Institute of Environmental Processes and Pollution Control, School of Environmental and Civil Engineering, Jiangnan University, Wuxi, 214122, China.
College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Marine Environment and Ecology, Ocean University of China, Qingdao, 266100, China.
Environ Pollut. 2018 Dec;243(Pt A):543-552. doi: 10.1016/j.envpol.2018.09.013. Epub 2018 Sep 6.
CuO engineered nanoparticles (NPs) are of increasing concern due to their extensive use in daily life and adverse effect on aquatic organisms. The investigations on the toxicity of CuO NPs to aquatic plants through uptake from roots versus fronds are limited. This paper discusses the interactions of CuO NPs with Lemna minor, a floating plant. After CuO NPs (150 μg L) exposure for 7 days, the frond number, frond surface area and dry weights of whole plants significantly decreased by 32%, 47% and 33%; the responses were dose-dependent. Microscopy imaging showed that the epidermis was severely damaged in fronds, edges were severely sloughed off and cell integrity was damaged in roots. Shrinkage of both chloroplast and starch grains were observed in the frond cells. Internalization of CuO NPs in root and frond cells during CuO NPs (1 mg L) exposure was confirmed with the root Cu levels of Lemna minor being three times higher than the fronds by using transmission electron microscopy and flame atomic absorption spectrophotometry. Reactive oxygen species, mainly HO (increased by 56%) and ·OH (increased by 57%), accumulated in Lemna minor tissues in response to CuO NPs exposure. Moreover, chloroplasts were confirmed as a site of ROS production. These findings are helpful for better understanding the biological responses of aquatic plants upon NPs exposure.
氧化铜纳米颗粒（NPs）由于在日常生活中的广泛应用及其对水生生物的不良影响而引起了越来越多的关注。通过根部与叶片吸收途径研究氧化铜 NPs 对水生植物的毒性的工作还很有限。本文讨论了氧化铜 NPs 与浮萍（一种漂浮植物）的相互作用。在暴露于 150μg/L 的氧化铜 NPs 7 天后，浮萍的数量、叶面积和整株植物的干重分别显著减少了 32%、47%和 33%；这些反应呈剂量依赖性。显微镜成像显示，叶片的表皮严重受损，边缘严重剥落，根部的细胞完整性受损。叶片细胞中的叶绿体和淀粉粒都出现了收缩。通过透射电子显微镜和火焰原子吸收分光光度法证实，在暴露于 1mg/L 的氧化铜 NPs 期间，根和叶片细胞内有氧化铜 NPs 的内化，浮萍的根中铜含量是叶片的三倍。活性氧（主要是 HO（增加了 56%）和·OH（增加了 57%））在浮萍组织中积累，以应对氧化铜 NPs 的暴露。此外，叶绿体被确认为 ROS 产生的部位。这些发现有助于更好地理解水生植物在 NPs 暴露下的生物学反应。
