Drought stress imposes a serious threat to crop productivity and nutritional security. Drought adaptation mechanisms involve complex regulatory network comprising of various sensory and signaling molecules. In this context, melatonin has emerged as a potential signaling molecule playing a crucial role in imparting stress tolerance in plants. Melatonin pretreatment regulates various plant physiological processes such as osmoregulation, germination, photosynthesis, senescence, primary/secondary metabolism, and hormonal cross-talk under water deficit conditions. Melatonin mediated regulation of ascorbate-glutathione (AsA-GSH) cycle plays a crucial role to scavenge reactive oxygen species generated in the cells during drought. Here, in this review, the current knowledge on the role of melatonin to ameliorate adverse effects of drought by modulating morphological, physiological and redox regulatory processes are discussed. The role of melatonin to improve water absorption capacity of roots by regulating aquaporin channels and hormonal cross-talk involved in drought stress mitigation are also discussed. Overall, melatonin is a versatile bio-molecule involved in growth promotion and yield enhancement under drought stress that makes it a suitable candidate for eco-friendly crop production to ensure food security.

中文翻译：

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褪黑激素介导的植物干旱胁迫缓解机制研究

干旱压力对作物生产力和营养安全构成严重威胁。干旱适应机制涉及由各种感觉和信号分子组成的复杂调节网络。在这种情况下，褪黑激素已成为一种潜在的信号分子，在赋予植物胁迫耐受性方面发挥着至关重要的作用。褪黑激素预处理调节各种植物生理过程，如渗透调节、发芽、光合作用、衰老、初级/次级代谢和缺水条件下的激素串扰。褪黑激素介导的抗坏血酸-谷胱甘肽 (AsA-GSH) 循环调节在清除干旱期间细胞中产生的活性氧方面起着至关重要的作用。在这里，在这篇评论中，讨论了目前关于褪黑激素通过调节形态、生理和氧化还原调节过程来改善干旱不利影响的作用的知识。还讨论了褪黑激素通过调节水通道蛋白通道和缓解干旱胁迫所涉及的激素串扰来提高根系吸水能力的作用。总体而言，褪黑激素是一种多功能生物分子，在干旱胁迫下参与促进生长和提高产量，使其成为确保粮食安全的生态友好作物生产的合适候选者。