Effects of salicylic acid on wheat salt sensitivity
Salicylic acid (SA), a plant phenolic compound, is now considered as a hormone-like endogenous regulator, and there is a great interest to clarify its role in the defence mechanisms against biotic and abiotic stressors. In this study, investigations on the effects of foliar-applied SA on salt sensitivity, hydrogen peroxide (H2O2) generation and activities of antioxidant enzymes like peroxidase (POX) and catalase (CAT) in plant tissues under salt stress was performed. SA treatment significantly increased the fresh and dry weights in both root and shoots of wheat plants under salt stress. Similarly, POX and CAT activities were also augmented by SA treatment. While the highest POX activity was recorded at SA+120 mM NaCl, CAT activity also exhibited an increase compared to salt treatment without SA. In parallel to increasing antioxidative activity, SA treatment decreased H2O2 content when compared to plants growing under salt stress without SA. The results revealed that salt-induced deleterious effect in wheat seedlings were significantly alleviated by the SA treatment. SA can be used as a signal molecule to investigate plant defense to abiotic stress. After the application of SA, increasing tolerance of wheat seedlings to salt stress may be related to increases in antioxidative enzyme activitiy.
Key words: Wheat, salicylic acid, antioxidative enzyme activities, peroxidase (POX), catalase (CAT), hydrogen peroxide (H2O2) content.