| 摘要: |
| 【目的】研究环境相关浓度微囊藻毒素-LR（MC-LR）慢性胁迫对水雍菜（Ipomoea aquatica）叶片光合系统的影响，为阐明低质量浓度MC-LR慢性暴露对水雍菜生长的影响机制提供理论依据。【方法】以含不同质量浓度（0（CK），1，10，30 μg/L）MC LR的营养液培养水雍菜30 d，通过小雍菜叶片叶绿素SPAD值、叶绿素荧光参数、H2O2含量、1，5-二磷酸核酮糖羧化酶（Rubisco）及Rubisco活化酶（RCA）活性的变化，分析MC-LR慢性暴露对水雍菜叶片光合生理的影响。【结果】MC-LR慢性暴露30 d后，与对照组相比，1 μg/L MC-LR处理组水雍菜叶片的光合参数均无显著变化；10 μg/L MC-LR处理组中，Rubisco及RCA活性显著降低，H2O2含量和非光化学淬灭系数（qN）显著上升，而叶绿素SPAD值、光系统Ⅱ（PSⅡ）最大量子产量（Fv/Fm）和PSⅡ有效量子产量(ΦPSⅡ) 无显著变化；30 μg/L MC LR处理组中，H2O2含量显著上升，而叶绿素SPAD值、Fv/FmΦPSⅡ、光化学淬灭系数（qP）及Rubisco、RCA活性均显著降低。【结论 1 μg/L MC-LR暴露对水雍菜叶片光合生理无显著影响；10 μg/L MC-LR暴露下，叶片通过增加热耗散来保护光合机构，但MC-LR对光合酶活性产生抑制从而对叶片光合活性产生影响；30 μg/L MC-LR暴露会抑制叶片光合系统对光能的转化效率、降低了叶片的光合酶活性，从而对水雍菜的光合能力产生不良影响。 |
| 关键词: 微囊藻毒素 慢性暴露 水雍菜 光合系统 |
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| 基金项目:国家自然科学基金面上项目（51878582）；厦门理工学院科研攀登计划项目（XPDKT19026） |
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| Effects of chronic exposure to microcystin-LR on photosynthetic physiology of Ipomoea aquatica |
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CHEN Guoyuan,LIAO Tengfang,LI Qingsong
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| Abstract: |
| 【Objective】The chronic effects of microcystin-LR (MC-LR) at environmental relevant concentrations on photosynthesis of Ipomoea aquatica were studied to elucidate mechanism of low concentrations MC-LR exposure on growth of Ipomoea aquatica.【Method】After incubation for 30 days in nutrient solution containing MC-LR at different concentrations (0 (CK),1,10,30 μg/L),the changes in chlorophyll SPAD values,chlorophyll fluorescence parameters,H2O2 contents,Ribulose-1,5-bisphosphate carboxylase (Rubisco) and Rubisco activase (RCA) activities were analyzed to investigate the effects of MC-LR on photosynthesis of Ipomoea aquatica.【Result】After exposure to 1 μg/L MC-LR for 30 days,there was no significant changes in photosynthetic parameters in leaves.After exposure to 10 μg/L MC-LR activities of Rubisco and RCA decreased significantly,contents of H2O2 and qN increased significantly,while SPAD values of chlorophyll,Fv/Fm and ΦPSⅡ had insignificant changes.After exposure to 30 μg/L MC-LR,contents of H2O2 increased significantly,while SPAD values of chlorophyll,Fv/Fm,ΦPSⅡ and qP,and activities of Rubisco and RCA decreased significantly.【Conclusion】Exposure to 1 μg/L MC-LR had no significant effect on photosynthetic physiological characteristics in leaves of Ipomoea aquatica.After exposure to 10 μg/L MC-LR,leaves protected photosynthetic apparatus by increasing heat dissipation,but MC-LR inhibited activities of photosynthetic enzymes and affected photosynthetic activity of Ipomoea aquatica.Exposure to 30 μg/L MC-LR inhibited transformation of light energy in photosynthetic system and decreased activities of photosynthetic enzymes,which had a negative effect on photosynthetic capacity of Ipomoea aquatica. |
| Key words: microcystin chronic exposure Ipomoea aquatica photosynthetic system |
