High atmospheric vapor pressure deficit (VPD) reduces the calcium (Ca) distribution in tomato (Solanum lycopersicum L.) fruits, severely reducing fruit mass. Reducing the VPD or increasing Ca fertilizer is an important measure to improve Ca distribution in fruits. However, the mechanism through which VPD and Ca regulate fruit Ca distribution remains unclear. This study investigated the effects of high and low VPD and Ca levels on Ca distribution and fruit mass based on carbon fixation, water transport dynamics, and pectin and Ca content and identified key differential genes and metabolites through transcriptome and metabolome analyses. The results showed that both reducing VPD under low Ca and increasing Ca under high VPD increased water and Ca transport to fruits. The increased Ca combined with pectin to form Ca pectinate, which effectively stabilized the cell wall and enhanced the fruit mass. Reduced VPD under low Ca increased the distribution of Ca to fruits but decreased the distribution of Ca to leaves. Lower Ca distribution in leaves increased their absorption of other nutrients, such as potassium, magnesium, copper, and zinc, which increased the stomatal size and density, thereby improving plant carbon absorption and assimilation efficiency. However, transcriptomic and metabolomic data indicated that carbohydrates, as important regulatory factors under drought stress, increased significantly under high VPD, thereby reducing the fruit water potential while improving fruit water and Ca absorption. Therefore, the carbon assimilation efficiency, water transport capacity, and differential genes and metabolites regulated Ca distribution. This work provides a theoretical basis for environmental and fertilizer management in greenhouse tomato production.

中文翻译：

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生理学、转录组学和代谢组学揭示了在蒸汽压不足和钙肥增加的情况下番茄中钙分布的调节


高大气蒸气压差 （VPD） 降低了番茄 （Solanum lycopersicum L.） 果实中的钙 （Ca） 分布，严重降低了果实质量。降低 VPD 或增加 Ca 肥料是改善 Ca 在水果中分布的重要措施。然而，VPD 和 Ca 调控水果 Ca 分布的机制尚不清楚。本研究基于固碳、水分运输动力学、果胶和 Ca 含量，研究了高低 VPD 和 Ca 水平对 Ca 分布和果实质量的影响，并通过转录组和代谢组分析确定了关键的差异基因和代谢物。结果表明，在低 Ca 下降低 VPD 和在高 VPD 下增加 Ca 都会增加水分和 Ca 向果实的运输。增加的 Ca 与果胶结合形成 Ca 果胶酸盐，有效稳定细胞壁，增强果量。低 Ca 下降低的 VPD 增加了 Ca 在果实中的分布，但减少了 Ca 在叶片中的分布。叶片中较低的 Ca 分布增加了它们对其他营养物质的吸收，如钾、镁、铜和锌，从而增加了气孔的大小和密度，从而提高了植物的碳吸收和同化效率。然而，转录组学和代谢组学数据表明，碳水化合物作为干旱胁迫下的重要调控因子，在高VPD下显著增加，从而降低了果实水分潜力，同时提高了果实水分和Ca的吸收。因此，碳同化效率、水分运输能力以及差异基因和代谢物调节 Ca 的分布。本研究为温室番茄生产中的环境和肥料管理提供了理论依据。