Muhammad Ihsan, Fahad Shah, Khalofah Ahlam, Zheng Bingsong, Shen Weijun
Guangxi Key Laboratory of Forest Ecology and Conservation, State Key Laboratory for Conservation and Utilization of Agro-Bioresources, College of Forestry, Guangxi University, Nanning, 530004, Guangxi, China.
Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Science, Northwest University, Xi'an, China.
Rice (N Y). 2025 Jul 21;18(1):70. doi: 10.1186/s12284-025-00825-0.
Melatonin (Mel), a multifunctional molecule, has emerged as a pivotal regulator of plant stress responses, enhancing antioxidant defenses, and modulating metabolic pathways. This meta-analysis evaluated the role of Mel in mitigating various abiotic stresses, including salinity, drought, heavy metals, light intensity, and humidity, across diverse experimental conditions in rice crop. The findings reveal significant improvements in enzymatic antioxidant activities such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX), with notable increases in POD (77%) and CAT (61%) activities under hydroponic application. Mel application reduced oxidative stress markers, such as hydrogen peroxide (HO) and malondialdehyde (MDA), by up to 45% and 54%, respectively, highlighting its capacity to alleviate cellular damage under stress conditions. Additionally, Mel enhanced osmotic regulator such as proline, soluble sugar, and protein accumulation, contributing to osmotic adjustment, with an exceptional increase of 987% proline contents in Thailand. Experimental type and application methods significantly influenced the efficacy of Mel. Hydroponic treatments and seed soaking methods consistently showed the highest improvement in stress tolerance, while field experiments exhibited variability. The effects were also modulated by light intensity and humidity. Under light intensity of 150 µmol m⁻ s⁻, Mel enhanced antioxidant activities and reduced oxidative damage, while humidity at 70-75% showed the highest stress alleviation effects. These findings highlight Mel's complex contribution to increasing plant resilience by control of antioxidant enzymes, reduction of oxidative damage, and enhancement of osmotic adaptations under abiotic pressures. The present study offers a thorough knowledge of Mel's potential as a plant growth regulator, therefore guiding sustainable development under demanding environmental conditions.
褪黑素（Mel）是一种多功能分子，已成为植物应激反应的关键调节因子，可增强抗氧化防御并调节代谢途径。这项荟萃分析评估了Mel在减轻水稻作物不同实验条件下的各种非生物胁迫（包括盐度、干旱、重金属、光照强度和湿度）方面的作用。研究结果表明，超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）和抗坏血酸过氧化物酶（APX）等酶促抗氧化活性有显著提高，水培施用时POD活性显著增加77%，CAT活性显著增加61%。施用Mel可使过氧化氢（HO）和丙二醛（MDA）等氧化应激标志物分别降低多达45%和54%，突出了其在胁迫条件下减轻细胞损伤的能力。此外，Mel增强了脯氨酸、可溶性糖和蛋白质等渗透调节物质的积累，有助于渗透调节，泰国的脯氨酸含量异常增加了987%。实验类型和施用方法显著影响了Mel的功效。水培处理和浸种方法始终显示出对胁迫耐受性的最高改善，而田间试验则表现出变异性。其效果还受光照强度和湿度的调节。在150 μmol m⁻² s⁻¹的光照强度下，Mel增强了抗氧化活性并减少了氧化损伤，而70-75%的湿度显示出最高的胁迫缓解效果。这些发现突出了Mel通过控制抗氧化酶、减少氧化损伤和增强非生物压力下的渗透适应能力，对提高植物恢复力的复杂贡献。本研究全面了解了Mel作为植物生长调节剂的潜力，从而为在苛刻环境条件下的可持续发展提供指导。
