title: The effect of plant growth-promoting rhizobacteria on the phytoextraction of Cd and Zn by Brassica napus L.
abstract: The test strains Bacteroidetes bacterium (Ba), Pseudomonas fluorescens (Pf) and Variovorax sp. (Va) were selected in advance for their in vitro capability for growth promotion of rapeseed in the presence of increased concentrations of Cd, Cu, Pb and Zn in the medium. In the pot experiment, the strains were used for single Ba, Pf, Va or combined Ba + Pf, Ba + Va, Pf + Va, and Ba + Pf + Va inoculation of B. napus growing in contaminated soil from alluvial deposits. The positive effect of bacterial strains on plant growth was observed in vitro, but was not confirmed in situ in the contaminated soil, where the tested strains inhibited biomass production, rather than stimulating it. However, single inoculation with Ba significantly increased the chlorophyll content and K+concentration in the leaves. The inoculation of rapeseed with Ba and Va strains was indicated to be the most promising combination for phytoextraction of Cd and Zn from contaminated soil. Combined inoculation with Pf+Va and Pf + Ba+Va significantly decreased the concentration of heavy metals in the roots of rapeseed. We conclude that suitable combinations of PGPR can control the metal uptake of B. napus, selectively increasing either metal extraction or metal stabilization in the rhizosphere and offering promising applications in soil remediation.
authors.affiliation: a Department of Genetics, Faculty of Biology and Environment Protection , Nicolaus Copernicus University , Toruń , Poland.
authors.forename: G
authors.initials: G
authors.lastname: Dąbrowska
authors.affiliation: b Department of Microbiology, Faculty of Biology and Environment Protection , Nicolaus Copernicus University , Toruń , Poland.
authors.forename: K
authors.initials: K
authors.lastname: Hrynkiewicz
authors.affiliation: c Department of Plant Physiology and Biotechnology, Faculty of Biology and Environment Protection , Nicolaus Copernicus University , Toruń , Poland.
authors.forename: A
authors.initials: A
authors.lastname: Trejgell
authors.affiliation: d Department of Soil Science , University of Rostock , Rostock , Germany.
authors.forename: C
authors.initials: C
authors.lastname: Baum
mesh_terms: D001673:Biodegradation, Environmental; D029688:Brassica napus; D002104:Cadmium / Q000378:metabolism*; D019216:Metals, Heavy; D038821:Mycorrhizae / Q000502:physiology*; D012989:Soil Pollutants; D015032:Zinc / Q000378:metabolism*
chemical_list: D019216:Metals, Heavy; D012989:Soil Pollutants; D002104:Cadmium; D015032:Zinc
keywords: heavy metals; phytoremediation; plant growth-promoting rhizobacteria (PGPR); rapeseed