文双喜²,
王毅力^1,,
1. 北京林业大学环境科学与工程学院, 北京 100083;
2. 贵阳学院生物与环境工程学院, 贵阳 550005

作者简介: 文双喜(1986—),男,博士,研究方向为环境修复与污染生态学,E-mail:wenshuangxide@126.com.

通讯作者: 王毅力,wangyilimail@126.com

基金项目: 国家水体污染控制与治理科技重大专项(2012ZX07105-002-03)
国家自然科学基金(51478041,21177010)


中图分类号: X171.5

Effect of Nano Titanium Dioxide with Different Particle Size on the Seed Germination and Plant Growth and Physiology of Ceratophyllum demersum in Hydroponic Experiments

Wen Shuangxi²,
Wang Yili^1,,
1. College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China;
2. College of Biological and Environmental Engineering, Guiyang University, Guiyang 550005, China

Corresponding author: Wang Yili,wangyilimail@126.com

CLC number: X171.5

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摘要:纳米二氧化钛(TiO₂-NPs)是目前应用最为广泛的纳米材料之一,在城市污水处理厂的出水、污泥以及地表水体中已均有检出,进入到天然湿地和人工湿地中的TiO₂-NPs会在湿地生物、基质、水体之间进行迁移转化和归趋。目前针对TiO₂-NPs对湿地植物金鱼藻的毒性研究很少。本文采用水培实验方法,研究了不同粒径TiO₂对金鱼藻种子发芽和植株生长的影响,解析了TiO₂-NPs对金鱼藻的生态毒理效应。研究结果表明:各粒径TiO₂-NPs对金鱼藻种子的发芽均具有一定的抑制作用,表现为发芽率、发芽幼苗重量、发芽指数、发芽势和活力指数的降低,且粒径越小、浓度越高对金鱼藻种子发芽的抑制作用越强,4 nm、20 nm和50 nm的TiO₂-NPs对金鱼藻种子发芽的半数有效浓度(EC₅₀)分别为1 180、1 520和1 810 mg·L^-1。TiO₂-NPs对金鱼藻植株的毒害作用表现为叶片失绿发黄、脱落,植株呈萎焉状,并且TiO₂-NPs的粒径越小、浓度越高毒害作用越明显。随TiO₂-NPs浓度升高,处理后金鱼藻叶片的叶绿素含量和植株体内的Mg含量均降低,丙二醛(malondialdehyde,MDA)含量均升高,而超氧化物歧化酶(superoxide dismutase,SOD)活性则先升高后降低,而且越小粒径的TiO₂-NPs对金鱼藻的处理效果越明显。3种粒径的TiO₂-NPs均能进入金鱼藻体内,粒径越小、浓度越高进入的量越多。综上表明,TiO₂-NPs对金鱼藻种子发芽和植株生长均有一定的抑制作用,且粒径越小、浓度越高抑制作用越强。
关键词: 纳米二氧化钛/
金鱼藻/
生态毒理/
累积/
分布

Abstract:Nano titanium dioxide (TiO₂-NPs) is one of the most widely used nanometer materials, which has been detected in the effluent of the sewage treatment plant, sludge and the surface water. The NPs will migrate and transform among the wetland biotas, substrate and water body as entering the natural wetland and constructed wetland. At present, there are few studies on the toxicity of TiO₂-NPs to the Ceratophyllum demersum. In this study, the effect of TiO₂-NPs with different sizes on the seed germination and plant growth of typical constructed wetland plant-C. demersum was explored through hydroponic experiments, and their ecotoxicological effects were also de- termined. The results showed that the seed germination of C. demersum was inhibited after treated by TiO₂-NPs with different sizes, and the germination rate, seedling weight, germination index, germination potential and vigor index decreased accordingly. The smaller the particle size or the higher the concentration of the TiO₂-NPs was, the stronger inhibitory effects on the seed germination of C. demersum occurred. Moreover, the EC₅₀ of 4 nm, 20 nm and 50 nm TiO₂-NPs on the seed germination of C. demersum were determined as 1 180, 1 520 and 1 810 mg·L^-1, respectively. The toxic effects of TiO₂-NPs on C. demersum were characterized as growth retardation and even stagnation, leaf chlorosis, plant wilting. Moreover, the decreased size or increased concentration of TiO₂-NPs could strengthen the aforementioned toxic effects. With the increase of TiO₂-NPs concentration, the chlorophyll and Mg content in plant of treated C. demersum decreased, the malondialdehyde (MDA) content increased, while the super- oxide dismutase (SOD) activity increased first and then decreased, and such treatment effect was more obvious as the smaller TiO₂-NPs were used. TiO₂-NPs with different sizes could enter the C. demersum, and small size or high concentration could favor this entrance. In summary, the seed germination and plant growth of C. demersum was inhibited after treated by TiO₂-NPs, and moreover, the smaller the particle size or the higher the concentration of the TiO₂-NPs was, the stronger inhibitory effects were detected.
Key words:TiO₂ nanoparticles/
Ceratophyllum demersum/
ecotoxicological effects/
accumulation/
distribution.