The effect of salicylic acid on physiological and biochemical responses of canola (Brassica napus L.) under salinity

Soil salinity is one of the most important environmental stresses that leads to ionic toxicity and osmotic stress in plants. Salinity especially sodium chloride stress stimulates the generation of reactive oxygen species and induces oxidative stress with peroxidation of membrane lipids. The aim of the present research is the study of salinity stress in canola plants and the role of probable protection of exogenous salicylic acid against sodium chloride salt stress. In this research, the interactive effects of NaCl salinity and salicylic acid (SA) on canola plants were examined. 21-day-old canola plants were exposed to different concentrations of NaCl (0, 75, 150 mM) and SA (0, 0.1 mM) for 10 days. Treatment with salinity decreased the dry weight of roots and shoots and reduced chlorophyll content in leaves, while SA moderated these effects. In NaCl-treated plants, level of lipoxygenase activity and the contents of malondialdehyde and H2O2 increased, as well as changes in the activities of the antioxidant enzymes, catalase, guaiacol peroxidase and superoxide dismutase, in leaves indicated that salinity caused an oxidative stress in canola plants. Adding of SA in the nutrient solution, increased the antioxidant enzymes activities and decreased lipid peroxidation in leaves of NaCl-treated plants. Consequently, SA by an increase in the activities of antioxidant enzymes markedly reduced NaCl salinity induced oxidative damage on canola plants.

کلیدواژه ها:

Salinity Stress ، Salicylic Acid ، Canola ، Antioxidant Enzymes