adaptation strategies in wetland plants: links between ecology and physiology. proceedings of a...

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The Lichen Symbiosis by V. Ahmadjian Review by: Jiří Liška Folia Geobotanica & Phytotaxonomica, Vol. 31, No. 1, Adaptation Strategies in Wetland Plants: Links between Ecology and Physiology. Proceedings of a Workshop (1996), pp. 167-168 Published by: Springer Stable URL: http://www.jstor.org/stable/4181433 . Accessed: 17/06/2014 04:18 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. . Springer is collaborating with JSTOR to digitize, preserve and extend access to Folia Geobotanica &Phytotaxonomica. http://www.jstor.org This content downloaded from 195.78.108.147 on Tue, 17 Jun 2014 04:18:27 AM All use subject to JSTOR Terms and Conditions

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Page 1: Adaptation Strategies in Wetland Plants: Links between Ecology and Physiology. Proceedings of a Workshop || The Lichen Symbiosisby V. Ahmadjian

The Lichen Symbiosis by V. AhmadjianReview by: Jiří LiškaFolia Geobotanica & Phytotaxonomica, Vol. 31, No. 1, Adaptation Strategies in Wetland Plants:Links between Ecology and Physiology. Proceedings of a Workshop (1996), pp. 167-168Published by: SpringerStable URL: http://www.jstor.org/stable/4181433 .

Accessed: 17/06/2014 04:18

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact [email protected].

.

Springer is collaborating with JSTOR to digitize, preserve and extend access to Folia Geobotanica&Phytotaxonomica.

http://www.jstor.org

This content downloaded from 195.78.108.147 on Tue, 17 Jun 2014 04:18:27 AMAll use subject to JSTOR Terms and Conditions

Page 2: Adaptation Strategies in Wetland Plants: Links between Ecology and Physiology. Proceedings of a Workshop || The Lichen Symbiosisby V. Ahmadjian

Bookreviews 167

analysis and chromosomal changes to explain reproductive isolation that exists in the hybrid zone between Torresian and Moreton samples of Caledia captiva.

In the case study of hybrid zones between red- and yellow-schafted flickers (Colaptes auratus), one of the most abundant birds in North America, Moore and Price illustrate how selection and the genetic system interact to maintain the integrity of the taxonomic units in the hybrid zones. Using evidence from the hybrid zone, the evolution and mode of initial divergence - parapatric or allopatric - in neotropical Heliconius color pattern races are discussed in Chapter 9 (Mallet). To clarify the structure of hybrid zones where Bombina bombina and B. variegata meet, several transects in central Europe were investigated in detail by Szymura, using molecular methods such as allozyme and mitochondrial DNA analysis.

Patton in his review has concentrated on the issues of hybridization and hybrid zones in pocket gophers (Rodentia, Geomyidae) to elucidate the species boundaries between geographically differentiated units (be these recognized at various taxonomic levels). The report by Searle "Chromosomal hybrid zones in Eutherian Mammals" starts with excellent description of numerous types of chromosomal variants. Showing the various types of karyotypic variation in hybrid zones of examined small mammals, Searle discusses several important topics such as staggered hybrid zones and radiation, and chromosomal hybrid zones as genetic barriers or speciation and chromosomal evolution.

This book gives a comprehensive overview of the interesting field of hybridization and its taxonomic, ecological and evolutionary implications. It presents good examples from hybrid zone research both in plants and animals. It can be highly recommended to all with an interest in the various fields of hybridization and introgression and should be in all zoological and botanical libraries.

Jitka 6t6pAnkova

V. Ahmadjian: THE LICHEN SYMBIOSIS; John Wiley & Sons, Inc., New York, 1993, 250 pp. Price GBP 58.-, ISBN 0-471-57885-1

Lichen symbiosis, revealed in 1869 by Schwendener, still remains an enigmatic aspect of life. Vernon Ahmadjian devoted many years of research to the interactions of alga and fungus in a lichen thallus. A great achievement was the artificial resynthesis of Cladonia cristatella (an excellent colour photograph is in the frontispiece). In 1967 Ahmadjian summarized existing knowledge and especially his own experience in an earlier version of The Lichen Symbiosis, which stimulated research into cultivation of lichen bionts. Recently a resynthesis of cyanolichens has been achieved with soil cultures and thallus fragments. Likewise, environmental experiments have yielded interesting and valuable data. Progress in physiology, ontogenesis and molecular biology concerning lichen symbiosis is well documented and summarized in a new book with the same title.

The introductory chapter gives the basic facts on the nature of lichens and discusses the definition of a lichen. The next two chapters are devoted to the ultrastructure and physiology of both individual symbionts, mycobiont and photobiont. Special attention is focussed on the isolation and growth of the mycobiont in culture and on problems of taxonomy and other controversial aspects of Trebouxia, the most common lichen photobiont. The following three chapters are the core of the book, dealing with the interactions of the symbionts. Artificial synthesis is the key to a better understanding of lichen symbiosis. The substantial phases of artificial resynthesis studies are summarized: recognition between bionts, their specificity and selectivity, early thallus development and fruiting of the mycobiont. Special attention is paid to the chemistry and ultrastructure of synthetic lichens. Physiological interrelationships and carbohydrate movement are fundamental aspects of lichen symbiosis, but are not yet completely understood. However, it appears obvious that the bionts have co-evolved a sophisticated system of nutrient exchange and movement that involves feedback controls and adaptive responses to specific habitats. Physiological buffering is a concept which explains the survival of lichens under environmental stress and the carbohydrate pool plays an important role in the effects of drying-and-wetting cycles. The factors influencing growth and nitrogen fixation are also discussed. Another special feature of lichens is their sensitivity to air pollution which started a boom of bioindication studies two decades ago and consequently. Lichen sensitivity studies and the effects of various pollutants are reviewed. The last chapter is devoted to molecular

This content downloaded from 195.78.108.147 on Tue, 17 Jun 2014 04:18:27 AMAll use subject to JSTOR Terms and Conditions

Page 3: Adaptation Strategies in Wetland Plants: Links between Ecology and Physiology. Proceedings of a Workshop || The Lichen Symbiosisby V. Ahmadjian

168 Bookreviews

biology and genetics, which now offer new insights into lichen symbiosis research. A review of isolation and culture methods is appended.

Ahmadjian's new book is a comprehensive review of all aspects of lichen symbiosis. It is not only a collection of facts but the author also raises many questions which have not yet been answered. The exhaustive literature list is most valuable (almost one quarter of the book !) including over 1000 references mostly published after the first edition; they provide a guide-line for future study.

Jiri Liika

A.S. Szab6: RADIOECOLOGY AND ENVIRONMENTAL PROTECTION; Akademiai Kiad6, Budapest, 1993, 258 pp., 36 Figs. Price USD 32.-, ISBN 963-05-6311-8

Radioecology, like ecotoxicology, is a part of a branch of science dealing with the transport of substances within ecosystems. To manage biogeochemical cycles requires a high standard of relevant knowledge. This has evoked an explosive increase in "deposition studies" during the last thirty or forty years and a frequent subject of recent investigations into pollution is the process of "self-cleaning" in nature.

In his most important Chapter 2, the author gives a list of the main components of ecosystems and evaluates the effect of different factors influencing either natural or artificial radioactivity. The subjects listed, however, include non-comparable entities: the basic components of the ecosystem, e.g. atmosphere, water, soil, plants and/or animals on the one hand, and the complex process of radionuclide transportation, such as in the food-chain between soil and plant, on the other. It would have been better if he had considered (1) the older (more "classical") approach used in pollution science which is related to the above mentioned ecosystem structures and/or to their response to the impact of pollution, and (2) the more recent approach which concerns rather the functioning of a given natural subsystem as an active entity in the transport of substances. This division is justifiable also on the basis of different methodological backgrounds. What a pity that this chapter - the bulk of the book - does not provide a special section concerning: conclusions for biomonitoring, which is such a frequent topic for regeneration and restoration practices. Nevertheless, I highly appreciate those chapters describing the relationship between the half-life of radionuclides and biological half-lives, between food-production processes and the contamination level, and somatic and genetic radiation damage.

An important part of the book, from the viewpoint of (Central) European collaboration in the field, is the informative chapter on radioecological research and organisations in Hungary. Regional focusses are oriented not only to the Chernobyl accident and the Danube river basin pollution, but also to the overall territorial background of environmental contamination.

The final chapter raises questions rather than provides answers: Are nuclear power plants dangerous to the environment? Can we calculate the biopositive effect of low-level radiation? What do nuclear techniques mean for the future - risk or improvement? The Nuclear Act as a legislative tool states that the application of nuclear energy can be utilized efficiently and economically under specified circumstances. Control of user behaviour is the necessary assumption for any further development of nuclear technology. The book is equipped with a useful Glossary and References containing a substantial number of citations dealing with radioactivity. It is highly recommended for both technologists and biologists concerned with the environment.

Pavel Kova;

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