Cumulative effect of nitrogen and sulphur on Brassica juncea L. genotypes under NaCl stress

In the present study, N and S assimilation, antioxidant enzymes activity, and yield were studied in N and S-treated plants of Brassica juncea (L.) Czern. & Coss. (cvs. Chuutki and Radha) under salt stress. The treatments were given as follows: (1) NaCl90 mM+N0S0 mg kg(-1) sand (control), (2) NaCl90 mM+N60S0 mg kg(-1) sand, (3) NaCl90 mM+N60S20 mg kg(-1) sand, (4) NaCl90 mM+N60S40 mg kg(-1) sand, and (5) NaCl90 mM+N60S60 mg kg(-1) sand. The combined application of N (60 mg kg(-1) sand) and S (40 mg kg(-1) sand) proved beneficial in alleviating the adverse effect of salt stress on growth attributes (shoot length plant(-1), fresh weight plant(-1), dry weight plant(-1), and area leaf(-1)), physio-biochemical parameters (carbonic anhydrase activity, total chlorophyll, adenosine triphosphate-sulphurylase activity, leaf N, K and Na content, K/Na ratio, activity of nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase, catalase, superoxide dismutase, ascorbate peroxidase and glutathione reductase, and content of glutathione and ascorbate), and yield attributes (pods plant(-1), seeds pod(-1), and seed yield plant(-1)). Therefore, it is concluded that combined application of N and S induced the physiological and biochemical mechanisms of Brassica. The stimulation of antioxidant enzymes activity and its synergy with N and S assimilation may be one of the important mechanisms that help the plants to tolerate the salinity stress and resulted in an improved yield.