Ameliorative effects of proline on salt stress-induced lipid peroxidation in cell lines of groundnut (Arachis hypogaea L.)

Cell lines of a salt-sensitive cultivar of groundnut (Arachis hypogaea L. cv. JL24) were selected on media amended with high NaCl concentrations. Comparative analyses of the water status and ionic relations of salt-sensitive and salt-tolerant cell lines showed a decrease in the water potential (ψ w) and solute potential (ψ π) with increases in salt stress. However, the maintenance of cellular turgor indicated active osmotic adjustments in response to salinity stress. In addition to the extrusion of Na⁺ in the NaCl-selected cell lines, a significant accumulation of proline was observed, which was probably associated with osmotic adjustments and the protection of membrane integrity. The addition of proline to the culture medium alleviated the salt stress-induced decline in fresh weight accumulation and reduced peroxidative damage to the lipid membranes, both in a concentration-dependent manner.