[Effects of GA, and CPPU on grape fruit adjacent leaf photosynthesis and fruit quality]

Taken the grape cultivar 'Shine Muscat' as the material, the effect of the combination of GA3 and CPPU on the light-response curves in the fruit adjacent leaves and fruit quality were investigated two weeks after blossoming. The results showed that non-rectangular hyperbolic model was more suitable for grape fruit adjacent leaf light response curve-fitting. Pn and g(s) of fruit adjacent leaves among all treatments increased with the increasing light intensity under the combination treat-ments of 25 mg · L(-1) GA3 and 5, 10, 15, 20 mg · L(-1) CPPU, respectively, but Ci decreased. Fruit quality increased with the increasing CPPU concentration under the combination treatments of 25 mg · L(-1) GA3 and 5, 10, 15 mg · L(-1) CPPU, respectively. Grape fruit adjacent leaf photosynthesis under the 25 mg · L(-1) GA3 + 20 mg · L(-1) CPPU treatment was higher than the other treatments. The fruit quality under the 25 mg · L(-1) GA3 + 20 mg · L(-1) CPPU treatment was lower than the 25 mg · L(-1) GA3 + 15 mg · L(-1) CPPU treatment. It indicated that reasonable CPPU treatment concentration could improve fruit adjacent leaf photosynthetic ability and fruit quality. Too high concentration made the fruit quality lower instead. The 25 mg · L(-1) GA3 + 15 mg · L(-1) CPPU treatment was most appropriate in two weeks after blossoming.