[International Journal of Plant Biology 2010; 1:e1] [page 1] Application of salicylic acidincreases contents of nutrientsand antioxidative metabolismin mungbean and alleviatesadverse effects of salinitystress

Salicylic acid (SA), a naturally occurring plant hormone, is an important signal molecule known to have diverse effects on biotic and abi-otic stress tolerance. Its growth-promoting effect on various plants has been shown, but the information on the response of mungbean, an important leguminous plant, to SA application under salt stress is limited. Mungbean (Vigna radiata L.) cultivar Pusa Vishal plants grown with 50 mM NaCl were sprayed with 0.1, 0.5, or 1.0 mM SA and basic physiological processes were studied to substantiate our understanding of their role in tolerance to salinity-induced oxidative stress and how much such processes are induced by SA application. Treatment of plants with 0.5 mM SA resulted in a maximum decrease in the content of Na+, Cl–, H2O2, and thiobarbituric acid reactive substances (TBARS), and electrolyte leakage under saline conditions compared to the control. In contrast, this treatment increased N, P, K, and Ca con-tent, activity of antioxidant enzymes, glu-tathione content, photosynthesis, and yield maximally under nonsaline and saline condi-tions. The application of higher concentration of SA (1.0 mM) either proved inhibitory or was of no additional benefit. It was concluded that 0.5 mM SA alleviates salinity-inhibited photo-synthesis and yield through a decrease in Na+, Cl–, H2O2, and TBARS content, and electrolyte leakage, and an increase in N, P, K, and Ca con-tent, activity of antioxidant enzymes, and glu-tathione content