Arbuscular mycorrhizal fungi alleviate salt stress in lupine (Lupinus termis Forsik) through modulation of antioxidant defense systems and physiological traits

The present study was carried with the aim to demonstrate and examine the impact of arbuscular mycorrhizal fungi (AMF) on the growth, anti-oxidants metabolism and some key physio-biochemical attributes including the osmotic constituents in Lupinus termis exposed to salt stress. Salt stress (250 mM NaCl) reduced growth, AMF colonisation, relative water content and chlorophyll pigment content. However, AMF ameliorated the negative effect of salinity on these growth parameters. Salt stress increased the activities of key antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD). Inoculation of AMF enhanced the activities of these enzymes and caused an increase in the accumulation of osmotic components resulting in the maintainence of tissue water content. Proline, glycine betaine and sugars increased with salinity stress and AMF inoculation. Plants subjected to salt stress showed considerable variations in the endogenous levels of growth hormones. Reduced lipid peroxidation and increased membrane stability in AMF inoculated plants and enhanced activity of anti-oxidants enzymes confers the role of AMF in assuaging the salt stress induced deleterious effects.