Abstract:Under the condition of lack of magnesium,effects of magnesium supplementation on reactive oxygen content and protective enzyme activity of magnesium deficiency grape leaves were studied in order to provide reference basis for formulating rational fertilization technique of grape.A field experiment with a split plot design was conducted,four soil gradients of 0,112.5,150,187.5 kg/hm2 were set up in the main area,three concentrations of foliar spraying,which was 0%,0.2%,0.4%,respectively,were set up in the deputy district.The results showed that:when the grapes had magnesium deficiency,ultra oxygen anion producing rate was accelerated,hydrogen peroxide content and superoxide dismutase (SOD) activity were increased,peroxidase and catalase activity significantly were reduced,leaf proline and malondialdehyde content increased,biological membrane was injured.Moderate amount of magnesium application through soil or spraying on the leaf decreased the reactive oxygen production rate,and increased protective enzyme peroxidase and catalase activity,reduced the product of membrane lipid peroxide malondialdehyde content,alleviated the injury degree of biological membrane and leaf senescence,but when the amount was too large,the yield was decreased.With 150 kg/hm2 soil application and foliar spraying 0.4% magnesium sulfate fertilizer at the same time,the ultra oxygen anion producing rate,hydrogen peroxide content and membranous peroxide malondialdehyde content are all low,while the yield is high,which indicated it is the best magnesium supplement measure in this experiment condition.