State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
Environ Pollut. 2023 Nov 15;337:122526. doi: 10.1016/j.envpol.2023.122526. Epub 2023 Sep 6.
Selenium (Se) elevates the antioxidant ability of rice against cadmium (Cd) stress, but previous studies only focused on the variation in antioxidant enzymes or nonenzymatic substances induced by Se under Cd stress and ignored the relationships between different antioxidant parameters during the interaction. Here, hydroponic experiments with rice were performed by adding both Cd and Se at doses in the range of 0-50 μM to explore the physiological responses of rice and their relationships in the presence of different levels of Se and Cd. Exogenous Cd markedly promoted the activity of antioxidant enzymes with the exception of catalase (CAT) and the concentration of nonenzymatic substances in aerial parts. Se enhanced the antioxidant capacity by improving the activities of all the enzymes tested in this study and increasing the concentrations of nonenzymatic compounds. The couplings among different antioxidant substances within paddy rice were then determined based on cluster and linear fitting results and their metabolic process and physiological functions. The findings specifically highlight that couplings among the ascorbic acid (AsA)-glutathione (GSH) cycle, glutathione synthase (GS)-phytochelatin synthetase (PCS) coupling system and glutathione peroxidase (GPX)-superoxide dismutase (SOD) coupling system in aerial parts helps protect plants from Cd stress. These coupling systems form likely due to the fact that one enzyme generated a product that could be the substrate for another enzyme. Noticeably, such coupling systems do not emerge in roots because the stronger damage to roots than other organs activates the ascorbate peroxidase (APX)-GPX-CAT and PCS-GS-SOD systems with distinct functions and structures. This study provides new insights into the detoxification mechanisms of rice caused by the combined effect of Se and Cd.
硒 (Se) 提高了水稻对镉 (Cd) 胁迫的抗氧化能力，但以前的研究仅关注 Se 在 Cd 胁迫下诱导的抗氧化酶或非酶物质的变化，而忽略了相互作用过程中不同抗氧化参数之间的关系。在这里，通过在 0-50 μM 的范围内添加 Cd 和 Se 进行水培实验，以探索水稻的生理反应及其在不同 Se 和 Cd 水平下的关系。外源性 Cd 明显促进了抗氧化酶的活性（除了过氧化氢酶 (CAT)）和地上部分非酶物质的浓度。Se 通过提高本研究中测试的所有酶的活性并增加非酶化合物的浓度来增强抗氧化能力。然后根据聚类和线性拟合结果以及它们的代谢过程和生理功能，确定了水稻不同抗氧化物质之间的偶联。研究结果特别强调了地上部抗坏血酸 (AsA)-谷胱甘肽 (GSH) 循环、谷胱甘肽合酶 (GS)-植物螯合肽合酶 (PCS) 偶联系统和谷胱甘肽过氧化物酶 (GPX)-超氧化物歧化酶 (SOD) 偶联系统之间的偶联有助于保护植物免受 Cd 胁迫。这些偶联系统可能是由于一种酶产生的产物可以成为另一种酶的底物而形成的。值得注意的是，由于根比其他器官受到更强的损伤，因此这些偶联系统不会出现在根部，这激活了具有不同功能和结构的抗坏血酸过氧化物酶 (APX)-GPX-CAT 和 PCS-GS-SOD 系统。本研究为 Se 和 Cd 联合作用下水稻解毒机制提供了新的见解。
