Ranjan Plant physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad, Prayagraj, 211002, India.
Department of Botany, Dayalbagh Educational Institute, Agra, 282005, India.
Ecotoxicology. 2022 Aug;31(6):933-947. doi: 10.1007/s10646-022-02553-3. Epub 2022 May 27.
The current study explored the role of ionic copper (CuCl; 0.2 µM and 1 µM) and synthesized copper nanoparticles (CuNPs; 0.2 mM and 1 mM) in the two paddy field cyanobacteria (Nostoc muscorum ATCC 27893 and Anabaena sp. PCC 7120) with respect to growth, photosynthetic pigments, photosynthetic efficiency (O evolution and photochemistry of photosystem II; PS II), oxidative stress biomarkers, and antioxidant system. The low doses of ionic Cu (0.2 µM) and CuNPs (0.2 mM) showed stimulating effects on growth, pigment content (chlorophyll a, phycobiliproteins, and carotenoids), oxygen evolution, and PS II photochemistry. High doses of Cu/CuNPs (1 µM Cu and 1 mM CuNPs) caused a decline in the above-mentioned parameters. The values of fluorescence kinetics parameters: ϕP, F/F, ϕE, Ψ, and PI, except for F/F, associated with PS II photochemistry in tested cyanobacteria and subjected to the high doses of ionic Cu and CuNPs, were decreased, while energy fluxes, ABS/RC, TR/RC, ET/RC, and DI/RC, were increased. Conversely, treatment with low doses of Cu and CuNPs caused a reverse trend, indicating normalization of PS II performance. Although the activity of enzymatic antioxidants (superoxide dismutase SOD; peroxidase POD; catalase CAT and glutathione-S-transferase GST) in both cyanobacteria exposed to high doses of ionic Cu and CuNPs was accelerated considerably, the oxidative stress remained high. Conversely, at low doses of ionic Cu and CuNPs, a significant enhancement in the activities of enzymatic antioxidants decreased the levels of oxidative stress biomarkers. Nevertheless, in Anabaena sp., the levels of biomarkers were greater than those of the control. The current study concluded that compared to synthesized CuNPs, ionic Cu at elevated concentration had a damaging effect on growth, photosynthetic pigments, and PS II photochemistry via increased oxidative stress, and this effect was enhanced in Anabaena sp. than N. muscorum.
本研究探讨了离子态铜（CuCl；0.2 μM 和 1 μM）和合成铜纳米颗粒（CuNPs；0.2 mM 和 1 mM）在两种稻田蓝藻（念珠藻 ATCC 27893 和鱼腥藻 PCC 7120）中的作用，涉及生长、光合色素、光合作用效率（O 演化和光系统 II 的光化学；PS II）、氧化应激生物标志物和抗氧化系统。低剂量的离子态 Cu（0.2 μM）和 CuNPs（0.2 mM）对生长、色素含量（叶绿素 a、藻胆蛋白和类胡萝卜素）、氧气演化和 PS II 光化学有刺激作用。高剂量的 Cu/CuNPs（1 μM Cu 和 1 mM CuNPs）导致上述参数下降。测试蓝藻中与 PS II 光化学相关的荧光动力学参数值：φP、F/F、φE、Ψ 和 PI，除了 F/F，与高剂量离子态 Cu 和 CuNPs 相关的参数值降低，而能量通量、ABS/RC、TR/RC、ET/RC 和 DI/RC 增加。相反，低剂量的 Cu 和 CuNPs 处理导致相反的趋势，表明 PS II 性能正常化。尽管暴露于高剂量离子态 Cu 和 CuNPs 的两种蓝藻中的酶抗氧化剂（超氧化物歧化酶 SOD；过氧化物酶 POD；过氧化氢酶 CAT 和谷胱甘肽-S-转移酶 GST）的活性明显加速，但氧化应激仍然很高。相反，低剂量的离子态 Cu 和 CuNPs 显著增强了酶抗氧化剂的活性，降低了氧化应激生物标志物的水平。然而，在鱼腥藻中，生物标志物的水平高于对照。本研究得出结论，与合成的 CuNPs 相比，高浓度的离子态 Cu 通过增加氧化应激对生长、光合色素和 PS II 光化学产生破坏性影响，这种影响在鱼腥藻中比在念珠藻中更为明显。
