Rhizosphere characteristics of indigenously growing nickel hyperaccumulator and excluder plants on serpentine soil.
Environ Pollut
; 123(1): 131-8, 2003.
Article
en En
| MEDLINE
| ID: mdl-12663213
ABSTRACT
The role of rhizosphere processes in metal hyperaccumulation is largely unexplored and a matter of debate, related field data are virtually not available. We conducted a field survey of rhizosphere characteristics beneath the Ni hyperaccumulator Thlaspi goesingense Hálácsy and the metal-excluder species Silene vulgaris L. and Rumex acetosella L. growing natively on the same serpentine site. Relative to bulk soil and to the rhizosphere of the excluder species, we found significantly increased DOC and Ni concentrations in water extracts of T. goesingense rhizosphere, whereas exchangeable Ni was depleted due to excessive uptake of Ni. Chemical speciation analysis using the MINTEQA2 software package revealed that enhanced Ni solubility in Thlaspi rhizosphere is driven by the formation of Ni-organic complexes. Moreover, ligand-induced dissolution of Ni-bearing minerals is likely to contribute to enhanced Ni solubility. Increased Mg and Ca concentrations and pH in Thlaspi rhizosphere are consistent with ligand-induced dissolution of orthosilicates such as forsterite (Mg(2)SiO(4). Our field data reinforce the hypothesis that exudation of organic ligands may contribute to enhanced solubility and replenishment of metals in the rhizosphere of hyperaccumulating species.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Contaminantes del Suelo
/
Raíces de Plantas
/
Thlaspi
/
Níquel
Idioma:
En
Revista:
Environ Pollut
Asunto de la revista:
SAUDE AMBIENTAL
Año:
2003
Tipo del documento:
Article
País de afiliación:
Austria