蜈蚣草孢子囊元素组成的X射线光谱分析  

Micro-Distribution of Elements and Speciation of Arsenic in the Sporangium of Pteris Vittata

作　　者：万小铭[1,2] 曾伟斌 雷梅 陈同斌[1,2] WAN Xiao-ming;ZENG Wei-bin;LEI Mei;CHEN Tong-bin(Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences(CAS),Beijing 100101,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院地理科学与资源研究所,北京100101 [2]中国科学院大学,北京100049

出　　处：《光谱学与光谱分析》2022年第2期478-482,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(42077136);中国科学院青年创新促进会项目(2017075)资助。

摘　　要：砷超富集植物蜈蚣草具有超强的砷吸收和富集能力,生物量大,被认为是修复砷污染土壤的理想植物材料。基于砷超富集植物蜈蚣草的植物修复技术已经推广应用到了我国20多个污染区的土壤修复实践中。目前所报道的所有蜈蚣草均具有砷超富集能力,并且该特性能够得到稳定遗传。蜈蚣草是如何通过仅仅几十个微米的孢子将这种砷超富集能力传递给下一代?与其他微区分析手段相比,基于同步辐射X射线的荧光光谱和吸收光谱分析灵敏度高、操作简便,近年来被广泛应用到超富集植物的研究中,它也使得研究几十个微米的孢子中砷及其他元素的分布成为可能。为了揭示砷超富集植物蜈蚣草孢子的化学元素组成,该研究采用同步辐射X射线荧光探针分析技术首次揭示了蜈蚣草的生殖细胞——孢子中砷、铜、锌等微量元素的浓度分布,以及钾、钙等大量元素的浓度分布;并将砷的分布趋势与大量营养元素钾、钙、铁、硫,以及微量元素铜、锌的分布趋势进行对比。蜈蚣草的微区元素分布研究表明,孢子囊中砷和钙、砷和硫的分布特征具有相似性,砷和硫、钙更有可能同时聚集在孢子中。这表明,在孢子产生和萌发过程中,砷、硫和钙可能发挥着重要作用。为了揭示变价元素砷在孢子中的存在形式,采用同步辐射X射线吸收光谱首次揭示了蜈蚣草孢子中砷的微区形态,结果表明,蜈蚣草孢子中砷的存在形态与羽叶一致,以低价态的AsⅢ为主。AsⅢ是活性和毒性都相对较强的一种砷存在形式。这表明蜈蚣草孢子对于高毒性高活性的三价砷具有较强耐性。通过采用高分辨率低检测限的X射线荧光探针和X射线吸收光谱技术,揭示砷超富集植物蜈蚣草孢子中砷的分布和存在形式,研究结果为了解蜈蚣草砷富集能力的遗传特性提供基础信息。The arsenic(As)hyperaccumulator Pteris vittata has super As accumulation ability and huge biomass,thus being ideal plant material for the phytoremediation of As-contaminated soil.Phytoextraction technology based on As hyperaccumulator P.vittata has been applied to more than 20 soil remediation projects in China.So far,the reported P.vittata populations all showed strong accumulation ability of As,and this hyperaccumulation ability was able to be stably inherited from the progenitor.How can this fern pass As hyperaccumulation ability on to the next generation through spores(the germ cell of fern plants)with the size of several micrometers?Compared to the traditional chemical analysis methods,Synchrotron Radiation X-ray Fluorescence Microprobe Analysis and X-Ray Absorption Spectroscopy show high sensitivity and are easy to operate,recently widely used to study hyperaccumulating mechanisms.This study investigated the micro-distribution pattern of As in spores using Synchrotron Radiation X-ray Fluorescence Microprobe Analysis micro-speciation of As in spores using Synchrotron Radiation X-ray Absorption Spectroscopy.The distribution of As was compared to that of potassium,calcium,iron,sulfur,copper and zinc.It has been found that the distribution of As,sulfur,and calcium was similar.It was indicating the role of their interaction in the stable inheritance of As hyperaccumulation.The micro speciation analysis indicated that the main species of As in spores and sporangium was arsenite(AsⅢ).Considering that AsⅢhas higher mobility and toxicity than arsenate in most organisms,the results indicated high tolerance of P.vittata to As throughout its life cycle.Using X-ray Fluorescence Microprobe Analysis and X-ray Absorption Spectroscopy with high resolution,results provide basic information for understanding the genetic characteristics of arsenic hyperaccumulation ability of P.vittata.

关 键 词：同步辐射X射线吸收光谱 X射线荧光探针 蜈蚣草 孢子 砷形态 

分 类 号：X53[环境科学与工程—环境工程]