Comparative studies on antioxidant enzyme action and ion accumulation in soybean cultivars under salinity stress

Plant biomass, antioxidant enzymes activity, ions accumulation and proline level in four soybean cultivars were investigated atdifferent NaCl concentrations (20, 40, 60, 80 and 100 mM) applied to plants 15 days after sowing. There was a significant decrease in plant biomass and soluble protein content with each NaCl treatment. Accumulation of Na+ and Cl- was maximum in roots, followed by the stem and leaves in all the treated cultivars; Pusa 9712 being the top accumulator. On the contrary, K+ and Ca2+ ion concentrations were inhibited in all the treated cultivars. Activities of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase and glutathione reductase) and proline content increased significantly in all the cultivars with each NaCl treatment. The maximum increase was found in Pusa 9712. However, catalase activity decreased in all the cultivars except in Pusa 9712. On the whole, Pusa 9712 was most efficient in managing protection against salinity stress.