Soil Moisture Influences Colonization of Prairie Cordgrass (Spartina Pec Tin Ata Lind.) by Vesicular‐arbuscular Mycorrhizal Fungi

Summary We examined mycorrhizal development in prairie cordgrass (Spartina pectinate Lind.), a mycorrhizal plant that typically occupies wet habitats, under different soil moisture conditions. The five experimentally induced soil moisture conditions ranged from continuous saturation to allowing soil moisture tensions to reach – 15 bars and then saturating the soil 48 h later. Colonization by vesicular‐arbuscular mycorrhizal (VAM) fungi occurred under all experimental conditions but was significantly greater when plants were grown under conditions of 24 h saturation followed by 48 h of drainage than under any other moisture regime. There was a significant negative correlation between VAM fungal colonization and the weight of the rhizome‐tiller units used to propogate experimental plants. Plant growth was not significantly affected by treatment conditions and there were no significant correlations between measured plant growth response and VAM colonization.