as a model system. It was found that increasing density of wheat plants with strong allelopathic potential could increase wheat competitiveness and significantly inhibit the growth and development of annual ryegrass. There was an upper density threshold for maximum weed suppression, which was influenced by wheat cultivar. By examining the associated root interaction, it was found that both total root length and total root surface area of ryegrass steadily decreased as the wheat density increased, while the average root diameter of ryegrass steadily increased. Annual ryegrass roots consisted of fibrous roots with diameters ranging between 0.0001 and 0.6mm. Their distribution and dominance was uneven and wheat density dependent. At a lower wheat density (0-10 plants/container) the dominant root diameter of annual ryegrass (>60% of roots) was between 0.001 and 0.2 mm. As wheat density increased the percentage was gradually dominated by the root diameter between 0.2 and 0.4 mm, up to 50%. It was postulated that increased root diameter and decreased root length and surface area might have resulted from strong allelopathic effects from a significant quantity of allelochemicals exuded from wheat plant roots at high densities. This might have ultimately led to the suppression of annual ryegrass growth and development. Further examination on chemical association is currently under the way. Those results suggest that density-dependent crop allelopathy may have agronomic potential to contribute to integrated weed management programs for the effective control of weeds in field. 129. Is the Allelochemical Parthenin Responsible for the Invasiveness of Parthenium hysterophorus L.? Carl Reinhardt1, Regina Belz2 & Karl Hurle2

1Department of Plant Production and Soil Science, University of Pretoria, Pretoria 0002, South Africa 2University of Hohenheim, Institute of Phytomedicine, Department of Weed Science, 70593 Stuttgart, Germany Email: [email protected] Parthenium hysterophorus L. (parthenium) is a particularly successful alien invader plant in many moderate and warm climate countries around the world. It belongs to the Asteraceae family (tribe Heliantheae) and originates from around the Gulf of Mexico including the West Indies and presumably central Argentina. The fast spread and rapid dominance of native vegetation by this


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weed are attributed to its rapid growth rate, high fecundity, competitive ability and allelopathic effects. Numerous studies have given allelopathy a potential role in the invasiveness of parthenium. The sesquiterpene lactone parthenin has been described as a major phytotoxin biosynthesized by parthenium and a role in allelopathy is presumed. However, phytotoxicity, concentration and location of parthenin in plants represent only part of the knowledge needed to ascribe the compound an ecological role. Further important factors determining allelopathic effects of parthenin in nature are its biosynthesis, bioavailability, phytotoxicity and persistence in soil. Our studies identified capitate-sessile trichomes on leaves as the main source of parthenin in P. hysterophorus; they contain almost 100 % parthenin which represents 2.4 % of fresh weight. Parthenin contributed between 16 and 100 % to overall phytotoxicity of aqueous leaf extracts. In dose-response bioassays, plant species differed considerably in their sensitivity towards leaf extracts and to pure parthenin. Despite a fast degradation rate in soil (average DT50 59 h), parthenin was phytotoxic in soil bioassays with ED50 values for growth inhibition ranging from 140-600 µg/g soil depending on soil type used. Parthenium biotypes from around the world showed diversity in sesquiterpene lactone production (parthenin, coronopilin, tetraneurin-A), which may account for differences in interference capacity based on allelopathic effects. Results indicate that parthenin may require high plant densities of parthenium biotypes that produce high levels of parthenin and soils with low degradation capacity for parthenin to contribute to the invasiveness of P. hysterophorus in nature. 130. Comparison of Allelopathy Potential between an Exotic Invasive Weed Alternanthera philoxeroides and a Local Weed A. sessilis Zhou Yong-jun1, Yoshiharu Fujii2, Yu Liu-qing1*, Zhang Jian-ping1, Lu Yong-liang1, Xuan Song-nan1

1State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China 2National Institute for Agro-Environmental Science, Tsukuba 305-8604, Japan Email: [email protected] This study aimed to estimate the allelopathic potential of Alternanthera philoxeroides by two methods: the sandwich method and the bioassay method. A native Chinese weed A. sessilis was used as a comparative control. Under the treatment of 50 mg of leaves of A. philoxeroides, the root growth of the lettuce and barnyardgrass was inhibited by 81% and 51%, respectively, and shoot growth by 49% and 48%, respectively, all of which were significantly greater than the contro1. However, there were no significant differences compared to that of the treatment with A. sessilis. The inhibition rate on the root length of barnyardgrass was 54% on average under the treatment using the root of A. philoxeroides, much higher than that of the treatments of its stem and leaf. In addition, with the dose of A. philoxeroides increasing, the inhibition rate against the root growth of lettuce was enhanced significantly, and the values were 54%, 61% and 83% with the treatments of 10 mg, 30 mg and 50 mg leaf of A. philoxeroides, respectively. Various concentrations of the 70% alcohol extracts from A. philoxeroides were bioassayed with A. sessilis used as a comparative control. Under the treatment

of 1% extracts of A. philoxeroides, the root growth of the lettuce was inhibited by 80.7%, significantly higher than the treatment of 1% extracts of A. sessilis (48.1%); the shoot growth of the lettuce was inhibited by 38.1%, with inhibition greater than the treatment of 1% extracts of A. sessilis (21.9%); however, no significant differences were observed. Similarly, with the concentrations of extracts of A. philoxeroides increasing, the rate of inhibition of lettuce root growth was increased significantly, and the values were 8.8%, 18.5%, 25.7% and 80.7% under the treatments of 0.001%, 0.01%, 0.1% and 1% of 70% alcohol extracts of A. philoxeroides, respectively. Our results suggest that A. philoxeroides is an exotic invasive weed with allelopathic potential. 131. Allelopathic Effects of an Invasive Species Solidago canadensis on Soilborne Pathogens: Implication of an Alternative Explanation for Plant Invasion Shanshan Zhang, Guodong Yu, Jianjun Tang, Xin Chen College of Life Sciences, Zhejiang University, Hangzhou 310058 Email: [email protected] Recent studies have suggested that invasive plants had significant effects on soil pathogens and in turn had significant effects on the process of plant invasion. However, how invasive plants directly affect soil pathogens was less well known. We conducted four experiments to test the hypothesis that invasive plant species may affect soilborne pathogens through exudation of allelochemicals by using the invasive plant Solidago canadensis L., a common native plant Kummerowia striata (Thunb.) Schindl and two common soilborne pathogens Pythium ultimum and Rhizoctonia solain as our model system. Tomato (Lycopersicon esculentum Mill) which is sensitive to soil pathogens was used to indicate pathogenic activity of the pathogens. In experiment 1 and 2 (in situ test), seedling mortality and damping-off of potato with both pathogens was reduced when using the soil in which S. canadensis was grown compared to that from which K. striata was grown, implying that S. canadensis soils possessed but K. striata did not possess allelopathic effects on soil pathogens through root and rhizome exudation. In experiment 3 and 4, extracts from roots and rhizomes of S. canadensis significantly suppressed the growth and pathogenic activity (in terms of seedling mortality and damping-off of potato) of both pathogens, providing direct evidence of allelopathic effects on these pathogens from S. canadensis. From our present experimental results, we suggest that invasive plant species may acquire advantages in non-native areas by using “novel weapons” to inhibit local natural enemies, including soil pathogens. 132. Evaluation of Invasive Alien Plants by Modified FAO-WRA (2005): Importance of Allelopathy in Weed Risk Assessment Yoshiharu Fujii , Syunji Kurokawa, and Syuntaro Hiradate

1National Institute for Agro-Environmental Science, Tsukuba 305-8604, Japan Email: [email protected]


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Risk assessment of invasive alien plants of Category No. 1 (the most invasive plants in Japan under the Invasive Alien Species Act (2005)) was conducted using the WRA (Weed Risk Assessment) scoring technique recommended by FAO (2005). Five plants, Pistia stratiotes L. var. cuneata Engler, Alternanthera philloxeroides Griseb., Sicyos angulatus L., Hydrocotyle ranumculoides L.f., and Gymnocoronis spilanthoides DC. showed the highest scores. Four of these plants, with the exception of Alternanthera philloxeroides, have already entered Japan and are now widely spreading along rivers and near ponds. Although Alternanthera philloxeroides is not yet widespread globally, its serious invasion in China prompted us to alert the Japanese Government. We have also evaluated the risk of the 100 most invasive plants in Japan, tentatively announced by the Ministry of Environment. Plants with highest scores are: Eichhornia crassipes (Mart.) Solms-Laub., Paspalum distichum L. var. distichum , Leucaena leucocephala (Lam.) de Wit, Robinia pseudacacia L. , Dactylis glomerata L. Iris pseudoacorus L. Datura sp. , Salvinia molesta Mitch. and Egeria densa (Planch.) St. John.The FAO-WRA technique evaluates the plant based on 13 factors. We further developed the technique considering the allelopathic potential, and then recalculated the scores of all the above- evaluated species. We also evaluated the importance of each factor through statistical analysis. Two factors, “Parasitic weed” and “viable seeds” are not correlated with the final results. Important factors with high contributions are “Distributed by human activities, 0.547”, “Allelopathy, 0.497”, “Propagation by vegetative organs, 0.455”, “The same species are also weeds, 0.446”. Omitting the two factors with limited correlation and combining the allelopathic factor, a modified FAO–WRA technique with 10 factors was developed. With this, we have evaluated 600 potential alien plants and screened potential invasive alien plants. 133. Phillyrea angustifolia as a Source of Potentially Phytotoxic Compounds Marina Della Greca, Lucio Previtera, Raffaella Purcaro, and Armando Zarrelli

Università degli Studi di Napoli Federico II, Dip. di Chimica Organica e Biochimica, Via Cinthia 4 80126 Napoli, Italy Email: [email protected] Until recently, it was generally held that in the Mediterranean Basin post-fire vegetation composition returned directly to the pre-fire state even after recurrent disturbances by fire. Disturbance by fire is purported to be an ancient ecological, whether natural or man-made, factor influencing the Mediterranean vegetation of Southern Europe. This high degree of vegetation resilience was explained by the adaptation of species to frequent historical fire occurrence. In the last few years, however, the idea of strong vegetation resilience was criticized as local observations provided evidence for changes in vegetation composition after fire events. It has been suggested that some plants take the upper hand due to strong allelopathic action through the production and release of secondary phytotoxic metabolites. One of the most aggressive plants in this region is Phillyrea angustifolia, a native Mediterranean evergreen sclerophillous species, which has recently been considered suitable for landscaping

purposes, tolerant to water stress and affected by drought conditions only when they are particularly severe. The methanol extract of P. angustifolia was investigated as a source of potentially phytotoxic compounds. It had a high total phenol content and contained secoiridoids. The characterization of the most abundant phenolic compound indicated the presence of oleuropein. Identification of other compounds was only feasible after isolation and NMR spectroscopic characterization. The compounds identified included oleuropein aglycone, verbascoside, ligstroside, and similar derivatives. The findings are promising for the potential exploitation of P. angustifolia extract as a source for bioactive ingredients. Their subsequent phytotoxic properties will be determined on the cultivated species L. sativa, using a range of concentrations between 10-4 and 10-7 M. 134. Allelopathic Assessment of Annual Ryegrass (Lolium rigidum) by Root Exudate Bioassay R. Amini1, M. An2 and J. Pratley2 1Department of Agronomy, College of Agriculture, University of Tehran, Karaj, Iran 2E.H. Graham Centre for Agricultural Innovation (a collaborative alliance between Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga, NSW 2650, Australia. Email: [email protected] Annual ryegrass (Lolium rigidum) is the Australia’s worst invasive weed of temperate crop production. The first worldwide incidence of evolved resistance to the herbicide Roundup was identified in annual ryegrass (Pratley, 1996). However, the mechanisms for its wider proliferation and successful invasion largely remain unknown. It has been long suspected that annual ryegrass may possess strong allelopathic potential due to the conclusive evidence of allelochemical involvement by its close relatives perennial ryegrass (Lolium perenne) and tall fescue (Festuca spp.). A laboratory-based root exudate bioassay was conducted to assess the allelopathic potential of annual ryegrass against wheat plants. It was found that living annual ryegrass seedlings severely suppressed the seedling growth of wheat plants, and the inhibition was ryegrass density dependent. At an equal density, the wheat inhibition was up to 40% while, at higher density of annual ryegrass seedlings, the growth of wheat plants was completely suppressed. Addition of activated charcoal to the growth media significantly alleviated the suppression of wheat plant growth, up to 40%, indicating the large quantity of biologically active compounds released from annual ryegrass living roots. Large varietal differences were also found among wheat varieties for their tolerance towards annual ryegrass allelopathy. Among the four varieties assessed, variety ww14921 showed the most sensitive response, while the other varieties, ie. Janz, Sunco, and Vertura, demonstrated strong tolerance to the annual ryegrass allelopathy. Those results indicate that annual ryegrass allelopathy plays an important role in its strong competitiveness against crop plants. Full understanding of annual ryegrass allelopathy will help form integrated weed management programs for its effective control.


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135. Rosmarinic Acid as Potent Allelochemical from Comfrey (Symphytum officinale L) Yoshiharu Fujii 1*, Zahida Iqbal 1, 2, Habib Nasir1, 2, Akihoro Furubayashi1, and Syuntaro Hiradate1

1National Institute for Agro-Environmental Science, Tsukuba 305-8604, Japan 2University of Arid Agriculture Rawalpindi, Rawalpindi, Pakistan Email: [email protected] Symphytum officinale, commonly known as comfrey, belongs to family Boraginaceae. The plant grows very quickly, producing a lot of biomass. It is tolerant of being cut several times a year. This plant is a native herb of Eurasia and often invades other places. S. officinale is widely consumed as a medicinal herb for the treatment of various illnesses. Many compounds have so far been isolated which might account for the therapeutic value of S. officinale, however none of these studies has focused on its allelopathic potential. S. officinale showed strong plant growth inhibitory activity on lettuce using the Plant Box Method. The results revealed that it releases some allelochemicals, which resulted in growth inhibition of neighboring plants. Total activity guided extraction and separation led to the isolation and purification of an active constituent which inhibited the growth of lettuce and three other common weeds. The crude ethanol extract of leaves of S. officinale showed inhibitory effects, and this inhibitory activity was noted in the subsequent ethyl acetate soluble fraction and was purified successively using reversed phase silica gel chromatography. Chromatographic separation of this fraction on lobar column using methanol-water yielded a pure compound identified as rosmarinic acid. Inhibitory activity of rosmarinic acid on the root elongation of lettuce seedlings was noted and 200 uM concentration of rosmarinic acid was required to inhibit the root growth of lettuce seedlings by 50 %. The dose required for 50 % growth inhibition of Amaranthus hypochondriacas, Brassica campestris and Phleum pretense was 200-277 uM. Plant growth inhibitory activities of comfrey were evaluated in the field. Compared to other ground cover plants, comfrey showed potent weed suppression activity. This practical weed suppression may prove useful as a ground cover plant to suppress weeds, but as an invasive plant, comfrey also has the potential to become a noxious weed that could become dominant in agroecosystems. 136. Demonstration of Allelopathy in Tissue Culture of Coffee and Guarana: Plant Cells Communicate through Production of Caffeine as an Autotoxic Allelochemical in Mixed Culture George R. Waller 1 , Zahida Iqbal2, and Yoshiharu Fujii 2* 1Oklahoma State University, Stillwater, Oklahoma 74078 USA 2National Institute for Agro-Environmental Science, Tsukuba 305-8604, Japan Email: [email protected] Caffeine is a naturally occurring, allelopathic compound found in a variety of plants: Coffea [coffee], Paullinia [guarana], Camellia [tea], Ilex [maté], Cola and Theobroma [cacao]. Coffea arabica and Camellia sinensis were used to elucidate the pathway for the metabolism of caffeine which has theobromine as the immediate precursor and theophylline as

the first product formed in the biodegradation pathway. Tissue culture of guarana produced predominately theobromine, whereas that of coffee produced largely caffeine. A mixed plant cell culture from Coffea arabica and Paullinia cupana was placed side by side and incubated for 3 months. A marked increase in caffeine and a concomitant decrease in theobromine were found as compared to the coffee and guarana controls. The high concentration of caffeine and other compounds produced by these tissue cultures are associated with autotoxicity in both species. It is known that theobromine is the immediate precursor of caffeine and this conversion was catalyzed by caffeine synthase. Based on the above observation, a mixed plant cell culture from Coffea arabica and Paullinia cupana was established to observe if the Coffea arabica cells take up theobromine produced by the Paullinia cupana cells for conversion to caffeine. In the mixed culture, the coffee tissue grew faster but exhibited increased brittleness. The mixed culture showed that the guarana/coffee interface served as a conduit for theobromine/caffeine biosynthesis through caffeine synthase. In September 2006, we visited Galapagos Islands and evaluated the allelopathic activity of these species by using the Sandwich method. Coffea arabica leaves showed strong inhibitory activity upon Acacia, Cordia and Brugmansia. Coffea arabica may become an invasive tree in Galapagos Islands if allowed to escape from plantations. 137. An Ivestigation into the Allelopathic Potential of Two Invasive Alien Species of Balsam (Impatiens) Found in the UK, using the Plant Box and Dish Pack Methods Owen Smith 1, Yoshiharu Fujii 2

1School of Biological Sciences, University of Plymouth, UK 2National Institute of Agro-Environmental Sciences, Tsukuba, Ibaraki, Japan Email: [email protected]

The genus Impatiens in the UK includes one native and several introduced species. The native species, I. noli-tangere, is uncommon, with a limited distribution. Two Asian species I. parviflora and I. glandulifera are the most common, with I. glandulifera being considered one of the UK’s top three weeds in terms of its visual impact. The Dish Pack method produced 40% inhibition of radicle growth in the case of I. glandulifera at a rate of 1mg of dried leaf/ml agar and 70% at 5mg dried leaf /ml agar. In the case of Impatiens parviflora the corresponding figures were 10% and 40%. In some instances the dried leaves produced an orange pigment that diffused into the agar. This was more pronounced in the case of I. glandulifera than in I. parviflora. In the Plant Box method, living roots embedded in low temperature agar produced a large degree of inhibition in lettuce radicle elongation, with both I.glandulifera and I.parviflora species causing approximately 80% inhibition of radicle elongation. Orange staining of the agar again took place, with this being more pronounced in I.glandulifera than I. parviflora. The orange staining may be due to the exudation of lawsone, one of the naphthoquinones found


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in both of these Impatiens species. Naphthoquinones are a group of biologically active compounds which are known to have anti-microbial and allelopathic properties. Both species are powerful inhibitors of lettuce seedling development.

These results suggest further investigation into the role of allelopathy in the spread of alien invasive balsam species is warranted.

Main Topic 8: Interactions in the rhizosphere 138. The Rhizosphere – The Hidden Half of the Hidden Half Markus Puschenreiter and Walter W. Wenzel University of Natural Resources and Applied Life Sciences - BOKU, Department of Forest and Soil Sciences, Peter-Jordan Strasse 82, A-1190 Vienna, Austria. E-mail: [email protected] The few millimetres of soil surrounding the plant roots are termed “rhizosphere”. While roots represent the hidden half of entire plants, the microenvironment around roots constituting the rhizosphere has been referred to as the “hidden half of the hidden half”, bearing numerous secrets yet not completely revealed. In spite of its limited volume the rhizosphere plays a key role in controlling the soil-plant relationship. Rhizosphere soil differs largely from the bulk soil and represents the microenvironment in which root activities and soil properties closely interact. Plant-microbe relationships ranging from symbiosis to parasitism as well as microbial population dynamics are also influenced by these particular conditions. Availability and uptake of nutrients are largely controlled by soil conditions in the rhizosphere and the bioavailability of pollutants may differ substantially from that in the bulk soil. The rhizosphere is an extremely dynamic environment characterised by numerous feedback processes linking phenomena in the biosphere with processes in the pedosphere. The high complexity of a multitude of plant-induced, microbial, soil physical and chemical processes linked to each other and occurring simultaneously at a micro-scale makes rhizosphere research an extremely difficult task. In particular, access to study these processes and phenomena in situ is limited as they occur below-ground and separation of the components involved, such as roots, root hairs, soil solid phase, soil solution, gaseous phase and microbes, is very challenging in respect of experimental designs and technology. Rhizosphere research can represent an essential tool to enhance agriculture practices and to improve technologies employed to remediate contaminated sites. Sustainable agriculture may benefit from rhizosphere research for the aspect regarding the management of nutrient availability and the biological disease control. Phyto- and bio-remediation technologies may benefit of an improved knowledge on the processes that regulate availability, uptake and degradation of the pollutants in the rhizosphere. 139. Rhizosphere Processes and Interactions in Cropping Systems in China F. S. Zhang, J. G. Wang, C. H Kong, J. B. Shen, X. J. Liu and L. Li College of Resources and Environmental sciences, China Agricultural University, Beijing 100094, China E-mail: [email protected]

Intercropping and rotation cropping systems have been practiced in China for more than 2000 years. This presentation summarized main research works on rhizosphere processes in recent 20 years. Research on interspecific relationships, especially below-ground interactions between intercropped species showed that interspecific rhizosphere effect is influencing the efficiency of Phosphorous uptake, resulting in higher productivity of efficient and inefficient P species due to intercropping. For instance, faba bean can utilize sparingly soluble P, which resulted from increased exudation of organic acids and elevated rhizosphere acidification. Chickpea uses organic P more efficiently than maize does, which derived from higher acid phosphatase activity in the rhizosphere. Furthermore, interspecific below-ground interactions benefit to N2 fixation of legumes intercropped with cereals. Wheat-maize rotation frequently suffers from nutrient stresses due to low temperature and drought at early stage and root senescence at late stage. Our studies found that rhizosphere management by localized nutrient supply and application of root-promotion techniques significantly enhanced the resistance of seedlings to stress and increased nutrient uptake. Harmonising nutrient supply and the plants demand at different growth stages through root-zone or rhizosphere nutrient management is a key step for developing sustainable crop production. The rice-wheat rotation system is a long-established major cereal cropping system with total area of 10 to 13 million ha in China. However, it is difficult to meet the nutrient (particularly micronutrient) requirement by both rice and wheat crops during the continuous wet and dry cycles. Manganese deficiency in wheat is a typical nutrient constraint for this cropping system which could be ameliorated by managing crops, soil and nutrients differently so as to promote rhizosphere processes that are more favourable and enhance crop yield. When Mn is deficient in the topsoil, sufficient Mn supply in the subsoil is crucial to improve the growth and uptake by wheat. Through extending the range of rhizosphere, for example, deep plough is a useful measure to overcome wheat Mn deficiency and increase total productivity in the whole rice-wheat system. The rhizosphere is also a hotspot where intensive interactions between plant roots and microorganisms occur. In a continuous soybean monocropping system, both soybean root exudates and allelochemicals released during decomposition of soybean residues resulted in a significant change of soil microbial community and, consequently, the growth and development of successive soybean crops were inhibited. Similarly, there are chemical interactions between rice and soil organisms in the rhizosphere to mention. In particular, allelopathic rice varieties could modify soil microorganisms to their advantage through release of root exudates, and the capacity of rice root exudates to affect


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soil microbes could be attributed to some of their individual components. The concentration and fate of discriminating allelochemicals between allelopathic and non-alleloparhic varieties in rice soil would result in the different pattern of microbial population and community structure in paddy ecosystem. 140. Fate of Phytotoxic Allelochemicals Produced by Cyperus rotundus in Environment and Change of Their Phytotoxicity Masanori Morimoto Dept. of Applied Chemistry, Kinki University, 3327-204 Nakamachi, Nara, 631-8505, Japan E-mail: [email protected] The phytotoxic allelochemicals released from Cyperus rotundus L. are sesquiterpene ketones, α-cyperone and cyperotundone. Knowledge about their localisation in the rhizosphere and environmantal fate is crucial for explaining allelopathy in a habitat. Therefore, α-cyperone and cyperotundone and corresponding precursor hydrocarbons, β-selinene and cyperene were investigated by environmental stability test and evaluation of oxidative products for phytotoxicity against lettuce seedlings. All of them were not stable under the light oxidative condition, they gave corresponding oxidative products. Phytotoxic sesquiterpene ketone, α-cyperone was easy to oxidize within 8 days and its oxidative products completely disappeared phytotoxicity against lettuce seedlings. Similarly, non-phytotoxic precursor, β-selinene also converted to high polar products under the light oxidative condition. Meanwhile, cyperotundone was more stable than α-cyperone under the light oxidative condition, but it was completely transformed by Aspergillus niger within 10 days. Though, oxidative products of cyperotundone decreased its phytotoxicity, oxidative product of α-cyperone did not show phytotoxicity. Oxidative products from both of their precursors also did not show phytotoxicity. The major oxidative product from α-cyperone was identified as α-cyperone-13-ol based on spectroscopic data. On the other, artificial oxidative compounds from cyperotundone showed various effects on lettuce seedlings. One of them inhibited p- hydroxyphenylpyruvate-dioxygenase acted on the biosynthetic pathway of carotenoids and plastquinones. Consequently, light oxidation of them was disadvantage for the plant growth inhibitor in this study, but a lot of phytotoxins are oxidized and these are critical moiety for phytotoxic property. It is required to observe the multi-organism participated and inorganic chemical conversion. 141. The Role of Soil Microorganisms in Transformation and Activity Change of Allelochemicals from Selected Plants Ines Fritz, Denise Schneider, Dominic Funk, Marcus Pruckner, Michaela Bauer, Rudolf Braun Universität für Bodenkultur Wien, Department IFA-Tulln, Konrad Lorenz Str. 20, A-3430 Tulln, Austria. E-mail: [email protected] In many cases Allelochemicals are transported and stored inside the plant as a less active variant, e.g. as glycoside. Activation may be initialised by an external stimulant, mostly catalysed by the plant, e.g. by hydrolysis and release of the

respective aglycone. The released substances will undergo different chemical reactions caused by microorganisms present in the soil, especially in the rhizosphere. These could be degradation and inactivation or transformation into a more active metabolite. This phenomenon was previously observed and described for Benzoxazinones from wheat which had been transformed into higher active and more stable Amino-phenoxazinoids. Current investigations now focus on the so called alien invasive species (AIS), plants known to be harmful to the native flora in central Europe due to high allelopathic activity. Since many allelochemicals are expected to become transformed within minutes and may be unstable even under sterile conditions, special experimental setups were developed within this project to screen for inhibition effects. Biological activity was investigated by applying and optimizing biotests with several aquatic and terrestrial organisms and by analytical follow up using HPLC-MS and molecular biological techniques. Even if causality between microbial population, transformation and biological activity could be confirmed, some initial questions remain open and some new arose. One of the most influential is: what is the ecological impact of allelochemicals released to soil? 142. Role of Root-mediated Allelopathy in the Rhizosphere of Ageratum conyzoides Daizy R. Batish1, Shalinder Kaur1, H.P.Singh2 and R.K.Kohli2 1Department of Botany, Panjab University, Chandigarh – 160014, India 2Centre for Environment and Vocational Studies, Department of Botany, Panjab University, Chandigarh – 160014, India. E-mail: [email protected] Rhizosphere – a zone surrounding the plant roots is an active site where a number of root-mediated interactions occur. Most allelopathic interactions that influence growth, establishment and productivity of other plants also occur in this zone. In fact, root secreted exudates, root residues or leachates accumulated in this zone have a marked effect on other plants. It is thus very important to establish allelopathic effect of rhizosphere soil and plant roots. Ageratum conyzoides L. (Asteraceae), an aromatic, annual invasive weed from tropical America, has naturalized various tropical and sub-tropical parts of the world, particularly South East Asia including India. The present study investigated the effect of its rhizosphere soil, root residues and leachates on crops such as Brassica campestris, Raphanus sativus, Triticum aestivum, Cicer arietinum, Phaseolus aureus and Oryza sativa. A drastic reduction in root and shoot length and biomass accumulation of crops was observed in the rhizosphere soil indicating the presence of putative allelochemicals in the soil. Growth of test crops was also retarded when root residues of A. conyzoides were amended in the soil at 5 to 20 g kg–1 soil. In general, growth of crops declined with increasing amount of root residues in soil. Growth reduction in crops occurred despite addition of activated charcoal or supplementation of nitrogen in the soil. Rhizosphere soil as well as soil amended with root


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residues or leachates possessed higher amount of organic matter and macro- and micro-nutrients compared to control soil ruling out the possibility of their deprivation resulting in observed growth reduction. On the other hand, various phenolic acids were identified as putative allelochemicals from the rhizosphere and root-amended soils. The study concludes that rhizosphere soil of A. conyzoides is rendered phytotoxic owing to the presence of phenolic allelochemicals released from its root residues and through leachates. 143. Allelochemical Interactions in the Rhizoshpere C. H. Kong Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China and College of Resources and Environmental sciences, China Agricultural University, Beijing 100093, China. E-mail: [email protected] The root-soil interface, particularly in the rhizosphere, is the key site of occurring chemical interactions between plants and soil animals, soil microbes or other plants. Chemical interactions between plants and other organisms in the rhizosphere are mediated by allelochemicals in root exudates. Rhizosphere interactions between plants and other organisms depend on the concentrations and types of allelochemicals in root exudates. Clarification of the allelochemicals and their transformation as well function would be helpful to improve our understanding of chemical interactions and cross talk in the rhizosphere. This presentation aims to outline recent advances in allelochemical interactions in the rhizosphere by studying the case of between rice and other organisms in paddy ecosystems, including (a) key allelochemicals exuded from allelopathic rice variety, (b) the dynamics of rice allelochemicals and their transformation in rhizosphere and bulk soils, (c) mobility and diffusion of rice allelochemicals through soil solution, (d) the fate and interactions between rice allelochemicals and soil microorganisms. These results provided limited information to help in understanding of how allelopathic rice works in paddy ecosystems. 144. Studies on Composition of Amino Acids in Watermelon Root Exudates and Their Effects on Growth and Development of Fusarium oxysporum f.sp.nevium Bo Liu, Fengzhi Wu, Yang Yang, and Xuezheng Wang Horticulture College, Northeast Agricultural University, Harbin, 150030, China Email: [email protected] Taking resistant, susceptible watermelon cultivars and calabash, pumpkin rootstocks as experimental material, we investigated the composition and content of amino acids in watermelon root exudates from own-rooted seedlings and grafted seedlings in hydroponics by automatic amino acid analyzer and also the effects of different amino acids concentrations (0, 0.6, 1.2, and 1.8 g·L-1) on growth and development of Fusarium oxysporum f.sp.nevium. The results showed that 15 kinds of amino acids were detected, and the contents of amino acids were the lowest in resistant cultivars, highest in susceptible cultivars, but there were no significant differences between two rootstocks treatments. Otherwise, the content of amino acids in grafted seedlings which resistant cultivars were grafted on calabash rootstock was significantly

higher than that in own-rooted seedlings, and also that in grafted seedlings which susceptible cultivars were grafted on pumpkin rootstock was significantly lower than that in own-rooted seedlings. Moreover, asparagine, methionine, leucine, glutamic acid and phenylalanine promoted the growth and development of Fusarium oxysporum f.sp.nevium at concentration of 1.2 g·L-1 or more; but methionine and phenylalanine inhibited the growth and development of Fusarium oxysporum f.sp.nevium at concentration of 0.6 g·L-1 or less. 145. Analysis of the Structure and its Function of Microbial Flora in the Rhizospheric Soil Mediated by Allelopathic and Non-allelopathic Rice Accessions Long Qiu1,2, Jun Xiong1,2, Yue e Zhuang2, Kaihui Hu2, Wenxiong Lin1,2

1Key Laboratory of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University (FAFU), C/O Ministry of Education China 2Institute of Agroecology C/O School of Life Sciences, FAFU, Fuzhou 350002, China Email: [email protected] Plant allelopathy is a rhizosphere biological process and rhizosphere microorganisms are the most active species lived in soil. In order to shed light on the rhizosphere biological character of allelopathy, the structure and function of microorganism population in the rhizosphere mediated by different allelopathic potential rice accessions were analyzed using cultivable and uncultivable methods. The results showed that the microbial diversity in rhizosphere of allelopathic rice PI312777 was significantly higher than that in its counterpart Lemont. Concretely, allelopathic rice PI312777 promoted nutrient cycle in soil compared with Lemont, performing the larger number of ammonifier, nitrate bacteria, aerobic Azotobacter, and sulphate reducer, and higher activities of urease, phosphatase and sucrase. Furthermore, the results obtained from T-RFLP analysis showed that there existed some special bacterial population in the rhizosphere of allelopathic rice PI312777, such as Burkholderia, a kind of plant growth promote bacteria (PGPB), and Azospirillum, which is a kind of joint symbiotic nitrogen-fixing microorganism with grass family. On the whole, allelopathic rice appeared to promote the healthy rhizosphere biological process, in turn ensued its healthy growth and development. In addition, some interesting microbes such as Streptomyces (158bp) and Rhodococcus (163bp) were detected in the rhizosphere of allelopathic rice, which are mainly associated with allelopathy. Moreover, we detected many kinds of bacteria functioned in degradation of phenolic compounds in the rhizosphere under the two rice accessions concerned. Nevertheless, the amount of species was higher in the rhizosphere of allelopathic rice PI312777 than that in Lemont, which might be attributed to the differences of the phenylpropanoid metabolism in the two rice plants, which might result in differences among a vast array of phenolic acids existing in soil. 146. Rice Root Exudates Induced by UV-irradiation in Rhizosphere Soil


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Khalid Mahmood1,2 and Ren Sen Zeng1,2 1Research Center for Chemical Ecology 2Institute of Tropical and Sub-tropical Ecology, South China Agricultural University, Wushan, Guangzhou, 510642, P.R. China Email: [email protected] Stratospheric ozone depletion has caused ground-level ultraviolet-B (UV-B) radiation to rise in temperate latitudes of both hemispheres. We tested the effect of elevated UV-irradiation on plant root exudates in two rice varieties. The secretion levels of root exudates from two rice (Oryza sativa L.) cultivars namely BR-41 (highly allelopathic) and Haujingxian (low allelopathic) into rhizosphere were examined through their effect on receptor plant seedlings (lettuce and barnyard grass). We did different experiments to assess (i) effect of UV-irradiation on allelochemicals in rhizosphere, (ii) effect of UV exposure time on root exudates and shoot extract phytotoxicity. We observed the hormesis phenomena on exposure to UV-irradiation. Both rice cultivars demonstrated fluctuation in root exudates on exposure to ultraviolet irradiations. Rhizosphere soil of rice plants of Haujingxian and BR-41 varieties exposed to UV- irradiation for 30 min stimulated the lettuce seedlings growth as compare to untreated rice plants in both cultivars. In case of 60 min exposure we found stimulation in root and shoot length of Haunjingxian but inhibition in case of BR-41. However, 90 min exposure of UV-irradiation led to inhibition of lettuce shoot and root length up to 25% and 30% by rhizosphere soils of Haujingxian. These inhibitory effects are most predominant in case of BR-41 variety i.e. up to 52% and 46.51%, respectively. Aqueous extract of rice shoots also showed inhibition effect on barnyard grass as compare to untreated rice plants. As root exudates acts as an antimicrobial and allelopathic agent, more secretion of root exudates into the rhizosphere may provide a competitive advantage for root establishment. These results indicate that ozone depletion and increase in UV-irradiation may enhance rice allelopathic potentials on paddy weeds. 147. Fate of Glucosinolates and Isothiocyanates in Soil A. L. Gimsing and H. C. B. Hansen Department of Natural Sciences, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark E-mail: [email protected] Glucosinolates are natural thioglucosides produced by plants belonging to the Capparales order. When glucosinolates are hydrolysed by the endogenous enzyme myrosinase biocidal isothiocyanates are produced. The biocidal properties of the isothiocyanates are utilized as an alternative to conventional soil fumigation by a technique termed biofumigation where glucosinolate-containg plants are incorporated into soil. However, as isothiocyanates are toxic to a wide range of organisms the environmental aspects of the biofumigation technique needs to be evaluated, and knowledge of the soil fate of glucosinolates and isothiocyanates is also needed to optimize the biofumigation technique. In a number of studies sorption and degradation of selected pure glucosinolates and isothiocyanates have been quantified. Glucosinolates are not sorbed in soil, whereas isothiocyanates adsorb to soil organic

matter. Both glucosinolates and isothiocyanates are degraded in soil, but the degradation rate depends strongly on soil type, moisture content and temperature. Glucosinolate degradation usually follows logistic kinetics with typical half-lives around 1 day in top soils and 8 to 9 days in subsoils. Degradation is faster in clayey soils than in sandy soils probably because of an association between myrosinase activity and the clay fraction. Isothiocyanate degradation follows first-order kinetics with half-lives from hours to a few days. Interestingly isothiocyanates appear to degrade more quickly in subsoils than topsoils. Mineralization experiments with 14C have shown that the rate and extent of mineralization of both glucosinolates and isothiocyanates is similar to what is seen for many pesticides. For glucosinolate 40-50% was mineralized after 60 d and for isothiocyanate 35-50% was mineralized after 45 d. A leaching study using intact soil columns demonstrated that isothiocyanates can leach to 1 m following simulated biofumigation, although at low concentrations (0.1 to 1 µM). Biofumigation may constitute an environmentally friendly alternative to fumigation with synthetic fumigants, but care must be taken to avoid leaching. 148. Root Associated Microorganisms Perform Degradation of Caffeine Absorbed by Salvia officinalis Margot Schulz, Mona Knop, Maritta Kunert● and Carmen Müllenborn IMBIO (Institut für Molekulare Physiologie und Biotechnology der Pflanzen, Universität Bonn, Karlrober Kreiten Str. 13, D-53115 Bonn, Germany; ●Max-Planck-Institut für chemische Ökologie, Beutenberg Campus, Hans-Knöll-Str. 8, D-07745 Jena, Germany. E-mail: [email protected] Aromatic plants as intercrops in coffee plantations may reduce the caffeine accumulation in the soil, which is an important factor of coffee plant autotoxicity. The uptake of caffeine by Mentha piperita, Ocimum basilicum, Salvia officinalis and Origanum vulgare was recently investigated. Caffeine was mainly found in the roots, whereas in the shoots only traces of the alkaloid were detected. All absorbed caffeine was released again by Mentha piperata and by Ocium basilicum after 24 h of incubation, when plants were transferred to caffeine free media. With Salvia officinalis and Oreganum vulgare a large portion of the alkaloid was neither released nor detectable in extracts. Monoterpene compositions of the aromatic plants were not altered by caffeine applications. In a continuing study with Salvia officinalis, 5 mM caffeine disappeared completely within five days. 2-3 µmol / g fresh weight were found in roots extracts, but only nanomol amounts in the shoots. Theobromine, a degradation product of caffeine, was found in the media. In presence of antibiotics, 80 % of the applied caffeine could be regained. From the roots, several microorganisms able to degrade caffeine were isolated. The isolated bacteria and fungi, belonging to the genera Trichoderma and Pseudomonas were less active than they were in association with the Salvia roots. Salvia plants, grown under sterile conditions, accumulated caffeine in high amounts in the shoots, no degradation products were


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identified in the media. The results indicate that caffeine degradation is mainly performed by plant associated microorganism, whereas the plants do not contribute to the degradation. The plant seems to create optimal conditions for the detoxifying microorganisms which may be endophytic or associated with the rhizosphere. The study underlines the importance of microorganisms in retarding the worldwide observed early degeneration of coffee plantations, which is partly due to caffeine accumulation in soil. 149. Analyses of the Components from the Root Exudates of the Cucumber Cultivars with the Different Resistance to Fusarium Wilt Pan Kai, Wu Fengzhi Horticulture College, Northeast Agricultural University, Harbin 150030, China E-mail: [email protected] The seedlings of cucumber cultivars with resistance to Fusarium oxysporum. F. sp. Cucumerinum owen and the susceptible cucumber cultivars were treated with different concentration of fungus suspension (0 and 1×107 /ml). Root exudates were collected to analyse amino acids using an Automatic Amino Acid Analyzer, and to analyse other compounds by GC-MS. The results showed that the exuded amino acids were different during the different cucumber cultivars, and the kinds of amino acids and their total amount were all higher in resistant than in susceptible cucumber cultivars. Phenylalanine, valine, methionine, glycine and cysteine were all found in the root exudates from the all cucumber cultivars seedlings. Total amount of these was higher in the un-inoculated seedling root exudates than in the inoculated. The total percent of the same amino acids in the susceptible cultivars was higher than that of the resistant cucumber cultivars. Expect the soluble amino acids, eighty-five kinds of other compounds were detected by GC-MS in the cucumber cultivars seedlings’ root exudates. Under the un-inoculated seedlings’ root exudates, the kinds and the concentration of the all compounds in the root exudates of the susceptible cucumber cultivars were higher than that of the

resistant cultivars. And the compound kinds and the concentration were higher in the root exudates from the inoculated seedlings than that of the un-inoculated seedlings’ root exudates. A further found that the organic acids (acetic acid and Benzoic acid) had an evidence correlation with the resistant of cucumber cultivars, and these organic acids could be found from resistant cultivars and the inoculated seedlings. 150. Biological Induction of DIMBOA in Wheat Seedlings by Weeds Yongquan Zheng, Jianlei Yu, Xingang Liu, Fengshou Dong

Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100094, P. R. China E-mail: [email protected] DIMBOA in wheat root exudates induced by six weed species was studied by hydroponic experiments. The results showed that DIMBOA content in both root exudates and shoot of wheat seedlings were significantly increased by three weed species, i.e. Digitaria sanguinalis, Avena fatua L, and Amaranthus retroflexus, and the induction effects happened to be in the three different resistant wheat cultivars (Zhongfu9507, Zhongbeizhong39, Jing411). The other three weed species Poa annua L., Lolium multiflorum Lam. and Capsella bursa-pastoris showed weak effects on DIMBOA in wheat root exudates and aerial parts. Grown in pot, the biological induction by the former three weeds gave the consistent results as those grown in hydroponic solution. DIMBOA content of aerial parts was higher when wheat has grown in the pot compared to that grown in the hydroponic solution. When wheat cultivars were intercropped with different density of D igitaria sanguinalis, the DIMBOA content in aerial parts was positively correlated with the density of Digitaria sanguinalis as a general trend. This result implies that changing the density of inducing plants may be a useful way to artificially improve crop resistance.

Main Topic 9: Allelopathy Methodologies 151. The Conundrum of Allelopathic Agents in Soils: Soil Extractions and Dose Response Studies Udo Blum Department of Plant Biology, North Carolina State University, Raleigh NC 27695-7612 Email: [email protected] Among the criteria required to establish plant-plant allelopathic interactions in nature are a) that the affected plant must come in contact with and interact with organic promoters or inhibitors produced by an allelopathic plant and b) that these promoters or inhibitors must be at sufficient concentrations andbe present for a sufficient length of time to modify plant function or growth of the receiving plant. To establish that these two criteria are actually met under field conditions researchers have generally done two things. First, they have used soil

extracts to isolate, identify, and quantify potential allelopathic agents. Second, they have used dose response studies of the alleged allelopathic agents identified to determine their potential as promoters or inhibitors. Utilizing the case history of phenolic acids, the effectiveness of soil extracts and dose response studies in establishing these two criteria in nature will be discussed. It turns out that soil extracts and dose response studies as presently used provide only a glimmer of insight regarding allelopathic plant-plant interaction in nature. Our inability to clearly demonstrate the above criteria in nature is a product of an inappropriate, albeit informal, mind set or paradigm and the lack of adequate tools. In hopes of stimulating renewed interest in this area of research, a more appropriate paradigm and several potential tools to improve the usefulness of soil extracts and dose response


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studies in establishing these criteria in nature will be presented. 152. Measurement of Allelochemical Dynamics and Movement with Polydimethylsiloxane Sorbents Jeffrey D. Weidenhamer Department of Chemistry, Ashland University, Ashland, OH 44805 USA Email: [email protected] The lack of tools to measure allelochemical dynamics in the rhizosphere has been a longstanding problem in investigations of allelopathy. Soils beneath suspected allelopathic plants typically contain low allelochemical concentrations, something which is cited as evidence that these compounds do not play a significant role in plant-plant interactions. However, static concentrations in the environment reflect the balance of input and output rates for a compound. Because roots compete with both microorganisms and other processes that remove allelochemicals from soil solution, flux rates are likely to be a key component of toxicity. Measurement of flux rates requires materials that trap allelochemicals as they are released. Polydimethylsiloxane (PDMS) sorbents are being applied to measure fluxes of lipophilic allelochemicals from roots. In this study, 5 cm lengths of stainless steel wire coated with PDMS were inserted into soil beneath marigold plants in the field. Probes were removed after 24 hours and analyzed by HPLC. Microgram quantities of both 5-(3-buten-1-ynyl)-2,2’-bithienyl (BBT) and α-terthienyl were detected on individual probes. The amount and relative proportion of each compound varied by plant and sampling date. Given the high potency of these thiophenes in bioassays, the concentrations found can readily be conceived to be biologically active. The distribution of marigold allelochemicals in the rhizosphere is spatially heterogeneous and dynamic over time. These techniques appear to be broadly applicable to the analysis of lipophilic root exudates. In addition, PDMS solid phase microextraction (SPME) fibers have been used to measure the uptake of exogenously applied monoterpenes in vivo. SPME could detect exogenously applied 1,8-cineole in tomato stems within 1-2 hrs of a single application of 0.5 mM cineole to soil, and this pulse persisted in the tomato stem for 72 hrs. The smallest exogenous concentration applied that resulted in a measureable pulse of cineole in the plant stem was 50 µM. Thus PDMS sorbents appear to be a powerful tool for tracking both the dynamics of allelochemicals in the rhizosphere and their movement into target plants. 153. Hormesis in Allelopathy Research – Modelling and Characteristic Features Regina G. Belz University of Hohenheim, Institute of Phytomedicine, Dept. Weed Science, 70593 Stuttgart, Germany Email: [email protected] Allelochemicals are known to be toxic at higher doses and sometimes stimulatory or even beneficial at low doses. This phenomenon of hormesis has been considered a biological property of allelochemicals for many years; however,

reports that clearly prove hormesis of allelochemicals are still rare. Experimental dose-response designs that include the stimulatory and inhibitory dose-range offer an opportunity to prove whether significant hormesis occurs, and mathematical modelling of such biphasic dose-response curves allows quantifying the size and the dose-range of the hormetic effect. Various examples will be given to demonstrate that the application of these models covers single allelochemical treatments, but also their natural mixtures (i.e., extracts or exudates of allelopathic plants) or degradation studies. Nevertheless, biphasic dose-response experiments must be conducted with care, as for example the dynamics of the hormetic response, the response parameter (growth rates, standing stock endpoints), environmental conditions (temperature, light, nutrients), or qualitative and quantitative differences in the chemical composition of allelopathic extracts or exudates may account for an absence of hormetic effects. Knowledge of these characteristic features of a hormetic response is essential to prove its significance, but can also considerably improve the conclusions drawn from such experiments. Examples of this will be given with both single allelochemicals and their natural mixtures. The given examples reflect that hormesis is substantial and reproducible and may thus constitute an important aspect of some plant/plant interference if doses released are low or degradation processes lead to stimulatory doses. Hormesis should therefore be regarded as a potential low dose component of plant/plant interference, and laboratory modelling may help to enhance our still limited understanding of this phenomenon and its possible implications for allelopathic interactions in a natural setting. 154. On Density-Dependence of Plant Growth Response to Toxic Compounds Aki Sinkkonen, Minna Vesterinen, Mari Hansi, Rauni Strömmer University of Helsinki, Dept. Ecol. Environmental Sciences, Niemenkatu 73, FIN-15140 Lahti, Finland Email: [email protected] Previous studies suggest that density-response experiments generally end up in a distinguishable pattern under homogenous exposure to toxins. Plant growth is supposed to be negligibly affected at high plant densities when numerous plants compete for the same toxin pool. As plant density decreases, toxin effects become more severe. At very low plant densities, plant growth may be totally inhibited. The hypothesis is based on studies that had been made under fair nutritional conditions and with toxins that are relatively mobile in soil. We tested the hypothesis with relatively immobile lead (Pb) and creosote and highly mobile copper (Cu). We used pine (Pinus sylvestris), baby’s breath (Gypsophila elegans) and Chinese cabbage (Brassica rapa subsp. pekinensis) as study objects. The effects of Cu on plant growth were diluted when plant density increased. Toxin effects were independent of plant density in most experiments made with Pb or creosote. When nutrient availability was low, the results of density-response experiments were highly variable. In some cases, toxin effects were diluted as in


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case of Cu. In other cases, an inverse density-response slope was found. This suggests that toxin effects were enhanced as plant density increased. The results were sensitive to soil type (humus versus mineral soil). We conclude that density-response experiments should be used with caution. Low toxin mobility in soil and harsh environmental conditions may drastically affect plant response. The ecological consequences of our findings are discussed in the context of allelopathy. Since many plants have to stand several severe stress factors simultaneously in nature, plant response to homogenous allelopathic exposure may not follow a foreseeable pattern in natural plant communities. We suggest avoiding the use of density-response experiments as the main method in studies searching for ecologically significant allelopathic effects. 155. Allelopathy: From Field Observation to Laboratory and Glasshouse Experiments J.R. Qasem Department of Plant Protection, Faculty of Agriculture, University of Jordan, Amman, Jordan Email: [email protected] In this work, the effect of four weed species; Anthemis sp., Matthiola sp., Malva sylvestris and Sisymbrium irio on wheat and barley will be presented and discussed as a model of the differences between the observed effect of plant species in nature and that obtained in laboratory and/or glasshouse experiments. Observation on the effect of the four weed species in the field was found in some cases to differ from their effects on the same crops under laboratory or glasshouse conditions. Similar conflicts in results were observed between laboratory and glasshouse experiments. Results showed the risk in relying on a single experimental technique to explain and to judge on the type of interference between plant species in nature. The interpretation and conclusion drawn based on the observed inhibitory zone of certain species in nature may not always be due to allelopathic effects, while strong inhibitory effects that certain species showed in laboratory experiments may not be obtainable in glasshouse pot experiments and opposite responses are possible. The observed inhibitory zones of Anthemis sp. and Matthiola sp. under field conditions on wheat and barley crops was hard to confirm in pot experiments under glasshouse conditions. Similar differences in the effect of the four weed species on both crops were obtained between laboratory and glasshouse experiments. It is concluded that plant-plant interactions lead to exclusion of certain species from spots in the field which are observed as inhibitory zones, but that these may be due to other plant interaction mechanisms than allelopathy. 156. Parasitic Plants as a New Target Plant for Bioassay Method of Evaluating or Screening Rice Allelopathic Potential Yiqing Guo1, 2, Donghyun Shin1, Kil-Ung Kim1

1Department of Agronomy, College of Agriculture & Life Science, Kyungpook National University, Daegu 702-701, Republic of Korea. 2Yunnan Academy of Agricultural Sciences Email: [email protected]

Allelopathy is any direct or indirect harmful or beneficial effect by one plant (including microorganisms) on another through production of chemical compounds that are released into the environment. Allelopathy as one component of integrated weed management technology can reduce a certain amount herbicide application and therefore also reduce concerns of consumers and environmental groups. Screening or evaluating the allelopathic potential of rice varieties is a first step toward implementing an allelopathic component of weed management. In this study, the parasitic plant Triphysaria versicolor was investigated as a new target plant and method for allelopathic potential assays. The effects of three rice cultivars, Koukesumochi, Dongjinbyeo and K21 on the haustorium induction rate, phytotoxicity and ROS (reactive oxygen species) activity ofTriphysaria versicolor were determined. Among the three cultivars, different rates of haustorium induction were observed, and UV irradiation to rice cultivars increased the rate of haustorium induction and phytotoxic effects on root growth of T. versicolor. Activity of reactive oxygen species (ROS) was assayed by staining root tips of T. versicolor with the probe CM-H2DCFDA [5-(and 6)-chloromethyl-2’, 7’ dichlorodihydro-fluoroescein diacetate, acetyl ester] and monitoring the change of fluorescence. The fluorescence was increased when the dye was oxidized by ROS. Fluorescence appeared in a short time for the Kouketsumochi cultivar (allelopathic), followed in order by K21 and Dongjinbyeo (non-allelopathic) cultivars. Results indicate that different haustorium induction rates of rice cultivars were related to different activity of ROS. Thus, it is suggested that T. versicolor can be used as a new target plant for evaluating the allelopathic potential of plant species. 157. Can Marigold Root Exudates Suppress Weed Growth? Shobha Sondhia, Jay G. Varshney National Research Centre for Weed Science, Jabalpur-482004 M.P., India Email: [email protected] Allelopathic substances, if present in crop varieties, may reduce the use of synthetic herbicides. Allelopathy alone may not be a perfect weed management technology but it may be a supplementary tool for weed control. A methodology has been developed to isolate allelochemicals from the root exudates of marigold plants, which were grown for 4 months. Root exudates of marigold plants were collected every 3-4 days and stored in the dark. Exudates were evaporated at low temperature and partitioned with various solvents of increasing polarity. This process yielded white crystals of a chemical compound which was non-polar in nature and insoluble in methanol. The phytotoxic effects of concentrated aqueous root leachates and isolated compound at concentrations of 1, 10, 50, 100 and 1000 ppm were evaluated on Vicia sativa, Lathyrus sativa, Parthenium hysterophorus, Phalaris minor, Avena ludoviciana, Convolvulus arvensis under laboratory conditions. Root and shoot growth of all the weeds was reduced as the concentration of isolated


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compound increased. The aqueous extract was more phytotoxic in reducing the growth of all the weeds as compared to the isolated compound alone. The phytotoxic effect of root leachates was equivalent to 10 and 1000 ppm of isolated compound in the case of Parthenium histerophorus and Lathyrus sativa respectively; however the phytotoxic effect was even more in case of Phalaris minor and Avena ludoviciana as compared to control. The phytotoxic effect of root exudates was in the order of L. sativa> P. minor> P. hysterophorus> A. ludoviciana> V. sativa> C. arvensis. Root growth of all the weeds was more severely affected as compared to shoot growth. Germination of P. minor, A. ludoviciana, V. sativa and L. sativa was less affected by the root leachates and various concentrations of isolated compound as compared to shoot and root growth. However, more than 67 and 51% reduction in germination of Parthenium hysterophorus and Convolvulus arvensis was observed by aqueous root exudates. It can be concluded that marigold root leachates have the capacity to reduce growth of these weeds under field conditions due to release of allelochemicals. 158. Allelopathy of Polish Winter Wheat Cultivars Helena Gawronska, Dorota Ciarka, Dariusz Ruszkowski, Stanislaw Gawronski Laboratory of Basic Research in Horticulture, Warsaw University of Life Sciences, ul. Nowoursynowska 159, 02-776 Warsaw, Poland Email: [email protected] Winter wheat, one of the major cereal crops in the world, is known for allelopathic activity but no such data for Polish wheat cultivars are available, despite of its cultivation in organic farms where this trait might be desired. This work reports the evaluation of: (i) activity of allelochemicals contained in: 1/ aqueous extracts of above ground organs and roots, 2/ leached out from above ground organs, 3/ volatiles, and 4/ root exudates, (ii) dynamics of plant development at early growth stages, and (iii) of competitiveness of winter wheat cultivars with weeds in the field. Studies were conducted in laboratory, greenhouse and in the field. Donors of allelochemicals were seedlings and fully developed plants of 3 to 11 Polish winter wheat cultivars. Acceptors of the allelochemicals were seeds and seedlings of mustard, ryegrass and seeds of 14 weed species. Germination tests, co-culture of donor and acceptor seedlings, observation and biometric measurements were used for evaluation of allelopathic activities, weed appearance in the field and wheat plant growth. Results showed that allelochemicals of winter wheat origin possessed allelopathic activity, which was manifested by delayed and reduced or even completely inhibited germination. Negative impact of these compounds was also recorded in early growth of acceptor seedlings though in some cases stimulation was also recorded. Leachates showed the least activity, while extracts showed the highest activity. Genotypic differences between tested cultivars exerted by allelochemicals were recorded with Sakwa cultivar usually showing the highest activity while Begra and Mewa showed the lowest. In most cases, donor concentration/biomass amount/seedling number dependent

activity was recorded. Field studies are in progress and results will be presented. 159. Current Allelopathic Research in Pakistan-Some Implications Zahid Ata Cheema, Abdul Khaliq and M. Naeem Mushtaq Weed Science-Allelopathy Laboratory, University of Agriculture, Faisalabad 38040, Pakistan. Email: [email protected] Present allelopathy-related research in Pakistan is mainly focused on using different plant/crop water extracts for weed control, using crop residues as mulches, combination of lower doses of herbicides with allelopathic water extracts, and the intercropping of allelopathic crops in main field crops for their effects on weeds and crop. Inclusion of allelopathic crops in rotation systems for weed suppression is under investigation. Investigations on the use of allelopathic plant extracts against insects and diseases are in their infancy. Early post-emergence application of the mixture of sorghum, sunflower, brassica or mulberry water extracts suppressed total weed dry weight by 40 to 75% and enhanced yield of wheat, maize, cotton and rice by 15 to 25%. Combined application of these water extracts reduced the herbicide(s) dose by 50 to 75%. The intercropping of mungbean in maize was effective to control weeds by 55% and was economical in terms of net benefits. Sorghum and berseem in rotation settings decreased weeds by 85%. Results of some of the latest experiments will be presented and discussed. 160. Effect of UV-B (280-320 nm) on the Enhancement of Allelochemicals (Phenols) in Catharanthus roseus Plants V. Selvakumar, P. Periyakaruppiah, K. Rajarathinam, M. Jayakumar Research Department of Botany, VHNSN College, Virudhunagar- 626 001, India Email: [email protected]

There are many reports on ultraviolet-B (UV-B, 280-320 nm) induced changes on plant growth, leaf morphology, foliar characteristics, chloroplast structure, and function in higher plants. Only very few reports have appeared on the effect of UV-B on secondary metabolism. Secondary metabolism not only helps plants overcome extreme environmental conditions but also acts as a defense tool to withstand UV-B stress. In this study, the influence of enhanced UV-B radiation on the synthesis of phenolic compounds was studied in the important medicinal plant Catharanthus roseus. Quantitative estimation of total phenolic acid content showed differences between control and treated plants. The phenolic acid content was higher in the UV-B treated plants than the control plants. The phenolic acid content in the plants treated with UV-B for two hours was very higher than those treated for one hour. Qualitative analysis of phenolic acids of control and UV-B treated plants showed significant differences in the number of phenolic acids. The phenolic acids were separated by TLC, paper chromatography and HPLC methods. The control plants and the plants grown under UV-B enhanced radiation showed changes in different


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phenolic acids. In the plants treated with UV-B, gallic, protocatechuic, p-hydroxybenzoic, chlorogenic, vanillic and caffeic acids were determined. These experiments indicate that in Catharanthus roseus plants, the content of phenolic allelochemicals can be enhanced by UV-B radiation.

161. Allelopathic Effect of Floral Volatile Chemicals on Behavioural and Electrophysiological Responses of a Female Predator Insect Mourad Shonouda1, Sergio Angeli2, Stefan Schuetz2, Stefan Vidal3

1Zoology Department, Faculty of Science, 21511 Mharam Bey, Alexandria University, Egypt 2Institute for Forestzoology and Conservation, University of Göttingen, Germany 3AgroEntomology Section, Crop Sciences Department, University of Göttingen, Germany Email: [email protected] Naïve gravid females of the predator syrphid fly Episyrphus balteatus (DeGeer) were significantly attracted to Ziziphus spina christi flowers in olfactometric assays. Also, the gravid females were stimulated by floral odorants and laid significantly high percent eggs as compared with control. The Floral odorants were extracted by closed-loop-stripping analysis (CLSA). The CLSA extract of Z. spina christi flowers was analyzed by gas chromatography-mass spectrometery-electroantennographic detector (GC-MS/EAD). Seven compounds of 26 identified compounds in the CLSA extract showed clear antennal response. The active identified compounds were 6-methyl-5-heptene-2-one; nonanal; linaloloxide; benzaldehyde; linalool; lavandulol and alpha-terpineol. High electroantennogram (EAG) responses of these compounds were confirmed in dose-response bioassays when used the standardized chemical compounds. It is imperative to know the chemical interaction between predator syrphid flies and the surrounding environment to enhance the biological control potential of the beneficial natural enemy. More studies are needed

in the field to evaluate the attractiveness of natural enemies to these volatile compounds and the possibility to use them as additive stimulants in integrated pest management program.

162. Methods for Analysis of the Distribution of Allelochemicals in Selected Plants Denise Schneider, Ines Fritz, Dominic Funk, Marcus Pruckner, Michaela Bauer, Rudolf Braun Universität für Bodenkultur Wien, Department IFA-Tulln, Konrad Lorenz Str. 20, A-3430 Tulln, Austria Email: [email protected] Allelopathic compounds are secondary metabolites playing an important role in plant-plant interactions. Some kinds of plants are able to produce a high amount of such bioactive substances and store them in nearly all compartments of the plant. Their concentration inside the compartments varies depending on the function and use. Within this project special methodology was developed to determine the distribution of allelochemicals in selected plants with high allelopathic potential, namely Impatiens glandulifera, Fallopia japonica and Heracleum mantegazzianum. This included both optimizing and applying an agar-diffusion bioassay and also the use of a range of standardized bioassays (e.g. Lumistox). The ground plant material of each compartment of the plants was used to produce methanolic extracts and to detect their toxicity against different test organisms. The results from the standardized bioassays were used to generate dose-response relationships while the agar-diffusion bioassay allowed only a screening concerning the inhibition. The dimension of the inhibition correlated both with the toxicity and the amount of allelopathic substances in the compartments. The flowers and leaves of I. glandulifera and the leaves of F. japonica have shown high allelopathic activity against all test organisms. In contrast all compartments of H. mantegazzianum were low effective in nearly all cases.

Main Topic 10: Invasion ecology and allelopathy 2 163. Biogeographical Approaches to Allelopathy Helps to Evaluate the Impact of Exotic Invaders Ragan M. Callaway* and Inderjit1

*Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; 1Centre for Environmental 1Management of Degraded Ecosystems (CEMDE), University of Delhi, Delhi-110007, India Email: [email protected] Understanding the mechanisms by which many exotic invasive plants suppress their neighbors in invaded ranges but coexist with neighbors in species-diverse systems in their native ranges remain unclear. However, taking a biogeographical approach, comparisons of the ecological traits of species in home and native ranges, has proved useful for evaluating allelopathy as an invasive mechanism. Comparing higher chemical production and/or accumulation, the effects of novel chemicals, and differences in the sensitivity of native residents to novel chemicals are important ways to tackle the problem. We discuss the biogeographical approach in studies

of the antimicrobial biochemistry of Alliaria petiolata and the allelopathic effects of Centaurea maculosa; in both cases finding stronger toxicity expressed against species in the invaded ranges than in the native ranges.

164. Invasion Success: Are Mode of Actions of Root and Exudate Chemicals Useful Indicators? Franz Hadacek, Vladimir Chobot Department of Chemical Ecology and Ecosystem Research, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria The biological activity of many secondary metabolites represents an often-considered factor utilized to explain phenomena ranging from interactions between species up to ecosystem processes. In particular, growth inhibitory effects of low-molecular-weight compounds are commonly interpreted as consequences of a function as chemical weapon, which might confer resistance to the


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producing plant against microbial and herbivore predators and advantages in competing with other co-occurring species (allelopathy). In vitro phytotoxic activities of many secondary metabolites constitute a basic principle in the hypothesis of allelopathy. Undoubtedly, side-by-side growing plants cause feedbacks on each other with negative but also with positive results (facilitation). Idiosyncratically, the same compound may, always depending on the concentration, cause both negative as well as positive effects. As a consequence, unambiguous decisions to what extent a chemical might contribute to biological phenomena are more difficult than ever. The complexity of this issue will be exemplified on two secondary metabolites, which are reputedly involved in allelopathic phenomena, also those of invasive plants: the naphtoquinone juglone and the flavan-3-ol (±)-catechin. To serve as contrast, a well-known antioxidant, the flavonoid quercetin, will also be included into the survey. A combined approach of phytotoxic, physiological and electrochemical assays aimed at exploring the potential of the tested compounds to cause allelopathic effects will be presented. Further, results from a current study exploring the contributions of secondary metabolites in root exudates from the black locust tree, Robinia pseudacacia, to its invasiveness in Europe, shall illustrate the applicability of such an approach in studies exploring the contribution of allelochemicals to plant invasiveness. 165. Allelopathic Interference of Cyperus rotundus L. with Some Crops Ibrahim S Alsaadawi1 and Nadia M. M. Salih2 1Department of Biology, College of Science, Baghdad University, Baghdad, Iraq 2Ministry of Higher Education and Scientific Research, Baghdad, Iraq Email: [email protected] Field observations indicated that Cyperus rotundus is able to spread rapidly in to heavy stands of several field and vegetable crops and caused significant reduction in their yield. The rapid encroachment of C rotundus suggests the possibility of an allelopathic mechanism in addition to competition. Results indicated that root exudates of C rotundus significantly reduced root and top growth of tomato and cucumber plants. Residues of C rotundus incorporated at rates of 3 and 6 g per kg soil significantly inhibited seedling growth of grain sorghum, soy bean and mung bean and the reduction increased with the increased rate of residues. Volatile compounds released from top and tubers of C rotundus caused a significant reduction to seedling growth of mung bean. The toxicity of C rotundus residues in soil started two weeks after decomposition and continued for 8 weeks then declined. Chromatographic analyses using HPLC revealed the presence of ferulic, caffeic, hydroxyl benzoic, syringic, chlorogenic and p-coumaric acids and three unidentified compounds in shoot and the same phenolic acids and one unidentified compound in tubers. Additional chromatographic analyses showed that the shoot and tuber of C rotundus contain 13 and 11 volatile compounds respectively. Ten of these compounds were identified as α-pinene, β-pinene, limonene, camsaicin, artimisin, camphene, camphor, citronellal, farnesol and petalostemumol. Most of the isolated compounds were reported to be phytoxic to several crop species. Thus it appears

that allelopathy is the causative factor responsible for the reduction of growth of the test crops by C rotundus with competition probably accentuating its effect. 166. Significance of Algal Allelochemicals in Natural and Agroecosystem A.S. Ahluwalia Department of Botany, Panjab University, Chandigarh, 160014, India Algae and cyanobacteria are known to employ allelochemicals in the offensive and defensive interactions among themselves and with higher plants, which play an important role in structuring the aquatic community. We, however, witness little progress in better understanding the role of algal chemicals in aquatic and wetland ecology. Demonstrating allelopathic activities in aquatic system, for example, is considered difficult because of dispersion of allelochemicals due to continuous movement of water and less chances of lack of contact between competing organisms and chemicals. This talk will discuss the significance of well-replicated field studies from different geographical locations in appreciating algal allelopathy. To understand wetland and aquatic ecology, bloom formation, lake succession, algal invasion and dominance of certain algae in a given ecosystem, more research is needed on chemical warfare between and among algae and cyanobacteria. 167. Conditional Effects of an Allelopathic Root Exudate: The Toxicity of (±)-Catechin is Affected by Interactions with Different Metals Jarrod Pollock, Ragan M Callaway, Inderjit1 and William E. Holben Organismal Biology and Ecology, Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; 1Centre for Environmental Management of Degraded Ecosystems (CEMDE), University of Delhi, Delhi-110007, India. Email: [email protected] Evaluating variation, or "conditionality", in plant interactions is crucial to understanding their ecological importance. Much is known about conditionality in competition, facilitation, and herbivory, but not allelopathy, which likely contributes to the equivocal nature of reports on this topic. Centaurea maculosa (spotted knapweed) is a highly invasive species in North America, whose success has been attributed in part to the allelochemical root exudate, (±)-catechin. Among other things, understanding the ecological relevance of an allelopathic root exudate necessitates measurements of toxicity in reasonably relevant ecological conditions and determining how it interacts with various soil components. We established low concentrations of catechin in nine different natural soils and then planted seeds of the native grass Koeleria macrantha. Catechin treatments demonstrated phytotoxicity. Additionally, low doses of catechin, resulting in soil concentrations below our detectable limit of 5 µg g-1, applied to the rhizospheres of three native species at nine different field sites in western Montana also demonstrated phytotoxicity. Furthermore, in


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other experiments we found that some metals caused rapid declines in measurable catechin in solution, while calcium prevented its auto-oxidation, which maintained catechin concentrations at higher levels for longer periods if time than was found for solutions of pure catechin. Using these solutions, we found that catechin was highly phytotoxic at low experimental soil concentrations, but certain (catechin-metal complexes were more phytotoxic than catechin alone. Other solutions showed decreased toxicity. The variable toxicity of these complexes indicates that catechin effects can be enhanced or diminished by pleiotropic interactions in soils, resulting from catechin forming complexes with different metals or other soil components.

168. Allelopathy Contributes to the Invasion Success by Creating a Negative Feedback for Native Residents Inderjit and Ragan M. Callaway1 Centre for Environmental Management of Degraded Ecosystems (CEMDE), University of Delhi, Delhi-110007 India 1Organismal Biology and Ecology, Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA Email: [email protected] Exotic invaders could encourage generalist soil pathogen, thus creating a negative feedback for native plant species, which are more sensitive to the pathogen than the invader itself. Through several soil manipulation experiments we show that allelochemicals influence soil microbial ecology to benefit the exotic invaders. This talk will discuss the role of soil biota on the invasion success of an exotic invader by taking examples from Chromolaena odorata, Ageratina adenophora and Centaurea maculosa. Invasives gain dominance in the invaded range through (i) their escape inhibitory soil biota in their native range and to inhibit soil biota in their invaded range, (ii) encouraging native soil communities, and (iii) exacerbating biotic interactions among native plants and native soil biota. 169. Allelopathy of Acacia dealbata Link in Invaded Areas in North West of Spain Paula Lorenzo, Eva Pazos, Luís González, Manuel J. Reigosa Dept. of Plant Biology and Soil Science, University of Vigo. As Lagoas, Marcosende. E-36310. Vigo, Spain Email: [email protected] The major problem that natural ecosystems are facing actually is the invasion by exotic species. Acacia dealbata Link is one of the most active plant invader species and its distribution area in Europe is enlarging where it threatens native flora, reduce biodiversity and can become a serious environmental problem. Allelopathy probably is one of the physiological traits that promote the invasive capacity of A. dealbata, affecting germination and seedling establishment of the native flora. The aim was to know the allelopathic effect of A. dealbata throughout the year on target species to know the role of allelochemicals on invasion process. The effects of throughfall (rain passing through the canopy), leatter leachate, macerate (apical branches mixed with distilled water) and soil macerate water extracts were studied in a grove of Acacia dealbata in 2006, and 2007. The allelopathic capacity of Acacia dealbata was tested using a crop species and several autochthonous species, two of which were located both inside

and outside the grove of A. dealbata, while the other two were present only outside the grove. Allelopathic interference related to A. dealbata extracts was found. Test species were affected in different way by silver wattle. It seems to indicate that different ecophysiological processes are affected. Through the year target species responded in a singular way to the same allelochemical stress induced by A. dealbata extracts, even within the same species. The fact that the extracts from A. dealbata produce both stimulatory and inhibitory effects on target species, it could mean that allelochemicals can alter a variety of physiological processes. Respiration of species located outside the grove of A. dealbata was mainly stimulated by the macerate extract. This suggests that A. dealbata can interact with native species by allelopathic interference, and may be responsible for biodiversity loss in introduced ranges.

170. Allelopathic Interaction between Two Co-occurring Ruderal Invasive Plant Species in the Kashmir Himalaya, India Zafar Reshi and Irfan Rashid Department of Botany, University of Kashmir, Srinagar-190 006, Jammu and Kashmir, India Email: [email protected]; [email protected]

While allelopathic interaction between alien invasives and native species has been widely studied for being central to ‘novel weapons hypothesis’, but explication of equally important interactions between two or more co-occurring invasive species in their non-native range have been rarely studied. Thus, we investigated interactions between two co-occurring invasive alien species, namely Anthemis cotula and Conyza canadensis which inhabit disturbed sites in the Kashmir Himalaya, India and exhibit similar growth and reproductive characteristics. Using filter paper and soil bioassays, response of seed germination and seedling growth of each species was studied in relation to different concentrations of its own aqueous leaf leachate and to leachate of the other species. Results indicate species-specific and dose-dependent response in seed germination and seedling characteristics. Though leachate of both the species promoted achene germination in A. cotula at low concentrations (2500 ppm), high leachate concentrations (10,000 ppm) had an inhibitory effect. Furthermore, the inhibitory effect was more pronounced in filter paper bioassay than in soil bioassay. Contributory role of allelopathy in invasiveness of the two species and ecological implications of interspecies interactions are also discussed in the present communication

171. Allelopathy as a Mechanism for Invasion by Non-Indigenous Species Robin Svensson Department of Marine Ecology, Gothenburg University, Tjärnö Laboratorium 45296 Strömstad, Sweden Email: [email protected] Allelopathy is one of the most important non-resource interactions in plant ecology and has long been suspected


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to be an important mechanism for invasive plants. It is, however, not until recently allelopathy has been acknowledged as an influential mechanism in invasion biology. The Novel Weapons Hypothesis (NWH) predicts that exotic invaders will be successful if they bring unique biochemicals to their new range. Since the native species are not adapted to these novel chemicals, the exotic species will establish and proliferate through allelopathic interactions. The novelty of a compound may be recognized by an index of the phytochemicals in a community, which allows the NWH to predict invasions a priori. Support for the NWH have been found for exotic plants in terrestrial communities and the novel biochemicals in exotic species have been shown to have strong effects on native generalist herbivores, pathogens and soil microbes in invaded ranges. In our experiment we investigated if the NWH can explain the presence of the chemically defended exotic red algae Bonnemaisonia hamifera on the west coast of Sweden. The ephemeral B. hamifera, which originates from Japan, was first observed in Sweden four decades ago and have since spread to become one of the most conspicuous red algae in Sweden. Results show that the secondary metabolite 4-bromo-heptanone, at natural concentrations, inhibits settlement of spores from native algal species, and that the substance can be transferred from B. hamifera to the native species. The mechanism of transferring the chemical compound to other surfaces might enable the algae to “reserve” the surface for future colonization, and possibly also to protect the surface from grazers. This is the first marine study to show invasion facilitated by allelopathy and also that it may be beneficial to transfer chemical defences from exotic to native species. 172. Seed Germination, Growth and Root Vessel Elements of Sesame Seedlings as Affected by Leaves, Stem and Root Extracts of Aristolochia esperanzae Alfredo G. Ferreira1, Ana B. Gatti2, Sonia C.J.G.A.Perez1 1Botany Department, Rio Grande do Sul Federal University, Porto Alegre, Brazi 2Ecological and Natural Course at São Carlos University, São Paulo, Brazil E-mail: [email protected] Aristolochia esperanzae is a climber species that occurs in Cerrado (Brazilian savannah) at central region of Brazil. This species is rich in secondary metabolites like terpenes and lignans. The goal of this studies was examined the allelopathical effects of this extracts on seed germination, seedling growth and measured the root vessels size of Sesame indicum (sesame). Aqueous extracts of leaves, stem and roots of Aristolochia esperanzae were prepared and bioassayed with sesame. No inhibition was caused by the extracts from A.esperanzae on germination of sesame seeds The extracts of aboveground parts had a discrete effects on growth and root aspect of sesame, but the extracts of undergrounds parts caused a severe reduction of sesame root growth and a root showed a darkness appearance. The sesame root vessels were about 150.9 µm of length but those that grew in the extracts were about 50% of this size, and a decrease in number of secondary roots were observed. Studies are underway to found out what chemical substances function as allelochemicals produced by A. esperanzae.

173. Allelopathic Effects of Black Locust (Robinia pseudoacacia L.) Litter on Soil Microbial Activity F. Esposito1, A. De Marco1, A. Zarrelli2, A. Virzo1 1Dipartmento di Biologia Strutturale e Funzionale, 2Dipartimento di Chimica Organica e Biochimica, Università degli Studi di Napoli ”FEDERICO II”, Complesso Universitario Monte S. Angelo via Cinthia, IT - 80126 Napoli, Italy Email: [email protected] We investigated microbial abundance, diversity and activity, in soils under Pinus nigra Arn. and under Robinia pseudoacacia L., planted, in the seventy’s, on lapillus from the last Vesuvius eruption (1944). Black locust soil was richer in organic matter and nutrients than pine soil. In contrast, microbial biomass, basal respiration and catabolic diversity were higher in pine soil. As compared to pine litter: 1) lignin concentration was higher in black locust litter in the late stage of decomposition, 2) the percentage of aromatic substances (110 – 165 ppm) in 13C CPMAS NMR spectra was higher both in fresh and in decomposed black locust litter. Living tissues of black locust are known to have allelopathic effects. In the hypothesis that black locust allelochemicals occur also in litter and may inhibit soil biological activity, we performed laboratory and field trials. In laboratory we added water extracts of fresh and of decomposed litter to pine and black locust soils. Microbial activity in pine soil amended with fresh litter water extracts was significantly (P<0.05) lower than in control soil, whereas no effect was observed in black locust soil, likely because in this soil microbial populations are adapted to allelochemicals. 1H NMR spectra of litter water exctracts showed: in the decomposed one more abundant sugars; in the fresh one more abundant aromatic or unsaturated compounds, in particular 4 – hydroxyacetophenone was isolated and identified. In field we put a known amount of fresh and decomposed black locust litter on pine soil, after removing needle litter, and we found a lower microbial and fungal biomass in the soil under fresh black locust litter. Moreover the pine soils amended with fresh black locust litter showed basal respiration and catabolic diversity lower than control soils. 174. The Bittersweet Paradox: Toxic Allelochemicals Also Facilitate Nutrient Acquisition NishanthTharayil1, Prasanta Bhowmik2 and Peter Alpert3

1Entomology Soil & Plant Sciences, Clemson University, Clemson, SC 29634, USA 2Plant Soil & Insect Sciences, Univ. of Massachusetts Amherst, MA 01003, USA 3Biology Department, Univ. of Massachusetts Amherst, MA 01003, USA Email: [email protected] Physiological traits that facilitate the efficient foraging of apparently deficient resources could increase the invasiveness of an exotic species in a resource-limited habitat. Overall species fitness would be further enhanced if this foraging trait can inhibit the native species, so that the non-natives could gain uncontested access to the limited resources. Based on our previous studies demonstrating the metal-nutrient mobilization ability of


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allelochemicals, we hypothesized that, along with the reported toxic effect on the neighbors, these compounds could be directly involved in the resource acquisition of the allelopathic plant. We tested this hypothesis using an allelopathic exotic species Centaurea diffusa that suppress the natives through its phytotoxic metabolite 8-hydroxyquinoline (8HQ). Since 8HQ is a metal chelator and since C. diffusa mostly invades the alkaline calcareous soils in United States where metal micronutrient are limiting, we asked whether C. diffusa increases the release of 8HQ in response to low nutrient availability, whether 8HQ directly increases the ability of the plant to acquire nutrients, and by what mechanisms 8HQ fulfills the functions of inducing phytotoxicity and procuring nutrients. Hydroponic studies with various nutrient treatments showed that 8HQ production by C. diffusa to be non-specific to nutrient deficiency. By demonstrating that C. diffusa was

able to utilize Fe from insoluble Fe(OH)3, and the addition of activated carbon that sequesters 8HQ caused severe Fe deficiency in Fe(OH)3 systems, we were able to confirm the direct role of 8HQ in Fe acquisition of this plant from unavailable Fe forms. 8HQ was highly specific and efficient at mobilizing the Fe from soil invaded by C. diffusa. Further, the Fe uptake mechanism facilitated by 8HQ was independent of both root-reductase activity and plasma-membrane transporter-proteins, and hence is novel and possibly more energy-efficient. Thus our study elucidates one of the adaptive physiological mechanisms that could increase the invasiveness of C. diffusa in resource-limited habitats.

Main Topic 11: Allelopathy in crop settings for weed suppression

175. The Challenge of Annual Ryegrass (Lolium rigidum) – Will Allelopathy be Part of the Solution? J. E. Pratley E. H. Graham Centre for Agricultural Innovation, Charles Sturt University, Wagga Wagga, NSW, Australia 2678 Email: [email protected] Annual ryegrass (Lolium rigidum) is one of the major weed challenges for the farmers of southern Australia. It infests almost all fields of winter crops and requires herbicides to enable the crop to produce an economic yield. The dependence on herbicides in the Australian conservation farming regime has resulted in the evolution of herbicide resistance in annual ryegrass to the extent whereby more than half the fields in winter crops are estimated to have resistant ryegrass. This raises the prospect that Australia may run out of effective herbicide options over the next 5 to 10 years for control of this weed. Much research has been conducted to improve the understanding of the biology of this species. This has been valuable information but its application in a chemical farming system has been limited. Until recently little has been known of its chemical interactions of annual ryegrass with other species in the field. The team at Charles Sturt University has devoted the last decade to its allelopathic interactions with the prospects of novel solutions for its management. This paper considers the prospects of breeding crops for allelopathic control of ryegrass (the work of Wu), the search for new herbicide options through phytotoxicity (the work of Haig), the allelopathic impact of ryegrass on other species (the work of An) and the role of endophytes on the fitness and competitiveness of ryegrass and generation of allelochemicals (the work of Kirkby). We know that there are good prospects for allelopathic varieties, that there are phytotoxins that may be useful as natural herbicides, that there are natural tolerances to ryegrass allelochemicals and that endophytes are playing a role. This systematic approach to weed control is discussed.

176. Role and Persistence of Rye Allelopathic Activity in Soil John R. Teasdale1, Clifford P. Rice1 and Inga A. Zasada2 USDA-ARS Sustainable Agricultural Systems Lab1 and Nematology Lab2, Beltsville, MD 20705, USA Email: [email protected] Many extracts and compounds isolated from winter annual cover crops have been demonstrated to have allelopathic activity. These compounds can contribute to weed suppression when cover crops are terminated before planting a cash crop. Although cover crop extracts can exhibit allelopathic activity in laboratory assays, they would be expected to have less activity and persistence in a soil environment. Literature suggests that, following cover crop termination, residues become less toxic as they decompose over a period of several weeks. An experiment was conducted to determine the allelopathic activity and persistence of rye (Secale cereale L.) after cover crop termination in 2006 and 2007 at two sites near Beltsville, MD. Rye in a late vegetative stage was killed by an application of paraquat and residue either shallowly incorporated or retained on the soil surface without tillage. The annual broadleaf weed, smooth pigweed (Amaranthus hybridus L.), and lettuce (Lactuca sativa L. ‘Great Lakes’) were planted into the incorporated rye, the no-tillage rye, or a control (with tillage similar to the incorporated rye treatment) immediately following and at approximately weekly intervals after tillage. Soil to a 10 cm depth was removed from each treatment at the same time that test species were planted in the field and assayed in a hoophouse pot experiment using the same test species. Soil was also collected for determination of benzoxazinoid concentrations in soil with LC-MS/MS at the same weekly intervals. Results of the field assay demonstrated a high level of suppression of both test species when planted immediately after rye termination (pigweed and lettuce plant mass was reduced 84 and 89%, respectively, by incorporated rye, and plant mass of both species was


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reduced 98% by surface rye residue compared to control plots). Suppression declined with subsequent plantings to less than 20% after approximately three weeks for incorporated rye and approximately five weeks for surface rye. Results of the hoophouse assay demonstrated a moderate suppression of both test species by soil from rye incorporated immediately after planting (pigweed and lettuce mass were reduced by 37 and 49%, respectively) but this suppression declined to less than 20% within one week after rye termination. Soil from no-tillage rye had no suppressive activity in the hoophouse assay. These results suggest that release of allelopathic compounds accounted for at least half of the field suppression observed with incorporated rye but this effect was short-lived. Allelopathy apparently made little contribution to field suppression by surface rye residue. 177. Rye Cover Crop Management to Enhance Allelopathic Weed Suppression James Burton, Christophe LaHovary, Christine Sickler, David Danehower, Chris Reberg-Horton, Michael Burton, and Paul Murphy Depts. of Horticultural Science and Crop Science, North Carolina State University, Raleigh, NC 27695 USA Email: [email protected] Rye (Secale cereale) is used as a winter cover crop, often for the allelopathic weed suppression provided by the mulch. However, weed suppression from a rye cover crop mulch is not always reliable. This may be due to many factors, but one aspect of cover crop mulch weed suppression that is not well understood is the relationship between cover crop management and the allelochemical levels resulting from the management system. Rye produces several allelochemicals, the principle allelochemical group include the benzoxazinone (BX), represented by DIBOA. The constitutive biosynthesis of allelochemicals in rye seems to be correlated with development; most is produced when the plants are at more juvenile stages of growth. It is likely that rye produces a constitutive amount of BX in each leaf, and does not produce more unless induced. This constitutive content is diluted as the plant grows, and the lowest concentration of BX is found in mature flowering plants. However, the biomass increases can result in significant total BX accumulation, resulting in 30 kg ha-1 at the time the cover crop is terminated (early to mid-May in NC). It is not known whether this high biomass to high allelochemical ratio is optimum for weed management. Mowing and nitrogen application in the early Spring can alter the biomass profile (leaf to stem tissue ratio). We have found that very little BX is present in the stem or flower tissue. Mowing with N increased the leaf:stem ratio at the early May sampling, when compared to the mowing only treatment. Mowing plus N did not result in a greater or lower BX concentration in the harvested tissue than the mowing alone treatment. These changes in the biomass profile as a result of cover crop management could result in improved weed suppression by the cover crop mulch.

178. Argentinean Rice Cultivars: Their Allelopathic Potential for Weed Control Florencia Urteaga Omar, Hugo D. Chludil1 and Silvia R. Leicach1

1Organic Chemistry, Agronomy School, Buenos Aires University, Avda. San Martín 4453. Buenos Aires (C1417DSE), Argentina Email: [email protected] Rice (Oryza sativa L.) allelopathic potential was investigated in the last decade with particular interest on the identification of allelochemicals. However, there are not systematic studies performed on rice cultivars commonly used in Argentina. The aim of present work was to explore the allelopathic potential of six different rice cultivars frequently used in Argentinean rice region. A modified relay seeding technique, a laboratory bioassay that measures root growth inhibition of a weed species due to

the presence of rice seedlings, was used to evaluate the allelopathic effect of the rice lines. Six rice cultivars: El Paso 144, Cambá, Blue Bonnet, IRGA 417, Yeruá, and El Supremo were selected for this bioassay. Barnyardgrass [Echinochloa crus-galli (L.) Beauv.], one of the most troublesome weeds in rice production was chosen as a target species. Experiments were conducted in the laboratory of the Organic Chemistry, FAUBA from August to November 2007. The inhibition degree was quantified in terms of Echinochloa crus-galli root growth. Each treatment was replicated eight times in a completely randomized block design and the experiment was repeated twice. Analysis of variance was performed for all data using the General Linear Model. Treatment means were compared using the least significant difference (LSD) at the 0.05 probability level. El Paso and Blue Bonnet were the cultivars showing strong and consistent allelopathic activity against Echinochloa crus-galli, whereas the remaining rice lines were weakly (or not) allelopathic. Utilization of allelopathic potential in rice might become an easy and affordable initial weed management strategy, accessible to all farmers reducing dependency on chemical herbicides, thus reducing environmental pollution. 179. Allelopathic Rice: From Theory to Practice in China Hu Fei, *Kong Chuihua and Chen Xionghui Laboratory of Weed Science, South China Agricultural University, Guangzhou, 510642, China Email: [email protected] Rice is one of the staple food crops in the World, nearly half of China’s populations have being fed with rice for thousands years. Weed is always one of the serious pathogens in rice production. Both manpower and chemical methods are not the best weed control strategy in modern rice production. However, the development of allelopathic rice with significantly will decrease herbicide applications and not increase manpower in weed rice management. Rice allelopathic research have been initiated and the progress has been fast both in theory and practices in China. Theoritical research includes rice allelochemicals, isolation and identification and their synthesis, gene analysis, GM rice for weed-suppress, mode of allelochemicals releasing and transformation, relations of rice allelopathic trait with biotic and abiotic factors (soil, meteorological, weed, growth stage, etc), chemical signal among weeds and rice plants. In China, both allelopathic and high yield yielding


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rice varieties have been breed for rice production. For the last 10 years we have developed three rice lines that have both weed-suppression trait and other commercial yield and quality attributes. Now these three lines are being evaluated under the control of government, meanwhile we are summarizing production management practices for these three line rice in the fields. These production practices may decrease herbicide uses and increase rice yields for the farmers. We believe that these alllelopathic rice lines along with their production practices may be adopted in 3 to 5 years by organic producers in China. 180. Molecular Physiological Properties of Different Allelopathic Potential Rice Accessions in Responses to Nutrition Deficiency Wenxiong Lin1, 2, Jun Xiong1, 2, Haibin He1, 2, Haibin Lin1 ,2 and Long Qiu1, 2 1Key Laboratory of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University (FAFU), C/O Ministry of Education China 2Institute of Agroecology C/O School of Life Sciences, FAFU, Fuzhou 350002, China Email: [email protected] Our previous studies showed that nutrient deficiency could influence the production of allelochemicals, as a result, affect allelopathic potential in the suppression of the target weeds. Experiments were conducted to study the mechanism of the changes in the suppression of barnyardgrass mediated by different allelopathic potential rice accessions under nutrient deficiency. The result showed that the inhibitory effect on barnyardgrass mediated by allelopathic rice PI312777 was significantly greater than that by non-allelopathic rice Lemont, especially under nutrition deficiency. Further analysis indicated that phenolic acids in root exudates and tissues of allelopathic rice PI312777 were higher than that in its counterpart under nutrition deficiency, which is attributed to the higher activity in phenylpropanoid metabolism. Furthermore, the expression property of nine genes encoding the key enzymes involved in phenylpropanoid pathway in rice was detected by real-time fluorescent quantitative PCR. It was found that all genes concerned in allelopathic rice PI312777 were up-regulated, while the reverse was true in its counterpart except for PAL performing a slight up-regulation pattern. The present result also showed that allelopathic rice PI312777 performed stronger acclimation ability to the nutrient stress than non-allelopathic rice Lemont, indicating its higher ability to absorb and utilize nitrogen, phosphorus, and potassium in hydroponic solution, as well as its higher activities to scavenge reactive oxygen species in rice plant. In addition, analysis of the related gene expression pattern for the key enzymes associated with absorption and utilization of nitrogen, phosphorus, and potassium nutrients in the two rice accessions showed that the related genes in allelopathic rice PI312777were significantly upregulated compared with non-allelopathic Lemont. It is therefore suggested that nutrient deficiency enhanced rice allelopathic potential by inducing the related gene transcription and increasing the activities of related enzymes, thus leading to increased phenolics in root exudates to inhibit the accompanying weed barnyardgrass. Moreover, the higher nutrient efficiency of allelopathic rice

ensured its relatively higher competitive capacity in the mixture of rice/weed.

181. FQ-PCR Analysis on Key Enzymatic Genes Related with Phenolic Acid Metabolism in Rice Accessions (Oryza Sativa L.) Exposed to Nitrogen Stress Jun Xiong1, Haibin Wang1, Long Qiu1, Hanwen Wu2, Haibin He1, Ruiyu Lin1 and Wenxiong Lin1 1Key Laboratory of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University (FAFU), C/O Ministry of Education China 2Institute of Agroecology C/O School of Life Sciences, FAFU, Fuzhou 350002, China Email: [email protected] The different expressions of the key enzyme genes related with the Phenylalanine pathway in allelopathic and non-allelopathic rice accessions under nitrogen stress were investigated using real-time fluorescence quantitative PCR(FQ- PCR).The results showed the expression of 5 core genes in mRNA level, which were closely correlated with phenolic acids metabolism, all increased in allelopathic rice PI312777 exposed to nitrogen starvation, and of which, the phenylalanine ammonia-lyase(PAL) was the most sensitive. Benzoic acid-2-hydroxylase responsible for the salicylic acid (SA) synthesis which is an important signal molecule was upregulated by 3.010 and 3.230 fold time in leaf and root, respectively. At the same time, the other core enzymes related to phenolic acid synthesis were decreased in non-allelopatic rice Lemont under low N supply except for the lightly increase of cinnamoyl-CoA in roots and cinnamoyl alcohol dehydrogenases in leaves. The contents of phenolic acids were higher in allelopathic rice PI312777 under lower nitrogen supply than under normal nitrogen supply. 182. Exploiting Rice Allelopathy for Management of Parthenium hysterophorus L. Arshad Javaid, Sobiya Shafique, Shazia Shafique and Tariq Riaz Institute of Mycology and Plant Pathology, University of the Punjab, Quaid-e-Azam Campus Lahore, Pakistan Email: [email protected]

Parthenium (Parthenium hysterophorus L.), an annual invasive weed native to tropical America, is rapidly spreading in many parts of the world. The present study was designed to manage this weed by exploiting allelopathic potential of rice (Oryza sativa L.). In a laboratory bioassay, effect of aqueous, methanol and n-hexane shoot extracts of 0, 2, 4…10% concentrations of three rice varieties viz. Basmati-385, Basmati-386 and Basmati Super was tested against germination and seedling growth of parthenium. Aqueous and methanol extracts exhibited phytotoxicity against the test weed species. Generally extracts of higher concentrations of 6–10% significantly suppressed germination, shoot length and total plant biomass. Root length was significantly suppressed by all the employed concentrations of aqueous and methanol extracts. Highest phytotoxicity was recorded in methanol extracts of Basmati 386 where 10% extract suppressed


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germination, shoot length, root length and plant biomass by 85, 87, 95 and 98%, respectively. In foliar spray bioassay, aqueous extracts of 5 and 10% concentrations of the three test rice varieties were sprayed on 7 days old pot grown parthenium seedlings. Two subsequent sprays were carried out at 5 days intervals each. All the extract treatments reduced root and shoot biomass. Effect of 5% extracts was more pronounced than 10% extract. In residue incorporation bioassay, crushed shoot materials of the three rice varieties were incorporated in the soil at 0.5, 1.0 and 1.5% w/w concentrations. Parthenium seeds were sown one week after residue incorporation and plants were harvested 4 weeks after sowing. All the residue treatments except 0.5% Basmati Super incorporation significantly declined shoot biomass of the target weed species. Highest concentration of 1.5% residue incorporation of three rice varieties resulted in 61 to 81% and 38 to 62% reduction of shoot and root biomass of parthenium weed, respectively.

183. Effect of Different Allelopathic Crop Residues Applied as Surface Mulch for Weed Management in Maize (Zea mays L.) Azhar Mahmood, Zahid Ata Cheema, Abdul Khaliq and M. Naeem Mushtaq Weed Science & Allelopathy Laboratory, Department of Agronomy, University of Agriculture, Faisalabad 38040, Pakistan. Email: [email protected] Weeds pose a major threat to the yield of maize crop. Allelopathy has emerged as a recent tool for manipulating the growth of different plant species. A field study was carried out at Agronomic Research Area, University of Agriculture, Faisalabad, during 2006 and 2007 to evaluate the allelopathic influence of mulches of different plant residues as sorghum (Sorghum bicolor), sunflower (Helianthus annus), rice (Oryza sativa) and maize (Zea mays) applied in a combination of three each at 6.0 Mg ha-1 as surface application at sowing. For comparison, the recommended rate of S-metolachlor + atrazine (Primextra Gold 720-SC) at 1.8 kg a.i. ha-1 as a standard herbicide treatment was applied at pre emergence and a weedy check was also maintained. Surface mulching of different crop residues was fairly good in controlling the weeds. Combination of rice + sunflower + maize each at 6.0 Mg ha-1 was relatively better in reducing the total weed dry weight by 70 to 85% and was followed by treatment combination of sorghum + sunflower + maize each at 6.0 Mg ha-1 with 58 to 81% reduction during both years. The combination of rice + sunflower + maize each at 6.0 Mg ha-1

increased maize yield by 54 to 69% as compared to the control and yield was similar to the yield obtained from S-metolachlor + atrazine treatment. It can be suggested that surface mulching of the crop residues is economical practice for controlling weeds in maize. 184. Allelopathic Potentials of a Non-Leguminous Cover Crop, Nelsonia canescens (Lam) Spreng, Family Acanthaceae A. G. N. Fongod1, D. A. Focho2, A. M. Mih1, Nukuna B. N.3 and V. P. K. Titanji1

1Department of Plant and Animal Sciences, University of Buea, PO Box 63, Buea. Cameroon

2Department of Plant Biology, University of Dschang, Cameroon 3Lerner Research Institute, Cleaveland, Ohio, USA. Email: [email protected] Nelsonia canescens (Lam.) Spreng belonging to Acanthaceae family was found to grow luxuriantly along the banks of a stream in Tiko, and was transplanted to a banana plantation to check the erosion there. This species established rapidly and its potentials as a non-leguminous cover crop became evident. Nelsonia canescens suppressed the weed species diversity to just nine species as compared to 73 species in other adjacent parts of the plantation not planted with it. Even the nine surviving weed species showed marked reduction in growth and vigor, and were usually chlorotic. Leachates from vegetative plant parts soaked in water for 24 h reduced the germination of maize seeds by 70% while infusions from macerated vegetative plant tissues soaked in water for 24 h reduced the germination of maize seeds by 50%. Separation of ultrasonification and microwave extracts of the plant by silica gel thin layer chromatography revealed the presence of three allelopathic compounds, affzelechin (a flavone catechin), scopolin (a 6-methoxy-7-glucosidyl coumarin) and myrecetin (a glucone flavanol). These compounds are probably responsible for the allelopathic interaction of Nelsonia canscens with other weeds in the banana agroeco-system. Allelopathic properties of a ground cover like Nelsonia canescens could be a cheap and environmentally friendly alternative to chemical weed control in weed management systems in plantation agriculture. Preliminary observations on other attributes of a good cover crop are quite promising and need to be further investigated for the possible adoption of this plant as a plantation cover crop. 185. Control of Weeds in Wheat Field by Applying Allelopathic Concept in Bangladesh P. K. Biswas1, M. M. Morshed1and P. C. Bhowmik2, 1Dept. of Agronomy, Sher-e-Bangla Agricultural Universit, Dhaka, Bangladesh 2University of Massachusetts, Amherst, MA 01003-7245 USA. Email: [email protected] Wheat (Tritucum aestivum) is successfully grown Bangladesh. The crop is frequently affected by weeds that cause about 20 to 30% yield reduction. A 2-yr research project was initiated at Agronomy department, Sher-e-Bangla Agricultural University, Bangladesh to study the allelopathic effects of Brassica spp. to control weeds in wheat. An experiment was laid out in a split-plot design with three cultivated Brassica species viz. Brassica campestris, Brassica juncea and Brassica napus as the main plot and five methods of biomass application as the sub-plot. Brassica crops were uprooted at initiation of flowering and applied in the same field as per treatment. Wheat seeds were sown in 20 cm row spacing. Weed samples were collected two times on 30 and 50 days after sowing (DAS) for counting weeds and measuring dry weight. Amaranthus spinosus, Amaranthus viridis, Heliotropium indicum, Polygonum hydropiper, Celosis argentina, Ageratum conyzoides, Brassica kaber and


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Digitaria ischaemum were not found to the wheat field. The highest weed dry matter yields was recorded in Brassica juncea plots (1.72 g/m2) at 30 DAS and in Brassica napus field (1.44 g/m2) at 50 DAS. The lowest weed dry matter (0.89 g/m2) was recorded when total Brassica biomass was incorporated into the soil 30 DAS and 50% incorporation plus 50% spreading 50 DAS. Weed population densities were not affected by Brassica species 30 and 50 DAS and by the incorporation methods 50 DAS, although the lowest weed population (15.33/m2) was recorded in spreading between lines that were similar to complete incorporation and 50% spreading plus 50% incorporation 30 DAS. Interaction of Brassica species and incorporation methods showed lowest weed dry matter (0.74 g/m2) 30 DAS in Brassica napus biomass incorporated into the soil. 186. Phytotoxicity of Wheat Straw on Selected Weed Species in Respect to Germination and Growth G.P. Satsangi, Garima Bartariya, and Anjali Saxena Department of Botany, Faculty of Science, Dayalbagh Educational Institute (Deemed University), Dayalbagh Agra-282005, India. Email: [email protected] Allelopathy has shown its potential for biological weed control. Present study was conducted to determine the phytotoxic effect of wheat straw (burned and unburned) on Chenopodium album L., Boerhaavia diffusa L. and Parthenium hysterophorus L. For the bioassay, leachates were prepared by soaking 50 gms wheat straw (burned and unburned separately) in 900 ml of distilled water for 72 hrs. and filtered by muslin cloth followed by Whatman filter paper no. 1. It was considered as 100% treatment dose. Appropriate amount of distilled water was added to obtain its 50% and 25% concentrations. Twenty seeds of each of the species were soaked in different treatment doses along with water control. After 24 hrs, seeds were transferred in petri plates lined with Whatman filter paper no. 1. Observations were recorded after 15 days of soaking. These straw treatments linearly decreased the germination and growth (root-shoot length) of the test seeds as compared to the control. Seed germination at higher concentration was least affected in Parthenium hysterophorus than in Chenopodium album and maximum in Boerhaavia diffusa with both burned and unburned straw treatments. At lower concentrations of burned straw treatment, no effects were observed as compared to the control. Seedling growth was less affected under lower concentrations as compared to germination. It is revealed that differential phytotoxicity of straw was species dependent and the effects were variable depending on type and amount of the leachates. The unburned straw demonstrated higher activity as compared to burned straw. Therefore, it is suggested that the straw management practices may be used to develop an integrated weed management programs. 187. Allelopathic Effect of Jatropha curcus Oil Cakes after Biodiesel Recovery on Zea mays and Sorghum vulgare. M. Jayakumar and P. Meena Research Department of Botany, VHNSN College, Virudhunagar- 626 001, India Email: [email protected]

In this study, the allelopathic potential of Jatropha curcus oil cakes after biodiesel recovery was determined on Zea mays and Sorghum vulgare crops. Different concentrations (5, 10, 15 and 20%) of aqueous extracts and hexane extracts of J. curcus oil cakes after biodiesel were prepared. The bioassay studies viz., germination, plumule length, radicle length were carried out in Z. mays and S. vulgare. In the bioassays studies, the aqueous and hexane extracts of Jatropha curcus oil cake showed inhibitory effect in 10, 15 and 20% concentrations, on seed germination, plumule length, radicle length in both seedlings. The post and pre emergence studies viz., shoot length, root length and biomass were determined in both Z. mays and S. vulgare crops using aqueous and hexane extracts. The inhibitory effect was more than 50% over that of the controls only in the 15 and 20% concentrations in both crops. The hexane extracts showed more inhibitory effect in all the parameters studied than the aqueous extracts. The pot culture experiments followed a similar trend of inhibition in both crops. Considerable inhibition by both extracts (20%) was observed in shoot length, root length, leaf area and seed weight in both crops. Qualitative analysis of phenolic acids by HPLC analyses in the oil cake of J. curcus revealed the presence of gallic acid, protocatechuic acid, p-hydroxybenzoic acid and chlorogenic acid. Qualitative analysis of phenolic acids by IR spectrophotometry in oil cake of J. curcus showed the presence of the functional groups viz., medium-strong hydrocarbon chromophore C-H stretching alkane (2923 cm-1) and (2852 cm-1), carbyl chromophore ketone stretching vibrations á-â unsaturated cyclic strong band (1708 cm-1) hydrocarbon chromophore C-H bending alkane- CH2 -medium band (1458 cm-1). The inhibitory effect may be due to the presence of these phenolic acids and other allelochemics in the J. curcus oil cakes after biodiesel recovery. 188. Weed Suppression in Organic Gardening and Farming: Is Allelopathy the Answer? Gerald R. Leather West Virginia University Agriculture Extension Service, P.O. Box 1880, Romney, WV 26757 USA Email: [email protected] Weed control is the biggest cost to certified organic farmers and gardeners. Crop rotation, mechanical cultivation, plastic mulching, and hand weeding are the most effective methods for weed suppression now used in organic vegetable and fruit production. Crotalaria juncea (Sunn hemp, var. Tropic Sun) contains a potent inhibitor of several weeds and may be useful as a cover crop, or with development of the identified allelochemical, as a natural herbicide. The allelochemical is found throughout the sunn hemp plant, but is highly concentrated in the seed. Re-growth of Euphorbia esula (leafy spurge) from crown and root buds in a sand-nutrient culture containing 2 sunn hemp seeds was 25% of plants growing in pots without sunn hemp. Growth of Brassica kaber, Echinochloa crus-galli, Datura stramonium, leafy spurge, and Sorghum halepense seedlings in nutrient culture was inhibited 50% by 25 ppm of a crude extract of the sunn hemp seeds. Using a Lemna bioassay, Lemna minor was significantly inhibited with 5 uM, 50% with 10 uM, and 90% with 15 uM of the purified


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allelochemical. The allelochemical was confirmed as 5-hydroxynorleucene, a nonprotein amino acid, previously identified by Pant and Fales in 1974. Other researchers (Adler and Chase, 2007) have compared sunn hemp as a cover crop in vegetables to Vigna unguiculata (cowpea) and Mucuna deeringiana (velvetbean). They found that phytotoxicity of the cover crops was greater for weed species than crop plants, and sunn hemp was inconsistent in its effect. There is evidence that the sunn hemp allelochemical is bound to soil, since leafy spurge growing in soil required 15 times the amount of the crude extract to obtain the same inhibition as plants growing in sand/nutrient culture. When the allelochemical was used as a spray or applied in agar to the cut stems of leafy spurge, re-growth was inhibited and the plants were devoid of chlorophyll. 189. Bio-control of Parthenium hysterophorus L. by Using Extracts of Selected Plant Species G.P. Satsangi, Anjali Saxena and Garima Bartariy Department of Botany, Faculty of Science, Dayalbagh Educational Institute (Deemed University), Dayalbagh, Agra 282005, India Email: gpsatsangi @yahoo.com Parthenium hysterophorus is most prominent obnoxious allelopathic weed, which reduces the growth and productivity of associated plants due to release and accumulation of phytotoxins from its decomposing biomass and root exudates in soil. The chemical content of the weed indicates that its all parts including trichomes and pollen contain toxic sesquiterpene, water soluble inhibitors. By considering its ill effects present study was carried out to control the weed with extracts and leachates of selected plants (three herbs and three shrubs). For observing the effect of selected herbs and shrubs, the foliar treatment doses were prepared by following the methodology of Oudhia and Tripathi, 2000 (Researches on Crops. 1:111-115), in which crushed (extracts) and uncrushed (leachates) leaves of selected plants were soaked in distilled water in ratio of 1:10,1:15,1;20 and 1;25 for 24 hrs. Twenty seeds of weed were soaked in the prepared extract for 24 hrs and transferred in Petri plates lined with Whatman filter paper no 1. Seeds soaked in distilled water were served as water control. Observations of seeds as well as seedlings were recorded after 15 days of soaking. It has been observed that extracts were found more effective than leachates and the degree of inhibition was directly proportional to the increasing concentration of the treatments. Among herbs Amaranthus virdis>Chenopoodium album>Acyranthus aspera and in shrubs Artemisia annua>Lantana camara>Tagetes erecta were found effective in inhibiting the germination and vegetative growth of the test weed. Therefore, these plants can be used to eradicate the noxious weed especially at initial phenophase of the weed. A bold program may be launched to train the people to come forward for eliminating Parthenium hysterophorus,to aquaint them from its ill effects upon their lives. 190. The Effects of Common Lambsquarters (Chenopodium album) Extracts on Sugar Beet (Beta vulgaris) and its Important Weeds Mohammad Armin and mosareza Hookmabadi

Department of Agriculture, Islamic Azad University of Sabzeva, Iran Email: [email protected] Broadleaf weeds such as Amaranthus biltoides and Amaranthus retroflexus and grass weeds like Setaria viridis and Setaria glauca are important weeds in sugar beet (Beta vulgaris) farms. This research was conducted to evaluate the allelopathic effects of root and shoot extract of common lambsquarters (Chenopodium album) on germination of sugar beet and its important weeds. The experiment was conducted in a completely randomized design. The results of this experiment showed that broadleaf weeds were more sensitive to allelopathic effect of Chenopodium extract as compared to grass weeds. While there were no significant differences in seedling dry weight and fresh weights, the Chenopodium extract had significant effect on germination percentage and germination rate of broadleaf weeds. Chenopodium extract decreased germination of grass weeds in comparison to the control but this was not significant. These results also demonstrated that the Chenopodium shoot extract had more effect on germination of sugar beet than the root extract, although there were no significant differences in seed germination, germination rate and fresh weight and dry weight of seedlings. Overall, alleopathic effect of Chenopodium was more on broadleaf weeds than grass weeds of sugar beet. 191. Exploring the Possibility for Canarygrass (Phalaris minor Ritz.) Control through Allelopathy Khawar Jabran, Muhammad Farooq, Hafeez-ur-Rehman and Mubashir Hussain Department of Agronomy, University of Agriculture, Faisalabad-38040, Pakistan Email: [email protected] Allelopathy is the naturally occurring ecological phenomenon that can be exploited for safe food production, environmental protection, soil conservation and resource regeneration. Allelochemicals extracted from various plant species can act as natural weed inhibitors. In the present laboratory experiment, four allelopathic plant extracts (sorghum (Sorghum bicolor L.), mulberry (Morus alba L.), barnyard grass (Echionoachloa crusgalli L.) and winter cherry (Withania somnifera L.) were tested for the inhibition of most problematic weed of wheat, canarygrass (Phalaris minor Ritz.). The plant parts were first grinded and then soaked in the distilled water with 1:15 (w/v) for overnight. Filtrate was then obtained by using Whatman No. 42 filter paper. Petri dishes containing 10 seeds of canarygrass between the two layers of Whatman. No. 45 were provided with 10 ml of the respective extracts and placed in the incubator at 27◦C. Mulberry, barnyard grass and winter cherry extracts resulted in the complete inhibition of canary grass. No germination was recorded in the canarygrass where the extracts from these plants were applied. Sorghum, however, exhibited least suppressive or in some cases the stimulatory effects on canarygrass. Plants revealing strong allelopathic potential can be utilized to derive bio-herbicides for natural weed control.


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192. DIBOA and BOA Production by Eight Rye Cultivars and Allelopathic Effect of the Mulch on Four Warm Season Weeds Vincenzo Tabaglio1, Carolina Gavazzi1, Margot Schulz2 and Adriano Marocco1

1Istituto di Agronomia Generale e Coltivazioni Erbacee, Facoltà di Agraria, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29100 Piacenza, Italy 2IMBIO, University of Bonn, Karlrobert Kreiten Str. 13, 53115 Bonn, Germany Email: [email protected] In conventional agriculture weed control by herbicides is an expensive practice and can also have a negative effect on the environment. Allelopathy permits sustainable weed management while reducing the impact of agriculture on the environment. We studied the content of 2,4-dihydroxy-1,4 (2H)-benzoxazin-3-one (DIBOA) and benzoxazolin-2(3H)-one (BOA), indicated as benzoxazinoids and considered effective for weed control, in 8 cultivars of rye grown in a greenhouse, and also tested the ability of mulches to inhibit the germination of four warm-season weeds. Our results show that all rye cultivars produced DIBOA, while BOA was found only in four of them. Total benzoxazinoid content ranged from 177 to 545 µg / g-1 and was statistically different among cultivars. Rye mulches were not able to suppress velvetleaf and common lambsquarters seedlings, while redroot pigweed and common purslane were significantly affected. Weed suppression ranged from 40 to 52% for redroot pigweed and from 40 to 74% for common purslane. No correlation was found between total benzoxazinoid content and the number of weed seedlings suppressed, with R2 = 0.076 for redroot pigweed and R2 = 0.003 for common purslane, indicating that benzoxazinoids are not the only source of phytotoxicity. 193. Allelopathic Effects of Circium arvensis (L.) Scop. on Germination and Growth of Some Crops and Weeds Masoumeh Younesabadi, Habib Ollah Kashiri, Leila Habibian and Ali Kian Poor Dept. of Plant Protection, Agricultural Research Center, Beheshti Avenue, Gorgan, Golestan 49156-77555, Iran Email: [email protected] Allelopathic effects of Canada thistle (Circium arvensis (L.) Scop.) were determined on germination and growth of some crops [rapeseed (Brassica napus), barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.)] and weeds [oat (Avena ludoviciana Durieu.) and littleseed canarygrass (Phalaris minor Retz.)]. This experiment was performed as randomized complete block design with five treatments and three replications. The treatments consisted of different concentrations of C. arvensis above ground water extract [25, 50, 75 and 100% (1:10, w/v)] and distilled water as control treatment. The results indicated that different concentrations of C. arvensis water extract had no effect on germination, root and stem length of wheat. C. arvensis 100% water extract treatment inhibited germination of barley significantly, however lower doses had a little increase on barley germination but this increase had no difference with control treatment. Rapeseed germination was significantly inhibited by all concentrations except 25% conc. Germination of P. minor and A. ludoviciana was reduced by C. arvensis extract

and this reduction was increased as the extract concentration increased. All doses of extract had inhibitory effect on root length of rapeseed but barley root length was decreased only by 75% and 100% extracts significantly. Root lengths of A. ludoviciana and P. minor were reduced by all doses but reduction of P. minor root length had no difference with control treatment. Among extracts, only 100% extract was decreased stem length of barley. Stem length of rapeseed was inhibited by all extracts except the 25% extract that had a little stimulatory effect on rapeseed stem length. 194. Use of Plant Extract in Control of Avena ludoviciana Durieu Masoumeh Younesabadi, Habib Ollah Kashiri and Koorosh Ghaderi Dept. of Plant Protection, Agricultural Research Center, Beheshti Avenue, Gorgan, Golestan 49156-77555, Iran Email: [email protected] Canarygrass (Phalaris minor Retz.) is one of the most important weeds in winter crops in Iran. Successive and excessive using of herbicides against P. minor caused its resistance to common herbicides. Searching natural compounds that can be replaced with herbicides is a useful method to solve this problem. In this experiment, herbicidal activity of water extracts of six plant species [Camel thorn (Alhgi camelorum fisch), Canada thistle Circium arvensis (L.) Scop., Horse mint (Mentha longifolia L.), Dwarf mallow (Malva neglecta Wallr.), Elder berry (Sambucus nigra L.), and Nettle leaf goose foot (Chenopodium murale L.)] was tested on the germination and growth of P. minor. All extracts were prepared from above ground organs, at vegetative phase except M. longifolia extract that prepared in flowering stage. The results showed that P. minor germination was inhibited by all extracts especially at 75 and 100% (1:10, w/v) concentration. Root length of P. minor was not affected by treatments, although a slight reduction in root length was observed. All extracts at 75 and 100% concentration significantly reduced stem length of P. minor but lower doses had no effects on stem length. A slight increase of P. minor stem length was observed with 25% extracts of S. nigra and A. camelorum but this increase was not different from the control treatment. 195. Herbicidal Potential of Nettle Leaf Goosefoot (Chenopodium murale L.) Masoumeh Younesabadi Dept. of Plant Protection, Agricultural Research Center, Beheshti Avenue, Gorgan, Golestan 49156-77555, Iran Email: [email protected] In this research the allelopatic effects of Nettle leaf goose foot (Chenopodium murale L.) was surveyed on germination and growth of three crops [rapeseed (Brassica napus L.), barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.)] and two weeds [oat (Avena ludoviciana Durieu.) and canarygrass (Phalaris minor Retz.)]. This experiment was conducted as complete block design with five treatments and three replications in 2008. The treatments consisted of different concentrations of C. murale aerial part water extracts. The findings indicated


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that, stem length, root length and germination of rapeseed were inhibited by all treatments significantly. Root and stem length of barley were decrease by all treatments but barley germination was affected only by treatments 3 and 4 (75 and 100% extracts). The treatments had no significant effects on root and stem length of wheat, but wheat germination was decrease by treatments 3 and 4 only. Growth and germination of A. ludoviciana was inhibited by all treatments significantly. P. minor root length was not affected by treatments. 2, 3 and 4 treatments decreased stem length of P. minor significantly. P. minor germination was inhibited by all treatments significantly. C. murale extract had herbicidal activity and lower doses of it can be used for weed control in some crops. However, more studies are necessary in this case. 196. Allelopathic Activity of Cauliflower (Brassica oleracea var. botrytis) on Certain Common Weed Species N. N. Issa and J. R Qasem Department of Plant Protection, Faculty of Agriculture, University of Jordan, Amman, Jordan. E-mail: [email protected] Laboratory and glasshouse experiments were carried out to investigate the allelopathic effects of cauliflower (Brassica oleracea var. botrytis) on Amaranthus retroflexus, Chenopodium murale, Eruca sativa, Malva sylvestris, Portulaca oleracea and Solanum nigrum. Results showed that extracts, leachates and volatile materials of cauliflower fresh shoots significantly reduced germination and seedlings growth of different weed species under laboratory conditions. Extract effects increased with concentration in the medium and roots were affected more than shoots. Dried shoot residues of cauliflower in potted soil were highly toxic to the weed species tested with P. oleracea, A. retroflexus and C. murale were most sensitive. Foliage applied extracts were ineffective on weeds while soil applied extracts reduced germination and growth of certain wed species. Root exudates of cauliflower showed high allelopathic effects on growth of most weed species studied with A. retroflexus, C. murale and S. nigrum were most reduced. Water leachate from cauliflower shoots was also toxic to different weed species grown in pots while M. sylvestris was the most tolerant weed. 197. Allelopathy in Cultivated Amaranth Varieties Solvejg K. Mathiassen, Per Kudsk and Inge S. Fomsgaard Department of Integrated Pest Management, Faculty of Agricultural Sciences, University of Aarhus, Forsøgsvej 1, DK-4200 Slagelse, Denmark Email: [email protected] Weedy Amaranth species have been reported to possess allelopathic properties. This study reports results from a preliminary screening of such properties in cultivated Amaranth varieties. The experiments were conducted in Petri dishes in a dark room and included two varieties of Amaranthus cruentus (Don Armando and Don Leon) and one variety of A. hypochondriacus (San Antonio). Amaranth seeds were placed on wet filter paper in 2 or 3 rows with 10 seeds per row, and seeds of the test species (Veronica agrestis, Poa annua and Lolium perenne) were placed in rows between the Amaranth. The test species were seeded on the same day or 2, 4 or 7 days later than Amaranth. The number of germinated

seeds of Amaranth and the test species were counted every second day and root and shoot lengths of the test plants were measured 9 days after seeding. Amaranth had no influence on the germination of the test species but affected the early growth of some species adversely. The root and shoot length of the small-seeded species (V. agrestis and P. annua) was reduced by up to 50% while the growth of L. perenne was unaffected. The time interval between the sowing of Amaranth and the test species had only minor influence on the reduction of shoot and root growth. No significant differences in the allelopathic properties of the tested Amaranth varieties were observed. The results clearly show that cultivated Amaranth species possess allopathic properties. Amaranth is sown late and at wide row distances and consequently competes poorly with weeds in the early growth stages. Further investigations using soil as growth medium are needed to reveal the potential to exploit allelopathy to suppress weed growth in Amaranth crops. Currently activity-guided fractionation techniques are performed for identification of the allelochemicals in Amaranth. 198. Effect of Walnut Phenolics on Germination of Dandelion Seeds Henryk Matok, Bogumil Leszczynski, Grzegorz Chrzanowski Department of Biochemistry and Molecular Biology, University of Podlasie, 12 B. Prusa Str., PL-08110, Siedlce, Poland Email: [email protected] Allelopathic action of walnut (Juglans regina L.) towards higher plants is well documented, however little is still known on its mechanism what cause a serious problems in its application to control a serious agricultural weed. In the present paper, we report on effect of phenolic extracts from the walnut leaves and roots on germination of dandelion seeds (Taraxacum officinale Web). Extraction of the phenolics from walnut leaves and roots was carried out with 80% methanol and the extracts were separated using HPLC Varian System equipped with UV detector. Effect of the walnut extracts and selected phenolics (caffeic and chlorogenic acids and (+)-catechin) on germination of the dandelion seeds was examined in three independent replicates.. One hundred seeds previously soaked in distilled water for 12h was treated in Petri dishes with 15 ml of the walnut extracts (diluted to 4% methanol solutions), tested phenolics (at three different concentrations) or distilled water (control seeds). Field observations showed absence of the dandelion plants in the area surrounding walnut trees. The extracts from walnut leaves and roots contained eight identified phenolics such as: (+)-catechin, chlorogenic acid, p- and o-coumaric acids, ferulic acid, tannic acid, caffeic acid and syringic acid. The leaf extracts inhibited germination of the dandelion seeds since they started to germinate about two days later and after seven days only about 25% of the seeds were germinated in comparison to non-treated control. The tested phenolics also reduced germination of dandelion seeds, especially at higher concentrations. The allelopathic potential of the walnut phenolics and possibility of their application for weed control is discussed.


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Main Topic 12: Allelopathy in aquatic environment 199. Impact of Allelopathy on the Periphyton of Submersed Freshwater Macrophytes D. Erhard Limnological Station, Technical University of Munich, Hofmark 3, D-82393 Iffeldorf, Germany E-mail: [email protected] Submersed macrophytes compete with other primary producers for light as the most important resource. Especially, epiphytic algae or cyanobacteria attached to the leaves of aquatic plants may severely reduce light availability for their hosts. Allelopathy could thus be an advantageous trait to avoid the light limitation caused by periphyton. In fact, many freshwater macrophytes have been shown to exhibit a high allelopathic potential, indicating that allelopathy influences biocoenoses in natural systems. However, few studies have been aimed at the ecological relevance of these chemical interactions in aquatic ecosystems. We focus on two submersed macrophyte species, Elodea canadensis and E. nuttallii. Both are invasive in Europe, form dense monospecific stands, and can displace native macrophytes. Elodea species are often reported to be less densely covered by epiphytes, and we could show in laboratory studies that extracts and exudates of Elodea inhibit growth of epiphytic cyanobacteria. Interestingly, epiphytic green algae exhibited a considerable lower susceptibility towards Elodea allelochemicals. We thus assume that the release of active compounds might reduce the abundance of some species, especially cyanobacteria, in epiphytic biofilms. To address this question, we collected Elodea shoots and determined the composition of their periphyton communities. The microscopic observations revealed a dominance of green algae (62% of the counted cells), whereas cyanobacteria accounted for only 7%. Extracts from the same plant material inhibited the growth of epiphytic cyanobacteria, but stimulated the growth of green algae. In contrast, green algae contributed only 37% to the periphyton community on submersed leaves of Nuphar lutea growing next to Elodea. The abundance of cyanobacteria was comparable to that found on Elodea. Nuphar extracts reduced growth of both groups of organisms, but the inhibition of cyanobacteria was more pronounced. These results indicate that allelopathic interactions impact the composition of natural periphyton communities. 200. Chemical Warfare in the Marine Plankton J. Kubanek1, E. Prince1, T. Myers1, and J. Naar2 1School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332, USA 2Center for Marine Science, University of North Carolina at Wilmington, Wilmington, N.C. 28403-3297, USA E-mail: [email protected] How individual species come to be dominant members of marine planktonic communities is not deeply understood; however, it is thought that chemistry plays a substantial role. For example, some red tide-forming dinoflagellates produce toxic secondary metabolites that are hypothesized to enhance dinoflagellate fitness by acting as grazer deterrents, allelopathic agents, or antimicrobial defenses. Recent field

and lab experiments have shown that the red tide dinoflagellate Karenia brevis (formerly Gymnodinium breve) is allelopathic to several co-occurring phytoplankton species, but that K. brevis natural products other than well-known brevetoxins are responsible for suppressing most of these species. Mechanisms of action of K. brevis allelopathy include increased cell membrane permeability and reduced photosynthetic output. At least one phytoplankton competitor, Skeletonema costatum, retaliates against K. brevis, reducing its allelopathic effects and degrading waterborne brevetoxins. Our results indicate that chemically-mediated interactions are reciprocal, and that ecosystem-level consequences of red tides (such as fish kills caused by waterborne toxins) may depend upon which other phytoplankton species are present. 201. Can Allelopathic Interactions Explain Plankton Blooms? P. Jonsson, G. Toth, and H. Pavia Tjärnö Marine Biological Laboratory, Department of Marine Ecology, Göteborg University, Strömstad, SE 45296, Sweden E-mail: [email protected] There is a growing awareness that harmful blooms of microscopic cyanobacteria and planktonic protists (know as harmful algal blooms or HABs) have increased globally with serious implications for human health and economy. Harmful effects by HAB species are largely mediated through the production of highly toxic compounds. Allelopathy has been suggested to convey a competitive advantage among planktonic cyanobacteria and protists, and to explain the initiation and continuation of plankton blooms. Lewis (1986) pointed out some potential problems with the evolution of allelopathic interactions among small plankton. In the dynamic water-column a major problem is that the benefit from the production of a costly allelopathic compound will be shared also by non-producers. Accordingly, Lewis (1986) found it difficult to envisage the evolution of allelopathic traits among small plankton that are continuously being mixed through turbulent motion and random swimming. Since the publication by Lewis (1986) a number of research papers have reported allelopathic effects for bloom-forming species. Do these papers support the significance of allelopathy as a key factor in bloom dynamics, and what is the current view on possible evolutionary mechanisms? In a meta-analysis of published studies we first consider the evidence for allelopathy among plankton and under what conditions effects were found. We then use simple models to analyze if found allelopathic effects may play a significant role under field conditions, and we also assess the likelihood for the evolution of allelopathy in plankton communities. Finally, we propose that reported allelopathic effects can be re-interpreted as predatory or "parasitic" cell-cell interactions. 202. Allelopathic Effects of Plant Growth Regulators on Growth Promotion of Marine Photosynthetic Bacteria L. Li, X. Wang, Y. Liu, J. Almeira, F. Li, and X. Hu


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Department of Environmental Studies and Environmental Engineering, College of Environmental Science and Engineering, Ocean University of China, Qingdao 266003, P.R.China E-mail: [email protected] As is known to us, to prevent eutrophication in the seawater, it is vital that phosphorus and nitrogen must be reduced effectively before urban sewage is discharged into the sea. The initial purpose of our researches was to increase marine Photosynthetic Bacteria (PSB) concentration for the effective reduction in nutrient concentrations in the sewage. Therefore, we sought some exogenous growth factor that promotes PSB growth. After five years of study, it was discovered that some certain plants and plant growth regulators promote PSB multiplication. Such plants as licorice, Baikal skullcap root, fructus trichosanthis, and pilose Asiabell root, but especially fructus trichosanthis, had allelopathic effects on growth promotion of PSB. With thin layer-paper chromatography-biological training selection identification method, it was discovered that 1-octadecene from fructus trichosanthis promoted growth of PSB most significantly. It was hypothesized that the mechanism might have been that 1-octadecene acted as a role analogous to a plant hormone. Further study showed that plant growth regulators, including triacontanol, gibberellin, indole-3-acetic acid, and α-naphthylacetic acid, had allelopathic effects on growth promotion of PSB. Most importantly, gibberellin at the concentration of 0.1 mg/L led to the most significant allelopathic effect, followed by triacontanol, Indole-3-acetic acid and α-naphthylacetic acid, in the concentration scope of 0.5 mg/L - 1.0 mg/L. The growth promotion mechanism complied with receptor and second messenger theory of plant hormones and growth regulators. Therefrom, our researches entered the ecological field of inter-species reciprocity in aquatic environments. 203. Chlorellin Production by Chlorella vulgaris: Qualitative and Quantitative Changes Influenced by Chemical and Biological Factors M. DellaGreca1, P. Fergola2, M. Cerasuolo2, A. Pollio3, G. Pinto3, and A. Zarrelli1 1Dipartimento di Chimica Organica e Biochimica; 2Dipartimento di Matematica e Applicazioni “R. Caccioppoli;” 3Dipartimento delle Scienze Biologiche, Sezione di Biologia Vegetale. Università degli Studi di Napoli Federico II, Via Cinthia, 80126 Napoli, Italy E-mail: [email protected] Several experiments carried out in chemostats proved that in mixed cultures of Chlorella vulgaris and Pseudokirkneriella subcapitata, under phosphate-limiting conditions, the latter alga goes to extinction. A constant release, by C. vulgaris, of chlorellin-like materials, mainly composed by different fatty acids, was observed. A mathematical model, built on the basis of the experimental results, confirmed that a valuable contribution to the final exclusion of P. subcapitata is due to the allelochemicals released by C. vulgaris. To solve some open questions, a new set of experiments has been performed to evaluate if the chlorellin production depends on the age of the culture, the phosphate concentration in the culture

medium, and the co-occurrence of the two algae. The analysis of chlorellin indicates that the content of fatty acids is influenced by the different culture conditions, its yield is greatest into mixed cultures, and almost exclusively constituted by C18 fatty acids. The toxicity of this mixture has been separately assayed on the two algae and a stimulation of growth at low concentrations has been observed for both algae. However, P. subcapitata is much more sensitive than C. vulgaris. The toxicity of fatty acids, present in major amount, and the effect of their combined action on P. subcapitata have been evaluated following the concentration addition model in short time bioassays, ensuring that their photo-oxidation does not occur during the experiments. Fatty acids exhibit a different toxicity in relation to their unsaturation number. Linolenic, linoleic, oleic, and stearic acids are the most active and display a hormetic behaviour, being stimulated or inhibited according to their concentration. By using some of these new experimental results, a mathematical model has been suggested describing the interference between C. vulgaris and P. subcapitata. In particular, the toxicity of chlorellin on both algae has been explicitly taken into account. 204. AllelopathicAactivities of Ceratophyllum demersum on Microcystis aeruginosa in Co-cultivation Q. Xian1, X. Li1, J. Xu1, S. Gao1, D. Yin2, and H. Zou1 1State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, China 2Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai, 200092, China. E-mail: [email protected] Submerged macrophytes are an important factor in maintaining clear water status in shallow aquatic ecosystems. Ceratophyllum demersum could secrete allelochemicals to inhibit the growth of blue-green algae, and C. demersum is considered as one of the preferential plants in restoration of eutrophication waters. This paper studied the allelopathic effects and mechanism of C. demersum on Microcystis aeruginosa in co-cultivation. Results showed that the growth of M. aeruginosa was substantially inhibited and they died out at 96 h. The inhibition of M. aeruginosa was due to the allelopathy but not competition of light and nutrition between them. Chlorophyll-a and phycobiliprotein (including PC, APC and PE) were damaged during the co-cultivation, especially, damage of PC was the most. SOD activity and MDA accumulation increased in the beginning, and then decreased. Although allelopathic inhibition of M. aeruginosa on C. demersum existed in co-cultivation, M. aeruginosa also hindered the growth of C. demersum resulting in the decrease of the content of chlorophyll-a and carotenoid. As a plant hormone, effects of exogenous abscisic acid (ABA) on the biomass and activities of some physio-biochemical indices such as chlorophyll, carotenoid, soluble protein, SOD, POD, and MDA also were investigated and compared in leaves of C. demersum with or without M. aeruginosa stress. Results showed that M. aeruginosa decreased activities of SOD and POD, increased MDA accumulation and leading to loss of


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chlorophyll-a, chlorophyll-b, carotenoid and soluble protein. Exogenous ABA of low concentration (≤1.0 mg·L-1) enhanced activities of SOD and POD, reduced MDA accumulation, and increased the content of chlorophyll-a, chlorophyll-b, carotenoid and soluble protein, thus enhancing the ability of C. demersum to stand M. aeruginosa stress. Exogenous ABA of high concentration decreased the content of chlorophyll and carotenoid, but the growth of C. demersum was not influenced. The most suitable concentration of ABA was defined to be in the range of 0.5-1.0 mg·L-1. 205. QTL Mapping and Identification of Candidate Compounds Associated with Allelopathic Effect of Rice Kazutoshi O.1, K. Ebana2, and M. M. Y. Hegab3

1Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennodai 1-1-1,Tsukuba, 305-8572 Japan 2National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, 305-8602 Japan 3Faculty of Science, Beni-Suef University, Beni-Suef, Egypt Email: [email protected] Allelopathy in rice can be used as a method for biological control of weeds in rice cropping. We have focused on detecting QTL for allelopathic effect and identifying chemical compounds associated with allelopathic effect in Asian cultivated rice (Oryza sativa L.). Firstly, we developed a reproducible bioassay to assess the allelopathic effect of rice. We analyzed QTL conferring allelopathic effect of rice using F2 plants of the cross between PI312777 (allelopathic) and Rexmont (non-allelopathic) and RFLP markers mapped on 12 rice chromosomes. Seven QTL underlying allelopathic effect were identified on chromosomes 1, 3, 5, 6, 7, 11 and 12. Major QTL were located on the chromosome 5, 6 and 7, explaining 13-16% of total phenotypic variation. A single QTL on chromosome 7 showed a positive effect on allelopathic effect without QTL on chromosomes 5 and 6. The QTL on chromosome 7 was responsible for inhibition of both root growth and necrosis on root tips of lettuce. We also identified candidate compounds associated with allelopathic effect of rice using HPLC. The allelopathic rice variety contained 20 detectable phenolic compounds while non-allelopathic variety contained only 10 compounds. Among 20 phenolic compounds detected in rice seedlings, at least 7 phenolic compounds might play a primary role in allelopathic effect of rice. 206. Response of a Native Insect to Allelochemicals from a Native and Invasive Watermilfoil M. D. Marko1,2,3, R. M. Newman1, and F. K. Gleason2 1Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota, St. Paul, MN 55108-6124, USA; 2Department of Plant Biology, University of Minnesota, St. Paul, MN 55108, USA 3Department of Biology, Concordia College, Moorhead, MN 56562, USA Email: [email protected] The milfoil weevil, Euhrychiopsis lecontei, has made a host range expansion from its native host northern watermilfoil, Myriophyllum sibiricum, to the nonindigenous Eurasian watermilfoil, M. spicatum. This host range expansion has

likely been facilitated by similarities in plant morphology and chemistry; both species have similar concentrations of nutrients, carbohydrates and nonpolar extracts. However, M. spicatum has a higher concentration of the herbivore deterrents lignin and polyphenols. Despite these defenses, the milfoil weevil prefers and performs better on the invasive M. spicatum than on its native host plant. The weevil’s preference is likely due to a higher concentration of the attractants glycerol and uracil in M. spicatum exudates. The weevil’s faster growth and higher survival on M. spicatum may be due to the lower concentration of ash, which in high amounts can reduce plant nutritional content or act as a physical defense. When given a choice of M. spicatum vs. control, the milfoil weevil was attracted to milfoil from several lakes, but not others; indicating discrimination by the weevil for specific populations of milfoil. Furthermore, one population of weevils preferred M. spicatum to control or hybrid milfoil, whereas a second population of weevils had no preference for any milfoil population. Therefore, different weevil populations have different levels of discrimination for the same watermilfoil populations. Further work is needed to identify other chemicals involved in weevil attraction, to determine how the milfoil plant and exudate chemistry change under different environmental conditions and to understand how those changes ultimately affect weevil preference and performance. This understanding is crucial to determining how the milfoil weevil can be used to control the invasive M. spicatum. 207. Utilization of Allelopathic Plant Water Extracts in Combination with Reduced Rate of Atrazine for Weed Management in Maize (Zea mays L.) Azhar Mahmood, Zahid Ata Cheema**, Abdul Khaliq and M. Naeem Mushtaq Weed Science & Allelopathy Laboratory, Department of Agronomy, University of Agriculture, Faisalabad 38040, Pakistan. Email: [email protected] Indiscriminate use of herbicides is posing environmental threats and development of resistance in weed biotypes. A field study to explore possibilities of reducing herbicide dose in combination with different allelopathic plant water extracts for weed management in maize was carried out at Agronomic Research Area, University of Agriculture, Faisalabad during 2006 and 2007. Atrazine (Atrazine 38-SC) at 0.167 kg a.i. ha-1 was tank mixed with 18 L ha-1

water extracts each of sorghum + brassica + mulberry, sorghum + brassica + sunflower, sorghum + sunflower + rice, sorghum+ sunflower + maize and sorghum + maize + rice and was applied as early post-emergence, i.e., 15 days after sowing (DAS). For comparison, atrazine alone at 0.5 kg ha-1 at 15 DAS and the recommended rate of S-metolachlor + atrazine (Primextra Gold 720-SC) at 1.08 kg ha-1 applied pre-emergence as standard treatments and a weedy check as a control treatment were included. Weed species present in the experimental area were Trianthema portulacastrum, Cyprus rotundus, Dactyloctenium aegyptium, Cynodon dactylon and Cleome viscosa. Combination of sorghum + sunflower + brassica each at 18 L ha-1 and 1/3 dose of atrazine (0.167 kg ha-1) reduced total


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weed dry weight by 86 to 75% at 45 DAS in 2006 and 2007, respectively. Maize yield increased by 48 to 51% by the combination treatment of sorghum + sunflower + brassica water extracts each at 18 L ha-1 and with 1/3 dose of atrazine (0.167 kg ha-1) as early post emergence (15 DAS) over the control in 2006 and 2007, respectively, and yields were equal to the yields obtained from the recommended rate of S-metolachlor + atrazine and atrazine alone. It is concluded that herbicide dose may be reduced up to 67%, if applied in combination with water extracts of sorghum + brassica + sunflower for weed management in maize. 208. Influence of Plant Population, Allelopathic Water Leachates and a Post-Emergence Herbicide on Weeds in Transplanted Rice (Oryza sativa L.) Arif Rehman*, Zahid Ata Cheema**, Abdul Khaliq and M. Naeem Mushtaq Weed Science & Allelopathy Laboratory, Department of Agronomy, University of Agriculture, Faisalabad 38040, Pakistan. Email: [email protected], A field study was carried out at agronomic research area, University of Agriculture Faisalabad, during 2005-2007 to investigate the effect of plant population (0.20, 0.25 and 0.30 million plants ha-1), sorghum, sunflower and rice water extracts each at 15 and 18 L ha- 1(20, 40 and 60 DAT) and a post-emergence herbicide Nominee (bispyribac-sodium 100SC) at 21 g a.i. ha-1 20 days after transplanting (DAT), on weeds in rice. Results revealed that plant population significantly influenced weed dry weight. On an average, 45 and 52% reduction in total weed dry weight during three years of experimentation was recorded at 75 DAT with 0.25 and 0.30 million plants ha-1 as compared to the recommended plant population of 0.20 million ha-1. Foliar spray of allelopathic extract mixtures at 15 and 18 L, each ha-1 significantly suppressed (46 to 61%) total weed dry matter production. The suppressive effect of water extracts at the highest rate (18 L ha-1) and the highest plant population (0.30 million ha-1) was relatively high. The herbicide at the recommended plant population (0.20 million ha-1) inhibited the weed dry weight by 56% while at higher population levels (0.25 and 0.30 million ha-1) decreases in weed dry weight were 61 and 68%, respectively. Rice yield was increased in all the treatments (19 to 87%) as compared to control. Economic

and marginal analyses show that plant population 0.25 million ha-1 gave higher net benefits (average of three years) followed by herbicide at 0.30 million ha-1 population and water extracts at 0.30 million plant population. 209. A Preliminary Study on Allelopathic Effect of Three Compositae Plants on Microcystis aeruginosa Weihao Zhang School of Resource and Environmental Science, Wuhan University, Wuhan 430079, China Email: [email protected] Based on common phenomena of biochemical interaction between plants and microorganisms, the inhibitive effects of three common terrestrial ompositae plants, namely Artemisia lavandulaefolia DC, Conyza canadensis L Cronq, and Kalimeris indica L Sch.-Bip on the blue algae Microcystis aeruginosa were studied. Live Compositae plants were co-cultivated with algae of two different inoculation cell concentration for 10 days in 5 pools incubators, to exclude the influence of bacteria and nutrient. Inhibitive effects of the three plants on the algae were observed by the decrease in optical density (OD680) of the culture. Data indicated that Artemisia lavandulaefolia had the most inhibitive potential among the three plants, with an inhibition rate of 93.3% (inoculation cell concentration 2.0×106 Cells/mL) and 89.3% (inoculation cell concentration 4.0×106 Cells/mL) respectively on the 10th day. The average inhibition rate during the last half period of the experiment was 0.76 (inoculation cell concentration 2.0×106 Cells/mL) and (inoculation cell concentration 4.0×106 Cells/mL), respectively. Logistic model analysis showed that Compositae plants such as A. lavandulaefolia DC caused the reduction of the growth limit of algae, resulting in shorter time taken to reach the limit value, and population decayed in some groups. Average inhibition rate model was used to evaluate the inhibitive effects and ANOVA analysis was used to determine the similarity and differences between every experimental group. Result showed that A. lavandulaefolia, which grew well in the aquatic environment, might have a great potential to be applied to inhibit algae bloom and control the eutrophication of water.

Main Topic 13: Genetics and Biochemistry 210. Exploitation of Allelopathic Interactions in Cereal Crops Ruth Gordon-Weeks and John Pickett Biological and Ecological Chemistry Department, Rothamsted Research, West Common, Harpenden Hertfordshire, AL5 5PJ, UK Email: [email protected] We are studying the role of allelopathic compounds in natural resistance to biotic stress in cereal crops. During early development, wheat, and some other cereals accumulate hydroxamic acids or benzoxazinones throughout their tissues.

These secondary metabolites are members of a family of broadly acting defence compounds, believed to protect plants from above ground pathogens, including bacteria, fungi and sucking and chewing insects. Benzoxazinones are also stored and released from roots to defend plants from soil pathogens and weeds and their biosynthetic regulation in roots may differ from that in the foliar tissue. Ultimately, we wish to establish if there is sufficient variation within wheat populations to form the basis of a breeding program to generate varieties that display general resistant to pathogens and weeds due to increased amounts of these compounds. We are using gene expression studies and


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chemical analysis to measure constitutive regulation and inducibility of the pathway in response to pathogens, and by natural plant defence inducers, to examine wider aspects of variation within the wheat population. To investigate their role in allelopathy we are studying the root specific regulation of the pathway including its response to nematodes. In addition to standard hexaploids we are studying wheat varieties from international breeding collections and a range of diploid and tetraploid wheats. We have access to some natural mutants of the diploid, Triticum Boeoticum, that lack the benzoxazinone pathway. Comparison of resistance in these mutants with wild type T. boeoticum will enable us to determine the extent to which resistance depends on the benzoxazinone pathway, and whether other defence mechanisms are also involved. In addition to the work on wheat we are investigating allelopathic interactions between maize and legumes. Intercropped legumes release compounds from their roots that can significantly reduce infestation of maize by parasitic weeds. The identification of the compounds involved in this interaction and its successful practical application in sub-Saharan Africa will be discussed. 211. Strigolactones: A Cry for Help Results in Fatal Attraction Carolien Ruyter-Spira1, Juan Antonio Lopez-Raez1, Catarina Cardoso1, Tatsiana Charnikhova1, Radoslava Matusova1, Wouter Kohlen1, Francel Verstappen1, 2, Harro Bouwmeester1,2 1Laboratory for Plant Physiology, Arboretumlaan 4, 6703 BD Wageningen, the Netherlands 2Plant Research International, P.O. Box 16, 6700 AA Wageningen, the Netherlands Email: [email protected]

During evolution, plants have adapted an ecological balance with their associates, competitors, predators and pests. Keeping this balance intact is an active process during which the plant needs to respond to many different stimuli in order to survive. For example, plants have developed an array of physiological and biochemical responses to phosphate deprivation. One of these responses is the formation of symbiotic associations of plant roots with arbuscular mycorrhizal (AM) fungi. AM fungi colonize the root cortex to obtain carbon from their host while assisting the plant in phosphate acquisition. Hyphal branching in mycorrhiza, a growth characteristic preceding penetration of the plant root, is stimulated by compounds called strigolactones which are present in the plant root exudate (Akiyama et al, 2005). Strigolactone production is specifically increased in plants suffering from low phosphate availability (Yoneyama et al, 2007) thereby actively inviting mycorrhizal invasion. Strigolactones also stimulate the germination of parasitic plants seeds. Only upon perception of the presence of a host through its strigolactone production, seeds of the parasites germinate and attach to the roots of many plant species such as several legumes, maize, tomato, sunflower, hemp and tobacco. In contrast to a mutualistic symbiotic relationship, where both partners benefit from the affiliation through an exchange of resources, the host is heavily exploited by a parasitic plant and suffers strongly from the interaction because it is robbed from its assimilates, water and nutrients. Previously, we have shown that the strigolactones are derived

from the carotenoid pathway (Matusova et al, 2005). In our current research we are further unraveling this pathway and elucidating which genes encode the dedicated biosynthetic steps that lead to the formation of the strigolactones. Furthermore, we are interested in the signal transduction pathway initiated by phosphate starvation and ultimately leading to an increased strigolactone production.

212. Biosynthesis and Allelopathic Activity of Diterpenoid Phytoalexins in Rice Hisakazu Yamane1, Atsush Okada1, Kazunori Okada1, Tomonobu Toyomasu2 1Biotechnology Research Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan 2Department of Bioresource Engineering, Yamagata University, Tsuruoka, Yamagata 997-8555, Japan Email: [email protected] Rice (Oryza sativa L.) produces four structurally distinct types of polycyclic diterpenoid phytoalexins, phytocassanes A to E, oryzalexins A to F, momilactones A and B, and oryzalexin S. Of these diterpenoid phytoalexins, momilactones have also been shown to play an important role as allelochemicals in rice and the moss Hypnum plumaeforme. In this talk, biosynthesis and allelopathic activity of rice diterpenoid phytoalexins including momilactones will be focused. Biosynthesis: The rice diterpenoid phytoalexins have been identified in suspension-cultured cells treated with biotic elicitors such as a chitin oligosaccharide and/or from rice leaves that were either infected with a pathogen or exposed to UV irradiation. The major ones are phytocassanes and momilactones. We have performed extensive studies on biosynthesis of the rice diterpenoid phytoalexins, and obtained the following results: (1) We identified all the six diterpene cyclase genes involved in biosynthesis of the diterpenoid phytoalexins. (2) We succeeded in identification of a series of methylerythritol phosphate pahtway enzymes involved in upstream steps of the diterpenoid phytoalexin biosynthesis. (3) We found that three enzyme genes involved in the downstream oxidation of the diterpene hydrocarbon 9�H-pimara-7,15-diene leading to momilactones, together with the diterpene cyclase genes OsCPS4 and OsKSL4, form a momilactone biosynthetic gene cluster on chromosome 4. (4) As part of studies to elucidate regulatory mechanisms for the expression of diterpenoid phytoalexin biosynthetic genes, we succeeded in identification of a bZIP protein, OsTGA1, as a transcriptional activator that regulates the elicitor-inducible expression of OsKSL4. Interestingly, OsTGA1 activated transcription not only of OsKSL4 but of the other four genes in the momilactone biosynthetic gene cluster. Allelopathic activity: Momilactone B was previously identified as an allelochemical exudated from the roots of rice. We found that momilactone A and phytocassanes were exudated from the roots of rice, the concentration of each compound being of the same order of magnitude as that of momilactone B. However, none of phytocassanes exhibited allelopathic activity against dicots, although momilactone A showed much weaker allelopathic activity than momilactone B. Biological functions of diterpenoid


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phytoalexins exudated from the roots of rice will also be discussed. 213. Glucosinolates in Brassica species: Weed Suppression, Biosynthesis and Engineering Hanwen Wu, Eric Koetz, Deirdre Lemerle EH Graham Centre for Agricultural Innovation (Charles Sturt University & NSW Department of Primary Industries), Wagga Wagga Agricultural Institute, PMB, Wagga Wagga NSW 2650, Australia Email: [email protected] Cover cropping has long been recognized for its potential to suppress weeds through competition, physical suppression, chemical suppression via allelopathy, and improved soil biological activity. Evidence has accumulated that Brassica cover crops and seed meals are phytotoxic to a range of weeds. We are currently investigating the allelopathic effects of a range of Brassica cover crops on annual ryegrass (Lolium rigidum Gaud.), the most important agricultural weed in Australia due to its widespread resistance to herbicides. Glucosinolates (GSLs) and their breakdown products have been identified as the responsible allelochemicals from Brassica species. The intact GSLs possess limited biological activity, while the enzymatic hydrolysis of GSLs by the endogenous enzyme myrosinase produces a complex variety of biologically active secondary compounds such as isothiocyanates (ITCs), ionic thiocyanates (SCN-), oxazolidine-2-thiones (OZT), nitriles, epithionitriles and organic cyanates. Several ITCs have been reported to suppress weed growth. The ionic thiocyanates (SCN-) have also been demonstrated to possess herbicidal potential. The triazole herbicide amitrole-T consists of a mixture of amino-1,2,4-triazole and NH4SCN and is a carotenoid biosynthesis inhibitor. The commercial nitrile herbicides such as bromoxynil and ioxynil are PS II inhibitors. In addition, the elevated activity of Pythium spp. by Brassica residues was recently found to partly contribute to the observed weed suppression. Biosynthesis and genetics of GSLs have been an intense area of study due to their anti-carcinogenic properties. Significant progress has been made in understanding the GSL biosynthetic pathway in the model plant Arabidopsis thaliana. GSL biosynthesis consists of three stages: side-chain elongation of amino acids, development of the core structure, and secondary side-chain modifications. Most of the structural genes in these biosynthetic steps have been identified and functionally characterized by biochemical and reverse genetics approaches. Progress has been made in genetic engineering for enhanced biosynthesis of target GSL. Enhanced levels of GSL in Brassica species might result in better weed suppression. The success of identifying genes encoding GSL biosynthesis has provided a research platform for improved understanding of other classes of allelochemicals, such as benzoxazinones, phenolics, alkaloids and terpenoids. 214. Investigating the Function of OsCYC1 and OsAOS Genes in Rice Allelopathy by RNA Interference Shiming Luo, Haihong Bi, Rensen Zeng Institute of Tropical and Sub tropical Ecology, South China Agricultural University, Guangzhou 510642, China Email: [email protected]

In order to understand the role of the syn-copalyl diphosphate synthase gene (OsCYC1; momilactone biosynthetic pathway), and the phenylalanine ammonia–lyase gene (OsPAL; phenolic acid biosynthetic pathway) in rice allelopathy, a study using the RNA interference (RNAi) method was conducted. OsCYC1 RNAi rice (denoted: RNAi-C) and OsAOS RNAi rice (denoted: RNAi-A) lines were successfully generated via agrobacterium-mediated transformation. The allelopathic effects on barnyard grass and rape seedlings were compared between wild-type (denoted: no-RNAi) and RNAi-impaired plants. The expression levels of the endogenous rice genes were also analyzed. These results showed that: (1) Following treatment of rice seedlings with methyl jasmonate (MeJA), salicylic acid (SA), or ultra-violet radiation (UV), the expression of OsCYC1 in RNAi-C was greatly reduced, and the expression of OsCYC1 was inversely correlated with bioassay results for allelopathic effects on barnyard grass and rape seedlings to a significant extent; (2) Following exposure of rice seedlings to abiotic stressors which included nitrogen deficiency (N), drought (Dry), mechanical damage (Dm), and UV, the result showed that N, Dry, and Dm treatments did not increase the allelopathic effects of RNAi-A, although it was greatly increased in no-RNAi. UV did however increase the allelopathic effects of RNAi-A. Correlation analysis showed that there was a significant negative correlation between OsAOS expression levels and the length of the stem and root of barnyard grass seedlings; and (3) The expression of OsCYC1 (the key gene for momilactones biosynthesis), OsOASA2 (the key gene for alkaloid and tryptophan biosynthesis), OsFPS (a gene participating in terpene biosynthesis), and OsPAL (a gene modulating phenolic acid biosynthesis) were all induced by N, Dm, and UV in both RNAi-A and No-RNAi rice, but the relative expression of these four genes in RNAi-A were much lower than that of No-RNAi. OsCYC1 and OsOASA2 expression also increased after RNAi-A and No-RNAi rice were exposed to drought, although the expression levels of OsFPS and OsPAL were not affected. The biochemical and molecular mechanisms of rice allelopathy will also be further discussed. 215. Evolution of Benzoxazinone Biosynthesis Monika Frey, Regina Dick, Katrin Schullehner, Alfons Gierl Lehrstuhl für Genetik, Technische Universität München, Am Hochanger 8, 85 350 Freising, Germany Email: [email protected] Secondary plant products often are differentially distributed among limited taxonomic groups within the plant kingdom. Benzoxazinoids represent protective and allelophatic metabolites that are abundant in the Poaceae. Outside the Poaceae these secondary metabolites are found sporadically in isolated dicotyledonous species. The committing enzyme of benzoxazinoid biosynthesis in the grasses, BX1, evolved via gene duplication and modification from the alpha subunit of the tryptophane synthase (TSA). Indole-3-glycerol phosphate (IGP) is cleaved by TSA and BX1 into indole and glyceraldehyde-3-phosphate (alpha-reaction).


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Hence both enzymes are indole-3-glycerol phosphate lyases (IGLs). The introduction of four oxygen atoms into the indole moiety that yields DIBOA (2-hydroxy-2H-1,4-benzoxazin-3(4H)-one), is catalyzed by the cytochrome P450 enzymes (P450s) BX2-BX5. The investigation of the benzoxazinoid biosynthetic pathway in three dicot plants, Aphelandra squarrosa (Acanthaceae), Consolida orientalis (Ranunculaceae) and Lamium galeobdolon (Lamiaceae) indicate that indole is an intermediate in biosynthesis. Indole is likely converted into indolin-2-one by a P450 enzyme in C. orientalis and L. galeobdolon. A comprehensive survey of Igl genes in C. orientalis and L. galeobdolon detected a wide spectrum of catalytic properties for IGLs in plants and identifies candidate genes for IGLs involved in benzoxazinoid biosynthesis. Phylogenetic analysis reveals that these branch point enzymes evolved by independent duplication events in dicot and monocot plants. 216. Molecular Characterization of Enzymes Involved in the Biosynthesis of the Allelochemical Sorgoleone Zhiqiang Pan, Scott R. Baerson, Franck E. Dayan, Agnes M. Rimando, Stephen O. Duke USDA, ARS, Natural Products Utilization Research Unit, P. O. Box 8048, University, MS 38677, USA Email: [email protected] Sorghum (Sorghum bicolor) root systems exude an allelochemical known as sorgoleone, which is produced in root hair cells and acts as a phytotoxin against many broadleaf and grass weed species. The biosynthesis of this compound initiates with the synthesis of an unusual 16:3 fatty acyl-CoA, which serves as the starter unit for polyketide synthase. Iterative condensation reactions catalyzed by the polyketide synthase enzyme using malonyl-CoA extender units results in the formation of a 5-pentadecatrienyl resorcinol intermediate. This resorcinolic intermediate is then methylated by an O-methyltransferase, and subsequently dihydroxylated to yield the reduced form of sorgoleone. To isolate genes involved in the biosynthesis of sorgoleone, an EST data set generated from sorghum root hair cells was mined. Candidate sequences representing all of the required enzyme classes were identified. Analysis of the Sorghum root hair transcriptome, strategies used for the identification and screening of candidate gene sequences, as well as functional characterization of these candidate genes will be presented. 217. Allelopathic Compounds Produced by Oat Anne Osbourn and Sam Mugford Department of Metabolic Biology, John Innes Centre, Norwich NR4 7UH, UK Email: [email protected] Oats (Avena spp.) are an important weed of cereal crops. Oats are unique amongst the cereals in that they synthesise triterpenoid glycosides (avenacins) which accumulate in the root epidermis and provide protection against a broad range of soil-borne pathogens. The major avenacin, A-1, fluoresces bright blue under UV-illumination due to the presence of an N-methyl anthranilate acyl group. This compound is released from the roots into water when oat seedlings are grown under hydroponic conditions. We have also shown that avenacin A-1 is released into the soil around the roots of oat plants, where

it influences the development of microbial communities. Triterpene glycosides have long been proposed to act as allelochemicals in legumes. We therefore tested the effects of avenacin A-1 on the growth of Arabidopsis and wheat and found that this compound is a potent phytotoxin. Previously we exploited the UV-fluorescence of avenacin A-1 as a simple screen to identify mutants of a diploid oat species (black oat; Avena strigosa) that are blocked in avenacin synthesis, following sodium azide mutagenesis. Our mutant screen allowed us to define nine loci required for avenacin biosynthesis, five of which we have now cloned. One of these cloned loci encodes Sad1, the gene encoding the enzyme for the first committed step in avenacin synthesis (β-amyrin). Sad1 function has been extensively characterized at the gene, protein and metabolite level. Since sad1 mutants are blocked in the first committed step in the pathway they represent ideal tools for tests of the biological significance of avenacin production. Null mutants for other early steps in the pathway (e.g. sad2) are also available. sad1 and other avenacin-deficient mutants of A. strigosa have enhanced susceptibility to soil-borne diseases such as “take-all”, indicating that avenacins protect oat roots against attack by pathogenic microbes. Importantly, preparations from wild type A. strigosa roots are toxic to the growth of Arabidopsis and wheat while preparations from sad1 mutants show little/no inhibition. These data indicate that avenacins are the primary phytotoxic compounds produced by oat roots, so implicating avenacins as allelopathic agents. The role of avenacins in competitive interactions with wheat and Arabidopsis will be discussed. 218. Identification and Analysis of meta-tyrosine Resistance in Arabidopsis thaliana Georg Jander Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA Email: [email protected] Recent research with Festuca rubra suggests that this grass species reduces competition by producing m-tyrosine, a phytotoxic non-protein amino acid, in its roots (Bertin et al, 2007, PNAS 104:16964-16969). Whereas F. rubra itself is resistant to m-tyrosine, root growth of most other plants is inhibited at micromolar concentrations. Accumulation of m-tyrosine is highest in F. rubra root tips, and lower levels were observed in all other plant parts that were tested. Endophyte-deficient isolates of F. rubra did not accumulate significantly less m-tyrosine. Experiments with isotopically labeled precursors and metabolic inhibitors indicate that m-tyrosine in F. rubra is synthesized by a phenylalanine hydroxylase. This pathway is distinct from that in Euphorbia myrsinitis, the only other plant species in which m-tyrosine biosynthesis has been observed. Root growth of Arabidopsis thaliana seedlings on agar was reduced 50% by two micromolar m-tyrosine. Shoot grow was inhibited to a lesser extent, and no significant transport of m-tyrosine from roots to the aerial portion of the plants was observed. Exogenous addition of other amino acids, in particular phenylalanine, rescued m-tyrosine-mediated inhibition of A. thaliana root growth. A. thaliana populations mutagenized with activation-tagging T-DNA insertions,


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fast neutron bombardment, and ethylmethanesulfonate (EMS) were used to select m-tyrosine-resistant lines. Whereas three activation-tagged lines showed small root growth increases in the presence of m-tyrosine, a gain-of-function EMS-induced mutation provided ten-fold higher resistance. Further phenotypic analysis of this mutant line, combined with map-based cloning of the mutation has determined a likely cause for the increased m-tyrosine resistance. Together, the identification of an m-tyrosine biosynthetic enzyme in F. rubra and a resistance mutation in A. thaliana may permit transfer of this allelopathic system to other plant species.

219. Breeding Rye Cover Crops for Increased Allelopathic potential Chris Reberg-Horton, Ashley Brooks, David Danehower, Michael Burton, James Burton, Guoying Ma, Paul Murph Depts. of Crop Science and Horticultural Science, North Carolina State University, Raleigh, NC 27695, USA Email: [email protected] The Rye Allelopathy Breeding Project at NC State was begun in 2000 to evaluate the potential for increasing the allelopathic potential in rye cover crops. Rye is of particular agronomic importance as a cover crop in many regions of the U.S. The crop generally produces more biomass and suffers fewer pests than other winter grasses. Rye has also received a lot of attention in the allelopathic literature and several of its allelochemicals have been well characterized. Like many cover crop species, this crop has received little attention from plant breeders. A sampling of 268 accessions was field grown in 2000 to 2001 and screened with a simple petri dish bioassay to identify 15 accessions with high allelopathic potential. These accessions were each crossed to the commercial cultivar ‘Wrens Abruzzi’ and subsequently all were randomly intermated for two generations to form a synthetic population. One Hundred fifty random half-sib families derived from the synthetic were field grown in 2006 to 2007 and in 2007 to 2008 at two locations. Multiple methods of screening are being employed on these samples including petri dish bioassays with redroot pigweed (Amaranthus retroflexus L.) and large crabgrass (Digitaria sanguinalis L.), greenhouse pot bioassays with the same weed species, and gas chromatography-mass spectroscopy quantification of 2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one (DIBOA). The heritabilities of, and correlations between these methods will help us determine how ongoing selection in the breeding program will occur. We are attempting to balance the sometimes opposing demands of finding a method that is fast and cheap enough to be practical in a breeding program, yet reproducible enough to give us confidence in our selections. Once the genetic variance and heritability of allelopathic potential in rye is quantified, we will understand the potential for improving this trait and the approximate time required for improvement. 220. Development of Weed-suppressing Rice Variety, Weed-suppressing No.1, via a Specific Secondary Metabolite Marker Shao-chuan Zhou, De-cheng Lu, Hong Li, Dao-Qiang Huang Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong 510640, China

Email: [email protected] Weed-Suppressing No.1 is a rice variety derived from a cross between Wu-shan-you-zhan and PI312777. F2 of the cross in the field showed an obvious weed-suppressing effect. Most individuals of the F2 had good agronomic traits and higher yield potential than PI312777. Leaves of seedlings at the 2.5-leaf stage were sampled and evaluated for allelopathic potential using the specific secondary metabolite marker method from F3 in the early season of 2004. In the early season of 2006, one plot showed outstanding performance with above 65% weed-suppression, an AI value of 0.56, high seed-setting rate, large panicles, high yield potential, and good resistance to bacterial blight (BB). In the late season of 2006, the yield of the line was 555.67kg/667m2 which was 21.50% higher than the control Jingxian 89, and ranked 3rd among 14 lines tested. The resistance of seedlings to rice blast strains A, B, C, and G in China were all 100%; leaf blast and neck blast were both ranked 1.0. The resistance to bacterial blight was ranked as medium. Agronomic traits of the line in Guangzhou were as follows: 110 days in duration, 2.58 million effective tillers per hectare, 99.8 cm in plant height, 21.6 cm in length of panicle, 140.5 spikelets per panicle, 88.3% in seed setting rate, and 25.8 g in 1000-grain weight. The line was named Weed-suppressing No.1. Its yield in Guangdong pre-trials in late season of 2007 was 7.27 ton.ha-1; 4.79% higher than the control Jing-Xian 89. It was advanced to take part in Guangdong trials in late season of 2008. 221. Selection for allelopathy in rye (Secale cereale) Ashley Brooks Box 7620, Dept. of Crop Science, North Carolina State University, Raleigh, NC 27695, USA Email: [email protected] Variation in allelopathy has been observed in rye (Secale cereale), which suggested that improvement through conventional breeding methods may be successful. The objectives of this research were: 1) to develop a reliable greenhouse protocol for screening allelopathy among large numbers of segregating rye genotypes, and 2) to obtain estimates of genetic variance and heritability for the allelopathy trait in rye. One hundred and fifty random half-sib families were grown at two locations during the 2006-07 season in North Carolina. Half-sib families were cut at ground level at the boot stage and oven dried. Ground field tissue of each half-sib family was mixed with soil media. A known number of redroot pigweed (Amaranthus retroflexus) and large crabgrass (Digitaria sanguinalis) seeds were planted into the mixture. Redroot pigweed and large crabgrass counts and fresh weights were quantified as allelopathy measures. All measures displayed normal distributions indicating allelopathy is a quantitative trait. There was significant genotype x location interaction. Genetic variation among half-sib families was significant for all measures of weed control. Estimates of narrow sense heritability ranged from 0.02 to 0.20 on per plot basis and 0.16 to 0.33 on a family mean basis. Standard errors for heritability were 0.08 on a per plot basis and ranged from 0.11 to 0.13 on a family mean basis. The greenhouse


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protocol was successful in handling the large number of genotypes for screening allelopathy. The protocol eliminated physical interference so that weed suppression could be attributed to allelopathy. Work in progress includes a quantitative gas chromatograph analysis of allelochemicals produced by rye and a seed germination assay using aqueous rye extracts. 222. Overcoming Plant Biotic Stresses through Allelopathy and Induced Resistance Rensen Zeng and Shiming Luo

Research Center for Chemical Ecology, Institute of Tropical and Sub-tropical Ecology, South China Agricultural University, Wushan, Guangzhou, 510642, China Email: [email protected] Plants use both constitutive and induced defense systems to deal with biotic stress. Insect damage and pathogen infection in many plant species leads to the initiation of a series of signal transduction processes, which in turn induce an array of defense genes to produce more compounds which can mount resistance to subsequent infection. Insect feeding induces local or systemic production of plant volatiles that attract predators of the herbivore. Multiple sustainable approaches to overcome plant biotic stresses are being developed at South China Agricultural University: (1) Allelopathy: More than 30 plant species have been investigated to be allelopathic. The allelochemicals have been identified from 11 plant species. Molecular mechanisms are being characterized. (2) Microorganisms: Biological control for crop disease were conducted by inoculation with mycorrhizal fungi, endophytic bacteria and fungi, application of non-pathogenic and antagonistic microbes. (3) Multi-trophic interactions: Plants, insects, natural enemies and pathogens are linked through chemical signals. (4) Natural compounds: Such as azadirachtin, rotenone and some other new products have been developed as natural plant protectants. These approaches are promising to reduce human dependency on synthetic chemicals to overcome plant biotic stresses. 223. In Vitro Comparisons of Root Allelopathy among Native and Invasive Asteraceae Guangyan Ni1, 2, Shaolin Peng2, Ragan Callaway1 1Division of Biological Sciences, The University of Montana, Missoula, MT, 59812 USA 2State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, Guangdong, 5I10275 China Email: [email protected] The release of phytotoxins from roots has the potential to be an important mechanism for successful exotic plant invasions. However, as for any invasive mechanism, to explain invasions allelopathic effects must be more important in the invaded regions than in the native regions of a species. The “novel weapons” hypothesis addresses this issue, positing that chemicals that are new to a region may have stronger allelopathic, anti-herbivore, or antimicrobial effects on species that have not had the opportunity to evolve to the chemical. This hypothesis has been supported in a number of experiments with different species in which the effects of invaders have been compared between sets of species native

to the invaded region and native to the original region of the invader species. For example, knapweeds have been shown to be more allelopathic to species native to North America than species native to Europe or Eurasia. However, invasive species may also simply be more phytotoxic in general than native species, either through chance or through the evolution of stronger allelopathic effects in invaded ranges (the Allelopathic Advantage against Resident Species hypothesis; AARS). We exposed the seeds of the model plant, Arabidopsis thaliana, to field-harvested roots of Centaurea maculosa (spotted knapweed) and Acroptilon repens (Russian knapweed), two exotic invaders in the Asteraceae suspected of root allelopathy, four native Asteraceae species, and Pseudoreogneria spicata, a native perennial bunchgrass. Excised roots and seeds were placed in Petri dishes containing static MS basal media, and the germination of Arabidopsis seeds was measured over 15 days. We found that the roots of all species inhibited the germination of Arabidopsis during the first few days, but the inhibitory effects of the natives were not significant after 15 days; whereas Centaurea and Acroptilon roots suppressed germination by 29±5% and 37±4%; respectively. Our results indicate that the invasive Asteraceae are inherently more allelopathic to Arabidopisis, a species that was “novel” to all other species in our experiments, but do not exclude the possibility that the invaders have evolved greater phytotoxicity since arriving in North America.


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Author Name Paper No. Abbassi, F. 114 Abdus Salem 100 Aguilar, Maria I. 47 Aguiliar-Laurents, M. I. 121 Ahluwalia, A. S. 166 Al-Asaadee, Z. M. 109 Ali, A. 96 Allen, D. 5 Allen, David 99 Almeira, J. 202 Alpert, Peter 174 Alsaadawi 165 Amini, R. 134

An, M. 23, 89, 93, 94, 128, 134

Anaya, Ana Luisa 4, 63, 81,104, 127 Andolfi, Anna 46 Andrade, Carlos K. Z. 52 Angeli, Sergio 161 Armin, Mohammad 190 Arroyo, Elena 44 Arslan, Mehmet 57 Arthurson, V. 3 Arumugam, K. 79 Asano, Maki 98 Averill, Kristine, M. 123 Aziz, A. 96 Babar, B. H. 96 Bacon, C. W. 18 Bacon, C. W. 19 Baelum, J. 31 Baerson,S. R. 216 Bajwa, R. 14 Baluska, F. 118 Bano, Asghari 107 Bartariya, Garima 186, 189 Bastiaans, L. 85 Batish, Daizy R. 83, 108, 142 Bauer, Michaela 141, 162 Bauer, Michaela 162 Bazubandi, M. 114 Belz, Regina 129, 153 Berenbaum, M. R. 7 Berestetskiy, Alexander 46 Bertholdsson, Nils-Ove 90 Bhowmik, Prasanta C. 33, 174, 185 Bi, Wu 59 Bialek-Kalinski, K 35

Author Name Paper No. Biswas, Parimal K. 185 Biswas, Shekhar R. 71 Blum, U. 151 Bogatek, R. 103, 116 Bouwmeester, H. 211 Boydston, Rick 87 Braun, Rudolf 141, 162 Brooks, A. 219, 221 Brooks, A. 221 Burton, J. 219 Burton, James 177 Burton, M. 219 Burton, Michael 177 Cabrera, Gema 61 Callaway, R. M. 163, 167, 168, 223 Cantero, Domingo 61 Cao, M. 25 Cao, Z. 27 Cardosa, C. 211 Carlsen, Sandra 28 Cedergreen, nina 38 Cerasuola, M. 203 Charnikhova, T. 211

Cheema, A. Zahid 86, 159, 183, 207, 208

Chen, Hui 39, 92 Chen, W. 13, 22 Chen, X. 179 Chen, Xin 131 Chick, Timothy A. 77 Chinchilla, Nuria 44 Chludil, Hugo D. 178 Chobot, Vladimir 164 Chrzanowski, G. 21, 24, 198 Ciarka, Dorota 158 Cimmino, Alessio 46 Cipoletti, J. R. 8 Colby, T. 101 Conteras-Ramos, Silvia M. 127 Cruz-Ortega, R. 81, 104 Cui-ping, Y. 37 Czerniewicz, P. 11 D'Abrosca, Brigida 48, 58, 64 Danehower, D. 177, 219 Dato, a. 74 Dayan, F. E. 31, 105, 216 Delabays, N. 9 Della Greca, Marian 133, 203


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Author Name Paper No. DeMarco, A. 173 Dendooven, Luc 127 Dick, R. 215 DiTommaso, Antonio 123, 124 Dmitriev, Andrey 46 Dong, Fengshou 150 Douglass, Cameron 124 Duan, G. 6 Duke, S. O. 216 Ebana, K. 205 Edwards, J. 5 El-Darier, S. M. 97 Elena, D'Errico 58 Erhard, D. 199 Esposito, Assunta 48, 58, 64 Esposito, F. 173 Evidente, Antonio 46 Farooq, Muhammad 191 Fei, H. 179 Fengzhi, Wu 149 Fergola, P. 203 Fernandez, Catherine 76 Ferreira, Alfredo G. 172 Fiorentino, Antonio 48, 64 Flint, Steve, M. 122 Flores-Carmona, M. 81 Focho, D. A. 184 Fomsgaard, Inge S. 28, 197 Fongod, A. G. N. 184 Frey, M. 215 Frey, M. 106, 215 Fritz, Ines 141, 162 Fu, Y. L. 93

Fujii, Yoshiharu 29, 51, 98, 130, 132, 135, 136, 137

Funk, Dominic 141, 162 Furubayashi, A. 29 Furubayashi, Akihoro 135 Galindo, Juan C. G. 49, 66, 68 Gallandt, E. r. 85 Gao, S. 204 Gao, Weiwei 59 Garau, A. 74 Garcia-Ciudad, A. 17 Garcia-Criado. B. 17 Garcia-Diaz, Maria D. 49 Gatti, Ana B. 172 Gatti, Ana B. 62

Author Name Paper No. Gavazzi, Carolina 192 Gawronska, Helena 158 Gawronski, Stanislaw 158 Gealy, David 82 Geng, R. 6 Gerivani, M. 120 Gerivani, Z. 120 Ghaderi, Koorosh 194 Ghorbani, R. 114 Gierl, A. 106, 215 Gimsing, A. L. 31, 42, 147 Glawischig, E. 106 Gleason, F. K. 206 Glenn, Anthony E. 2, 4, 15, 18, 19, 63 Gniazdowska, A. 103, 116 Gniazdowska, A. 116 Golino, Annunziata 58 Gomez, Jose M. 61 Gonzalez, Louis 169 Gonzalez, M. C. 4 Gonzalez, Maria C. 63 Gordon-Weeks, R. 210 Gounder, Rajendra 99 Granhall, U. 3 Guarnaschelli, A. B. 74 Guo, Yiqing 156 Gupta, Rajendra 50 Habibian, Leila 193 Hadacek, F. 164 Haddadchi, Gh. R. 120 Hafeez-ur-Rehman 191 Halder, S. 12 Han, C. 117 Han, L. 27 Hanlin, R. 4 Hanlin, Richard 63 Hansen, H. C. B. 38, 41, 42, 147 Hansi, Mari 154 Hao, Jing 67 Haramoto, E. R. 85 Harzen, A. 101 Hasegawa, Koji 54 Hashimoto, Hirofumi 98 He, Chunnian 59 He, HaiBin 91, 180, 181 Hegab, M. M. Y. 205 Hernandez-Bautista, B. E. 4, 63


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Author Name Paper No. Hernandez-Ortega, Simon 63 Hinton, D. M. 19 Hiradate, S. 29, 132 Hiradate, Syuntaro 51, 135 Hiraishi, Kanae 98 Hirose, Katsutoshi 54 Hohli, R. K. 142 Holben, William E. 167 Hong, R. 37 Hooker, J. 34 Hookmabadi, Mosareza 190 Hu, Kaihui 145 Hu, X. 202 Hu, X. H. 32 Hu, X. Y. 13, 22 Huang, Dao-Qiang 220 Huang, J. H. 25 Hume, D. E. 23 Hurle, Kurl 129 Hussain, M. Iftikhar Hussain, Mubashir 191 Inderjit 163, 167, 168 Ino, T. 102 Iqbal, Javid 86 Iqbal, Zahida 135, 136 Issa, N. N. 196 Iwasawa, Hiroko 98 Izzo, Angelina 48, 64 Jabran, Khawar 191 Jacobson, C. S. 31, 41, 42 Jaderlund, L. 3 Jander, G. 218 Javid, Arshad 14, 182 Jaykumar, M. 160, 187 Jensen, John 38 Jensen, P. H. 41, 42 Jessing, Karina K. 38 Jha, P. K. 126 Jiang, Hongyun 20 Jiang, Hui-Dong 13, 22 Jimenez-Estrada, Manuel 63 Jonczyk, R. 106 Jones, Alicia 68 Jonsson, P. 201 Jose, Shibu 72 Joshi, S. 126 Jubrael, J. M. S. 109

Author Name Paper No. Juhler, R. K. 42 Kadamban, D. 78 Kai, Pan 149 Kamal, J. 107 Kamo, Tsunashi 51 Kant, S. 101 Kashiri, Habib O. 80, 193, 194 Kato-Noguchi, Hisashi 45, 60, 100, 102 Kaur, Shalinder 108, 142 Kazutoshi, O. 205 Khaliq, Abdul 159, 183, 207, 208 Khanh, T. D. 36, 40 Khanh, T. D. 40 Kim, Kil-Ung 156 King-Diaz, Beatriz 47, 65, 121 Kirby, K. A. 23 Kiyotake, Suenaga 60 Knop, M. 101 Knop, Mona 148 Kobayashi, K. 30, 43 Koetz, E. 213 Kohlen, W. 211 Kohli, R. K. 108 Kohn, L. M. 15, 83 Kong, Chuihua H. 32, 55, 139, 143, 179 Kostrzewa, Z. 116 Kriegs, B. 118, 119 Kruidhof, H. M. 85 Krzyzanowski, R. 26 Kubanek, J 200 Kudsk, Per 28, 197 Kujime, H. 102 Kumar, Mrintunjay 113 Kunert, Maritta 148 Kurek, W. 103, 116 Kurokawa, Syunji 132 Lacret, Rodney, R. 52 LaHovary, Christophe 177 Lara-Nunez, A. 104 Leather, Gerald R. 188 Leicach, Silvia 74, 178 Lemerie, D. 213 Leszczynski, Bogumil 11, 21, 24, 26, 198 Letizia, Marianna 64 Lewis, Norman 1 Li, C. J. 128 Li, F. 202


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Author Name Paper No. Li, H. 110 Li, Hong 220 Li, L. 139, 202 Li, X. 204 Li, Zhenfang 39, 92 Lin, H. B. 180 Lin, R. Y. 181 Lin, W. X. 181 Lin, Wenxiong 39, 91, 92, 145, 180 Liu, Bo 144 Liu, Na 67 Liu, X. J. 139 Liu, Xingang 150 Liu, Y. 202 Liu, Y. H. 89, 93 Lopez-Raez, J. A. 211 Lorenzo, Paula 169 Lotina-Hensen, Blas 47, 65, 121 Lu, Bo 67 Lu, De-cheng 220 Lu, Y. 6 Lu, Yixiu 67 Lu, Yong-liang 130 Luo, S. 214 Luo, S. M. 25 Luo, Shi Ming 222 Ma, G. 219 Macias, Francisco A. 19, 44, 49, 52, 61, 62 Macias-Rubalcava, M. L. 4, 63 Maharjan, S. 126 Mahmood, Azhar 183, 207 Mahmood, Khalid 146 Mallik, Azim 71 Mandal, S. S. 113 Mann, R. 5 Marin, D. 19 Marko, M. D. 206 Marocco, Adriano 192 Martinez Ascension Torres 66 Martinez, Ascension T. 68 Martinez-Penalver, A. 111 Mathiassen, Solvejg 28, 197 Matok, H. 21 Matok, Henryk 198 Mattice, John 82 Mattner, S. 5 Mattner, Scott 99

Author Name Paper No. Matusova, R. 211 Meena, P. 187 Meixueiro-Galan, C. J. 121 Melendez-Gonzalez, Claudio 63 Mezori, H. A. M. 109 Mih, A. M. 184 Milbrath, Lindsey R. 123 Milewska, K. 21 Mitina, Galina 46 Mohler, Charles L. 123 Moldenhauer 82 Molinillo, Jose M. G. 44, 52, 61, 62 Monaco, Pietro 48 Monnier, Yogan 76 Morimoto, Masanori 140 Morshed, M. M. 185 Mugford, S. 217 Mullenborn, Carmen 148 Muria-Gonzalez, Jordi M. 63 Murph, P. 219 Murphy, Paul 177 Mushtag, M. N. 159, 207, 208 Mushtaq, M. Naeem 183 Myers, T. 200 Naar, J. 200 Nadeem, M. A. 96 Nasir, Habib 135 Natale, Angelina 64 Nejad, Ali R. S. 80 Nejad, Rusta M. R. 114 Newman, R. M. 206 Ni, Guangyan 223 Nilsson, Marie-Charlotte 69 Ninkovic, V. 10 Nishiuchi, Takumi 53 Niu, G. 7 Nogueira, Clara 52 Nukuna, B. N. 184 Ohse, K. 29 Okada, A. 212 Okada, K. 212 Okamoto, Yumi 43 Oles, Hilary 122 Omar, Florencia Urteaga 178 Osbourn, A. 217 Owuor, Okindo P. 95 Pacifico, Severina 58


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Author Name Paper No. Pan, K. 110, 117 Pan, Z. 216 Panaccione, D. G. 8 Pascarella, Maria Teresa 58 Pavia, Adrianna 66 Pavia, H. 201 Pazos, Eva 169 Pederson, R. B. 41 Peisker, H. 119 Peng, Shaolin 223 Perez, S. C. J. Gualtieri 62 Perez, Sonia C. J. G. A. 172 Periyakaruppiah, P. 160 Picket, J. 210 Pieterson, E. Corrie 72 Pinto, G. 203 Pollio, A. 203 Pollock, Jarrod 167 Poor, Ai Kian 193 Porter, I. 5 Porter, Ian 99 Potter, Da. A. 8

Pratley, J. E. 23, 88, 89, 125, 128, 134, 175

Previtera, Lucio 133 Prince, E. 200 Pruckner, Marcus 141, 162 Purcaro, Raffaella 133 Puschenreiter, M. 138 Qasem, J. R. 155, 196 Qing-tie, X. 37 Qiu, Long 145, 180, 181 Rafieiolhossaini, M. 16 Rafiq, Muhammad 94 Rajarathinam, K. 160 Ramanujam, M. P. 78 Rashid 170 Ray, M. B. 12 Reberg-Horton, C. 177, 219 Rehman, Arif 208 Reigosa, Manuel J. 111, 112, 169 Reinhardt, Carl 129 Reshi, Z. 170 Riaz, Tariq 182 Rice, Clifford P. 35, 175 Riley, R. T. 2 Rimando, A. M. 216 Rodriguez, I. Gonzalez 73

Author Name Paper No. Roger Reigosa, M. J. 73 Romagni, Joanne G. 66, 68 Romagni, Joanne G. 68 Romo, M. 17 Rudzinska-Langwald, A. 103, 116 Rui-yu, L. 37 Ruszkowski 158 Ruyter-Spira, C. 211 Saeed, M. 89 Saeed, Muhammad 94 Salih 165 Samajova, O. 118 Sanchez-Gomez, Pablo 49 Sanchez-Moreiras, A. M. 111, 112 Sathya, M. 78 Satsangi, G. P. 186, 189 Sattar, Aamer 94 Saucedo-Garcia, A. 4, 63 Saunders, M. 15 Saxena, Anjali 186, 189 Schardl, C. L. 8 Schlicht, M. 118 Schmidt, J. 101 Schneider, Denise 141, 162 Schuetz, Stefan 161 Schuler, M. A. 7 Schullehner, K. 215

Schulz, Margot 101, 118, 119, 148, 192

Seal, A. N. 23, 88, 125 Selvakumar, V. 160 Shafique, Shazia 182 Shafique, Sobiya 182 Shaw, L. 34 Shen, J. B. 139 Shigemori, Hideyuki 54 Shin, Donghyun 156 Shonouda, Mourad 161 Shrestha, B. B. 126 Sicker, D. 101, 106, 177 Siegwart, Laura C. 71 Singh, Devendra 113 Singh, H. P. 83, 108, 142 Singh, Nawalesh K. 113 Sinkkonen, A. 154 Smith, Owen 137 Sodaeizadeh, H. 16 Sodaeizadeh, Hamid 101


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Author Name Paper No. Soltys, D. 103 Sondhia, Shobha 157 Spada, Daniel M. 122 Steffensen, Stine Krogh 28 Strobel, B. W. 41 Strommer, R. 154 Suganthi, P. 78 Sun, Q. X. 13 Sun, Q. X. 22 Svensson, Robin 171 Sztarker, N. 74 Tabaglio, Vincenzo 192 Tammam, A. A. 97 Tang, Jianjun 131 Tang, W. P. 13, 22 Tanveer, A. 96 Tawata, S. 36 Tawata, Sinshichi 40 Teasdale, J. R. 35, 84, 176 Tharayil, Nishanth 33, 174 Thi, Ho Le 60 Thiffault, Nelson 70 Timsina, B. 126 Titanji, V. P. K. 184 Tomita-Yokotani, Kaori 98 Torbati, leila 80 Toshiaki, Teruya 60 Toth, G. 201 Toyomasu, T. 212 Ulbrich, A. 119 Uludag, Ahmet 57 Uremis, Ilhan 57 Uzzo, Piera 64 Valle, Antonio 61 Van Damme, P. 16 Van Damme, Patrick 101 Varela, Rosa M. 44, 52, 62 Varshney 157 Vazquez de Aldana, B. R. 17 Verstappen, F. 211 Vesterinen, M. 154 Vidal, Stefan 161 Vila, Bruno 76 Virzo, A. 173 Von Kiparski, guntram 75 Wachira, Farncis N. 95 Waller, George R. 136

Author Name Paper No. Wang, HaiBin 91, 181 Wang, J. G. 110, 117, 139 Wang, P. 32 Wang, W. X. 13, 22 Wang, X. 202 Wang, Xuezheng 144 Wang, Y. 110, 117 Weidenhamer, J. 152 Wen, Z. 7 Wen-xiong, L. 37 Wenzel, Walter 138 Weston, Leslie A. 124 Wu, Fengzhi 144 Wu, H. 23, 181, 213 Wu, J. 13, 22 Xian, Q. 204 Xiong, Jun 39, 92, 145, 180, 181 Xu, J. 204 Xu, X. H. 55 Xuan, Song-nan 130 Xuan, Tran Dang 36, 40 Yadav, Raj Nath 56 Yamada, Kosumi 54 Yamaji, Keiko 43 Yamane, H. 212 Yamashita, Masamichi 98 Yan, Wengui 82 Yang, Jiaxue 59 Yang, Y. 13, 22 Yang, Yang 144 Yasin, M. 96 Yin, D. 204 Younesabadi, Masoumeh 80, 193, 194, 195 Yu, Guodong 131 Yu, Jianlei 150 Yu, L. 6 Yu, Liu-Qing 130 Yun, W. L. 13, 22 Yuzikhin, Oleg 46 Zarrelli, Armando 133, 173, 203 Zasada, Inga A. 35, 175 Zavaleta-Fernandez, de Cordova A. 65 Zeng, Ren Sen 7, 25, 146, 214, 222 Zhang, F. S. 139 Zhang, J. 6 Zhang, Jian-Ping 130 Zhang, Shanshan 131


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Author Name Paper No. Zhang, Weihao 209 Zhang, Xu-Dong 13, 22 Zhang, Xuesong 59 Zhang, Zhongyi 39, 92 Zhao, Yangjing 59 Zheng, Yongquan 150 Zhou, Baoli 67 Zhou, Shao-chuan 220 Zhou, Y. 6 Zhou, Yong-jun 130 Zhuang, Yue 145 Zitomer, N. C. 2 Zou, H. 204

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