Changes in growth and antioxidant capacity of canola by salinity and salicylic acid under in vitro

ABSTRACT: The study was conducted to evaluate alterations in growth and antioxidant capacity of salt stressed canola plants in present of salicylic acid (SA). Seeds of Brassica napuscultivar Ocapy were cultured in MS (Murashig and Skoog) medium containing 0, 50 and 100 mMNaCl and different levels of SA (0, 2 and 5 µM) under in vitro condition. After 4 weeks, the effect of salinity and SA treatments were studied on growth and the antioxidant enzymes activity, ascorbate peroxidase (APX) and catalase (CAT), in roots and shoots. The percentage of seed germination was decreased with increase in salt levels. SA significantly increased it under salinity. Shoot length and fresh weight decreased not only under salt and SA treatments but also in response to NaCl and SA interactions, whereas enhancement of root length and fresh weight was presented under salt stress in the absence of SA. Treatment with SA and interaction of NaCl and SA reduced root length. Total anthocyanin content was significantly reduced under salt concentrations and SA in comparison to the control. Salt stress increased significantly reducing sugars in roots, while SA-treated plants exhibited high accumulation of reducing sugars in shoots under salinity. Individual NaCl treatment did not show a significant effect on antioxidant activity (CAT and APX) while the presence of SA decreased CAT activity in root and APX activity in shoot under salt stress.