9318003 McGinley Vesicular-arbuscular mycorrhizal (VAM) fungi form associations with many species of plants. These associations are thought to be mutualistic. Recently, however, the constancy of this putative mutualism has been questioned. This project examines the geographic variation in the costs and benefits of vesicular-arbuscular mycorrhizal associations with little bluestem grass. A full factorial design is used to examine the growth characteristics of grasses and fungi from four geographic regions grown in a common environment. The growth of plants and fungi in all combinations of local fungal and grass races and soil types will be measured. %%% It is important to examine the costs and benefits of VAM fungi-plant associations in more detail than in previous studies. This study is novel in providing information on the geographic basis of variation in the nature of the symbiotic relationship. Results from this research will provide important information on: 1) geographic variation in the importance of the mycorrhizal association, 2) the effect of the variation in mycorrhizal infection and soil characteristics on plant growth and allocation patterns, and 3) the effects of plant characteristics and soil on fungal morphology and reproduction. The results of this research will have potential applications in forestry, agriculture, and conservation biology. *** ! ! ! ! F x x O Times New Roman Symbol & Arial 1 Courier 5 Pitch 1 Courier 10 Pitch " h H eH e 1 Deborah Johnson Deborah Johnson
