Abstract:

With the rapid development of nanotechnology and the extensive usage of nanoproducts, it is inevitable for nanoparticles to enter into the soil environment and become a potential environmental contaminant, which poses a threat to soil ecosystems. In order to study the effects of nanoparticles on the growth and the main metabolites of plants, silver nanoparticles (AgNPs) were used as the test material, maize (Zea may L.) was used as the experimental plant, the effects of different levels of AgNPs (0 mg·kg^-1, 1.0 mg·kg^-1, 5.0 mg·kg^-1, and 10.0 mg·kg^-1) on the biomasses and the spectral characteristics of maize roots and leaves with Fourier transform infrared spectroscopy were investigated based on a pot experiment. Results showed that AgNPs at high concentration (10.0 mg·kg^-1) significantly decreased the aboveground and underground biomasses of maize seedlings by 16.5% and 22.2%, respectively. Different concentrations of AgNPs exerted distinct influences on the organic matter in the roots and leaves of maize seedlings. AgNPs at low concentrations (1.0 mg·kg^-1, 5.0 mg·kg^-1) increased the contents of hydroxyl and carboxyl groups, organic acids, and proteins in the maize roots, which might combine with Ag ions and thus reduce the stress of AgNPs on maize. AgNPs at high concentrations (10.0 mg·kg^-1) decreased organic matter contents related to functional groups at 4000-400 cm^-1 in the maize roots and leaves. Therefore, a low concentration of AgNPs may induce plants to resist AgNPs by adjusting the contents of hydroxyl and carboxyl groups, organic acids, and proteins. AgNPs at high concentrations may inhibit the synthesis of organic matter and thus inhibit plant growth. These results may provide a theoretical basis for revealing the mechanism of the effects of AgNPs on the growth and physiological metabolism of maize seedlings.

Key words: Silver nanoparticles, Maize, Biomass, Fourier transform infrared spectroscopy, Material composition and structure

摘要：

随着纳米科技的飞速发展和纳米产品的广泛使用，纳米颗粒不可避免地进入土壤环境成为一种潜在环境污染物，对土壤生态系统产生潜在威胁。傅里叶变换红外光谱是一种基于有机物分子中极性键振动简便快速和高分辨率分析物质组成和含量的技术。为明确纳米颗粒对植物生长和主要代谢物的影响，以纳米银为供试材料，以玉米（Zea may）为供试植物，基于盆栽试验探究不同浓度纳米银（0、1.0、5.0、10.0 mg·kg^-1）的植物生物效应，分析了不同浓度纳米银对玉米幼苗生物量的影响，利用傅里叶红外光谱法研究了不同浓度纳米银对玉米幼苗根系和叶片有机物质的影响。研究结果表明，随着纳米银浓度增加玉米幼苗地上部和地下部生物量均呈降低趋势，高浓度纳米银（10.0 mg·kg^-1）显著降低了玉米幼苗地上部和地下部生物量，降幅分别达16.5%和22.2%。不同浓度纳米银对玉米幼苗根系和叶片有机物质产生了不同程度的影响。低浓度纳米银（1.0、5.0 mg·kg^-1）提高了玉米幼苗根系羧基、羟基等基团和有机酸、蛋白质等有机物质含量，有助于吸附和固定银离子，降低纳米银对玉米幼苗生长的影响。高浓度纳米银（10.0 mg·kg^-1）降低了玉米幼苗根系和叶片4000-400 cm^-1波数范围内官能团相关有机物质含量。由此可见，低浓度纳米银下植物可通过调节羟基、羧基等基团相关有机物质含量的变化抵抗纳米银对植物的影响，但高浓度纳米银不利于植物有机物质的合成，进而影响植物生长。该结果可为揭示纳米银对玉米幼苗生长和生理代谢的影响机理提供理论依据。

关键词: 纳米银, 玉米, 生物量, 傅里叶变换红外光谱, 物质成分和结构