Mycorrhizas influence functional traits of two tallgrass prairie species

Over the past decade, functional traits that influence plant performance and thus, population, community, and ecosystem biology have garnered increasing attention. Generally lacking, however, has been consideration of how ubiquitous arbuscular mycorrhizas influence plant allometric and stoichiometric functional traits. We assessed how plant dependence on and responsiveness to mycorrhizas influence plant functional traits of a warm-season, C4 grass, Andropogon gerardii Vitman, and the contrasting, cool-season, C3 grass, Elymus canadensis L. We grew both host species with and without inoculation with mycorrhizal fungi, across a broad gradient of soil phosphorus availabilities. Both host species were facultatively mycotrophic, able to grow without mycorrhizas at high soil phosphorus availability. A. gerardii was most dependent upon mycorrhizas and E. canadensis was weakly dependent, but highly responsive to mycorrhizas. The high dependence of A. gerardii on mycorrhizas resulted in higher t...