|Daniel Sloan - Plant
Wesleyan University, Middletown, CT
Ecology and Specificity of a Local Orchid-Fungal Association
orchids rely on symbiotic associations with fungi (mycorrhizas) to obtain
carbon and soil nutrients. A
16-week project carried out in the Plant
Ecology Lab at the Smithsonian Environmental Research Center (SERC)
investigated the degree of temporal and spatial variation that exists
within the mycorrhizal relationship between Goodyera pubescens, a terrestrial orchid native to SERC property,
and its fungal symbionts. An
experiment conducted in the laboratory showed that orchids are able to
switch their symbionts when exposed to a new fungus, although the process
of switching appears to be an extremely difficult one, significantly
impeding the growth of the orchid. A
study of the populations on SERC property found that plants that were
closer together were more likely to associate with genetically similar
fungi. In addition, all roots
from a single plant and all ramets from a single clone appeared to
associate with genetically identical fungi.
plants in the populations of G.
pubescens at SERC appear to associate with a wide range of fungi
relative to some of the other local terrestrial orchid species, and there
seems to be a relatively large degree of spatial and temporal variation in
their mycorrhizal relationships. Conducting
similar studies on other orchids could help identify which species are
particularly dependent on one very specific type of fungus.
These species would be the most susceptible to slight changes in
fungal communities resulting from climate change and habitat destruction.
Thus, they would be good candidates to be targeted for
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