| 摘要: |
| 【目的】为了阐明水体中常见毒性污染物硝磺草酮与铜对水生植物的潜在毒性作用，本研究探究了二者对长江流域的优势种苦草（Vallisneria natans）的生长及生理响应，旨在为水生植物复合污染的生态毒性效应和生态安全评估提供依据。【方法】本研究采用水培法，研究了不同浓度硝磺草酮（0.01，1，10，20，50mg/L）、铜（0.1，0.3，0.5，1，2mg/L）以及硝磺草酮+铜（0+0，0.01+0.1，1+0.3，10+0.5，20+1，50+2 mg/L）对苦草的相对生长率、光合色素（叶绿素a、叶绿素b、类胡萝卜素）、抗氧化酶（SOD、POD、CAT）以及可溶性蛋白含量变化的影响。【结果】单一硝磺草酮对苦草的生长和光合色素的合成、CAT活性和可溶性蛋白含量具有抑制作用，而对苦草POD活性具有激活效应；单一铜胁迫对苦草生长、光合色素的合成、CAT活性以及可溶性蛋白含量具有显著抑制作用，而对苦草SOD和POD活性具有激活效应；苦草的相对生长率、光合色素、可溶性蛋白含量、CAT活性等指示物对硝磺草酮与铜联合胁迫表现出受害响应。而POD活性显著上升，SOD活性呈现低浓度抑制高浓度促进效应；毒性效应评估结果显示，随着复合胁迫浓度的升高，硝磺草酮和铜对苦草的联合毒性由拮抗作用转为协同作用。【结论】硝磺草酮与铜在水体中赋存可能对水生植物产生潜在的生物安全风险，因此要更加关注水体中不同污染物之间综合效应的防治。 |
| 关键词: 硝磺草酮 铜 苦草 生理胁迫 生理响应 |
| DOI： |
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| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| The growth and physiological responses of mesotrione and copper to Vallisneria natans under individual and joint exposure |
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Zhu Haoyu, Ning Shiqi, Wu zhonghua
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College of Life Sciences, Wuhan University
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| Abstract: |
| In order to elucidate the potential toxic effects of common aquatic pollutants, mesotrione and copper, on aquatic plants, this study investigated their impact on the growth and physiological responses of Vallisneria natans, a dominant species in the Yangtze River basin. The aim was to provide insights for the ecological toxicity effects and ecological safety assessment of compound pollution on aquatic plants. Hydroponic experiments were conducted to assess the effects of different concentrations of mesotrione (0.01, 1, 10, 20, 50 mg/L), copper (0.1, 0.3, 0.5, 1, 2 mg/L), and mesotrione + copper (0+0, 0.01+0.1, 1+0.3, 10+0.5, 20+1, 50+2 mg/L) on Vallisneria natans. Parameters studied included RGR, photosynthetic pigments (chlorophyll a, chlorophyll b, carotenoids), antioxidant enzymes (SOD, POD, CAT), and soluble protein content. In this study, the impact of individual exposure to mesotrione and copper, as well as their combined stress, on the growth, synthesis of photosynthetic pigments, CAT activity, and soluble protein content in Vallisneria natans was investigated. Mesotrione exhibited inhibitory effects on the growth and photosynthetic pigment synthesis, CAT activity, and soluble protein content in Vallisneria natans, while activating POD activity. Conversely, single copper stress significantly inhibited growth, photosynthetic pigment synthesis, CAT activity, and soluble protein content, while activating SOD and POD activities. The combined stress of mesotrione and copper induced adverse responses in terms of RGR, photosynthetic pigments, soluble protein content, and CAT activity in Vallisneria natans. Notably, POD activity increased significantly, whereas SOD activity displayed a concentration-dependent inhibitory effect at low concentrations and a stimulating effect at high concentrations. Toxicity assessment revealed that with an increase in the concentration of combined stress, the joint toxicity of mesotrione and copper shifted from antagonistic to synergistic effects. The coexistence of mesotrione and copper in aquatic ecosystems may pose potential biological risks to aquatic plants. Therefore, greater attention should be paid to the prevention and control of the combined effects of different pollutants in aquatic environments. |
| Key words: mestrione, Cu, Vallisneria natans, physiological stress,physiological responses |
