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Title: In Situ Synchrotron X-ray Fluorescence Mapping and Speciation of CeO2 and ZnO Nanoparticles in Soil Cultivated Soybean (Glycine max)

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1140160
Report Number(s):
SLAC-REPRINT-2014-223
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Nano 7: 1415-1423, 2013
Country of Publication:
United States
Language:
English
Subject:
CHEM

Citation Formats

Hernandez-Viezcas, Jose A., Castillo-Michel, Hiram, Andrews, Joy Cooke, Cotte, Marine, Rico, Cyren, Peralta-Videa, Jose R., Ge, Yuan, Priester, John H., Holden, Patricia Ann, and Gardea-Torresdey, Jorge L. In Situ Synchrotron X-ray Fluorescence Mapping and Speciation of CeO2 and ZnO Nanoparticles in Soil Cultivated Soybean (Glycine max). United States: N. p., 2014. Web.
Hernandez-Viezcas, Jose A., Castillo-Michel, Hiram, Andrews, Joy Cooke, Cotte, Marine, Rico, Cyren, Peralta-Videa, Jose R., Ge, Yuan, Priester, John H., Holden, Patricia Ann, & Gardea-Torresdey, Jorge L. In Situ Synchrotron X-ray Fluorescence Mapping and Speciation of CeO2 and ZnO Nanoparticles in Soil Cultivated Soybean (Glycine max). United States.
Hernandez-Viezcas, Jose A., Castillo-Michel, Hiram, Andrews, Joy Cooke, Cotte, Marine, Rico, Cyren, Peralta-Videa, Jose R., Ge, Yuan, Priester, John H., Holden, Patricia Ann, and Gardea-Torresdey, Jorge L. Thu . "In Situ Synchrotron X-ray Fluorescence Mapping and Speciation of CeO2 and ZnO Nanoparticles in Soil Cultivated Soybean (Glycine max)". United States. doi:.
@article{osti_1140160,
title = {In Situ Synchrotron X-ray Fluorescence Mapping and Speciation of CeO2 and ZnO Nanoparticles in Soil Cultivated Soybean (Glycine max)},
author = {Hernandez-Viezcas, Jose A. and Castillo-Michel, Hiram and Andrews, Joy Cooke and Cotte, Marine and Rico, Cyren and Peralta-Videa, Jose R. and Ge, Yuan and Priester, John H. and Holden, Patricia Ann and Gardea-Torresdey, Jorge L.},
abstractNote = {},
doi = {},
journal = {ACS Nano 7: 1415-1423, 2013},
number = ,
volume = ,
place = {United States},
year = {Thu Jul 10 00:00:00 EDT 2014},
month = {Thu Jul 10 00:00:00 EDT 2014}
}
  • The influence of water stress at two soil temperatures on allocation of net photoassimilated carbon in soybean (Glycine max (L.) Merr.) was investigated using compartmental analysis. The experimental phase employed classical {sup 14}C labeling methodology with plants equilibrated at soil water potentials of {minus}0.04, {minus}0.25 and {minus}0.50 MPa; and soil temperatures of 25 and 10C. Carbon immobilization in the shoot apex generally followed leaf elongation rates with decreases in both parameters at increasing water stress at both soil temperatures. However, where moderate water stress resulted in dramatic declines in leaf elongation rates, carbon immobilization rates were sharply decreased only atmore » severe water stress levels. Carbon immobilization was decreased in the roots and nodules of the nonwater stressed treatment by the lower soil temperature. This relation was reversed with severe water stress, and carbon immobilization in the roots and nodules was increased at the lower soil temperature. Apparently, the increased demand for growth and/or carbon storage in these tissues with increased water stress overcame the low soil temperature limitations. Both carbon pool sizes and partitioning of carbon to the sink tissues increased with moderate water stress at 25C soil temperature. Increased pool sizes were consistent with whole plant osmotic adjustment at moderate water stress. Increased partitioning to the sinks was consistent with carbon translocation processes being less severely influenced by water stress than is photosynthesis.« less
  • The possible occurrence of reducing microsites in synthetic soil aggregates and their influences on the distribution of selenium species with redox-dependent mobilities was tested using the synchrotron X-ray fluorescence microprobe (SXRFM). Synthetic, effectively two-dimensional soil aggregates of diameters ranging from 10 to 30 mm were constructed, with and without inclusion of sections of Scirpus robustus and S. californicus root sections. Each aggregate was uniformly wetted with a saline solution containing 240 g m{sup {minus}3} Se [98% as Se(VI), and 2% as Se(IV)]. Gas-phase porosities varied between individual aggregates from 0.00 to 0.40 and were maintained relatively constant during the incubationmore » period of up to 17 days. Exchanges of soil gases with atmospheric air occurred only along the periphery of the aggregates. Scanning of the aggregates using SXRFM demonstrated that Se was essentially homogeneously distributed in soils without Scirpus root sections, suggesting that Se remained primarily as the soluble Se(VI) species. The SXRFM results revealed large accumulations of total Se was measured in water-saturated soils within 1 to 4 mm of decomposing roots. These observations provide support for a model of localized reducing zones in which Se(VI) is reduced to less mobile Se(IV) and to insoluble Se(0), resulting in local accumulation of total Se. The measured Se accumulation in one microsite compared reasonably well with a simple transient Se(VI) diffusion model. It is postulated that such mechanism may account for similar heterogeneities observable in some Se-contaminated soils at Kesterson Reservoir. Such heterogeneities in concentrations of Se and other constituents within individual soil aggregates have important implications with respect to reactivity and need to be included in any detailed mechanistic modeling of chemical cycling within soils. This work provides an example of the substantial capabilities of SXRFM in studies of soils. 45 refs., 11 figs.« less
  • No abstract prepared.
  • The acidity of ambient rainfall and its effect on soil and plants is a growing concern. Glass microelectrodes were used to investigate the effect of soil pH and foliar application of acid rain on the rhizosphere pH of alfalfa (Medicago sativa L. cv. Arrow), corn (Zea mays L. cv. B72 {times} MO17), and soybean (Glycine max (L.) Merr. cv. Williams 82). Plant roots were grown in minirhizotrons containing a reformed sample of Seymour silt loam A horizon over a silty clay loam Bt horizon. Low and high pH levels of 4.9 and 6.2 in the A horizon and 4.0 andmore » 5.7 in the Bt horizon were established using dilute sulfuric acid or calcium ozide, respectively. Palnts received daily applications of simulated rain, which was either acid (pH 3.1) or non-acid (pH 5.6). After 5,6, or 15 d of foliar applications to corn, soybean, or alfalfa, respectively, the rhizosphere pH was measured using a glass microelectrode. The pH values for corn and soybean increased with distance from the root while the pH values for alfalfa decreased with distance. As the soil pH increased from 4 to near 6, the difference between the pH at the root surface and the bulk soil increased from 0 to near 1. A trend for lateral root pH values at all distances to be slightly higher than main roots was observed. Increasing the pH of the A horizon had no significant effect on the rhizospehre pH of corn roots growing in the Bt horizon, but significantly increased soybean rhizosphere pH in the Bt horizon. Acid rain applications caused foliar damage, and tended to decrease rhizosphere pH, but few effects were significant.« less