Influence of of salycilic acid on antioxidant enzyme system in Brassica napus under salt strees

Salicylic acid (SA) is a naturally produced compound and has been implicated to play important roles in tolerance of plants against diverse biotic and abiotic stresses. Experiments were conducted to study the regulatory role of SA on antioxidant enzyme induction in two salt sensitive (Y3000) and relative salt tolerant (H420) cultivar of canola. The experiment was conducted in Hajiabad country, Qom. The seeds were cultivated as a completely randomized block. SA treatment carried out with 0, 0.5 and 1μM of SA solution in the early morning when the plants fourth leaf completely expanded. The samples were taken at up to120 (vegetative phase) days after germination for analysis. The results revealed that salicylic acid increased peroxidase, polyphnol oxidase and superoxide dismutase activities in Y300 cv. By contrast antioxidant enzymes activities decreased in H420 cv. PAGE gel electrophoresis analysis of antioxidant enzymes revealed that salicylic acid increased peroxidase activity and intensity in Y 300 cv. Poly phenol oxidase activity was unchanged and Cu,/ Zn-SOD was the most abundance isozyme. The activity of this izozyme increased in treated plants. Fe- SOD was observed in Y 300 cv. and Mn-SOD was observed in H420 cv. Therefore ROS involve in different signaling pathway in different compartments of the cell in salt sensitive and relative salt tolerant cultivars. As a result SA increased salt tolerance in salt sensitive cultivar by increasing antioxidant enzyme activity.