柑橘新梢生长一段时间后，顶端1-3节会自然脱落，称为"自剪",自剪改变了柑橘枝梢的生长节奏和发育方向。前期研究发现：枳属植物春梢发生自剪的时间与花芽启动分化的时间高度吻合，而柑橘属植物春梢自剪后需要经过一段时间等待，进一步感受低温或干旱才能进入花芽分化。因此，自剪可能是柑橘植物自身扩张或积累的分界信号，是枝梢发育成熟的标致，也是实现营养生长向生殖生长转变的必经步骤。本项目拟以早实枳和甜橙为材料，在各种外源激素、低温和不同光周期处理条件下与自然条件相比较，分析两种春梢自剪过程中内源激素等生理指标的变化，利用TUNEL技术检测枝条近顶端离层区域细胞凋亡情况，并通过转录组测序比较两类柑橘植物在自剪前后基因表达动态变化，在人工控制条件下研究自剪后养分积累及其与成花和生长发育转变的关系，以探索柑橘春梢自剪发生的内在机理，揭示植物生长节律与环境变化的响应关系和进一步调控发育转变的分子机制。

Citrus new shoots growth after a period of time, citrus shoot tips abscise at an anatomically distinct abscission zone that separates the shoot apical meristem into basal and apical portions, and this physiological phenomenon is called self-pruning in citrus, citrus self-pruning changed the direction of growth and development rhythm citrus of new shoots. Previous studies indicated that the time of trifoliate orange spring shoots self-pruning in consistent with flower bud differentiation time, while the sweet orange spring shoots need to a period of time to wait after self-pruning and further feel cold or drought can enter flower bud differentiation. Therefore, self-pruning may be a signal for the expansion of the plant or accumulation or shoot maturation, but also to achieve vegetative growth to reproductive growth changes necessary step. The project planted to analyzed the change of endogenous hormones other physiological indicators used precocious trifoliate orange and sweet orange as materials under different exogenous hormones, low temperature and photoperiod treatment conditions compared with natural conditions compared during spring shoots self-pruning process, detect the hallmarks of programmed cell death used TUNEL experiments and a histochemical staining assay; compare of the dynamic gene expression changes between precocious trifoliate orange and sweet orange by transcriptome sequencing; investigative the relationship flower bud differentiation and nutrient accumulation under controlled conditions. This purpose is to explore the internal mechanism of citrus spring shoots self-pruning, revealing plant growth rhythms and response to environmental change relationships and further changes in the molecular mechanisms regulating development.