title: Use of micro-PIXE to determine spatial distributions of copper in Brassica carinata plants exposed to CuSO4 or CuEDDS.
abstract: A better understanding of the mechanisms that govern copper (Cu) uptake, distribution and tolerance in Brassica carinata plants in the presence of chelators is needed before significant progress in chelate-assisted Cu phytoextraction can be made. The aims of this study were therefore to characterise (S,S)-N,N'-ethylenediamine disuccinic acid (EDDS)-assisted Cu uptake, and to compare the spatial distribution patterns of Cu in the roots and leaves of B. carinata plants. The plants were treated with 30 μM or 150 μM CuSO(4) or CuEDDS in hydroponic solution. Quantitative Cu distribution maps and concentration profiles across root and leaf cross-sections of the desorbed plants were obtained by micro-proton induced X-ray emission. In roots, the 30 μM treatments with both CuSO(4) and CuEDDS resulted in higher Cu concentrations in epidermal/cortical regions. At 150 μM CuSO(4), Cu was mainly accumulated in root vascular bundles, whereas with 150 μM CuEDDS, Cu was detected in endodermis and the adjacent inner cortical cell layer. Under all treatments, except with a H(+)-ATP-ase inhibitor, the Cu in leaves was localised mainly in vascular tissues. The incubation of plants with 150 μM CuEDDS enhanced metal translocation to shoots, in comparison to the corresponding CuSO(4) treatment. Inhibition of H(+)-ATPase activity resulted in reduced Cu accumulation in 30 μM CuEDDS-treated roots and 150 μM CuEDDS-treated leaves, and induced changes in Cu distribution in the leaves. This indicates that active mechanisms are involved in retaining Cu in the leaf vascular tissues, which prevent its transport to photosynthetically active tissues. The physiological significance of EDDS-assisted Cu uptake is discussed.
authors.affiliation: Department of Biology of Crop Plants, University of Pisa, Via del Borghetto 80, 56121 Pisa, Italy. benedettacestone@yahoo.it
authors.forename: Benedetta
authors.initials: B
authors.lastname: Cestone
authors.forename: Katarina
authors.initials: K
authors.lastname: Vogel-Mikuš
authors.forename: Mike Frank
authors.initials: MF
authors.lastname: Quartacci
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Rascio
authors.forename: Paula
authors.initials: P
authors.lastname: Pongrac
authors.forename: Primož
authors.initials: P
authors.lastname: Pelicon
authors.forename: Primož
authors.initials: P
authors.lastname: Vavpetič
authors.forename: Nataša
authors.initials: N
authors.lastname: Grlj
authors.forename: Luka
authors.initials: L
authors.lastname: Jeromel
authors.forename: Peter
authors.initials: P
authors.lastname: Kump
authors.forename: Marijan
authors.initials: M
authors.lastname: Nečemer
authors.forename: Marjana
authors.initials: M
authors.lastname: Regvar
authors.forename: Flavia
authors.initials: F
authors.lastname: Navari-Izzo
mesh_terms: D001673:Biodegradation, Environmental; D001937:Brassica / Q000378:metabolism*; D003300:Copper / Q000378:metabolism*; D019327:Copper Sulfate / Q000378:metabolism*; D005029:Ethylenediamines / Q000378:metabolism*; D008658:Inactivation, Metabolic; D018515:Plant Leaves; D018517:Plant Roots / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism; D012989:Soil Pollutants; D013052:Spectrometry, X-Ray Emission; D013386:Succinates / Q000378:metabolism*; D014638:Vanadates / Q000378:metabolism
chemical_list: D005029:Ethylenediamines; D012989:Soil Pollutants; D013386:Succinates; C041447:N,N'-ethylenediamine disuccinic acid; D014638:Vanadates; D003300:Copper; D019327:Copper Sulfate