effect of salicylic acid priming on some morpho-physiologic characteristics

effects of seed priming by salicylic acid on some morpho-physiologic characteristics and yield of cowpea (vigna unguiculata l.) cultivar “parastou” was investigated under water deficit. experiment was conducted as a split block design with 3 replications in 2008-2009 at research farm of zanjan university. factors were including drought stress as a main factor in 2 levels (irrigation, water deficit at flowering stage) and priming with salicylic acid rates as a sub factor (0, 900, 1800, 2700, 3600μm). analysis of variance showed that irrigation had a significant effect on all characteristic except plant height but effect of salicylic acid was significant on all characteristic. mean comparison showed that relative water content, biomass and seed yield decreased in water deficit condition compared with irrigation condition, whereas proline content and leaf soluble carbohydrate content increased under water deficit. these traits increased in seeds priming with salicylic acid except leaf soluble carbohydrate content compared with untreated seeds. seeds priming with 2700μm salicylic acid had more proline content, so cell structures such as plasma lemma unaffected and increased relative water content. as a result, the resulting plants had better growth and prevented the accumulation of soluble carbohydrates and then increased biomass and seed yield in both irrigation and water deficit conditions. also between these traits with grain yield there was a high correlation that finally to lead that seed priming with 2700 μm salicylic acid have highest seed yield (4424 and 3437kg.ha-1) in regular irrigation and water deficit, respectively).