319 Biological Transformations of Nanoparticles in Soybean Plants Via X-Ray Absorption Spectroscopy

Thursday, November 5, 2009: 2:10 PM
Angus (Camino Real Hotel)
Jorge Gardea-Torresdey , Department of Chemistry, University of Texas at El Paso, El Paso, TX
G de La Rosa , Department of Chemistry, University of Texas at El Paso, El Paso, TX
M López-Moreno , Department of Chemistry, University of Texas at El Paso, El Paso, TX
J Hernández-Viezcas , Department of Chemistry, University of Texas at El Paso, El Paso, TX
H Castillo-Michel , Department of Chemistry, University of Texas at El Paso, El Paso, TX
J Peralta-Videa , Department of Chemistry, University of Texas at El Paso, El Paso, TX
Nanoecotoxicology studies the interaction of engineered nanoparticles (NPs) with living organisms. Reports have described the toxicity of various nanomaterials on micro and macroorganisms, but this information is still scarce. As for plants, the toxicity of some NPs on model plants and crop species has been reported. However, to the authors’ knowledge, there is no information about the plant biotransformation of metal NPs. In this study, for the first time, we show evidence pertaining to the biotransformation of ZnO and CeO2 NPs by soybean seedlings. Although the NPs did not affect germination, they produced a differential effect on plant growth and element uptake. The root length was reduced by 40% in seedlings treated with 4000 mg L-1 ZnO NPs, but increased by 75% in seedlings treated with 4000 mg L-1 CeO2 NPs. At 4000 mg L-1 treatment, seedlings treated with CeO NPs had 462 mg Ce kg-1 DW, which was about 3-fold the amount of Zn found in seedlings treated with ZnO NPs (153 mg kg-1 DW). The synchrotron X-ray absorption spectroscopy showed clear evidence of the presence of CeO2 NPs in roots, whereas the ZnO NPs were clearly not present within the roots. Our results will assist in elucidating the possible interactions of some nanomaterials with living plants and further explore the potential ability of some plant species to generate defense mechanisms for metal NP detoxification.