title: Combined application of Triton X-100 and Sinorhizobium sp. Pb002 inoculum for the improvement of lead phytoextraction by Brassica juncea in EDTA amended soil.
abstract: The process of EDTA-assisted lead phytoextraction from the Bovisa (Milan, Italy) brownfield soil was optimized in microcosms vegetated with Brassica juncea. An autochthonous plant growth-promoting rhizobacterium (PGPR), Sinorhizobium sp. Pb002, was isolated from the rhizosphere of B. juncea grown on the Pb-contaminated soil in presence of 2 mM EDTA. The strain was augmented (10(8) CFU g(-1) soil) in vegetated microcosms to stimulate B. juncea biomass production and, hence, its phytoextraction potential. Triton X-100 was also added to microcosms at 5 and 10 times the critical micelle concentration (cmc) to increase the permeability of root barriers to the EDTA-Pb complexes. Triton X-100 amendment determined an increase in Pb concentration within plant tissues. However it contextually exerted a phytotoxic effect. Sinorhizobium sp. Pb002 augmentation was crucial to plant survival in presence of both bioavailable lead and Triton X-100. The combination of the two treatments produced up to 56% increase in the efficiency of lead phytoextraction by B. juncea. The effects of these treatments on the structure of the soil bacterial community were evaluated by 16S rDNA denaturing gradient gel electrophoresis (DGGE).
authors.affiliation: Department of Science and Technology, University of Verona, Strada le Grazie 15, 17134 Verona, Italy. digregorio@sci.univr.it
authors.forename: Simona
authors.initials: S
authors.lastname: Di Gregorio
authors.forename: Meri
authors.initials: M
authors.lastname: Barbafieri
authors.forename: Silvia
authors.initials: S
authors.lastname: Lampis
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Sanangelantoni
authors.forename: Eliana
authors.initials: E
authors.lastname: Tassi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Vallini
mesh_terms: D001673:Biodegradation, Environmental; D002614:Chelating Agents / Q000494:pharmacology; D004269:DNA, Bacterial / Q000032:analysis; D004492:Edetic Acid / Q000494:pharmacology; D007854:Lead / Q000032:analysis* / Q000633:toxicity; D009149:Mustard Plant / Q000737:chemistry* / Q000254:growth & development / Q000382:microbiology*; D017830:Octoxynol / Q000494:pharmacology*; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D020579:Sinorhizobium / Q000235:genetics / Q000302:isolation & purification; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity
chemical_list: D002614:Chelating Agents; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D007854:Lead; D017830:Octoxynol; D004492:Edetic Acid