State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China; Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968, United States; The Connecticut Agricultural Experiment Station, New Haven, CT 06504, United States.
State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China.
NanoImpact. 2021 Jul;23:100336. doi: 10.1016/j.impact.2021.100336. Epub 2021 Jun 18.
Nanoscale zero-valent iron (nZVI) has been widely applied in the environmental field to degrade organic pollutants. The potential risk posed from nZVI on crop species is not well understood and is critical for sustainable application in the future. In this study, maize (Zea mays L.) plants were cultivated in field soils mixed with nZVI at 0, 50, and 500 mg/kg soil for four weeks. Upon exposure to 500 mg/kg nZVI, ICP-MS results showed that Fe accumulated by roots and translocated to leaves was increased by 36% relative to untreated controls. At 50 mg/kg, root elongation was enhanced by 150-200%; at 500 mg/kg, pigments, lipid peroxidation, and polyphenolic levels in leaves were increased by 12, 87 and 23%, respectively, whereas the accumulation of Al, Ca, and P were decreased by 62.2%, 19.7%, and 13.3%, respectively. A gas chromatography-mass spectrometry (GC-MS) based metabolomics analysis of maize roots revealed that antioxidants and stress signaling-associated metabolites were downregulated at 50 mg/kg, but were upregulated at 500 mg/kg. At 50 mg/kg, the content of glutamate was increased by 11-fold, whereas glutamine was decreased by 99% with respect to controls. Interestingly, eight metabolic pathways were disturbed at 50 mg/kg, but none at 500 mg/kg. This metabolic reprogramming at the lower dose represented potential risks to the health of exposed plants, which could be particularly important although no phenotypic impacts were noted. Overall, metabolites analysis provides a deeper understanding at the molecular level of plant response to nZVI and is a powerful tool for full characterization of risk posed to crop species as part of food safety assessment.
纳米零价铁（nZVI）已广泛应用于环境领域，用于降解有机污染物。然而，人们对 nZVI 对作物品种可能造成的潜在风险了解甚少，这对于其未来的可持续应用至关重要。在本研究中，将玉米（Zea mays L.）植株种植在添加了 0、50 和 500 mg/kg 土壤 nZVI 的田间土壤中，培养四周。暴露于 500 mg/kg nZVI 后，ICP-MS 结果显示，与未处理对照相比，根部积累并转运到叶片的铁增加了 36%。在 50 mg/kg 时，根伸长增加了 150-200%；在 500 mg/kg 时，叶片中的色素、脂质过氧化和多酚水平分别增加了 12%、87%和 23%，而铝、钙和磷的积累分别减少了 62.2%、19.7%和 13.3%。基于气相色谱-质谱（GC-MS）的玉米根代谢组学分析表明，抗氧化剂和应激信号相关代谢物在 50 mg/kg 时下调，但在 500 mg/kg 时上调。在 50 mg/kg 时，谷氨酸含量增加了 11 倍，而谷氨酰胺含量与对照相比减少了 99%。有趣的是，在 50 mg/kg 时有 8 条代谢途径受到干扰，但在 500 mg/kg 时没有。这种在较低剂量下的代谢重编程代表了暴露植物健康的潜在风险，尽管没有观察到表型影响，但这可能尤其重要。总体而言，代谢物分析提供了对植物对 nZVI 响应的分子水平的更深入理解，并且是作为食品安全评估的一部分对作物品种造成的风险进行全面特征描述的有力工具。
