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Gewählte Dissertation:

Alireza Golestanifard (2021): Rhizodeposition in response to metal pollution and P depletion controls metal solubility and speciation in the rhizosphere of accumulator and nonaccumulator plants.
Dissertation - Institut für Bodenforschung (IBF), BOKU-Universität für Bodenkultur, pp 69. UB BOKU obvsg

Datenquelle: ZID Abstracts
The mobility of metals in the rhizosphere is of fundamental importance affecting the success of phytoremediation technologies and the management of polluted soils. Additionally, metal-polluted sites are characterized by nutrient deficiency which can induce rhizodeposition and subsequently affect metal solubility and speciation. This research aimed: (1) to evaluate hyperaccumulation of Zn, Cd and Pb by Noccaea rotundifolia ssp. cepaeifolia; and metal acquisition strategies of this species in terms of root and rhizosphere processes, using hydroponic, rhizobox and split-pot experiments; (2) to explore the effect of rhizodeposition triggered by phosphorus (P) depletion on Cu and Zn solubility and speciation in the rhizosphere of canola and corn cultivars. Our results (1) suggest that the investigated N. rotundifolia behaves as a Zn- and Pb-accumulator but does not comply to the full set of hyperaccumulation criteria. The enhanced mobility of Zn, Pb, and Cd in the rhizosphere of metal-enriched highly contaminated soil was associated to pH reduction and formation of organometallic complexes. Split-pot experiment showed that apart of its accumulator properties, avoidance of metal-enriched patches is a major tolerance strategy of N. rotundifolia. (2) Concentration of dissolved organic carbon (DOC) in the rhizosphere and bulk soil solution was strong and inversely correlated with total soluble P in corn and canola cultivars, an indication of rhizodeposition in response to limited P availability. Consequently, 83% and 63% of the variation of increased total dissolved Cu in the rhizosphere of canola and corn cultivars respectively, could be explained by changes in DOC concentrations. This study contributes to our understanding of biogeochemical processes controlling metal solubility and speciation in the rhizosphere of accumulator and excluder plants, which can be used for implementing targeted rhizosphere manipulation in the management and remediation of metal-polluted sites.

Betreuer: Wenzel Walter
1. Berater: Klik Andreas
2. Berater: Puschenreiter Markus

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