Physiological changes of wheat plants which seed pretreated by salicylic acid under late sowing date

wheat، cv. Alvand، under late sowing condition and comparison with conventional sowing date was investigated in a field experiment in 2009-2010. The factors were seven levels of priming by SA، including control or untreated seeds، 400، 800، 1200، 1600، 2000 and 2400 µM SA and two sowing dates including conventional sowing date (23 October) and late sowing (22 November). Results showed that priming with SA had signifi The effects of seed priming by salicylic acid (SA) on some physiological traits of cant effects on leaf area index، plant dry weight (total، stem، crown، spikelet and leaf)، membrane stability، relative water content، canopy temperature and seed yield. The highest dry weight) total، crown and leaf)، seed yield and the lowest concentration of electrolyte leakage were found in 1200 µM salicylic acid. Application of SA improved plant water status and relative water content and leaf area index. On the other hand، canopy temperature in treated plants was significantly lower than control plants. Reduction in leaf temperature indicates that there is more transpiration and stomatal extension in SA treated plants because of plant water status improvement. Reduction in electrolyte leakage and increment in leaf area and photosynthesis led to increase in biomass and plant dry matter.