Response of Pea Leaves Antioxidant System to Soil Water in Filling Stage

A pot experiment was conducted to investigate the response of pea(Pisum sativum Linn.) leaves antioxidant system to soil water in filling stage.Effect of different degree and duration drought stress and rewater under simulated conditions on the protective enzymes-superoxide dismutase(SOD),catalase(CAT) and peroxidase(POD) activity,the cell materials-soluble protein,proline,soluble sugar and malonaldehyde(MDA) content,as well as plasma membrane permeability(RC) were determined.The antioxidant ability of pea leaves was also comprehensively evaluated.Results showed that drought stress declined SOD activity and soluble protein content,increased POD and CAT activity as well as proline,MAD and soluble sugar content,improved RC.And the decrease/increase rate was more significant with increasing stress intensity and time.Rewater produced partial and equal compensation to protective enzymes,cell materials,MDA and RC changes caused by drought stress,and the compensation was more remarkable with rewater time.Total antioxidant ability of pea leaves enhanced under drought stress,and the trend had continued during rewater after 5 d stress,while for the 10 d drought stress treatment,the antioxidant ability presented decreasing trend at the time when rewater for 10 d.Consequently,moderate wetting-dry alternative irrigation was helpful for keeping stronger antioxidant ability,preventing from earlier senescence and obtaining higher yield.