Projects: Plant-Fungal-Bacterial Interactions
Plant photosynthesis creates the conditions for life within forests, especially life within soil. Plants convert solar radiation into energy, in the form of simple and complex sugars and acids. These carbon compounds are used by heterotrophic organisms like animals, fungi and bacteria, to fuel their own growth and metabolism. Carbon compounds enter soil either during leaf fall and degradation, through root death and growth or through the leakage of sugars directly from roots into soil. Rhizosphere organisms metabolize these substances for their growth and reproduction. Root growth, death and carbon transfer to soil is patchy and pulsed in time and space. This creates a mosaic of environmental conditions within which different fungal and bacterial species may thrive. Soil patchiness may be important for maintaining the diversity of soil microbes. Since soil microbes are involved in nutrient cycling and nitrogen-fixation, they have an important role to play in maintaining soil fertility and the health and productivity of forests. How microbial diversity affects soil fertility is not well understood. For example, are more diverse communities of soil microbes associated with or responsible for creating more fertile conditions for forest plants? We are conducting research in forests to explore effect of mycorrhizal fungi on soil bacterial groups involved in important ecological processes such as nitrogen-fixation.
Plants like these beech and maple trees capture the energy of sunlight through photosynthesis and create simple and complex sugars and acids that can be used by other organisms. Carbon enters soil either through leaf fall or root activity.
Mycorrhizal fungi colonize tree roots and produce fungal filaments or hyphae that extensively explore forest soil. These hyphae can change soil environmental conditions, and may also be an important source or carbon and energy for other organisms, ranging from microscopic nematodes to bacteria. How mycorrhizas effect soil bacteria is an important goal of our research.
Nitrogen-fixing bacteria are a potentially important functional group of bacteria in forest soils. Some research has indicated that a close relationship may exist between nitrogen-fixers and mycorrhizal fungi. Our lab is exploring these relationships.
