微区X射线荧光光谱仪研制及元素生物地球化学动态分布过程研究

发布时间：2018-02-02 16:59

本文关键词： 微区X射线荧光生物膜玉米解毒与耐受机制微量元素毒性元素铅　出处：《光谱学与光谱分析》2017年04期 　论文类型：期刊论文

【摘要】：微区无损分析可提供物质组成元素的原位分布信息,以揭示物质形成条件、元素动态分布过程与相互作用机理、生物代谢作用等。文章报道了实验室型微区X射线荧光(μXRF)光谱仪的研发和元素生物地球化学动态分布过程研究结果。μXRF光谱仪采用15μm光斑的聚束毛细管X射线透镜为激发源,选用分辨率为135eV的硅漂移探测器(SDD),样品和探测器间角度可调,使之可进行异型样品如地质样品的原位分析,利用五轴自控实现样品时空四维元素分布测定。利用该μXRF光谱仪测定了矿物-生物膜间的元素迁移和玉米种发芽过程中的元素分布,发现(1)生物膜可吸附、富集毒性元素铅,是重金属的重要汇集地,最大富集系数1.7。(2)生物膜是金属从固态矿物相经水相进入生态系统的重要途径。(3)在玉米种子中,可检测到K,Ca,Mn,Fe,Cu,Zn和Pb。Zn主要在胚乳中分布,胚中有少量Zn存在;在胚乳和胚中存在微量Fe;胚乳中存在微量Pb,胚中未观测到Pb。(4)经含Pb溶液浸泡发芽后,K在玉米种中胚和胚乳中部分富集,Fe分布在种皮和胚乳中,Cu和Zn主要在胚乳中分布;Pb主要在胚根、胚轴和胚芽中分布,且Pb在新生根中高度富集。研究表明,在种子萌发阶段,Pb等毒性元素可被植物滞留于根部,制约了其向地上部的转移,从而揭示了植物对毒性元素的耐受机制。
[Abstract]:The in-situ distribution information of the elements can be provided by the non-destructive analysis of the micro-region, which can reveal the formation conditions of the material, the dynamic distribution process and the interaction mechanism of the elements. Biological metabolism, etc. In this paper, the microregion X-ray fluorescence (渭 XRFs) of laboratory type was reported. The research and development of spectrometer and the dynamic process of element biogeochemistry were studied. The 渭 XRF spectrometer used 15 渭 m spot spot capillary X-ray lens as the excitation source. The silicon drift detector with a resolution of 135 EV is selected. The angle between the sample and the detector can be adjusted so that it can be used for in-situ analysis of abnormal samples such as geological samples. The distribution of four dimensional elements in time and space was determined by means of five axis automatic control. The element migration between mineral and biofilm and the distribution of elements in the germination of maize seeds were measured by the 渭 XRF spectrometer. It is found that biofilm can be adsorbed and enriched with lead, which is an important accumulation site of heavy metals. The biofilm is an important way for metals to enter the ecosystem from solid mineral phase through aqueous phase. Zn and Pb.Zn were mainly distributed in endosperm and a small amount of Zn existed in embryo. Microamounts of Fe exist in endosperm and embryo. Trace amount of Pb in endosperm and no Pb. 4) K was partially enriched in embryo and seed coat and endosperm after soaked in Pb solution. Cu and Zn mainly distributed in endosperm. Pb was mainly distributed in radicle, hypocotyls and germ, and Pb was highly enriched in new rooting. Therefore, the mechanism of plant tolerance to toxic elements was revealed.
【作者单位】：国家地质实验测试中心;
【基金】：国家高新技术研究发展计划(863)项目(2007AA06Z124) 国家自然科学基金项目(20775018,41201527)资助
【分类号】：P593;O657.34
【正文快照】： 引言微区X射线荧光光谱分析技术(μXRF)可以识别并定量测定物质组成元素,获得元素三维分布信息和元素相关性数据,利用微区X射线衍射分析技术(μXRD)可以识别元素所在的矿物相,利用微区X射线吸收光谱(μXAS)可以测定待测元素的化学键和氧化态[1]。这种可非破坏同时测定多种物质

【相似文献】