Relation between sugar accumulation and sucrose-metabolizing enzymes in fruit of ‘Lingwuchangzao'(Zizyphus jujuba Mill.)

【Objective】The aim of the paper was to study the relationship between the sugar accumulation and its metabolizing enzymes in development fruit. 【Method】 ‘Lingwuchangzao'(Zizyphus jujuba Mill.) was uses as materials to investigate the dynamic growth index of fruit,the content of glucose,fructose,sucrose, starch and the activities of sucrose metabolism-related enzymes. 【Result】(1)The fruit growth was ‘double S' curve,and the fruit mainly accumulated glucose and fructose at the early stage,sucrose was accumulated rapidly in late period,and the mature fruit mainly accumulated sucrose.(2)The neutral invertase(NI) activity was low in the whole growth development period of fruit,the acid invertase(AI) activity was high at the early stage but dropped rapidly with the fruit development until the fruit matured. The activity of sucrose phosphate synthase(SPS) was on the decrease which started high and ended low,the sucrose synthase(SS) activity in decomposition direction was higher than that in the synthetic direction at the early stage, the sucrose synthase(SS) activity in synthetic direction was chief in late period,and the sucrose synthase activity in the decomposition direction(SSd) reduced but increased gradually in the sucrose synthesis direction(SSs) with fruit development.(3)The AI, NI and SS partook together the catabolism of sucrose at the early stage of fruit development,while the sucrose synthase(SS) in the synthetic direction and sucrose phosphate synthase(SPS) are chief enzymes which catalyzed synthesizing sucrose in the fruit development late period.【Conclusion】The sucrose synthase(SS) in the synthetic direction plays the important regulative role in sugar metabolism in fruit of Zizyphus jujuba Mill. ‘Lingwuchangzao'.