TY - JOUR
T1 - Influence of Surface Charge on the Phytotoxicity, Transformation, and Translocation of CeO 2 Nanoparticles in Cucumber Plants
AU - Liu, Mengyao
AU - Feng, Sheng
AU - Ma, Yuhui
AU - Xie, Changjian
AU - He, Xiao
AU - Ding, Yayun
AU - Zhang, Junzhe
AU - Luo, Wenhe
AU - Zheng, Lirong
AU - Chen, Dongliang
AU - Yang, Fang
AU - Chai, Zhifang
AU - Zhao, Yuliang
AU - Zhang, Zhiyong
PY - 2019/5/8
Y1 - 2019/5/8
N2 - The physiochemical properties of nanoparticles (NPs), including surface charge, will affect their uptake, transformation, translocation, and final fate in the environment. In this study, we compared the phytoxoxicity and transport behaviors of nano CeO 2 (nCeO 2 ) functionalized with positively charged (Cs-nCeO 2 ) and negatively charged (PAA-nCeO 2 ) coatings. Cucumber seedlings were hydroponically exposed to 0-1000 mg/L of Cs-nCeO 2 and PAA-nCeO 2 for 14 days and the contents, distribution, translocation, and transformation of Ce in plants were analyzed using inductively coupled plasma mass spectrometry, micro X-ray fluorescence (μ-XRF), and X-ray absorption near-edge spectroscopy (XANES), respectively. Results showed that the seedling growth and Ce contents in plant tissues were functions of exposure concentrations and surface charge. Cs-nCeO 2 was adsorbed strongly on a negatively charged root surface, which led to significantly higher Ce contents in the roots and lower translocation factors of Ce from the roots to shoots in Cs-nCeO 2 group than in PAA-nCeO 2 group. The results of μ-XRF showed that Ce elements were mainly accumulated at the root tips and lateral roots, as well as in the veins and at the edge of leaves. XANES results revealed that the proportion of Ce(III) was comparable in the plant tissues of the two groups. We speculated that Cs-nCeO 2 and PAA-nCeO 2 were partially dissolved under the effect of root exudates, releasing Ce 3+ ions as a result. Then, the Ce 3+ ions were transported upward in the form of Ce(III) complexes along the vascular bundles and eventually accumulated in the veins. The other portion of Cs-nCeO 2 and PAA-nCeO 2 entered the roots through the gap of a Casparian strip at root tips/lateral roots and was transported upward as intact NPs and finally accumulated at the edge of the blade. This study will greatly advance our information on how the properties of NPs influence their phytotoxicity, uptake, and subsequent trophic transfer in terrestrial food webs.
AB - The physiochemical properties of nanoparticles (NPs), including surface charge, will affect their uptake, transformation, translocation, and final fate in the environment. In this study, we compared the phytoxoxicity and transport behaviors of nano CeO 2 (nCeO 2 ) functionalized with positively charged (Cs-nCeO 2 ) and negatively charged (PAA-nCeO 2 ) coatings. Cucumber seedlings were hydroponically exposed to 0-1000 mg/L of Cs-nCeO 2 and PAA-nCeO 2 for 14 days and the contents, distribution, translocation, and transformation of Ce in plants were analyzed using inductively coupled plasma mass spectrometry, micro X-ray fluorescence (μ-XRF), and X-ray absorption near-edge spectroscopy (XANES), respectively. Results showed that the seedling growth and Ce contents in plant tissues were functions of exposure concentrations and surface charge. Cs-nCeO 2 was adsorbed strongly on a negatively charged root surface, which led to significantly higher Ce contents in the roots and lower translocation factors of Ce from the roots to shoots in Cs-nCeO 2 group than in PAA-nCeO 2 group. The results of μ-XRF showed that Ce elements were mainly accumulated at the root tips and lateral roots, as well as in the veins and at the edge of leaves. XANES results revealed that the proportion of Ce(III) was comparable in the plant tissues of the two groups. We speculated that Cs-nCeO 2 and PAA-nCeO 2 were partially dissolved under the effect of root exudates, releasing Ce 3+ ions as a result. Then, the Ce 3+ ions were transported upward in the form of Ce(III) complexes along the vascular bundles and eventually accumulated in the veins. The other portion of Cs-nCeO 2 and PAA-nCeO 2 entered the roots through the gap of a Casparian strip at root tips/lateral roots and was transported upward as intact NPs and finally accumulated at the edge of the blade. This study will greatly advance our information on how the properties of NPs influence their phytotoxicity, uptake, and subsequent trophic transfer in terrestrial food webs.
KW - cucumber
KW - nCeO
KW - phytotoxicity
KW - surface charge
KW - transformation
KW - translocation
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U2 - 10.1021/acsami.9b01627
DO - 10.1021/acsami.9b01627
M3 - Article
C2 - 30993970
AN - SCOPUS:85065496342
VL - 11
SP - 16905
EP - 16913
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
SN - 1944-8244
IS - 18
ER -