Abstract: Seeds of Indian mustard (Brassica juncea L.) Czern & Coss were exposed to 0, 50, 100, 150 mM NaCl for 8 h. and seeds were sown in an earthen pot. These stressed seedlings were subsequently sprayed with 10 礛 salicylic acid (SA) at 30-day stage and were sampled at 60-day to assess the changes in growth, photosynthesis and antioxidant enzymes. The seedlings raised from the seeds treated with NaCl significantly reduced the growth, the activities of carbonic anhydrase and nitrate reductase and photosynythesis and the decrease was proportional to the increase in NaCl concentaration. However, the antioxidant enzymes (catalase, peroxidase and superoxide dismutase) and proline content was enhanced in response to NaCl and/or SA treatment, where their interaction had an additive effect. Moreover, the toxic effects generated by the lower concentration of NaCl (50 mM) were completely overcome by the application of SA. It was, therefore, concluded that SA ameliorated the stress generated by NaCl through the alleviated antioxidant system.

Key words: Carbonic anhydrase, Catalase, Mustard, Net photosynthetic rate, Nitrate reductase