Effect of Populus alba L.var.pyramidalis Leaves Chlorophyll content and Protective activity under Foliage spray

The test studied law of effect of Populus.alba L.var.pyramidalis leaves chlorophyll content and protective activity under foliage spray and in order to provide a theoretical basis for the best urea concentration in foliage spray.The results showed that:foliage spray can increase the chlorophyll content in Populus.alba L.var.pyramidalis leaves and with the increase of the urea concentration to rised,when the concentration higher than 2.10%significantly higher than the control;POD activity significantly higher than the control when urea concentration higher than 2.10% and other concentrations treatment was no significant difference with control;SOD activity only 2.10%concentrations treatment significantly higher than the control in October,other concentrations treatment was no significant difference with control;PPO activity performanced with the increase of the urea concentration was reduced in July,August to October 2.10%concentrations treatment significantly higher than the control.Comprehensive analysis that foliage spray urea concentration of 2.10%is best.