Abstract: Dual infection of host plants by Epichlo endophytes and AMF occurs in natural and agricultural ecosystems. Previous studies have focused largely on the effects of endophytes and a single artificial inoculation of AMF on the growth of hosts. However, few studies have investigated the interactive effects between endophytes and AMF on host grasses in natural habitats. In this study, we used benomyl, a specific inhibitor of AMF, manipulating AMF presence or not, to determine the effects of endophytes and/or AMF on the growth of Leymus chinensis. We conducted a pot experiment under two endophyte infection statuses (endophyteinfected, E+; endophytefree, E) and three benomyl addition levels (B0, control; B1, 0.6 g·L^-1 benomyl; B2, 1.2 g·L^-1 benomyl), using L. chinensis as a model. The results showed that endophyte infection significantly increased AMF colonization rate and spore density, and significantly increased tiller numbers, fresh leaf numbers, shoot and root biomass of L. chinensis. The colonization rate and spore density of AMF were significantly reduced by benomyl, especially under the B2 treatment, and the growth advantage of E+ relative to EL. chinensis disappeared under the B2 treatment.

Key words: Epichlo endophytes, arbuscular mycorrhizal fungi (AMF), benomyl, Leymus chinensis, growth.