Improving plant growth and alleviating photosynthetic inhibition from salt stress using AMF in alfalfa seedlings

The effects of arbuscular mycorrhizal fungi Glomus mosseae (+AMF) on the growth, nutrient uptake and leaf photosynthetic characteristics of alfalfa (Medicago sativa) under salt stress were studied. In alfalfa, 100 mM salt stress had no obvious effect on plant growth, nutrient content and photosynthetic capacity, however, 200 mM salt stress significantly inhibited biomass accumulation and NPK uptake. In addition, 200 mM salt stress led to decreased photosynthetic carbon assimilation capacity and lower PSII and PSI activity levels. Cultivation of alfafa with +AMF promoted biomass accumulation and uptake of nutrients, increased its underground growth, and promoted accumulation of P over N and K. +AMF increased PSII and PSI activities in alfalfa leaves under salt stress, and increased the electron transfer ability of PSII donor and acceptor sides. +AMF not only made alfalfa have relatively high stomatal conductance under salt stress, but also significantly enhanced its ability to utilize CO2.