Physiological impacts of zero valent iron, Fe3O4 and Fe2O3 nanoparticles in rice plants and their potential as Fe fertilizers.

Mingshu Li, Peng Zhang, Muhammad Adeel, Zhiling Guo, Andrew J Chetwynd, Chuanxin Ma, Tonghao Bai, Yi Hao, Yukui Rui

Environmental pollution (Barking, Essex : 1987) 2021 Jan 15

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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), Fe3O4 and Fe2O3 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-1) of ZVI and Fe3O4 NPs improved the rice growth under Fe(-) condition, while Fe2O3 NPs did not improve plant growth and caused phytotoxicity at high concentration (500 mg L-1). 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-1 evidenced by reduced root volume and leaf biomass and enhanced oxidative stress in plant. Under Fe(-) condition, low dose (50 mg L-1) of ZVI NPs and Fe3O4 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 Fe3O4 NPs treatments resulted in higher Fe accumulation in plants compared to Fe2O3 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 Fe3O4 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-1 in this study) of the Fe-based NPs can impair rice growth. Copyright © 2020 Elsevier Ltd. All rights reserved.

Citation

Mingshu Li, Peng Zhang, Muhammad Adeel, Zhiling Guo, Andrew J Chetwynd, Chuanxin Ma, Tonghao Bai, Yi Hao, Yukui Rui. Physiological impacts of zero valent iron, Fe3O4 and Fe2O3 nanoparticles in rice plants and their potential as Fe fertilizers. Environmental pollution (Barking, Essex : 1987). 2021 Jan 15;269:116134