Roles of Sucrose-metabolizing Enzymes in Sugar Accumulation in Leaves and Carpopodiums of Ziziphus jujuba Mill.cv.Lingwuchangzao Cytochemical Localization and Functional Analysis of ATPase during Fruit Development of Ziziphus jujuba Mill.cv.lingwuchangzao Sugar Accumulation and Related Enzyme Activities in Shielding Light Fruit of Ziziphus jujuba Mill.cv.Lingwuchangzao