Arbuscular mycorrhizal (Funneliformis mosseae) improves alfalfa (Medicago sativa L.) re-growth ability in saline soil through enhanced nitrogen remobilization and improved nutritional balance

Sa？etak 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