Abstract: The effects of DA-6 at different concentration on leaf photosynthesis and fruit quality were studied in strawberry. The results showed that DA-6 of 10 and 20 mg·L^-1 could increase leaf photosynthetic rate, stormatal conductance, chlorophyll content, Rubisco activity and soluble protein content compared with control. Moreover, 20 mg·L^-1 DA-6 significantly enhanced leaf photosynthetic rate, Rubisco activity and soluble protein content from 7 to 21 days after treatment. However, the results also indicated that 40 mg·L^-1 DA-6 had inhibiting effects on leaf photosynthetic rate, chlorophyll content and Rubisco activity and no significant differences found with control during the whole treatment period. On the other hand, DA-6 applied in different concentrations all increased the quality of strawberry and 20 mg·L^-1 DA-6 showed the remarkable effect. It is concluded that DA-6 applied at appropriate concentration improved photosynthetic ability and finally increased fruit quality and yield.

Key words: strawberry, plant growth regulator, net photosynthetic rate, fruit quality