Leaf senescence constitutes the final stage of leaf development and is critical for plants' fitness as nutrient relocation from leaves to reproducing seeds is achieved through this process. Leaf senescence involves a coordinated action at the cellular, tissue, organ, and organism levels under the control of a highly regulated genetic program. Major breakthroughs in the molecular understanding of leaf senescence were achieved through characterization of various senescence mutants and senescence-associated genes, which revealed the nature of regulatory factors and a highly complex molecular regulatory network underlying leaf senescence. The genetically identified regulatory factors include transcription regulators, receptors and signaling components for hormones and stress responses, and regulators of metabolism. Key issues still need to be elucidated, including cellular-level analysis of senescence-associated cell death, the mechanism of coordination among cellular-, organ-, and organism-level senescence, the integration mechanism of various senescence-affecting signals, and the nature and control of leaf age.

中文翻译：

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叶片衰老

叶子衰老构成了叶子发育的最后阶段，对植物的健康至关重要，因为通过这个过程实现了从叶子到繁殖种子的营养重新分配。叶片衰老涉及在高度调控的遗传程序控制下在细胞、组织、器官和生物体水平上的协调作用。通过对各种衰老突变体和衰老相关基因的表征，在叶片衰老的分子理解方面取得了重大突破，揭示了调节因子的性质和叶片衰老背后的高度复杂的分子调节网络。遗传鉴定的调节因子包括转录调节因子、激素和应激反应的受体和信号成分，以及代谢调节因子。