Effect of arbuscular mycorrhizal fungi and phosphorus on growth and physiological properties of alfalfa seedlings under drought stress

Arbuscular mycorrhizal fungi (AMF) are soil microorganisms that play important roles in the ecosystem. AMF have been widely used for drought resistance in plants. The alfalfa cultivar WL 168 was used to examine the effect of AMF and P on plant biomass and plant growth, proline, MDA, and other physiological and biochemical properties under drought stress. The results demonstrated that the change in P concentration had no significant effect on the growth of alfalfa, but the drought resistance of alfalfa could be significantly improved after the use of AMF. Alfalfa growth was best in the presence of sufficient water content (75%~80%). As water content decreased, the biomass and plant height of alfalfa decreased significantly, proline and malondialdehyde content increased, and SOD activity decreased. Inoculation with AMF on alfalfa growth status and related physiological and biochemical indicators were significantly improved. The results of AMF and P treatment showed that the drought resistance of Hogland (KH2PO4: 0.25 mmol·L-1) nutrient solution and AMF was the best, which indicated that, under drought stress, AMF applied at the same time to use a certain level of P can effectively improve the drought resistance of alfalfa.