钴、镍对不同形态汞在水稻植株内蓄积与转化的影响

发布时间：2018-06-09 15:40

本文选题：汞 + 钴　；参考：《安徽工业大学》2017年硕士论文

【摘要】：汞(Hg)是一种具有强烈毒性的全球性污染物,我国汞污染地区居民甲基汞(MeHg)摄入的重要途径是食用稻米。汞暴露影响水稻对微量元素的吸收与蓄积,因此,探究微量元素特别是有益元素对水稻吸收与蓄积汞的影响有利于应对汞污染。本论文主要探究了钴(Co)、镍(Ni)两种微量元素对不同形态汞在水稻植株内的蓄积与转化的影响,同时也研究了不同形态汞对水稻蓄积转运钴、镍的影响。1.利用电感耦合等离子体质谱(ICP-MS)、高效液相色谱-电感耦合等离子体质谱法(HPLC-ICP-MS)结合同步辐射-X射线近边吸收谱(SR-XANES)、同步辐射-X射线荧光成像(SR-XRF)技术分析了不同形态汞暴露以及添加钴后水稻组织中无机汞(IHg)和甲基汞的转运、转化情况,及Co-MeHg共同暴露下汞在水稻组织中的分布情况。研究结果表明,Co-IHg共同暴露下,钴的添加促进水稻根中汞的蓄积,抑制茎叶对汞的吸收。Co-MeHg共同暴露下,钴的添加促进水稻根和茎叶总汞含量,同时促进汞由水稻根部向茎叶的转运。钴的添加未改变无机汞暴露下水稻组织中汞的形态,但能够促进甲基汞暴露前期(8天)水稻根部甲基汞的去甲基化;随着暴露时间的增加(16天后),钴对水稻根部甲基汞去甲基化产生抑制。SR-XANES结果还表明水稻根中蓄积的甲基汞及无机汞或者是转化生成的无机汞主要以同含巯基的生物分子结合的形式存在,如CH3Hg-SR和SR-Hg-SR。SRXRF结果表明钴的添加使汞更多的分布在水稻根部中柱部位,但汞在茎叶中的分布变化不大。2.利用ICP-MS和HPLC-ICP-MS技术分析了不同形态汞暴露以及添加镍后水稻组织中无机汞和甲基汞的吸收、转运、转化情况。结果表明,镍的添加能够促进各暴露组水稻根和茎叶组织中总汞含量,且随着镍暴露浓度的增加,水稻组织总汞含量增加。Ni-IHg暴露时,镍的添加不改变水稻组织中汞的形态;Ni-MeHg暴露时,水稻根和茎叶中检测到大量的无机汞,各暴露组水稻根中甲基汞含量随着培养时间的增加逐渐降低,无机汞含量随培养时间的增加而增加;水稻茎叶中无机汞与甲基汞含量均随着培养时间的增加而增加。说明Ni-MeHg暴露时水稻植株内发生了甲基汞的去甲基化,并且镍的添加促进水稻植株甲基汞去甲基化。3.利用ICP-MS分析了不同形态汞分别与钴、镍暴露时汞对水稻组织中钴、镍含量的影响。结果表明,添加无机汞时,暴露早期汞增加水稻根部总钴含量,随培养时间的增加又会对水稻吸收钴产生抑制作用;汞抑制水稻根部对镍的吸收添加甲基汞时,汞抑制水稻根部对钴、镍的吸收。除0.5MeHg+10Co暴露组茎叶中由于汞的添加钴含量有所降低外,其余各暴露组在添加汞后茎叶中钴、镍含量增加。无论无机汞还是甲基汞,均能促进钴、镍由水稻根部向茎叶部位的转移,且甲基汞促进作用较无机汞强。
[Abstract]:Hg) is a global pollutant with strong toxicity. The important way to ingest MeHg in mercury polluted areas of China is to eat rice. Mercury exposure affects the absorption and accumulation of trace elements in rice. Therefore, to explore the effects of trace elements, especially beneficial elements, on the absorption and accumulation of mercury in rice is helpful to deal with mercury pollution. In this paper, the effects of two kinds of trace elements on the accumulation and transformation of different forms of mercury in rice plants were studied, and the effects of different forms of mercury on the accumulation and transport of cobalt and nickel in rice were also studied. Using inductively coupled plasma mass spectrometry (ICP-MS), high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MSM) and synchrotron radiation-X-ray near-edge absorption spectroscopy (SR-XANESX), different types of mercury storms were analyzed by synchrotron radiation-X-ray fluorescence imaging (SR-XRFs). Transport of inorganic mercury (IHg) and methylmercury in rice tissues after exposure and addition of cobalt, Transformation and distribution of mercury in rice tissues under co-exposure to Co-MeHg. The results showed that the addition of cobalt promoted the accumulation of mercury in rice roots, inhibited the uptake of mercury by stems and leaves, and promoted the total mercury content in roots and leaves of rice under Co-IHg exposure. At the same time, the transport of mercury from rice roots to stems and leaves was promoted. The addition of cobalt did not change the form of mercury in rice tissues exposed to inorganic mercury, but could promote the demethylation of methylmercury in rice roots after 8 days of exposure to methylmercury. After 16 days of exposure, cobalt inhibited methylmercury demethylation in rice roots. SR-XANES also showed that methylmercury and inorganic mercury accumulated in rice roots, or inorganic mercury generated by transformation, were mainly generated from mercapto-containing mercury. The form of molecular binding exists, The results of CH3Hg-SR and SR-Hg-SR.SRXRF showed that the addition of cobalt increased the distribution of mercury in the root column of rice, but the distribution of mercury in stem and leaf had little change. ICP-MS and HPLC-ICP-MS techniques were used to analyze the absorption, transport and transformation of inorganic mercury and methylmercury in rice tissues after exposure to different forms of mercury and the addition of nickel. The results showed that the addition of nickel could promote the total mercury content in the root and stem and leaf tissues of rice exposed to nickel, and with the increase of nickel exposure concentration, the total mercury content of rice tissue increased. When the addition of nickel did not change the form of mercury in rice tissues, a large amount of inorganic mercury was detected in rice roots and stems and leaves, and the content of methylmercury in rice roots decreased with the increase of culture time. The contents of inorganic mercury and methylmercury in rice stem and leaf increased with the increase of culture time. The results showed that there was demethylation of methylmercury in rice plants under Ni-MeHg exposure, and the addition of nickel promoted demethylation of methylmercury in rice plants. The effects of different forms of mercury and cobalt on the content of cobalt and nickel in rice tissues were analyzed by ICP-MS. The results showed that when the inorganic mercury was added, the total cobalt content in the roots of rice was increased at the early stage of exposure, and the absorption of cobalt was inhibited with the increase of culture time, and when mercury inhibited the absorption of nickel from the roots of rice, the addition of methylmercury, Mercury inhibits the absorption of cobalt and nickel from the roots of rice. Except for the decrease of cobalt content in stem and leaf of 0.5 MeHg 10Co exposure group, the cobalt and nickel content in stem and leaf of other exposed groups increased after adding mercury. Both inorganic mercury and methylmercury could promote the transfer of cobalt and nickel from the root of rice to the stem and leaf, and the promotion of methylmercury was stronger than that of inorganic mercury.
【学位授予单位】：安徽工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S511

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