Black-tip disorder, an ailment in the fruits of the Hupingzao cultivar of jujube trees (Ziziphus jujuba Mill. ‘Hupingzao’), seriously affects the edible quality of the fruits. To characterize the relationship between the disorder and sugar transport capacity, transportation of soluble sugar in the vascular bundles of Hupingzao fruits was analyzed using UPLC and the fluorescence tracing method. Phloem cell viability of the vascular bundles was also analyzed by staining. Results showed that black-tip disorder mainly occurred from the white-ripe period onwards during the development of Hupingzao fruits, and disease spots only appeared in the blossom end of the fruits. There was a significantly higher rate of large disorder fruits than small disorder fruits. The accumulation and transportation rate of soluble sugar in the blossom end of the fruits was significantly lower than that in the shoulder regions from the white-ripe period onwards. At the same developmental stage, the soluble sugar content in the blossom end of disorder fruits was significantly lower than that in the blossom end of healthy fruits. In disorder fruits, the soluble sugar content of large fruits was lower than that of small fruits. In disorder fruits, phloem activity was weaker in large fruits than small fruits. In summary, the ability of the vascular bundles to transport soluble sugar weakened and sugar supply in the blossom end of the fruits was insufficient to sustain health, and this was likely to cause black-tip disorder from the white-ripe period onwards during the development of Hupingzao fruits.

中文翻译：

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枣果实黑尖病与糖分转运及积累的关系

黑尖病是枣树虎平枣品种（Ziziphus jujuba Mill.'Hupingzao'）果实的一种病害，严重影响果实的食用品质。为了表征这种紊乱与糖转运能力之间的关系，使用UPLC和荧光示踪法分析了虎平枣维管束中可溶性糖的转运。还通过染色分析了维管束的韧皮部细胞活力。结果表明，在虎屏枣果实发育过程中，黑尖病主要发生在白熟期以后，病斑仅出现在果实的花端。大杂果率明显高于小杂果率。从白熟期开始，果实开花端可溶性糖的积累和运输速率显着低于肩部区域。在同一发育阶段，无序果实的花端可溶性糖含量显着低于健康果实的花端。在无序果实中，大果实的可溶性糖含量低于小果实。在无序果实中，大果实的韧皮部活性弱于小果实。综上所述，维管束运输可溶性糖的能力减弱，果实开花端的糖供应不足以维持健康，这很可能在发育过程中从白熟期开始造成黑尖病。虎平枣果实。