Majewska Monika, Kapusta Małgorzata, Aksmann Anna
Department of Plant Experimental Biology and Biotechnology, Faculty of Biology, University of Gdańsk, ul. Wita Stwosza 59, 80-308 Gdańsk, Poland.
Bioimaging Laboratory, Faculty of Biology, University of Gdańsk, ul. Wita Stwosza 59, 80-308 Gdańsk, Poland.
Plants (Basel). 2024 Aug 8;13(16):2189. doi: 10.3390/plants13162189.
Diclofenac, often detected in environmental samples, poses a potential hazard to the aquatic environment. The present study aimed to understand the effect of this drug on photosynthetic apparatus, which is a little-known aspect of its phytotoxicity. Chloroplasts and thylakoids isolated from spinach () were used for this study and treated with various concentrations of diclofenac (from 125 to 4000 μM). The parameters of chlorophyll fluorescence (the OJIP test) as measurements for both the intact chloroplasts and the thylakoid membranes revealed that isolated thylakoids showed greater sensitivity to the drug than chloroplasts. The relatively high concentration of diclofenac that is required to inhibit chloroplast and thylakoid functions suggests a narcotic effect of that drug on photosynthetic membranes, rather than a specific interaction with a particular element of the electron transport chain. Using confocal microscopy, we confirmed the degradation of the chloroplast structure after DCF treatment, which has not been previously reported in the literature. In conclusion, it can be assumed that diclofenac's action originated from a non-specific interaction with photosynthetic membranes, leading to the disruption in the function of the electron transport chain. This, in turn, decreases the efficiency of photosynthesis, transforming part of the PSII reaction centers into heat sinks and enhancing non-photochemical energy dissipation.
双氯芬酸在环境样品中经常被检测到，对水生环境构成潜在危害。本研究旨在了解这种药物对光合机构的影响，这是其植物毒性中一个鲜为人知的方面。本研究使用从菠菜（）中分离出的叶绿体和类囊体，并用不同浓度的双氯芬酸（125至4000μM）进行处理。叶绿素荧光参数（OJIP测试）作为完整叶绿体和类囊体膜的测量指标，结果显示分离出的类囊体对该药物的敏感性高于叶绿体。抑制叶绿体和类囊体功能所需的双氯芬酸浓度相对较高，这表明该药物对光合膜具有麻醉作用，而非与电子传递链的特定元素发生特异性相互作用。通过共聚焦显微镜，我们证实了双氯芬酸处理后叶绿体结构的降解，这在以前的文献中尚未有报道。总之，可以推测双氯芬酸的作用源于与光合膜的非特异性相互作用，导致电子传递链功能紊乱。进而降低光合作用效率，将部分PSII反应中心转化为热阱并增强非光化学能量耗散。
