Seed treatment with ascorbic acid and proline improved salt tolerance in tomato (Solanum lycopersicum L. cv. Roma) by enhancing antioxidant enzyme activity

Salt stress has an inhibitory effect on the physiological as well as biochemical parameters during seedling development. In the present investigation, seeds of tomato (Solanum lycopersicum L. cv. Roma) were given different seed treatments (hydration; different concentrations of ascorbic acid and proline) and subjected to varying levels of salt stress (25 mM, 50 mM, and 75 mM NaCl concentrations). Physiological and biochemical parameters were done from the 14 days old seedlings after germination. Seed soaking with water, (5 mM and 10 mM) proline, and (1 mM and 4 mM) ascorbic acid improved the physiological parameters (percent germination and seedling growth) as well as biochemical parameters (sugars, proteins, and antioxidant enzymatic activities) of seedlings of treated seeds as compared to control. Results indicated that 10 mM proline and 4 mM ascorbic acid were more effective in mitigating salt stress at different salinity levels.