Effects of foliage spraying of phosphorus and potassium fertilizer on leafcolor and physiological properties of Fraxinus

In order to solve the problem of leaf regreening phenomenon of FraxinusLinn in summer and to increase its ornamental value,Fraxinus Linn was used to study pigment contents and leafcolor parameters(L*,a*,b*)and physiological properties by foliage spraying phosphorus and potassium fertilizers.The results showed that:(1)Separate spraying 0.4%,0.8%,1.2% potassium fertilizer and separate spraying 0.5%,1% phosphorus fertilizer could improve Car/Chl and increase leafcolor parameters(L*,b*).Meanwhile,SOD activity and POD activity increased.On the twenty-fifth day,Car/Chl of spraying 0.4%,0.8%,1.2% potassium fertilizer was 2.33%,3.49%,6.98% higher than that of CK and Car/Chl of spraying 0.5%,1% phosphorus fertilizer was 36.36%,39.77% higher than that of CK,respectively.Meanwhile,Car/Chl of spraying 1.2% potassium fertilizer and spraying 0.5%,1% phosphorus fertilizer were significantly(P0.05)higher than that of CK,respectively.(2)The most appropriate potassium and phosphorus fertilizers concentrations were 1.2% and 1%.1% phosphorus fertilizer was better than 1.2% potassium fertilizer.