College of Environmental Science and Engineering, and Ministry of Education Key Laboratory of Marine Environment and Ecology, Ocean University of China , Qingdao 266100, China.
Institute of Environmental Processes and Pollution Control, and School of Environmental and Civil Engineering, Jiangnan University , Wuxi 214122, China.
Environ Sci Technol. 2017 Jul 5;51(13):7686-7695. doi: 10.1021/acs.est.7b01602. Epub 2017 Jun 21.
Engineered nanoparticles (NPs) are being released into aquatic environments with their increasing applications. In this work, we investigated the interaction of CuO NPs with a floating plant, water hyacinth (Eichhornia crassipes). CuO NPs (50 mg/L) showed significant growth inhibition on both roots and shoots of E. crassipes after 8-day exposure, much higher than that of the bulk CuO particles (50 mg/L) and their corresponding dissolved Cu ions (0.30 mg/L). Scanning electron and light microscopic observations showed that the root caps and meristematic zone of E. Crassipes were severely damaged after CuO NP exposure, with disordered cell arrangement and a destroyed elongation zone of root tips. It is confirmed that CuO NPs could be translocated to shoot from both roots and submerged leaves. As detected by X-ray absorption near-edge spectroscopy analysis (XANES), CuO NPs were observed in roots, submerged leaves, and emerged leaves. CuS and other Cu species were also detected in these tissues, providing solid evidence of the transformation of CuO NPs. In addition, stomatal closure was observed during CuO NPs-leaf contact, which was induced by the production of HO and increased Ca level in leaf guard cells. These findings are helpful for better understanding the fate of NPs in aquatic plants and related biological responses.
工程纳米颗粒（NPs）在其应用的不断增加下被释放到水生环境中。在这项工作中，我们研究了氧化铜 NPs 与漂浮植物水葫芦（ Eichhornia crassipes ）的相互作用。8 天暴露后，CuO NPs（50mg/L）对水葫芦的根和茎都表现出明显的生长抑制作用，比大块的 CuO 颗粒（50mg/L）及其相应的溶解 Cu 离子（0.30mg/L）高得多。扫描电子显微镜和光学显微镜观察表明，CuO NP 暴露后，水葫芦的根冠和分生区受到严重破坏，细胞排列紊乱，根尖伸长区被破坏。可以证实，CuO NPs 可以从根和水下叶片转移到地上部分。通过 X 射线吸收近边结构光谱分析（XANES）检测到，CuO NPs 存在于根、水下叶和露出叶中。在这些组织中也检测到了 CuS 和其他 Cu 物种，为 CuO NPs 的转化提供了确凿的证据。此外，在 CuO NPs-叶片接触时观察到气孔关闭，这是由叶片保卫细胞中 HO 的产生和 Ca 水平的升高引起的。这些发现有助于更好地理解 NPs 在水生植物中的命运和相关的生物反应。
