In current study, the influence of arbuscular mycorrhizal fungi (AMF) on salinity tolerance in terms of root’s reserves remobilization to shoot and its relationship with re-growth ability and ionic status of alfalfa (Medicago sativa L.) plants were investigated. In a pot experiment, a factorial experiment in base of randomized complete blocks design in three replications was carried out. Alfalfa plants (Iranian cultivar-Baghdadi) inoculated with AMF (Funneliformis mosseae) or retained as un-inoculated, were grown in soil and irrigated with three salt concentrations including 1.4 (control), 7 and 12 dS/m. Three harvests were carried out at 10% of flowering stage. AMF inoculation increased the size of root sugars and soluble N pools at harvest time. The shoot biomass production following harvest had a close correlation with nitrogen (N) remobilization from root (r=0.92, P≤0.01). However salinity stress significantly reduced amount and percentage of N remobilization to re-growing shoot but AMF plants exhibited greater amount and percentage of root N pools dedicated to remobilization. AMF inoculation also affected ionic relations of plants as AM+ plants contained greater K+ within both root and shoot organs while Ca2+ and Na+ were affected by AMF only within shoot tissue. AMF plants exhibited higher K+/Na+ within shoot and Ca+2/Na+ within root organs. There was a high positive correlation coefficient between K+/Na+, Ca+2/Na+ ratios and N remobilization from root (respectively, r=0.92, 0.88; P≤0.01). To sum up, ionic status within both root and shoot organs, got more balanced by AMF inoculation so that AMF reduced limitations within both source (root) and sink (re-growing shoot) organs concerning N remobilization to re-growing shoot.
