Zinc distribution and speciation in Arabidopsis halleri x Arabidopsis lyrata progenies presenting various zinc accumulation capacities

Geraldine Sarret (1) , Glenda Willems (2) , M.-P. Isaure (1) , Matthew A. Marcus (3) , Sirine Fakra (3) , Helene Frerot (2) , Sébastien Pairis (4) , Nicolas Geoffroy (1) , Alain Manceau (1) , Pierre Saumitou-Laprade (2)

1 LGIT - Laboratoire de Géophysique Interne et Tectonophysique
2 GEPV - Génétique et évolution des populations végétales
3 ALS - Advanced Light Source [LBNL Berkeley]
4 NEEL - C2MA - Croissance Cristalline et MicroAnalyse

The purpose of this study was to investigate the relationship between the chemical form and localization of zinc (Zn) in plant leaves and their Zn accumulation capacity. * An interspecific cross between Arabidopsis halleri sp. halleri and Arabidopsis lyrata sp. petrea segregating for Zn accumulation was used. Zinc (Zn) speciation and Zn distribution in the leaves of the parent plants and of selected F1 and F2 progenies were investigated by spectroscopic and microscopic techniques and chemical analyses. * A correlation was observed between the proportion of Zn being in octahedral coordination complexed to organic acids and free in solution (Zn-OAs + Znaq) and Zn content in the leaves. This pool varied between 40% and 80% of total leaf Zn depending on the plant studied. Elemental mapping of the leaves revealed different Zn partitioning between the veins and the leaf tissue. The vein : tissue fluorescence ratio was negatively correlated with Zn accumulation. * The higher proportion of Zn-OAs + Znaq and the depletion of the veins in the stronger accumulators are attributed to a higher xylem unloading and vacuolar sequestration in the leaf cells. Elemental distributions in the trichomes were also investigated, and results support the role of carboxyl and ⁄ or hydroxyl groups as major Zn ligands in these cells.

Mots clés: scanning electron microscopy coupled to energy dispersive X-ray analysis (SEM-EDX); Arabidopsis halleri; Arabidopsis lyrata; extended X-ray absorption fine structure (EXAFS) spectroscopy; interspecific crossing; micro X-ray fluorescence (lXRF); scanning electron microscopy coupled to energy dispersive X-ray analysis (SEM-EDX).

Domaines: Interfaces continentales, environnement; Milieux et Changements globaux

Geraldine Sarret, Glenda Willems, M.-P. Isaure, Matthew A. Marcus, Sirine Fakra, et al.. Zinc distribution and speciation in Arabidopsis halleri x Arabidopsis lyrata progenies presenting various zinc accumulation capacities. New Phytologist, 2009, 184 (3), pp.581-595. ⟨10.1111/j.1469-8137.2009.02996.x⟩. ⟨hal-00425670⟩