INFLUENCE OF SEED TREATMENT WITH UV-C ON SALINE STRESS TOLERANCE IN GREEN BEANS (Phaseolus vulgaris L.)

Abstract

In the present investigation, germinated green bean seeds were exposed to UV-C (254 nm) for periods of 7, 15, 30 and 60 min, then grown plants were subjected to saline stress (50 mM NaCl) as a challenge. Tolerance to saline stress was evaluated by determination of fresh weight and dry weight of both shoots and roots. Also, biochemical changes associated with UV-C induced resistance were investigated by determination of lipid peroxidation, proline concentration and antioxidant enzymes activities (SOD, CAT, G-POD and APX) in leaves and roots. Results showed that plants grown from UV treated seeds were less affected by saline stress which was obvious in increased fresh and dry weights of shoots and roots as compared with control. However, MDA showed higher levels in leaves and roots of plants grown from UV treated seeds. Also, UV seed treatments led to significant increases in proline concentration in leaves and roots of grown plants under saline or non saline conditions which contributed to protection from osmotic shock. Antioxidant enzymes (SOD, CAT, G-POD and APX) exhibited higher activities in leaves and roots of plants grown from UV treated seeds. Such effect was more pronounced in roots than leaves. Generally, it could be concluded that treatment of green bean seeds with UV-C induced plant tolerance to saline stress via activation of antioxidant system.