Study of Foliar Application of Salicylic Acid on some Biochemical Properties of Two Canola Cultivars (Brassica napus L.) under Cold Stress Condition



Cold stress is considered as a restricting factor in plant production. Recently, many different compounds were applied to minimize the harmful effects of stress. In this study, the effects of foliar application of salicylic acid was studied on some biochemical properties of two different cold resistant canola cultivars. Salicylic acid was sprayed at four concentrations (0, 100, 200 and 400 µM) on RGS (Spring canola, sensitive to cold) and LICORD (Winter canola, resistant to cold). Leaf samples were collected after 24 h after spraying. The effects of salicylic acid and cold stress on the quantity of chlorophyll a, b, total chlorophyll, carotenoid, anthocyanin, flavonoids, proline, lipid peroxidation )MDA) and sugar contents in leaves and root of canola plants were investigated. The results showed that under cold conditions chlorophyll a and b, total chlorophyll, carotenoids and sugar contents decreased in sensitive spring canola but lipid peroxidation in leaves of sensitive spring canola significantly increased. Salicylic acid spray significantly increased chlorophyll a, b, total chlorophyll, carotenoid, anthocyanin, flavonoids, proline and sugar contents but decreased significantly MDA content in both cultivars. Salicylic acid increased photosynthetic pigments and sugars along with reduction in peroxidation of lipids indicated damage reduction caused by oxidative stress. In conclusion, salicylic acid in concentrations of lower than 200 µM had a significant role on mitigation of oxidative-stress damage.