Peng Cheng, Zhang Hai, Fang Huaxiang, Xu Chen, Huang Haomin, Wang Yi, Sun Lijuan, Yuan Xiaofeng, Chen Yingxu, Shi Jiyan
Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang Province, People's Republic of China.
College of Life Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang Province, People's Republic of China.
Environ Toxicol Chem. 2015 Sep;34(9):1996-2003. doi: 10.1002/etc.3016. Epub 2015 Jun 24.
Natural organic matter (NOM) can interact with engineered nanoparticles (NPs) in the environment and modify their behavior and toxicity to organisms. In the present study, the phytotoxicity of copper oxide (CuO) NPs to rice seedlings in the presence of humic acid as a model NOM was investigated. The results showed that CuO NPs induced the inhibition of root elongation, aberrations in root morphology and ultrastructure, and losses of cell viability and membrane integrity. The adverse effects partly resulted from the generation of reactive oxygen species caused by CuO NPs, which led to lipid peroxidation, mitochondrial dysfunction, and programmed cell death in rice seedlings. However, all the phytotoxicity was alleviated with the addition of humic acid because humic acid coatings on nanoparticle surfaces enhanced electrostatic and steric repulsion between the CuO NPs and the plant cell wall/membrane, reducing contact between NPs and plant and CuO NP-induced oxidative damage to plant cells. The present study's results shed light on the mechanism underlying NP phytotoxicity and highlight the influence of NOM on the bioavailability and toxicity of NPs.
天然有机物（NOM）可在环境中与工程纳米颗粒（NPs）相互作用，并改变其对生物体的行为和毒性。在本研究中，以腐殖酸作为模型NOM，研究了氧化铜（CuO）纳米颗粒对水稻幼苗的植物毒性。结果表明，CuO纳米颗粒导致根伸长受到抑制、根形态和超微结构出现畸变，以及细胞活力和膜完整性丧失。这些不利影响部分源于CuO纳米颗粒引起的活性氧生成，这导致了水稻幼苗中的脂质过氧化、线粒体功能障碍和程序性细胞死亡。然而，添加腐殖酸后所有植物毒性均得到缓解，因为纳米颗粒表面的腐殖酸涂层增强了CuO纳米颗粒与植物细胞壁/细胞膜之间的静电和空间排斥力，减少了纳米颗粒与植物的接触以及CuO纳米颗粒对植物细胞的氧化损伤。本研究结果揭示了纳米颗粒植物毒性的潜在机制，并突出了天然有机物对纳米颗粒生物可利用性和毒性的影响。
