title: Formation of biomineral iron oxides compounds in a Fe hyperaccumulator plant: Imperata cylindrica (L.) P. Beauv.
abstract: We report a detailed work of composition and location of naturally formed iron biominerals in plant cells tissues grown in iron rich environments as Imperata cylindrica. This perennial grass grows on the Tinto River banks (Iberian Pyritic Belt) in an extreme acidic ecosystem (pH∼2.3) with high concentration of dissolved iron, sulphate and heavy metals. Iron biominerals were found at the cellular level in tissues of root, stem and leaf both in collected and laboratory-cultivated plants. Iron accumulated in this plant as a mix of iron compounds (mainly as jarosite, ferrihydrite, hematite and spinel phases) was characterized by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), Mössbauer spectroscopy (MS), magnetometry (SQUID), electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX; TEM-EDX; HRSTEM). A low fraction of phosphorous was detected in this iron hyperaccumulator plant. Root and rhizomes tissues present a high proportion of ferromagnetic iron oxide compounds. Iron oxides-rich zones are localized in electron dense intra and inter-cellular aggregates that appear as dark deposits covering the inner membrane and organelles of the cell. This study aims to contribute to a better understanding of the mechanisms of accumulation, transport, distribution of iron in Imperata cylindrica.
authors.affiliation: Departamento de Biología, Facultad de Ciencias, UAM, Cantoblanco, 28049 Madrid, Spain. Electronic address: vicenta.fuente@uam.es.
authors.forename: V
authors.initials: V
authors.lastname: Fuente
authors.affiliation: Departamento de Biología, Facultad de Ciencias, UAM, Cantoblanco, 28049 Madrid, Spain; Departamento de Farmacia, Universidad Francisco de Vitoria, 28233 Pozuelo de Alarcón, Madrid, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Rufo
authors.affiliation: Departamento de Química Física Aplicada, Facultad de Ciencias, UAM, Cantoblanco, 28049 Madrid, Spain; IMDEA Nanociencia, C/Faraday 9 Campus Universitario de Cantoblanco, 28049 Madrid, Spain.
authors.forename: B H
authors.initials: BH
authors.lastname: Juárez
authors.affiliation: Departamento de Química Física Aplicada, Facultad de Ciencias, UAM, Cantoblanco, 28049 Madrid, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Menéndez
authors.affiliation: Laboratoire de Matière et Systèmes Complexes (MSC), Université Paris Diderot, 75013 Paris, France.
authors.forename: M
authors.initials: M
authors.lastname: García-Hernández
authors.affiliation: SpLine Spanish CRG Beamline, ESRF, 6 Rue Jules Horowitz, BP 220, F-38043 Grenoble Cedex 09, France.
authors.forename: E
authors.initials: E
authors.lastname: Salas-Colera
authors.affiliation: Laboratoire de Matière et Systèmes Complexes (MSC), Université Paris Diderot, 75013 Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Espinosa
mesh_terms: D005290:Ferric Compounds / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism*; D018547:Plant Stems / Q000378:metabolism*; D006109:Poaceae / Q000378:metabolism*; D013052:Spectrometry, X-Ray Emission; D056928:X-Ray Absorption Spectroscopy; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide; D007501:Iron
keywords: Biomineralization; Imperata cylindrica; Iron oxide spinel phases; Jarosite