Centre for Water in the Minerals Industry, Sustainable Minerals Institute, The University of Queensland, Brisbane, Australia.
Department of Chemistry, The University of Adelaide, Adelaide, Australia.
Metallomics. 2023 Aug 1;15(8). doi: 10.1093/mtomcs/mfad047.
Pityrogramma calomelanos and Pteris vittata are cosmopolitan fern species that are the strongest known arsenic (As) hyperaccumulators, with potential to be used in the remediation of arsenic-contaminated mine tailings. However, it is currently unknown what chemical processes lead to uptake of As in the roots. This information is critical to identify As-contaminated soils that can be phytoremediated, or to improve the phytoremediation process. Therefore, this study identified the in situ distribution of As in the root interface leading to uptake in P. calomelanos and P. vittata, using a combination of synchrotron micro-X-ray fluorescence spectroscopy and X-ray absorption near-edge structure imaging to reveal chemical transformations of arsenic in the rhizosphere-root interface of these ferns. The dominant form of As in soils was As(V), even in As(III)-dosed soils, and the major form in P. calomelanos roots was As(III), while it was As(V) in P. vittata roots. Arsenic was cycled from roots growing in As-rich soil to roots growing in control soil. This study combined novel analytical approaches to elucidate the As cycling in the rhizosphere and roots enabling insights for further application in phytotechnologies to remediated As-polluted soils.
pityrogramma calomelanos 和 pteris vittata 是世界性的蕨类物种，是已知最强的砷（as）超积累者，具有用于修复砷污染的矿山尾矿的潜力。然而，目前尚不清楚是什么化学过程导致了根中砷的吸收。这些信息对于确定可以进行植物修复的砷污染土壤，或改善植物修复过程至关重要。因此，本研究使用同步加速器微 x 射线荧光光谱和 x 射线吸收近边结构成像相结合的方法，确定了导致 pityrogramma calomelanos 和 pteris vittata 吸收的根界面中砷的原位分布，从而揭示了这些蕨类植物根际-根界面中砷的化学转化。土壤中砷的主要形式是 as(v)，即使在施加了 as(iii)的土壤中也是如此，而在 pityrogramma calomelanos 根中主要形式是 as(iii)，而在 pteris vittata 根中则是 as(v)。砷从生长在富含砷的土壤中的根循环到生长在对照土壤中的根中。本研究结合了新的分析方法来阐明根际和根中的砷循环，为进一步在植物修复技术中应用于修复砷污染土壤提供了见解。
