Effects of Exogenous H_2O_2 on the Chilling Stress Resistance of Cucumber Seedlings

To study the effects of H2O2 on the chilling stress resistance of cucumber seedlings,this paper made an experiment by spraying different concentrations of H2O2 onto the seedlings and exposing them to 7 ℃ low temperature for 12 h.Results show that under a chilling stress,the seedlings present a sharp increase of electric conductivity and MDA content with an obvious drop of POD activity and soluble protein content;and that contrasted to the control,exogenous H2O2 increases the POD activities and soluble sugar contents of the seedlings and alleviates their cell membrane leakage and membrane lipid peroxidation during the chilling stress and recovery periods.It is clear that exogenous H2O2 enhances the chilling stress resistance of cucumber seedlings,the effect of 10 mmol·L-1 H2O2 being most significant.