Kobra Mahdavian - Department of Biology, Faculty of Science, Payame Noor University, Tehran ۱۹۳۹۵-۳۶۹۷, Iran

Soil salinity is one of the critical challenges for development of culture area of agricultural crops. In the present study a pot experiment was conducted in factorial based on completely randomized design aimed to investigate the impact of exogenous application of salicylic acid (SA ۰, ۰.۷۵ and ۱.۵ mM) and calcium chloride (CaCl۲ ۰, ۵۰ and ۱۰۰ mM), solely or in combination, on plant growth, photosynthetic pigments (total chlorophyll (Chl), carotenoids, anthocyanin), and some metabolic parameters (reducing sugars, proline, lipid peroxidation and scavenging ability on DPPH (۲,۲-diphenyl-۱-picrylhydrazyl) radical) of red bean exposed to salt stress (۰, ۲۵ and ۷۵ mM NaCl). Results showed that exogenous application of SA or calcium (Ca) alone improved plant performance under NaCl stress. Growth slowed down under salinity. Malondialdehyde (MDA), DPPH radical, anthocyanin, and proline content were increased under salinity stress. However, application of SA and Ca enhanced the growth parameters, improved the Chl, carotenoids, and reducing sugars content, and significantly reduced MDA and DPPH radical in plants. Therefore, induced tolerance to salinity as the result of SA and Ca application may be related to the regulation of antioxidative responses. Furthermore, the beneficial effect of SA and Ca were achieved by applications of ۰.۷۵ mM SA and ۵۰ mM CaCl۲, which are recommended to improve red bean performance under saline conditions. In conclusion, exogenous application of SA and Ca improved salinity stress tolerance through the regulation of antioxidant system.

CaCl۲, photosynthetic pigments, proline, reducing sugars, NaCl