mycorrhizal presentation, megan mclin, hubbard brook reu talks
TRANSCRIPT
The effect of nitrogen on mycorrhizal colonization associated
with Populus grandidentata
Megan McLinBartlett Experimental ForestMELNHE Project
Bartlett, NH
The MELHNE project-studying N and P acquisition and limitation through a
series of nutrient manipulations in northern hardwood forests
Mycorrhizal Fungi
Background: Mycorrhiza the root fungus
• Symbiotic Fungi
• Crucial link between root system and
soil
• Creates surface area
• Releases enzymes in soil to
to break down nutrientsEgli, S.; Brunner, I. (2011): Mykorrhiza. Eine faszinierende Lebensgemeinschaft im Wald. 3. Aufl. Merkbl. Prax. 35 8 S
Nitrogen Deposition
Nitrogen Deposition: Questions?
• Will nitrogen exceed the nutritional needs of the ecosystem causing a decrease in mycorrhizal abundance?
• Studies have shown that ecosystems have been susceptible to decline in response to nitrogen deposition. (Bevege, 102)
Arbuscular vs Ecto Mycorrhizae
Arbuscular vs Ecto Mycorrhizae
• Ecto can be seen within the naked eye or dissecting microscope 10x-50x magnification
• Arbuscular can be seen with high magnification 200x magnification
• In spite of their profound morphological and taxonomic differences,some of the effects of AM fungi and ECM fungi on host physiology are similar (Tinker, Jones & Durall,1992).
Bigtooth Aspen
Methods
• Mycorrhizal colonization will be measured by directly
collecting Populus grandidentata roots. Both AM and
EM mycorrhizal colonization will be quantified on each
root with a microscope and staining techniques.
Field Methods
• The collection of the roots came from nitrogen plot.
• Three treatment trees and three control trees were sampled
• Control trees were sampled outside buffer and also on same slope
• Organic horizon depth was used to root trace
Field Methods cont.
• Tree DBH was taken for trees as well as nearby neighbors
• Four Cardinal directions for root tracing
• Tree roots were placed in corresponding test tubes
Lab Methods: Ectomycorrhizal
• Roots were separated from soil.
• Cut into 5 mm sections
• Examined under dissecting microscope
• The portion of ectomycorrhizal root tips were calculated
Lab Methods: Ectomycorrhizal
Gridline intersect method(Figure 4.5A in Brundrett et al. 1996).
Lab Methods: Arbuscular
Figure 4.4B in Brundrett et al. 1996).
Figure 4.4B in Brundrett et al. 1996).
Results
Data
Control Ecto Quantifying
Treatment Ecto Quantifying
Data cont.
Conclusion
• Nitrogen decreases mycorrhizal colonization
• Control showed more mycorrhizal activity
• Treatment trees showed more DSE hyphae
• Different staining technique
Future Work
• Continue work with senior thesis
• Molecular work
• Trying different staining techniques
Cited sourcesBevege DI. 1968. A rapid technique for
clearing tannins and staining intact roots
for detection of mycorrhizas caused by
Endogone spp. and some records of
infection in Australasian plants.
Transactions of the British Mycological
Society 51: 808- 810.
Cripps, C. L. 2001. Mycorrhizae of Aspen
Forests: ecology and potential
application. In: Sustaining Aspen in
Western Landscapes: Proceedings of the
Symposium on Western Aspen Forests,
Grand Junction, CO, June 2000. pp. 285-
298.
Acknowledgments
The Shoestring crew
Ruth Yanai
Craig See
Adam Wild
Franklin Diggs
Tougaloo College