Abstract: The characteristics of sugar metabolism and accumulation in parthenocarpic white flesh loquat(Eriobotrya japonica Lindl. ‘Ninghai Bai’) fruit induced by 0.5 and 1.0 g·L ^{- 1} GA₃ were studied. The contents of sucrose, glucose, fructose and total sugar in parthenocarpic seedless fruit induced by two concentrations of GA₃ were lower than those in the control loquat fruit, and the reduction in sugar content was increased with GA₃ concentration. The differences of various sugar content between treated and control fruit were significant ( P = 0.05) at full ripe stage. As a result of the application of different concentrations of GA₃, the activities of sucrose metabolizing enzymes ( sucrose synthase, sucrose phosphate synthase and invertase) , hexose metabolizing enzymes (hexokinase and fructokinase) and sorbitol dehydrogenase ( SDH) in GA₃ induced seedless fruit were lower than in the control seeded fruit, and the activities also decreased with the increase of GA₃ concentration. These results indicate that GA₃ induced seedless loquat fruit resulted in lower activities of
sugar metabolizing enzymes, which caused the lower sugar content in seedless loquat.

Key words: Eriobotrya japonica Lindl., GA₃ , Parthenocarpic fruit, Sugar metabolism, Sugar accumulation