In apples, a bottleneck effect in calcium (Ca) transport within fruit stalk has been observed. To elucidate that how auxin affects Ca forms and distribution in the apple fruit stalk, we investigated the effects of different concentrations of auxin treatment (0, 10, 20, and 30 mg·L−1) on Ca content, forms, distribution, and fruit quality during later stages of fruit expansion. The results showed that auxin treatment led to a dramatic reduction in total Ca content in stalk, while an approximately 30 % increase in fruit. Furthermore, auxin treatment effectively enhanced the functionality of xylem vessels in vascular bundles of the stalk in bagged apples. Finally, TOPSIS method was used to assess fruit quality, with treatments ranked as follows: IAA20 > NAA20 > IAA30 > IAA10 > CK > NPA. The findings lay a foundation for further studies on the bottleneck in Ca transport within stalk, uneven distribution of Ca in fruit, and provide insights into Ca utilization efficiency in bagged apples.

中文翻译：

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优化“红富士”苹果品质：装袋实践中生长素介导的钙通过果茎分布


在苹果中，已经观察到钙 （Ca） 在果茎内运输的瓶颈效应。为了阐明生长素如何影响苹果果茎中 Ca 的形成和分布，我们研究了不同浓度的生长素处理（0、10、20 和 30 mg·L−1） 对果实膨化后期 Ca 含量、形态、分布和果实品质的影响。结果表明，生长素处理导致茎秆中总 Ca 含量显著降低，而果实中约 30% 的增加。此外，生长素处理有效地增强了袋装苹果茎维管束中木质部血管的功能。最后，采用 TOPSIS 方法评价果实品质，处理顺序为： IAA20 > NAA20 > IAA30 > IAA10 > CK > NPA。研究结果为进一步研究 Ca 在茎内运输的瓶颈、Ca 在果实中的分布不均匀奠定了基础，并为袋装苹果中 Ca 的利用效率提供了新的见解。