College of Resources and Environmental Sciences, China Agricultural University, Beijing 100093, China.
School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
Environ Pollut. 2021 Jan 15;269:116134. doi: 10.1016/j.envpol.2020.116134. Epub 2020 Dec 1.
Fe-based nanoparticles (Fe-based NPs) have great potential as a substitute for traditional Fe-fertilizer; however, their environmental risk and impact on plant growth are not fully understood. In this study, we compared the physiological impacts of three different Fe-based NP formulations: zero-valent iron (ZVI), FeO and FeO NPs, on hydroponic rice after root exposure for 2 weeks. Fe-normal (Fe(+)) and Fe-deficiency (Fe(-)) conditions were compared. Results showed that low dose (50 mg L) of ZVI and FeO NPs improved the rice growth under Fe(-) condition, while FeO NPs did not improve plant growth and caused phytotoxicity at high concentration (500 mg L). Under Fe(+) conditions, none of the Fe-based NPs exhibited positive effects on the rice plants with plant growth actually being inhibited at 500 mg L evidenced by reduced root volume and leaf biomass and enhanced oxidative stress in plant. Under Fe(-) condition, low dose (50 mg L) of ZVI NPs and FeO NPs increased the chlorophyll content by 30.7% and 26.9%, respectively. They also alleviated plant stress demonstrated by the reduced oxidative stress and decreased concentrations of stress related phytohormones such as gibberellin and indole-3-acetic acid. Low dose of ZVI and FeO NPs treatments resulted in higher Fe accumulation in plants compared to FeO NPs treatment, by down-regulating the expression of IRT1 and YSL15. This study provides significant insights into the physiological impacts of Fe-based NPs in rice plants and their potential application in agriculture. ZVI and FeO NPs can be used as Fe-fertilizers to improve rice growth under Fe-deficient condition, which exist in many rice-growing regions of the world. However, dose should be carefully chosen as high dose (500 mg L in this study) of the Fe-based NPs can impair rice growth.
基于铁的纳米颗粒（Fe-based NPs）作为传统铁肥的替代品具有很大的潜力；然而，其环境风险和对植物生长的影响尚未完全了解。在这项研究中，我们比较了三种不同的基于铁的 NP 制剂（零价铁（ZVI）、FeO 和 FeO NPs）在根系暴露 2 周后对水培水稻的生理影响。比较了 Fe 正常（Fe(+)）和 Fe 缺乏（Fe(-)）条件。结果表明，低剂量（50 mg/L）的 ZVI 和 FeO NPs 在 Fe(-)条件下促进了水稻的生长，而 FeO NPs 并未改善植物的生长，且在高浓度（500 mg/L）下引起了植物毒性。在 Fe(+)条件下，没有一种基于铁的 NPs 对水稻植株表现出积极影响，实际上，在 500 mg/L 时，植物生长受到抑制，表现为根体积和叶片生物量减少，植物氧化应激增强。在 Fe(-)条件下，低剂量（50 mg/L）的 ZVI NPs 和 FeO NPs 分别使叶绿素含量增加了 30.7%和 26.9%。它们还减轻了植物的应激，表现为氧化应激降低，与应激相关的植物激素如赤霉素和吲哚-3-乙酸的浓度降低。与 FeO NPs 处理相比，低剂量的 ZVI 和 FeO NPs 处理导致植物中 Fe 的积累更高，这是通过下调 IRT1 和 YSL15 的表达实现的。本研究为基于铁的 NPs 在水稻植物中的生理影响及其在农业中的潜在应用提供了重要的见解。ZVI 和 FeO NPs 可作为铁肥在世界上许多水稻种植地区用于改善 Fe 缺乏条件下的水稻生长。然而，剂量应谨慎选择，因为本研究中高剂量（500 mg/L）的基于铁的 NPs 会损害水稻的生长。
