Effect of Seed Soaking with Spermidine on Tolerance of Wheat (Triticum aestivum L.) Seedlings to Osmotic Stress

The changes in relative dry weight increase rate(RDWIR),leaf relative water content(LRWC),leaf relative electrolyte leakage(LREL)and spermidine content were investigated in seedling leaves of two wheat(Triticum aestivum L.)cultivars,Yumai 18(drought-tolerant)and Yangmai 9(drought-sensitive)under osmotic stress.On the 7th day,after polyethylene glycol(PEG)-6000 treatment,LREL of seedlings of Yangmai 9 increased more significantly than that of Yumai 18,while the Spd content in latter increased more significantly;RDWIR and LRWC of seedlings of Yangmai 9 decreased more significantly than that of Yumai 18.Under osmotic stress,treatment of seed-soaking with Spd resulted in the increases in RDWIR,LRWC and Spd,in concert with an decrease in LREL of seedlings of Yangmai 9.The results suggested that Spd seed-soaking could enhance growth and the tolerance of wheat seedlings,especially of the drought-sensitive cultivar,to osmotic stress,via increasing Spd contents in seedling leaves.