The association of physicochemical properties of CeO₂-NPs (CeO₂ nanoparticles) per se with their transformation is not well understood. This study for the first time compared the translocation and transformation of octahedral, cubic, rod, and irregularly shaped CeO₂-NPs in hydroponic cucumber plants. Cerium contents in roots were close between different treatments, while the largest amount (153 mg/kg) of Ce accumulated in rod-like CeO₂-NP treatments. Transmission electron microscopy and X-ray absorption near edge spectroscopy show that rod CeO₂-NPs transformed faster and more than other CeO₂-NPs, with nearly 40% of Ce in the form of Ce(III) species in roots (CePO₄) and shoots (Ce carboxylates). Rod-like CeO₂-NPs transformed to a degree greater than those of the other CeO₂-NPs in solution simulating the plant exudates, indicating that rod-like CeO₂-NPs have the highest chemical reactivity. These results suggest that the intrinsically different chemical reactivity of differently shaped CeO₂-NPs resulted in their different transformation and translocation capacities in plants. This study provides new insight into plant–NP interaction, highlighting the significance of the shape of nanoparticles in assessing their environmental behavior and impacts. We suggest that the influence of shape should be also considered for other nanomaterials and systems in developing an accurate understanding of the nano–bio interactions.

中文翻译：

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黄瓜植物中二氧化铈纳米粒子的形状依赖性转化和易位

CeO ₂ -NPs（CeO ₂纳米颗粒）本身的物理化学性质与其转化之间的联系尚不清楚。这项研究首次比较了水培黄瓜植株中八面体，立方，棒状和不规则形状的CeO ₂ -NP的易位和转化。在不同处理之间，根中的铈含量接近，而在棒状CeO ₂ -NP处理中，Ce的累积量最大（153 mg / kg）。透射电子显微镜和近边缘光谱的X射线吸收表明，棒状CeO ₂ -NPs的转化速度更快，并且比其他CeO ₂ -NPs更快，其根中近40％的Ce以Ce（III）的形式存在（CePO ₄）和芽（Ce羧酸盐）。棒状的CeO _2个-nps变换到更大的程度比其它的CeO _2个-nps在溶液模拟植物渗出物，表明棒状的CeO _2个-nps具有最高的化学反应性。这些结果表明，不同形状的CeO ₂具有本质上不同的化学反应性-NP在植物中导致其不同的转化和易位能力。这项研究提供了对植物与NP相互作用的新见解，强调了纳米颗粒形状在评估其环境行为和影响方面的重要性。我们建议在发展对纳米生物相互作用的准确理解时，还应考虑形状的影响对其他纳米材料和系统的影响。