title: Compartmentalization and ultrastructural alterations induced by chromium in aquatic macrophytes.
abstract: The aim of the present study was to identify the sites of accumulation of Cr in the species of macrophytes that are abundant in the Cachoeira river, namely, Alternanthera philoxeroides, Borreria scabiosoides, Polygonum ferrugineum and Eichhornia crassipes. Plants were grown in nutritive solution supplemented with 0.25 and 50 mg l(-1) of CrCl(3)·6H(2)O. Samples of plant tissues were digested with HNO(3)/HCl in a closed-vessel microwave system and the concentrations of Cr determined using inductively-coupled plasma mass spectrometry (ICP-MS). The ultrastructure of root, stem and leaf tissue was examined using transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS) in order to determine the sites of accumulation of Cr and to detect possible alterations in cell organelles induced by the presence of the metal. Chromium accumulated principally in the roots of the four macrophytes (8.6-30 mg kg(-1) dw), with much lower concentrations present in the stems and leaves (3.8-8.6 and 0.01-9.0 mg kg(-1) dw, respectively). Within root tissue, Cr was present mainly in the vacuoles of parenchyma cells and cell walls of xylem and parenchyma. Alterations in the shape of the chloroplasts and nuclei were detected in A. philoxeroides and B. scabiosoides, suggesting a possible application of these aquatic plants as biomarkers from Cr contamination.
authors.affiliation: Departamento de Ciências Biológicas, Centro de Microscopia Eletrônica, Universidade Estadual de Santa Cruz, Rodovia Ilhéus-Itabuna km 16, Ilhéus, Bahia, Brazil. pamangabeira@uesc.br
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Mangabeira
authors.forename: Aluane S
authors.initials: AS
authors.lastname: Ferreira
authors.forename: Alex-Alan F
authors.initials: AA
authors.lastname: de Almeida
authors.forename: Valéria F
authors.initials: VF
authors.lastname: Fernandes
authors.forename: Emerson
authors.initials: E
authors.lastname: Lucena
authors.forename: Vânia L
authors.initials: VL
authors.lastname: Souza
authors.forename: Alberto J
authors.initials: AJ
authors.lastname: dos Santos Júnior
authors.forename: Arno H
authors.initials: AH
authors.lastname: Oliveira
authors.forename: Marie F
authors.initials: MF
authors.lastname: Grenier-Loustalot
authors.forename: Fréderique
authors.initials: F
authors.lastname: Barbier
authors.forename: Delmira C
authors.initials: DC
authors.lastname: Silva
mesh_terms: D027703:Amaranthaceae / Q000033:anatomy & histology / Q000187:drug effects; D002857:Chromium / Q000032:analysis / Q000494:pharmacology*; D031806:Eichhornia / Q000033:anatomy & histology / Q000187:drug effects; D046529:Microscopy, Electron, Transmission; D018515:Plant Leaves / Q000737:chemistry / Q000648:ultrastructure; D018517:Plant Roots / Q000737:chemistry / Q000648:ultrastructure; D018547:Plant Stems / Q000737:chemistry / Q000648:ultrastructure; D028502:Polygonum / Q000033:anatomy & histology / Q000187:drug effects; D045483:Rivers; D019666:Rubiaceae / Q000033:anatomy & histology / Q000187:drug effects; D018629:Spectrometry, Mass, Secondary Ion; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000494:pharmacology*
chemical_list: D014874:Water Pollutants, Chemical; D002857:Chromium