Shade-Induced Leaf Senescence in Plants

Leaf senescence is a vital developmental process that involves the orderly breakdown of macromolecules to transfer nutrients from mature leaves to emerging and reproductive organs. This process is essential for a plant's overall fitness. Multiple internal and external factors, such as leaf age, plant hormones, stresses, and light environment, regulate the onset and progression of leaf senescence. When plants grow close to each other or are shaded, it results in significant alterations in light quantity and quality, such as a decrease in photosynthetically active radiation (PAR), a drop in red/far-red light ratios, and a reduction in blue light fluence rate, which triggers premature leaf senescence. Recently, studies have identified various components involved in light, phytohormone, and other signaling pathways that regulate the leaf senescence process in response to shade. This review summarizes the current knowledge on the molecular mechanisms that control leaf senescence induced by shade.

Automated summary

Leaf senescence is a crucial developmental process for plants, involving the breakdown of macromolecules to transfer nutrients. It is regulated by various factors, including leaf age, hormones, stress, and light environment. When plants are shaded, changes in light quantity and quality trigger premature leaf senescence. Recent studies have identified components involved in light and hormone signaling pathways that regulate leaf senescence induced by shade. This review provides an overview of the molecular mechanisms controlling shade-induced leaf senescence.