Research Impacts

Mycorrhizal Soils and Plant Drought Resistance In most native soils and many cropping situations, plant roots develop a symbiotic relationship with naturally-occurring soil micro-organisms called mycorrhizal fungi. This root/fungus relationship has many agricultural and environmental benefits. The symbiosis preserves and reforms soil structure, and it can remediate contaminants in soils. Often, mycorrhizal plants fare better when confronted by a variety of stresses, including nutrient deficiency, drought, salinity, herbicide carryover, and some diseases. Our work is focused on how the symbiosis improves plant resistance to drought stress. Mycorrhizal fungi send out very large amounts of hyphae into the soil, which help stabilize soils and retard erosion. We have learned that these hyphae can also contribute to increased drought resistance of crops. In testing fungi from different climates, we found that isolates from arid climates not only produced more hyphae in soils than an isolate accustomed to ample water, but the arid isolates actually changed the physiology of their host plants more dramatically in terms of ability to withstand severe leaf dehydration. Such impacts are valuable, as water shortage continues to be the nation's chief environmental limitation of crop productivity. We are also examining the effect of these mycorrhizal symbionts on water quality, of crucial agronomic and ecological concern.