Salt-induced stress responses of Brassica (Brassica juncea L.) genotypes

Abstract

The effects of salt stress were evaluated in two Brassica juncea cultivars, Varuna and TM2, in relation to growth, osmolyte accumulation and antioxidant enzymes at 50, 100 and 200 mmol l−1 NaCl concentration. In general, significant reduction in shoot and root growth and relative water content was observed under salt stress.Among the varieties, extent of reduction for these parameters was more pronounced and significant in the case of Varuna than TM2. Significant accumulation of glycine betaine was observed in Varuna and TM2 in 100 and 200 mmol l−1 salt stress treatments than control but the magnitude of increase was significantly higher in TM2. In general, salt stress led to increased activities of Superoxid dismutase, Catalase and Guaiacol peroxidase. The SOD activity was significantly higher in Varuna than TM2. Catalase activity showed an increase up to 100 mmol l−1 NaCl concentration whereas it decreased at 200 mmol l−1 in both the cultivars. Based on the results, TM2 appears to have higher salt tolerance than Varuna. It is also suggestive that osmotic adjustment and antioxidant enzymes play an important role in contributing to salinity tolerance in Brassica juncea L.