研究了褪黑素(MT)和还原型谷胱甘肽(GSH)在减轻甘薯中铬(Cr)毒性中的作用。植物,用不同的MT和GSH剂量预处理,暴露于Cr(40μM)。Cr通过破坏叶片光合作用严重阻碍了生长,根系,和氧化过程和增加Cr吸收。然而,外源施用1μM的MT和2mM的GSH通过提高叶绿素含量显著改善了生长参数,气体交换(Pn,Tr,Gs,和Ci),和叶绿素荧光(Fv/Fm,ETR,qP,和Y(II))。此外,丙二醛(MDA),过氧化氢(H2O2),超氧离子(O2·-),电解液泄漏(EL),施用MT和GSH可显着降低根对Cr的吸收(21.6和27.3%)及其向芽的转运,保护细胞膜免受Cr毒性的氧化损伤。显微分析表明,MT和GSH维持了叶绿体结构和叶肉细胞的完整性;它们还增加了气孔长度,宽度,和密度,加强光合系统和植物生长和生物量。MT和GSH改善了渗透保护剂(脯氨酸和可溶性糖),基因表达,以及酶促和非酶促抗氧化活性,减轻Cr胁迫下的渗透胁迫和增强植物防御能力。重要的是,GSH预处理降低Cr毒性的效率超过MT。结果表明,MT和GSH通过增强光合器官的稳定性来减轻Cr的有害作用,组分积累,和抗氧化应激。这项研究是在污染土壤中面临Cr胁迫的植物的宝贵资源,但进一步的现场验证和详细的分子探索是必要的。
Melatonin (MT) and reduced glutathione (GSH) roles in mitigating chromium (Cr) toxicity in sweetpotato were explored. Plants, pre-treated with varying MT and GSH doses, were exposed to Cr (40 μM). Cr severely hampered growth by disrupting leaf photosynthesis, root system, and oxidative processes and increased Cr absorption. However, the exogenous application of 1 μM of MT and 2 mM of GSH substantially improved growth parameters by enhancing chlorophyll content, gas exchange (Pn, Tr, Gs, and Ci), and chlorophyll fluorescence (Fv/Fm, ETR, qP, and Y(II)). Furthermore, malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide ion (O2•-), electrolyte leakage (EL), and Cr uptake by roots (21.6 and 27.3%) and its translocation to shoots were markedly reduced by MT and GSH application, protecting the cell membrane from oxidative damage of Cr-toxicity. Microscopic analysis demonstrated that MT and GSH maintained chloroplast structure and integrity of mesophyll cells; they also enhanced stomatal length, width, and density, strengthening the photosynthetic system and plant growth and biomass. MT and GSH improved osmo-protectants (proline and soluble sugars), gene expression, and enzymatic and non-enzymatic antioxidant activities, mitigating osmotic stress and strengthening plant defenses under Cr stress. Importantly, the efficiency of GSH pre-treatment in reducing Cr-toxicity surpassed that of MT. The findings indicate that MT and GSH alleviate Cr detrimental effects by enhancing photosynthetic organ stability, component accumulation, and resistance to oxidative stress. This study is a valuable resource for plants confronting Cr stress in contaminated soils, but further field validation and detailed molecular exploration are necessary.