Effects of native arbuscular mycorrhizal fungi on the growth and competition of Elymus nutans and Poa crymophila

To study the effect of native arbuscular mycorrhizal fungi (AMF) on the growth and competition of grass species of different sizes, Elymus nutans and Poa crymophila were planted singly, in pairs, or in mixed pairs in an artificial grassland, which simulated non-competition, intraspecies competition, and interspecies competition conditions, respectively, and some of the plantings were inoculated with native AMF. The native AMF successfully colonized the roots of both E. nutans and P. crymophila and significantly improved the biomass, height, and tiller number of both plants. In contrast, the AMF significantly reduced the competitive ability (relative yield, relative yield total, and aggressivity index) of E. nutans, but increased that of P. crymophila. These results demonstrate that, even though AMF can promote the growth of both species in the absence of interspecific competition, it preferentially promotes the growth of P. crymophila under interspecific competition and may differentially contribute to the competitive ability of the two plant species in natural communities. The results also indicate that AMF plays an important role in the regulation of plant interspecific relationships and in the maintenance of community species diversity.