Nanoparticle (NP) physiochemical properties, including surface charge, affect cellular uptake, translocation, and tissue localization. To evaluate the influence of surface charge on NP uptake by plants, wheat seedlings were hydroponically exposed to 20 mg/L of ∼4 nm CeO2 NPs functionalized with positively charged, negatively charged, and neutral dextran coatings. Fresh, hydrated roots and leaves were analyzed at various time points over 34 h using fluorescence X-ray absorption near-edge spectroscopy to provide laterally resolved spatial distribution and speciation of Ce. A 15-20% reduction from Ce(IV) to Ce(III) was observed in both roots and leaves, independent of NP surface charge. Because of its higher affinity with negatively charged cell walls, CeO2(+) NPs adhered to the plant roots the strongest. After 34 h, CeO2(-), and CeO2(0) NP exposed plants had higher Ce leaf concentrations than the plants exposed to CeO2(+) NPs. Whereas Ce was found mostly in the leaf veins of the CeO2(-) NP exposed plant, Ce was found in clusters in the nonvascular leaf tissue of the CeO2(0) NP exposed plant. These results provide important information for understanding mechanisms responsible for plant uptake, transformation, and translocation of NPs, and suggest that NP coatings can be designed to target NPs to specific parts of plants.
|Number of pages||8|
|Journal||Environmental Science and Technology|
|State||Published - Jul 5 2017|
Bibliographical noteFunding Information:
This material is based upon work supported by the U.S. National Science Foundation (NSF) and the Environmental Protection Agency (EPA) under NSF Cooperative Agreement EF-1266252, Center for the Environmental Implications of NanoTechnology (CEINT), from the NSF Integrated Graduate Education and Research Traineeship Nanotechnology Environmental Effects and Policy (IGERT-NEEP) (DGE- 0966227), and CBET-1530563 (NanoFARM). The synchrotron work was conducted using the XFM beamline (AS162/ XFM/10714) at the Australia Synchrotron, Victoria, Australia. We thank J. Li and E. Oostveen for synthesis of the NPs.
© 2017 American Chemical Society.
ASJC Scopus subject areas
- Chemistry (all)
- Environmental Chemistry