纳米银对水稻的生物有效性研究

发布时间：2018-01-12 12:43

  本文关键词：纳米银对水稻的生物有效性研究　出处：《苏州科技学院》2015年硕士论文　论文类型：学位论文

  更多相关文章： 纳米银 粒径分布 吸收速率 溶解 团聚

【摘要】：本文首先对比研究了AgNP的不同定性与定量分析方法,包括不同分离与消解方法的对比以及动态光散射(DLS)与透射电子显微镜(TEM)表征方法的对比。并在此基础上研究了AgNP对水稻的生物有效性,主要从其对水稻的毒性、能否被水稻吸收、积累以及有机质对水稻吸收AgNP速率的影响开展相关工作。研究发现超高速离心的分离效果受溶液总Ag浓度的影响,分离效果不稳定。对于体系单纯的AgNP样品,可通过1:2的液酸(溶液:浓硝酸)体积比、常温消解的方法达到较好的消解效果。对比动态光散射(DLS)与透射电子显微镜(TEM)两种表征方法发现,DLS表征获得的AgNP的水合粒径显著高于TEM图统计得到的粒径,分析可能的原因为AgNP颗粒表面的包被物聚乙烯吡咯烷酮(PVP)的存在增大了AgNP颗粒的水合粒径,而TEM表征得到的粒径只有AgNP颗粒本身。在根系暴露与叶片喷施暴露两种途径下,水稻吸收并积累了AgNP,且叶片喷施暴露的叶片积累量远高于同等剂量根系暴露叶片的积累量,比如AgNP暴露浓度均为1 mg/L时,根系暴露叶片中银的积累量为0.44 mg/kg,而叶片喷施暴露叶片中银的积累量高达8.40 mg/kg。借助单颗粒电感耦合等离子质谱技术(sp-ICP-MS)得出两种暴露途径下,不论是AgNP还是银离子暴露,均在水稻叶片中检测到粒径在30-40 nm范围内的AgNP颗粒,且通过透射电子显微镜能谱仪(TEM-EDS)对喷施处理的水稻叶片中的AgNP进行定性和半定量分析发现,水稻叶片中AgNP的粒径在30-40 nm,与sp-ICP-MS结果一致,均远高于暴露溶液中AgNP(13.3±3.7 nm)的粒径。生物量指标表明,水稻根系暴露AgNP后,AgNP显著抑制了水稻的生长,叶片喷施暴露则没有显著的毒性效应。在此基础上研究了水稻秸秆腐解液作为模型有机质对水稻吸收AgNP速率的影响。研究结果表明水稻对AgNP的吸收速率(0.21 mg/(g·h)—0.03 mg/(g·h))随水稻秸秆腐解液中总有机碳(TOC)浓度(0 mg/L—20 mg/L)的升高而线性降低;当TOC浓度达到20 mg/L—80 mg/L,AgNP的吸收速率趋于稳定(~0.03mg/(g·h))。同时,对溶液中的AgNP的动力学过程研究表明,水稻秸秆腐解液抑制了AgNP溶出银离子的过程(降低了27.5%—95.5%),且TOC浓度越高,抑制作用越显著,使得溶液中银离子的浓度降低,从而降低了水稻对AgNP的吸收速率;同时,水稻秸秆腐解液能够促进AgNP颗粒的团聚,使得AgNP颗粒的尺度变大,更不易被水稻所吸收。研究表明不同分子量的组分对水稻吸收AgNP速率的影响不同,且低分子量的组分(3 KDa)和水稻秸秆腐解液的有机质对AgNP吸收速率影响相近,说明低分子量组分(3 KDa)对AgNP吸收起着重要的作用。研究结果可以为研究AgNP在植物体内的富集与迁移以及会否沿食物链实现生物放大提供基础数据,并为进一步预测其对较高等生物甚至人类的潜在风险提供数据支持。
[Abstract]:In this paper, different qualitative and quantitative methods of AgNP are compared. The comparison of different methods of separation and digestion and the comparison of dynamic light scattering (DLS) and transmission electron microscopy (TEM) characterizations were carried out. The bioavailability of AgNP to rice was also studied. Mainly from its toxicity to rice, can be absorbed by rice. The accumulation of organic matter and the effect of organic matter on the absorption rate of AgNP in rice were studied. It was found that the separation effect of ultra-high speed centrifugation was affected by the concentration of total Ag in the solution. The separation effect is unstable. For the pure AgNP sample, the volume ratio of liquid acid (solution: concentrated nitric acid) of 1: 2 can be used. The results were compared between dynamic light scattering (DLSs) and transmission electron microscopy (TEM). The hydration particle size of AgNP characterized by DLS was significantly higher than that obtained by TEM diagram. The possible reason is that the existence of polyvinylpyrrolidone (PVP) on the surface of AgNP particles increases the hydration diameter of AgNP particles. However, only AgNP particles were obtained by TEM characterization. The rice absorbed and accumulated AgNP by root exposure and leaf spray exposure. The accumulation of leaves exposed to spraying was much higher than that of roots exposed to the same dose, such as when the concentration of AgNP was 1 mg/L. The accumulation of silver in root exposed leaves was 0. 44 mg/kg. The accumulation of silver in the leaves exposed by spraying was up to 8.40 mg / kg. By means of single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS), two exposure pathways were obtained. Whether AgNP or silver ions were exposed, AgNP particles with diameter in the range of 30-40 nm were detected in rice leaves. The AgNP in rice leaves treated by spraying was qualitatively and semi-quantitatively analyzed by transmission electron microscope (TEM) energy dispersive spectrometer (TEM-EDS). The diameter of AgNP in rice leaves ranged from 30 to 40 nm, which was consistent with the results of sp-ICP-MS. The biomass index indicated that the growth of rice was inhibited significantly after AgNP exposure to rice roots. The results showed that the grain size of rice roots was significantly higher than that in exposed solution (AgNP(13.3 卤3. 7 nm) and the biomass index showed that AGP significantly inhibited the growth of rice. The effects of rice straw decay as model organic matter on the uptake rate of AgNP in rice were studied. The results showed that rice absorbed AgNP from rice. Rate (. 0. 21 mg/(g 路htchum -0.03 mg/(g 路htchl) 0 mg/L-20 mg / L with the concentration of total organic carbon (TOC) in the decomposed solution of rice straw (TOC) = 0 mg/L-20 / L). Increased and decreased linearly; When the concentration of TOC reached 20 mg/L-80 mg / L, the absorption rate of AgNP tended to be stable. The kinetic process of AgNP in solution was studied. The results showed that the decomposing solution of rice straw inhibited the dissolution of silver ions by AgNP (27.5- 95.5U), and the higher the TOC concentration was, the higher the concentration of TOC was. The more significant the inhibition effect, the lower the concentration of silver ions in the solution, thus reducing the absorption rate of AgNP in rice. At the same time, rice straw decomposed solution can promote the agglomeration of AgNP particles, making the size of AgNP particles larger. It is more difficult to be absorbed by rice. The results show that different molecular weight components have different effects on the uptake rate of AgNP in rice. The effects of low molecular weight fraction (3kDa) and organic matter of rice straw decomposed solution on AgNP absorption rate were similar. Low molecular weight component 3KDa). The results can provide basic data for studying the enrichment and migration of AgNP in plants and whether biomagnification will be realized along the food chain. It also provides data support for further prediction of potential risks to higher organisms and even humans.
【学位授予单位】：苏州科技学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X503.231

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