Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes and Centre National de la Recherche Scientifique (CNRS) , 38041 Grenoble, France.
ID21, European Synchrotron Radiation Facility (ESRF) , CS 40220, 38043 Grenoble Cedex 9, France.
Environ Sci Technol. 2017 May 16;51(10):5774-5782. doi: 10.1021/acs.est.7b00422. Epub 2017 May 5.
Agricultural soils are major sinks of silver nanoparticles in the environment, and crops are directly exposed to these emerging contaminants. A clear picture of their chemical transformations, uptake and transport mechanisms, and phytotoxic impacts is still lacking. In this work, wheat plants were exposed to pristine metallic (Ag-NPs) and sulfidized (AgS-NPs) silver nanoparticles and ionic Ag. Data on Ag distribution and speciation, phytotoxicity markers, and gene expression were studied. A multi-technique and multi-scale approach was applied, combining innovating tools at both the laboratory and synchrotron. Various chemical transformations were observed on the epidermis and inside roots, even for AgS-NPs, leading to an exposure to multiple Ag forms, which likely evolve over time. Genes involved in various functions including oxidative stress, defense against pathogens, and metal homeostasis were impacted in different ways depending upon the Ag source. This study illustrates the complexity of the toxicity pattern for plants exposed to Ag-NPs, the necessity of monitoring several markers to accurately evaluate the toxicity, and the interest of interpreting the toxicity pattern in light of the distribution and speciation of Ag.
农业土壤是环境中银纳米粒子的主要汇，而农作物直接暴露于这些新兴污染物中。对于它们的化学转化、吸收和转运机制以及植物毒性影响，我们仍缺乏清晰的认识。在这项工作中，小麦植株被暴露于原始金属态（Ag-NPs）和硫化态（AgS-NPs）银纳米粒子以及离子态 Ag 下。我们研究了 Ag 的分布和形态、植物毒性标志物和基因表达的数据。我们采用了多技术和多尺度的方法，结合了实验室和同步加速器的创新工具。在表皮和根内观察到了各种化学转化，即使是对于 AgS-NPs，也导致了多种 Ag 形态的暴露，这些形态可能随着时间的推移而演变。根据 Ag 的来源，参与各种功能（包括氧化应激、抵御病原体和金属稳态）的基因受到不同方式的影响。本研究说明了暴露于 Ag-NPs 的植物的毒性模式的复杂性，有必要监测多种标志物来准确评估毒性，并根据 Ag 的分布和形态来解释毒性模式的意义。
