School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China.
Horticulture Development Department, Teagasc, Ashtown Food Research Centre, Dublin D15 KN3K, Ireland.
J Hazard Mater. 2024 Jul 15;473:134452. doi: 10.1016/j.jhazmat.2024.134452. Epub 2024 Apr 26.
Agricultural lands with vanadium (V), pose a significant and widespread threat to crop production worldwide. The study was designed to explore the melatonin (ME) treatment in reducing the V-induced phytotoxicity in muskmelon. The muskmelon seedlings were grown hydroponically and subjected to V (40 mg L) stress and exogenously treated with ME (100 μmol L) to mitigate the V-induced toxicity. The results showed that V toxicity displayed a remarkably adverse effect on seedling growth and biomass, primarily by impeding root development, the photosynthesis system and the activities of antioxidants. Contrarily, the application of ME mitigated the V-induced growth damage and significantly improved root attributes, photosynthetic efficiency, leaf gas exchange parameters and mineral homeostasis by reducing V accumulation in leaves and roots. Additionally, a significant reduction in the accumulation of reactive oxygen species (ROS), malondialdehyde (MDA) along with a decrease in electrolyte leakage was observed in muskmelon seedlings treated with ME under V-stress. This reduction was attributed to the enhancement in the activities of antioxidants in leaves/roots such as ascorbate (AsA), superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione peroxidase (GPX), glutathione S-transferase (GST) as compared to the V stressed plants. Moreover, ME also upregulated the chlorophyll biosynthesis and antioxidants genes expression in muskmelon. Given these findings, ME treatment exhibited a significant improvement in growth attributes, photosynthesis efficiency and the activities of antioxidants (enzymatic and non-enzymatic) by regulating their expression of genes against V-stress with considerable reduction in oxidative damage.
农田土壤中的钒（V）对全球作物生产构成了重大且广泛的威胁。本研究旨在探索褪黑素（ME）处理对减轻甜瓜 V 胁迫毒性的作用。采用水培法培养甜瓜幼苗，施加 40mg/L 的 V 胁迫和 100μmol/L 的 ME 进行外源处理，以减轻 V 诱导的毒性。结果表明，V 毒性对幼苗生长和生物量有显著的不利影响，主要表现为抑制根系发育、光合作用系统和抗氧化剂活性。相反，ME 的应用减轻了 V 诱导的生长损伤，通过减少叶片和根系中 V 的积累，显著改善了根系特性、光合效率、叶片气体交换参数和矿物质稳态。此外，在 V 胁迫下，ME 处理的甜瓜幼苗中活性氧（ROS）、丙二醛（MDA）的积累显著减少，电解质渗漏也减少。这归因于叶片/根系中抗氧化剂活性的增强，如抗坏血酸（AsA）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）、谷胱甘肽过氧化物酶（GPX）和谷胱甘肽 S-转移酶（GST）。此外，ME 还上调了甜瓜中叶绿素生物合成和抗氧化剂基因的表达。鉴于这些发现，ME 处理通过调节基因表达，显著改善了生长特性、光合作用效率和抗氧化剂（酶和非酶）的活性，减轻了氧化损伤。
