Leaves are primary plant organs harbouring chloroplasts that enable the sensing of changes in environmental conditions and contribute to maintaining cellular homeostasis. Carotenoids, carotenoid-derived phytohormones and apocarotenoid metabolites facilitate photosynthesis, photoprotection and stress acclimation in leaves. The thylakoids in the chloroplasts from the photosynthetically functional leaves accumulate a specific composition of lutein, β-carotene, violaxanthin, and neoxanthin that act as accessory pigments to chlorophyll and maintain optimal photosynthetic performance. The developmental state of leaves and environmental conditions can affect carotenoid metabolism and, hence, chloroplast functions in leaves. The etioplasts in the cotyledons from the germinating seedlings abundantly accumulate lutein. The light exposure of cotyledons triggers ultrastructural development of chloroplast accumulating all primary foliar carotenoids and chlorophylls. The accumulation of zeaxanthin and antheraxanthin during intense light and high temperature maintains the functional integrity of thylakoid membranes and chloroplasts. Carotenoids are continuously synthesised and degraded in leaves, yet their composition remains tightly maintained. The disintegration of chloroplast, such as during the leaf senescence, ceases the carotenoid biosynthesis and triggers carotenoid degradation. This review sheds light on the fundamental aspects of carotenoid metabolism. The effects of altered light regimes, carbon dioxide (CO2), temperature, drought, and soil nutrient levels are discussed in the context of carotenoid metabolism in leaves. The outstanding questions on how environmental perturbations can alter carotenoid metabolism and chloroplast development in leaves are highlighted. This review provides further insights on how carotenoid regulatory networks could be engineered to enrich carotenoids in the leaves of food and horticultural crops.

中文翻译：

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环境对叶片类胡萝卜素代谢的影响

叶子是包含叶绿体的主要植物器官，能够感知环境条件的变化并有助于维持细胞稳态。类胡萝卜素、类胡萝卜素衍生的植物激素和类胡萝卜素代谢物促进叶片的光合作用、光保护和胁迫驯化。来自具有光合作用功能的叶子的叶绿体中的类囊体积累了特定成分的叶黄素、β-胡萝卜素、紫黄质和新黄质，它们作为叶绿素的辅助色素并保持最佳光合性能。叶子的发育状态和环境条件会影响类胡萝卜素代谢，从而影响叶子中的叶绿体功能。来自发芽幼苗的子叶中的叶质体大量积累叶黄素。子叶的光照触发叶绿体的超微结构发育，积累所有主要的叶面类胡萝卜素和叶绿素。玉米黄质和花黄素在强光和高温下的积累保持了类囊体膜和叶绿体的功能完整性。类胡萝卜素在叶子中不断合成和降解，但它们的组成仍然保持紧密。叶绿体的分解，例如在叶子衰老期间，停止类胡萝卜素生物合成并触发类胡萝卜素降解。这篇综述阐明了类胡萝卜素代谢的基本方面。在叶子中类胡萝卜素代谢的背景下讨论了改变光照条件、二氧化碳 (CO2)、温度、干旱和土壤养分水平的影响。强调了环境扰动如何改变叶中类胡萝卜素代谢和叶绿体发育的突出问题。这篇综述提供了关于如何设计类胡萝卜素调节网络以丰富食物和园艺作物叶子中的类胡萝卜素的进一步见解。