title: Use of X-ray absorption spectroscopy and biochemical techniques to characterize arsenic uptake and reduction in pea (Pisum sativum) plants.
abstract: Arsenite (As(III)) and arsenate (As(V)) uptake by peas was investigated using inductively coupled plasma/optical emission spectroscopy (ICP-OES) at pH below 4 and at pH 5.8. Additionally, total amylolitic activity and alpha-amylase (1,4-alpha-d-glucan glucanohydrolase; EC 3.2.1.1) activity was assayed in plants exposed to arsenic treatments. At pH below 4, the uptake for As(III) and As(V) in roots was 137 and 124 mg As kg(-1) dry weight (d wt), respectively. Translocation of arsenic to the aerial part was relatively low ( approximately 5mg As kg(-1) d wt). The uptake for As(III) and As(V) in roots at pH 5.8 was about 43 and 30 mg As kg(-1) d wt, respectively, and translocation of As to the aerial part was not detectable. None of the arsenic treatments affected the total amylolitic activity in roots; however, the shoots from all treatments showed an increase in the total amylolitic activity. Alpha-amylase activity in the pea leaves was not significantly affected by arsenic treatments. X-ray absorption spectroscopy (XAS) studies showed a reduction of As(V) to As(III) in the roots. From linear combination X-ray absorption near edge structure (LC-XANES) fittings, it was determined that arsenic was present as a mixture of As(III) oxide and sulfide in pea roots.
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968-0513, USA.
authors.forename: H
authors.initials: H
authors.lastname: Castillo-Michel
authors.forename: J G
authors.initials: JG
authors.lastname: Parsons
authors.forename: J R
authors.initials: JR
authors.lastname: Peralta-Videa
authors.forename: A
authors.initials: A
authors.lastname: Martínez-Martínez
authors.forename: K M
authors.initials: KM
authors.lastname: Dokken
authors.forename: J L
authors.initials: JL
authors.lastname: Gardea-Torresdey
mesh_terms: D000681:Amylases / Q000187:drug effects / Q000378:metabolism; D001151:Arsenic / Q000378:metabolism* / Q000494:pharmacology*; D001692:Biological Transport; D018532:Pisum sativum / Q000187:drug effects / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D013052:Spectrometry, X-Ray Emission / Q000379:methods*; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D000681:Amylases; D000516:alpha-Amylases; D001151:Arsenic