Effects of interaction of Epichloë gansuensis and arbuscular mycorrhizal fungi on the seedling growth and cadmium (Cd) tolerance of Achnatherum inebrians

The present study was conducted to measure the colonization rate of arbuscular mycorrhizal (AM) fungi under different growth conditions and to analyze the effects of interaction between Epichloë gansuensis, AM fungi, and Cd²⁺ on the growth of Achnatherum inebrians seedlings. The results indicated that colonization rate of AM fungi increased first and then decreased with the increase of Cd²⁺ concentration. AM fungi colonization rate of endophyte-infected (EI) A. inebrians was significantly (P < 0.05) higher than that of endophyte-free (EF) A. inebrians under a high concentration (0.9 mmol·L^–1) Cd²⁺. However, the interaction of Cd and E. gansuensis had no significant (P > 0.05) effect on AM fungi colonization rate. Low Cd²⁺ concentration (0.3 mmol·L^–1) significantly (P < 0.05) promoted plant growth, whereas high Cd²⁺ concentration (0.9 mmol·L^–1) significantly (P < 0.05) inhibited plant growth. E. gansuensis significantly (P < 0.05) alleviated the damage to host plants under a high Cd²⁺ concentration (0.9 mmol·L^–1). AM fungi significantly (P < 0.05) promoted aboveground growth but significantly (P < 0.05) inhibited belowground growth. The interaction of the three factors significantly (P < 0.05) promoted chlorophyll content and aboveground fresh weight, but significantly inhibited root length (P < 0.05). These results showed that both E. gansuensis and Cd²⁺ affected AM fungi colonization rate, but there was no interaction between them, and the interaction between these three factors affected the growth of A. inebrians seedlings aboveground and belowground.