The Effect of Brassinolide on Chilling Resistance of Watermelon Seedlings under Low Temperature and Poor Light Stress

Watermelon variety 'Liaoyin No.1' were treated at the age of three leaves by spraying brassinolide in the concentration of 0(CK),0.01,0.05,0.10,0.50,1.00 mg/L,and then were stressed under temperature(10±1)℃ and light 100 μmol·m-2·s-1.In order to improve chilling resistance of watermelon seedlings,the physiological and biochemical characteristics of watermelon seedlings were measured to screen a optimum concentration of brassinolide(BR).The results showed that the best seedlings growth was observed under the treatment 0.10 mg/L of BR,which could reduce the chilling injury index significantly,increase the activities of superoxide dismutase(SOD),peroxidase(POD) and catalase(CAT) and reduce the content of malondialdehyde(MDA) and superoxide anion radical.