The influence of salinity stress on antioxidant activity in canola cultivars (Brassica napus L.)

The effects of increasing salinity stress on plant growth and antioxidant enzymes in five cultivars of canola (cv. SLM046, Okapi, Fornax, Licord and Elite) were investigated. Salt stress was imposed on 30-days-old cultivars with five different concentrations of NaCl (0, 50, 100, 150 and 200 mM). The shoots of Elite showed greater reduction in fresh weight, dry weight and water content when compared to the other cultivars with increasing salt stress. Under salinity stress, Elite exhibited higher Na:K ratio than the other cultivars. The activities of reactive oxygen species (ROS) scavenging enzymes and reduced glutathione (GSH) concentration were found to be higher in the leaves of SLM046, whereas oxidized glutathione (GSSG) concentration was found to be higher in the leaves of Elite compared to the other cultivars. Our studies on oxidative damage in five canola cultivars showed lower levels of lipid peroxidation and H2O2 concentration in SLM046 under salt stress conditions. High accumulation of proline and glycine betaine under salt stress was also observed in SLM046 when compared to the other cultivars. Our data demonstrate that oxidative stress plays a major role in salt-stressed canola cultivars and SLM046 has efficient antioxidative characteristics which could provide better protection against oxidative damage in leaves under salt-stressed condition.