Abstract:In this study, Riesling annual nutrition bag cuttings were used as experimental material. We conducted artificial climate chamber hydroponic experiments to investigate the effect of various concentrations EBR (0.05, 0.10 and 0.20 mg/L) pretreatments on active oxygen, antioxidants, antioxidant enzymes activities and osmotic adjustment substance contents in grape (Vitis vinifera L.) seedlings with PEG simulating drought stress, revealing the mechanism of drought resistance of EBR on grape seedlings under drought stress. The results showed that: (1) compared with the growth control in normal, simulating drought stress significantly increased the contents of anion radical (O2-·), hydrogen peroxide (H2O2) and malondialdehyde (MDA) in the leaves of grape seedlings. Compared with the PEG treatment alone, different concentrations of EBR pretreatment could reduce the contents of O2-·, H2O2 and MDA in leaves. (2) Compared with the growth control in normal, the contents of ascorbic acid (AsA) and reduced glutathione (GSH) were significantly reduced in PEGtreated seedlings. Compared with PEG treatment, EBR pretreatment significantly increased AsA and GSH contents in grape leaves, and 0.10 mg/L EBR treatment was the best. (3) Superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) activities in grape seedling leaves showed a trend of rising first and then decreasing in PEG treatment alone and it remained basically unchanged under normal growth conditions. Moreover, the activities of SOD, CAT, POD and APX in EBR pretreatment were always higher than those in PEG treatment. (4) The contents of proline and soluble protein in PEG treatment alone was higher than that growth control in normal. Different concentrations of EBR pretreatment could significantly increase the contents of proline and soluble protein in grape leaves during middle and late stages of drought stress. It was showed that under drought stress, EBR pretreatments could effectively reduce the excessive accumulation of reactive oxygen species (ROS) and the increase of membrane lipid peroxide level induced by drought stress through improving antioxidant defense system activities and osmotic adjustment substance contents in the leaves of grape seedlings, resulting in improving the drought resistance of wine grape seedlings. Among these, 0.10 mg/L EBR pretreatment got the most remarkable effect.