不同种群蜈蚣草中砷形态的X射线吸收光谱研究

A Comparison of Arsenic Speciation in 13 Pteris Vittata L.Populations

研究选择了分布于我国安徽、重庆、湖南、台湾、福建、广西、广东等7个省、市、自治区中10个不同地理区域的13个蜈蚣草种群,通过同步辐射X射线吸收光谱研究不同种群蜈蚣草中的砷形态差异,为揭示其富集机理奠定基础。蜈蚣草根部的砷主要以与O结合的方式存在,各种群的蜈蚣草根部还存在As—S配位的砷,但含量较少。蜈蚣草根部中的砷以As（Ⅴ）为主,As（Ⅴ）的比例为59.6%±0.6%～83.8%±3.8%。不同种群的根部砷形态具有较大差异,HN5种群具有明显高于其他种群的As（Ⅲ）比例,FJ种群具有明显低于其他种群的As（Ⅲ）比例,而来自湖南和广西的几种种群具有较高的As-GSH比例。As（Ⅴ）比例由低到高的顺序为：HN5HN3〉HN1〉TW〉CQ〉AH〉FJ〉HN5〉HN2〉GX2〉GX3〉HN4〉GX1。对蜈蚣草中砷形态的种群差异揭示有利于对蜈蚣草砷富集能力的种群差异来源机制进行深入研究。

Synchrotron radiation X-ray absorption near edge structure was employed to study the arsenic（As）speciation in 13 Pteris vittata L.populations collected from 7provinces,cities,and autonomous regions in China.As in roots of P.vittata was mainly combined with oxygen（O）,with a small amount of As combined with glutathione（GSH）.Populations from Hunan and Guangxi provinces showed higher percentages of As-GSH in soots.As in roots of P.vittata was predominated with As（Ⅴ）,with the percentage of As（Ⅴ）to the total As being 59.6±0.6%～83.8±3.8%.The As（Ⅴ）percentage was in the order of HN5〈GX2〈HNI〈CQ〈GX1 〈〈GD〈 HN3〈 HN4〈GX3〈 HN2〈TW〈AH〈FJ.Similar with that in roots,As in shoots was also mainly combined with O,with few combined with GSH.The percentage of As-GSH to the total As was in the order of HN5HN3〉HN1〉TW〉CQ〉AH〉FJ〉HN5〉HN2〉GX2〉GX3〉HN4〉GX1,within the range of 2.4%～12.9%.Different from that in roots,As in shoots was predominated with As（Ⅲ）,with no As（Ⅴ）detected.The disclosure of As speciation in the roots and shoots of P.vittatacontributes to the future research on As accumulation mechanism.