Projects: Mycorrhizal Diversity
Many important forest trees form associations with mycorrhizal soil fungi that colonize plant roots. Mycorrhizal fungi form non-reproducing filaments (hyphae), within plant root tissue, acquiring carbon from the plant host while generating an extensive network of hyphae outside the root that efficiently exploits soil resources. In exchange for plant carbon, mycorrhizas can enhance plant nutrient acquisition, and increase resistance to pathogens (in particular, root pathogens), and drought stress. This mutualism may be necessary for the success of some native tree species since 90% of the roots of some trees are mycorrhizal. The benefit of mycorrhizas may vary with the fungal species, with some fungal species providing a greater benefit to the individual tree than others. Consequently, it is important to understand factors affecting mycorrhizal diversity in forest soils, since diversity could affect the growth and health of individual trees and overall forest health and productivity.
The natural areas of the Holden Arboretum contain some of the finest examples of mature, intact beech-maple forest in Ohio. We are currently conducting research into the effects of soil physical and chemical properties on the diversity of mycorrhizal fungi in both Bole woods and Stebbins Gulch, which together partly comprise the Holden Natural Areas National Natural Landmark. Our laboratory is using molecular techniques that extract and amplify DNA from environmental samples to identify mycorrhizal fungi on beech trees in these forests. We are also using DNA-based techniques to determine the diversity and relative abundance of these important soil fungi.
Left Column: Mushrooms of Holden Forests. Mushrooms are the reproductive structures of fungi, including ectomycorrhizal fungi that colonize tree roots. From top: the genus Russula, Boletus, and Chanterellus.
Right Column: Typical ectomycorrhizal fungi of beech trees found within the Holden Arboretum natural areas. These are photos of beech tree roots, and each morphological type is indicative of the presence of a different mycorrhizal species.
