Pseudometallophytes colonising Pb/Zn mine tailings: A description of the plant–microorganism–rhizosphere soil system and isolation of metal-tolerant bacteria

• Published in: Journal of Hazardous Materials
• Main Authors: Becerra-Castro, C., Monterroso, C., Prieto-Fernández, Ángeles, Rodríguez-Lamas, L., Loureiro-Viñas, M., Acea, M. J., Kidd, P.
• Other Authors: Ministerio de Ciencia e Innovación (España), European Commission
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2012
• Subjects: Greenland
• Online Access: http://hdl.handle.net/10261/198160; https://doi.org/10.1016/j.jhazmat.2012.03.039; https://doi.org/10.13039/501100000780; https://doi.org/10.13039/501100004837

The plant-microorganism-soil system of three pseudometallophytes (Betula celtiberica, Cytisus scoparius and Festuca rubra) growing in a Pb/Zn mine was characterised. Plant metal accumulation, soil metal fractions (rhizosphere and non-vegetated) and bacterial densities were determined. Total Cd, Pb and Zn in non-vegetated soils was up to 50, 3000 and 20,000 mg kg−1 dry weight, respectively. The residual fraction dominated non-vegetated soils, whereas plant-available fractions became important in rhizosphere soils. All plant species effectively excluded metals from the shoot. F. rubra presented a shoot:root transport factor of ≤0.2 and this population could be useful in future phytostabilisation trials. Culturable bacterial densities and diversity were low (predominantly Actinobacteria). Rhizosphere soils hosted higher total and metal-tolerant bacterial densities. Seventy-four metal-tolerant rhizobacteria were isolated, and characterised genotypically (BOX-PCR, 16S rDNA) and phenotypically [Cd/Zn tolerance, biosurfactant production and plant growth promoting (PGP) traits]. Several isolates resisted high concentrations of Cd and Zn, and only a few presented PGP traits. Fourteen isolates were evaluated for promoting plant growth of two species (Salix viminalis and Festuca pratensis). Thirteen inoculants enhanced growth of F. pratensis, while only three enhanced growth of S. viminalis. Growth enhancement could not always be related to isolate PGP traits. In conclusion, some isolates show potential application in phytostabilisation or phytoextraction techniques. This research was supported by the Ministerio de Ciencia e Innovación ( CTM2009-14576-C02-01 and CTM2009-14576-C02-02 ) and FP7 EC project “Gentle remediation of trace element contaminated land”(Greenland 266124; Theme 2:Food, Agriculture and Fisheries, and Biotechnology). Peer reviewed