NaCl-PRIMING MITIGATES OXIDATIVE DAMAGE AND Na+ ACCUMULATION AND ENHANCES SALT TOLERANCE IN SORGHUM PLANTS

Abstract

ABSTRACT:In this study, we tested the hypothesis that priming with NaCl alleviates saltinduced damages by upregulating enzymatic antioxidant system and controlling ionic homeostasis in sorghum plants. After germination, uniform Sorghum bicolor seedlings were primed with NaCl at 0 (control), 10 (P10), 20 (P20) and 30 mM (P30) (pre-treatment), for seven days, and then subjected to 80 mM NaCl-stress. The most striking effects of NaCl-priming were registered in plants from P10-treatment. After five and ten days of salinity, lipid peroxidation and Na + accumulation was found to be drastically improved in roots and shoots; however, the increase was more severe in non-primed stressed plants. The lower oxidative damage in P10-stressed plants positively correlated with higher activity of catalase (CAT), dismutase superoxide (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (G-POD) enzymes under salinity. In general, CAT and SOD were the most responsive enzymes to NaCl priming, while APX and G-POD were responsive only after onset of salinity (five days) and/or in a single plant organ. In conclusion, NaCl priming enhances plant's capacity to retain overaccumulation of Na + , and limit oxidative damage by stimulating effectively antioxidant system. KEYWORDS:Antioxidant enzymes,ionic homeostasis,salt stress. PRÉ-TRATAMENTO COM NaCl MINIMIZA OS DANOS OXIDATIVOS E