This study compared the impact and uptake of root-administered CeO₂ nanoparticles (NPs) in rice growing under flooded and aerobic soil conditions, which are two water regimes commonly used for rice cultivation. CeO₂ NPs at 100 mg/kg improved photosynthesis and plant growth by reducing the oxidative damage and enhancing plant tolerance to stress, while a higher concentration (500 mg/kg) of CeO₂ NPs negatively affected plant growth. More significant effects were observed under the flooded condition than under the aerobic condition. CeO₂ NPs of 100 and 500 mg/kg resulted in 78% and 70% higher accumulation of Ce in shoots under the flooded condition compared to the aerobic condition. CeO₂ NPs partially transformed to Ce(III) species in soils and plants under both conditions. A higher extent of transformation under the flooded condition, which was partly attributed to the lower soil pH and redox potential under the flooded condition, leads to higher plant uptake of Ce. A higher extent of transformation in rhizosphere soil was observed. A higher plant transpiration rate (TR) under flooded conditions resulted in a higher accumulation of CeO₂ species in shoots. This study, for the first time, reported that water regimes influenced the biotransformation of CeO₂ NPs and their uptake and impact in rice plants.

中文翻译：

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种植水稻 ( Oryza sativa ) 有氧降低 CeO ₂纳米颗粒的植物毒性、吸收和转化

本研究比较了根部施用的 CeO ₂纳米粒子 (NPs) 在淹水和好氧土壤条件下生长的水稻中的影响和吸收，这是水稻种植常用的两种水体。100 mg/kg 的CeO ₂ NPs 通过减少氧化损伤和增强植物对胁迫的耐受性来改善光合作用和植物生长，而较高浓度 (500 mg/kg) 的 CeO ₂ NPs 对植物生长产生负面影响。在淹没条件下观察到比在有氧条件下更显着的影响。与有氧条件相比，在水淹条件下，100 和 500 mg/kg 的CeO ₂ NPs 导致芽中 Ce 的积累高 78% 和 70%。氧化铈₂在两种条件下，NPs 在土壤和植物中部分转化为 Ce(III) 物种。淹水条件下更高程度的转化，部分归因于淹水条件下较低的土壤 pH 值和氧化还原电位，导致植物对 Ce 的更高吸收。在根际土壤中观察到更高程度的转化。淹水条件下较高的植物蒸腾速率 (TR) 导致枝条中 CeO ₂种类的积累较高。该研究首次报道了水分状况影响了 CeO ₂ NPs的生物转化及其在水稻中的吸收和影响。