Effect of exogenous ascorbic acid on wheat tolerance to salinity stress conditions

ABSTRACT

In vitro experiments were performed to determine responses of wheat calli to ascorbic acid [AsA] concentrations [0, 250, 500, 1000 and 2000 ppm] under different levels of sea water [0, 15, 30 and 45%] and to determine suitable concentrations of AsA for exogenous treatments to enhance wheat tolerance to salinity. Results of this study indicated that AsA of [500, 1000 and 2000 ppm] concentrations improved tolerance of wheat calli to salinity. Two pot experiments were conducted during the two successive seasons 2004-2005 and 2005-2006 to determine the effect of exogenous AsA of 0, 500, 1000 and 2000 ppm concentrations at 45 and 75 days after sowing on growth, chemical composition and yield of wheat plants cv. Giza 168 [salt sensitive] irrigated with different levels of sea water [0, 15, 30 and 45%] in comparison with plants of cv. Sids 1 [partially salttolerant]. The obtained results in this study clearly proved the role of AsA in increasing tolerance of wheat plants to salt stress. Exogenous AsA enhanced plant growth, chemical composition and consequently the productivity of wheat plants under salinity stress conditions. These effects may be attributed to the protective role of AsA in plant cells from the oxidative stress induced by salinity. It could be concluded that exogenous AsA of 1000 ppm concentration at 45 and 75 days after sowing is the most effective treatment to increase wheat tolerance to salinity