Auteurs : Fabienne Baraud ¹; Teresa W.M. Fan ²; Richard Higashi ³

• 1 Aliments Bioprocédés Toxicologie Environnements
• 2 Department of Land, Air and Water Resources
• 3 John Muir Institute of the Environment

[en]
Phytoremediation is a remediation process that can be used to clean up soils contaminated with heavy metals. Three main approaches can be utilized: phytoextraction, phytovolatilization, and phytostabilization, each of them exploiting the natural ability of plants to accumulate or exclude/stabilize elements from soils. To implement this alternative technology, a better understanding of the various processes controlling metal mobilization, uptake and sequestration by plants is needed. Metal chelation is recognized as an important factor, regulating to a large extent metals solubility and availability to plants. Natural ion chelators (or MIL: Metal Ion Ligand), produced in the tissus or exuded by the roots, are involved in these phenomena, but their exact nature and the various mechanisms have to be précised. We investigated the influence of elevated metals concentrations on MIL profiles and on metal accumulation in the plant tissues in wheat (Triticum aestivum L.CV Chinese Spring) genetically modified by disomic addition of wheatgrass (Lophopyrum elogatum L.) chromosomes. Qualitative and quantitative determinations of MIL profiles are realised by GC-MS and RMN 1-D and 2-D. Concentrations of metals in the tissues are obtained by energy dispersive X-ray fluorescence spectroscopy. Correlations between some metals (ie, Fe, Zn, Mn) and some MIL exuded or present in the roots (ie, acetate), depending on the various genotypes, have been observed. The results suggest possible chromosomal location(s) of gene(s) involved in mobilization and/or sequestration of metals.

[fr]
La phytoremédiation est un procédé de traitement des sols applicable in situ pour traiter des pollutions métalliques. L'amélioration de ce type de procédé passe par une meilleure compréhension des processus de mobilisation, d'absorption et de séquestration des métaux par les plantes. La chélation est reconnue comme un phénomène important régulant la solubilité, la biodisponibilité et le stockage interne des métaux. L'influence de teneurs élevées en métaux sur les profils d'agents chélatants produits par les plantes a été étudiée sur des plants de blés modifiés génétiquement. L'ensemble des résultats suggère de possibles localisations de gènes gouvernant la mobilisation et la séquestration des métaux par ces plantes.