Toxicologia Ambiental e Analítica

Fe Absorption and Distribution of Imperata cylindrica (L.) P. Beauv. under Controlled Conditions

Abstract

Alejandro Franco, Lourdes Rufo and Vicenta de la Fuente

Background and aims: Imperata cylindrica (L.) P. Beauv. is a grass whose capacity to hyperaccumulate Fe and biomineralize jarosite has been proved in its natural habitat. Here we carried out an experiment to reproduce the Fe hyperacummulation under laboratory controlled conditions and a study to locate and identify the Fe compounds formed in the process. Methods: The experiment was conducted with plants cultivated in a hydroponic culture in Hoagland solution enriched with 300 mg/kg of Fe at pH 3 for 60 days. Samples were analyzed with mass spectrometry (ICP-MS) for its elemental analysis; with electronic microscopy (SEM, TEM) and energy dispersive X-ray (EDX) analysis to analyze the different organs, tissues and cell content; and with X-ray diffraction (XRD) to identify the possible biomineral production. Results: I. cylindrica specimens reached 4805, 7976 and 53886 Fe mg/kg d.w. in leaves, rhizomes and roots respectively. Fe was visible as a plaque in the root and as deposits inside all the organs. Part of these accumulations corresponds to crystallized jarosite and iron oxides. Conclusions: We induced Fe hyperaccumulation and biomineralization in I. cylindrica under specific controlled conditions. Considering this we think this species could be an interesting candidate to phytoremediate soils.