摘要
纳米氧化锌(ZnO NPs)在水环境中的存在形态对水生植物的生态风险有重要影响,研究了ZnO NPs在水体中的稳定性及对沉水植物金鱼藻的毒性效应.ZnO NPs进入到培养液中后观察到明显的团聚行为,且团聚体粒径随着浓度的升高逐渐增加,放置7天后其粒径要远大于实验初始粒径.另一方面,ZnO NPs释放了0.08~4.54mg·L^(-1)的锌离子(Zn^(2+))到培养液中,加入金鱼藻使纳米颗粒的离子释放量显著降低(0.06~3.88mg·L^(-1)).金鱼藻体内的锌含量随着ZnO NPs暴露浓度的升高而显著增加.金鱼藻体内超氧阴离子(O_2~)含量,过氧化物酶(POD)活性先升高后降低,膜脂质过氧化产物丙二醛(MDA)含量逐渐升高,均表明金鱼藻受到了氧化胁迫.同时金鱼藻的叶绿素含量在ZnO NPs暴露下也显著降低,但透射电镜结果显示其叶绿体形态并未受到影响.研究认为金属离子的释放是ZnO NPs致毒的重要原因.
The toxic effects of zinc oxide nanoparticles（ZnO NPs）（0.1~50 mg·L^（-1））on Ceratophyllum demersum were determined to investigate the potential risk of metal-based nanoparticles on aquatic macrophytes,as well as the factors affecting the stabilization of ZnO NPs aggregates.Once the nanoparticles were introduced to the test medium,they underwent significantly agglomeration at all the five exposure concentrations with large particles settled out of the suspension and accumulated in the bottom of vessels in 50mg·L^（-1） nanoparticles treatment.And the size of particle aggregates was remarkably influenced by the existence of Ceratophyllum demersum.This result might mainly be caused by the reduction of the inter-particle repulsion.During exposure period,ZnO NPs released large amount of zinc ions（Zn^（2＋））into the medium,while the existence of Ceratophyllum demersuminhibited the release of Zn^（2＋）.And the accumulation of Zn^（2＋）in plants significantly increased with the increase of ZnO NPs concentration.The O_2~content and peroxidase（POD）activity increased at first and then decreased with the exposure concentration,while MDAcontents increased with the increase of ZnO NPs concentration,which meant that the lipid peroxidation occurred in plant cells.These results showed that Ceratophyllum demersum was adversely affected by the oxidative stress caused by ZnO NPs.The contents of chlorophyll a and b in Ceratophyllum demersum were decreased in 10mg·L^（-1）and 50mg·L^（-1） ZnO NPs treatments,which indicated that the photosynthetic activity was influenced by nanoparticles.Results suggest that the release of Zn^（2＋）from ZnO NPs would be the main reason causing toxicities in plants.
作者
赵桂琦
周燕
尹颖
郭红岩
Zhao Guiqi Zhou Yan Yin Ying Guo Hongyan(School of the Environment, Nanjing University, Nanjing, 210023, China)
出处
《南京大学学报（自然科学版）》
CAS
CSCD
北大核心
2017年第5期894-902,共9页
Journal of Nanjing University（Natural Science）
基金
江苏省基础研究计划面上研究(BK20161404)
关键词
金鱼藻
纳米氧化锌
生物累积
氧化胁迫
离子释放
Ceratophyllum demersum
ZnO NPs
bioaccumulation
oxidative stress
ion release
