University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Barbara Gruber
(2015):
Phytosiderophores in the Plant-Soil Environment
Effect of DMA exudation on metal mobilization in contaminated soils.
Master / Diploma Thesis - Institut für Bodenforschung (IBF),
BOKU-Universität für Bodenkultur,
pp 70.
UB BOKU
obvsg
- Abstract:
- Graminaceous plant species overcome Fe deficiency by the release of non-proteinaceous amino acids, so called phytosiderophores (PS), which have a high potential to solubilize Fe by the formation of Fe-DMA complexes. In metal-rich soils, however, the release of PS may have an effect on the bioavailability of other heavy metals as well. Therefore, we examined the effect of DMA exudation, the major PS released by wheat plants, on different heavy metals (Zn, Cu, Ni, Cd and Pb) in soils high in total metal concentrations. In a first experiment, the effect of different DMA concentrations (0–1000 µM) on metal mobilization in four contaminated soils, with varying contamination levels and pH values, was examined. In a second experiment, common wheat (Triticum aestivum cv. Tamaro) was grown in the RHIZOtest set-up (Chaignon and Hinsinger; 2003) under Fe deficient (-Fe) or sufficient (+Fe) supply. DMA exudation rates by wheat plants and their impact on metal mobilization in the rhizosphere and metal plant uptake, involving the role of the apoplastic-metal pool, were investigated. The first experiment showed that DMA was able to mobilize Fe, Zn, Cu and Ni in four contaminated soils, while no mobilization of Cd and Pb was detected. Nonetheless, metal mobilization was strongly soil dependent and mainly influenced by (i) total metal concentration in soil; (ii) chemical properties of each metal; (iii) physico-chemical properties of the soil; (iv) the affinity of a metal to form a complex with DMA; and (v) the presence of competing ions in soil. DMA exudation rates of wheat ranged from 21.6 to 1900 pmol g-1 root dwt s-1 depending on experimental soil and level of soil contamination. The apoplastic metal pool served as a transient metal storage pool during plant uptake, especially for Fe, Zn, Ni and Pb, depending on soil and Fe treatment.
- Beurteilende(r): Puschenreiter Markus