Department of Environmental Geosciences, Faculty of Environmental Sciences , Czech University of Life Sciences Prague , Kamýcká 129 , 165 00 Prague-Suchdol , Czech Republic.
Department of Mycorrhizal Symbioses, Institute of Botany , Czech Academy of Sciences , 272 53 Pruhonice , Czech Republic.
Environ Sci Technol. 2018 Jul 17;52(14):7640-7651. doi: 10.1021/acs.est.7b05516. Epub 2018 Jun 26.
Nano zero-valent iron (nZVI) has great potential in the remediation of metal(loid)-contaminated soils, but its efficiency in metal(loid) stabilization in the plant-microbe continuum is unclear. This study investigated nZVI-mediated metal(loid) behavior in the arbuscular mycorrhizal (AM) fungal-maize ( Zea mays L.) plant association. Plants with AM fungal inoculation were grown in metal(loid)- (mainly Zn and Pb) contaminated soils (Litavka River, Czech Republic) amended with/without 0.5% (w/w) nZVI. The results showed that nZVI decreased plant metal(loid) uptake but inhibited AM development and its function in metal(loid) stabilization in the rhizosphere. AM fungal inoculation alleviated the physiological stresses caused by nZVI and restrained nZVI efficiency in reducing plant metal(loid) uptake. Micro proton-induced X-ray emission (μ-PIXE) analysis revealed the sequestration of Zn (possibly through binding to thiols) by fungal structures in the roots and the precipitation of Pb and Cu in the mycorrhizal root rhizodermis (possibly by Fe compounds originated from nZVI). XRD analyses further indicated that Pb/Fe mineral transformations in the rhizosphere were influenced by AM and nZVI treatments. The study revealed the counteractive effects of AM and nZVI on plant metal(loid) uptake and uncovered details of metal(loid) behavior in the AM fungal-root-nZVI system, calling into question about nZVI implementation in mycorrhizospheric systems.
纳米零价铁（nZVI）在修复金属（类）污染土壤方面具有巨大潜力，但它在植物-微生物连续体中稳定金属（类）的效率尚不清楚。本研究调查了 nZVI 介导的丛枝菌根（AM）真菌-玉米（Zea mays L.）植物联合体中金属（类）的行为。在受金属（类）（主要是 Zn 和 Pb）污染的土壤（捷克共和国 Litavka 河）中，用/不用 0.5%（w/w）nZVI 处理接种 AM 真菌的植物。结果表明，nZVI 降低了植物对金属（类）的吸收，但抑制了 AM 的发育及其在根际稳定金属（类）的功能。AM 真菌接种缓解了 nZVI 引起的生理压力，并抑制了 nZVI 降低植物金属（类）吸收的效率。微质子诱发 X 射线发射（μ-PIXE）分析表明，真菌结构在根中螯合了 Zn（可能通过与硫醇结合），Pb 和 Cu 在丛枝菌根根根皮中沉淀（可能通过源自 nZVI 的 Fe 化合物）。XRD 分析进一步表明，根际中 Pb/Fe 矿物转化受到 AM 和 nZVI 处理的影响。该研究揭示了 AM 和 nZVI 对植物金属（类）吸收的拮抗作用，并揭示了 AM 真菌-根-nZVI 系统中金属（类）行为的细节，这对在菌根际系统中实施 nZVI 提出了质疑。
