Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Int J Mol Sci. 2022 Feb 10;23(4):1952. doi: 10.3390/ijms23041952.
Tomato flower abscission is a critical agronomic problem directly affecting yield. It often occurs in greenhouses in winter, with the weak light or hazy weather leading to insufficient photosynthates. The importance of carbohydrate availability in flower retention has been illustrated, while relatively little is understood concerning the mechanism of carbohydrate regulation on flower abscission. In the present study, we analyzed the responding pattern of nonstructural carbohydrates (NSC, including total soluble sugars and starch) and the potential sugar signal pathway involved in abscission regulation in tomato flowers under shading condition, and their correlations with flower abscission rate and abscission-related hormones. The results showed that, when plants suffer from short-term photosynthesis deficiency, starch degradation in flower organs acts as a self-protection mechanism, providing a carbon source for flower growth and temporarily alleviating the impact on flower development. Trehalose 6-phosphate (T6P) and sucrose non-fermenting-like kinase (SnRK1) signaling seems to be involved in adapting the metabolism to sugar starvation stress through regulating starch remobilization and crosstalk with IAA, ABA, and ethylene in flowers. However, a continuous limitation of assimilating supply imposed starch depletion in flowers, which caused flower abscission.
番茄落花是一个直接影响产量的重要农艺问题。它常在冬季温室中发生，弱光或阴霾天气导致光合作用产物不足。碳水化合物供应在保持花器官中的重要性已得到说明，然而，关于碳水化合物对落花的调控机制，人们的了解相对较少。本研究分析了番茄花在遮荫条件下，非结构性碳水化合物（NSC，包括总可溶性糖和淀粉）的响应模式及可能参与落花调控的糖信号途径，及其与落花率和与落花相关激素的相关性。结果表明，当植物遭受短期光合作用不足时，花器官中的淀粉降解作为一种自我保护机制，为花的生长提供碳源，暂时缓解对花发育的影响。海藻糖-6-磷酸（T6P）和蔗糖非发酵相关激酶（SnRK1）信号似乎通过调节淀粉再利用，并与花中的 IAA、ABA 和乙烯进行互作，来适应糖饥饿胁迫下的代谢。然而，持续的同化供应限制导致花中淀粉耗竭，从而引起花的脱落。
