Ji Ying, Sarret Géraldine, Schulin Rainer, Tandy Susan
ITES, Institute of Terrestrial Ecosystems, ETH Zürich, 8092 Zürich, Switzerland.
ISTerre, Institut des Sciences de la Terre, Univ. Grenoble Alpes & CNRS, 38058 Grenoble, France.
Environ Pollut. 2017 Dec;231(Pt 2):1322-1329. doi: 10.1016/j.envpol.2017.08.105. Epub 2017 Sep 19.
Antimony (Sb) is a contaminant of increased prevalence in the environment, but there is little knowledge about the mechanisms of its uptake and translocation within plants. Here, we applied for the synchrotron based X-ray absorption near-edge structure (XANES) spectroscopy to analyze the speciation of Sb in roots and shoots of rye grass (Lolium perenne L. Calibra). Seedlings were grown in nutrient solutions to which either antimonite (Sb(III)), antimonate (Sb(V)) or trimethyl-Sb(V) (TMSb) were added. While exposure to Sb(III) led to around 100 times higher Sb accumulation in the roots than the other two treatments, there was no difference in total Sb in the shoots. Antimony taken up in the Sb(III) treatment was mainly found as Sb-thiol complexes (roots: >76% and shoots: 60%), suggesting detoxification reactions with compounds such as glutathione and phytochelatins. No reduction of accumulated Sb(V) was found in the roots, but half of the translocated Sb was reduced to Sb(III) in the Sb(V) treatment. Antimony accumulated in the TMSb treatment remained in the methylated form in the roots. By synchrotron based XANES spectroscopy, we were able to distinguish the major Sb compounds in plant tissue under different Sb treatments. The results help to understand the translocation and transformation of different Sb species in plants after uptake and provide information for risk assessment of plant growth in Sb contaminated soils.
锑（Sb）是环境中普遍存在的污染物，但对于其在植物体内的吸收和转运机制却知之甚少。在此，我们应用基于同步加速器的X射线吸收近边结构（XANES）光谱技术，分析黑麦草（Lolium perenne L. Calibra）根和地上部分中锑的形态。将幼苗种植在添加了亚锑酸盐（Sb(III)）、锑酸盐（Sb(V)）或三甲基锑（V）（TMSb）的营养液中。虽然暴露于Sb(III)导致根部的锑积累量比其他两种处理高约100倍，但地上部分的总锑含量并无差异。在Sb(III)处理中吸收的锑主要以锑-硫醇络合物形式存在（根：>76%，地上部分：60%），这表明与谷胱甘肽和植物螯合肽等化合物发生了解毒反应。在根部未发现积累的Sb(V)有还原现象，但在Sb(V)处理中，转运的锑中有一半被还原为Sb(III)。在TMSb处理中积累的锑在根部仍以甲基化形式存在。通过基于同步加速器的XANES光谱技术，我们能够区分不同锑处理下植物组织中的主要锑化合物。这些结果有助于理解植物吸收后不同锑物种在植物体内的转运和转化，并为受锑污染土壤中植物生长的风险评估提供信息。
