Effects of AMF inoculation on low-temperature tolerance physiology of Elymus nutans ‘Aba’ roots

In this study, we sought to determine the effects of arbuscular mycorrhizal fungi (AMF) on the low-temperature tolerance of Gramineae grasses using the fungus Glomus intraradices (GI) and grass Elymus nutans ‘Aba’. Pot-based experiments were conducted to investigate the effects of inoculation with GI on the root physiological characteristics of E. nutans ‘Aba’ at low temperature (15 ℃/10 ℃,16 h/8 h, day/night). The results revealed that low temperature had no significant effects on the rate of mycorrhizal infection of E. nutans ‘Aba’. However, low temperature was found to promote increases in the contents of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) and reductions the rate of superoxide anion production (O₂^•−) in the root system of E. nutans ‘Aba’, whereas GI inhibited the accumulation of H₂O₂ and MDA caused by low temperature, although had no significant effects on O₂^•−. Low temperature was also found to enhance the activities of superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX), although caused a reduction in the activity of catalase (CAT). Moreover, the activities of SOD, POD, and APX in the inoculation group (LT-AMF) were significantly lower than those in the non-inoculation group (LT) (P < 0.05). Furthermore, low temperature promoted significant increases in the content of soluble protein (SP) and reductions in the content of betaine (Gb), although had no significant effects on the content of free proline (Pro). Inoculation with GI contributed to a significant reduction in the content of SP, although had no significant effects on the contents of Pro and Gb. In conclusion, by promoting the activities of antioxidant enzymes and reducing the intensity of osmotic stress, inoculation with G. intraradices can enhance the low-temperature tolerance of E. nutans ‘Aba’.