cv. Merrillii is a well-known nut in South China with high nutritional value. Severe premature seed abscission limits the industrial development of by causing serious economic losses. However, the physiological mechanisms of seed abscission in remain poorly understood. To gain insight into the relationships between carbohydrate status and seed abscission, three-year-old seed-bearing branches were taken as representative materials for the entire tree. Furthermore, the time course of changes in the photosynthetic rate and the non-structural carbohydrate (NSC) dynamics were monitored in the main sources (the one-year-old and two-year-old shoots), and the dry weight and NSC levels of sinks (the seeds, current female cone cluster, and current vegetative cluster) across all seed development stages were recorded. The cumulative seed abscission rate significantly increased, reaching 91.5% from 0 to 72 days after seed protrusion time (SPT). NSC levels in the main sources significantly decreased by 56%–79%, accompanied by a significantly increased photosynthesis rate of 17.1%–49.1% during that period and increased NSC levels in the three sinks. The gene expression level of cell wall invertase () was significantly correlated with sucrose, fructose, and glucose levels. The carbon storage capacity of the main sources significantly decreased from 6.03 to 3.14 mmol C · d, with a stable photosynthetic capacity, from 0 to 72 days after SPT, whereas the carbon demand of the three sinks showed a continuously increasing trend from 3.14 to 7.71 mmol C · d. In addition, sucrose supplementation significantly decreased the cumulative seed abscission rate. These results suggest that storage carbohydrates play a major role in the regulatory mechanism of seed abscission in . Our study provides a theoretical basis for improving yield through establishing a better carbon balance between sources and sinks using timely fertilization or proper pruning procedures.

中文翻译：

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储存碳水化合物短缺是香榧种子脱落的主要原因


简历。梅里利是我国南方著名的坚果，营养价值很高。种子过早脱落严重，限制了产业发展，造成严重的经济损失。然而，人们对种子脱落的生理机制仍知之甚少。为了深入了解碳水化合物状态与种子脱落之间的关系，以三年生的结籽枝作为整棵树的代表材料。此外，还监测了主要来源（一年生和两年生芽）的光合速率和非结构碳水化合物（NSC）动态变化的时间过程，以及干重和 NSC 水平记录所有种子发育阶段的库（种子、当前雌性圆锥簇和当前营养簇）。种子突出时间（SPT）后0至72天，累积种子脱落率显着增加，达到91.5%。主要来源中的NSC水平显着下降了56%~79%，同时光合作用率显着增加了17.1%~49.1%，三个库中的NSC水平也有所增加。细胞壁转化酶基因表达水平与蔗糖、果糖和葡萄糖水平显着相关。 SPT后0~72 d，主要源碳储量显着下降，由6.03 mmol C·d下降至3.14 mmol C·d，光合能力稳定，而三个汇的碳需求则呈现持续增加趋势，由3.14~7.71毫摩尔C·d。此外，补充蔗糖显着降低了累积种子脱落率。这些结果表明，储存碳水化合物在种子脱落的调节机制中发挥着重要作用。 我们的研究为通过及时施肥或适当的修剪程序在源和汇之间建立更好的碳平衡来提高产量提供了理论基础。