Possible mechanisms of increasing salt tolerance in lentil plants after pre-exposure to low salt concentration

The main objective of the present study is to test the effect of short preexposure of lentil (Lens culinaris Medik.) plants to low salt concentration on shoot growth, oxidative stress and activity of antioxidant enzymes under high salt stress. To fulfill this objective, lentil plants were pretreated with 10 mM NaCl for 3 days and then they were exposed to high salt concentration of 300 mM for 7 days. After that, shoot growth was evaluated in terms of shoot length, fresh and dry weight. Biochemical changes in terms of oxidative stress and activity of antioxidant enzymes were also assessed in lentil plants. The shoot growth of lentil plants preexposed to low salt concentration was significantly enhanced under high salt stress, whereas it was severely retarded in lentil plants that were directly exposed to high salt stress. Moreover, lipid peroxidation and the accumulation of hydrogen peroxide were highly reduced in the shoot of lentil plants preexposed to low salt concentration. The activity of antioxidant enzymes (catalase and superoxide dismutase) was significantly higher in the shoot of lentil plants preexposed to low salt concentration than those directly exposed to high salt concentration. Overall, the results revealed an enhanced salt tolerance in lentil plants after short exposure to low salt concentration.