Effects of Spraying GA₃ in Florescence Period on Yield and Quality of Jun Jujube and Its Residue Analysis

【Objective】 To determine the effect of spraying GA₃ on the yield and quality of Jujube during flowering period, and to evaluate the residual risk GA₃ jujube in mature period. 【Methods】 Taking Junzao as the research object, the effects on yield and quality with different concentrations of G ${{\mathrm{A}}_3}_{}$were studied, and on the basis of screening out the appropriate concentration, the variation of GA₃ content in flowers and fruits at different development stages after GA₃ spraying was studied. A total of 6 treatments were set up for spraying GA₃ during the flowering period: one time, treatment concentrations: 0 (CK), 10, 20, 40, 60和80 mg/L, and three times, treatment concentrations: 40 mg/L (one time every 7 days). Yield and quality were investigated in fruit full red period. The GA₃ content of different treatment concentrations and different stages of development (6 h, 1 d, 3 d, 5 d, 10 d, 15 d, 30 d, 50 d, 80 d, 120 d) were measured by HPLC. 【Results】 After spraying GA₃ one time, the single fruit weight decreased, the fruit shape index and the tensile strength of the fruit handle increased, and the yield increased. As the GA₃ concentration increased, the soluble sugar content of jujube fruit increased first and then decreased, the protein and total acid content decreased first and then increased, and the cellulose content increased gradually. With the development GA₃ content of jujube flower decreased gradually, the GA₃ content of young fruit increased significantly, and the GA₃ content decreased rapidly at the end of fruit expansion period. GA₃ treatment could significantly improve the GA₃ content of jujube flower and fruit. The GA₃ content in the whole red fruit was 0.281,2-0.397,6 higher than that in the control fruit mg/L, but the difference of the residue in 40 times was not significant. 【Conclusion】 The effect of increasing yield was most obvious when the spraying concentration of GA₃ was 40 mg/L at the flowering stage. At the same concentration, it was sprayed for 3 times to further improve the yield and quality, the nutrient quality showed the characteristics of high sugar and low acid. It is suggested that this measure be adopted in the jujube orchard where field water and fertilizer are guaranteed. Spraying GA₃ can improve the GA₃ content level of jujube flowers and fruits in the whole growth period, and the degradation law is basically consistent with the control. Treatment with different concentrations of GA₃ showed that low concentration promoted and high concentration inhibited the synthesis of endogenous GA₃.