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1.
Environ Pollut ; 231(Pt 1): 237-251, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28802993

RESUMO

Gentle remediation options (GRO) are based on the combined use of plants, associated microorganisms and soil amendments, which can potentially restore soil functions and quality. We studied the effects of three GRO (aided-phytostabilisation, in situ stabilisation and phytoexclusion, and aided-phytoextraction) on the soil microbial biomass and respiration, the activities of hydrolase enzymes involved in the biogeochemical cycles of C, N, P, and S, and bacterial community structure of trace element contaminated soils (TECS) from six field trials across Europe. Community structure was studied using denaturing gradient gel electrophoresis (DGGE) fingerprinting of Bacteria, α- and ß-Proteobacteria, Actinobacteria and Streptomycetaceae, and sequencing of DGGE bands characteristic of specific treatments. The number of copies of genes involved in ammonia oxidation and denitrification were determined by qPCR. Phytomanagement increased soil microbial biomass at three sites and respiration at the Biogeco site (France). Enzyme activities were consistently higher in treated soils compared to untreated soils at the Biogeco site. At this site, microbial biomass increased from 696 to 2352 mg ATP kg-1 soil, respiration increased from 7.4 to 40.1 mg C-CO2 kg-1 soil d-1, and enzyme activities were 2-11-fold higher in treated soils compared to untreated soil. Phytomanagement induced shifts in the bacterial community structure at both, the total community and functional group levels, and generally increased the number of copies of genes involved in the N cycle (nirK, nirS, nosZ, and amoA). The influence of the main soil physico-chemical properties and trace element availability were assessed and eventual site-specific effects elucidated. Overall, our results demonstrate that phytomanagement of TECS influences soil biological activity in the long term.


Assuntos
Biodegradação Ambiental , Microbiologia do Solo , Poluentes do Solo/análise , Oligoelementos/análise , Bactérias/efeitos dos fármacos , Betaproteobacteria , Biomassa , Eletroforese em Gel de Gradiente Desnaturante , Europa (Continente) , França , Plantas , Solo/química , Poluentes do Solo/toxicidade , Oligoelementos/toxicidade
2.
J Environ Manage ; 186(Pt 2): 301-313, 2017 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-27817970

RESUMO

(Aided) phytostabilisation has been proposed as a suitable technique to decrease the environmental risks associated with metal(loid)-enriched mine tailings. Field scale evaluations are needed for demonstrating their effectiveness in the medium- to long-term. A field trial was implemented in spring 2011 in Cu-rich mine tailings in the NW of Spain. The tailings were amended with composted municipal solid wastes and planted with Salix spp., Populus nigra L. or Agrostis capillaris L. cv. Highland. Plant growth, nutritive status and metal accumulation, and soil physico- and bio-chemical properties, were monitored over three years (four years for plant growth). The total bacterial community, α- and ß-Proteobacteria, Actinobacteria and Streptomycetaceae were studied by DGGE of 16s rDNA fragments. Compost amendment improved soil properties such as pH, CEC and fertility, and decreased soil Cu availability, leading to the establishment of a healthy vegetation cover. Both compost-amendment and plant root activity stimulated soil enzyme activities and induced important shifts in the bacterial community structure over time. The woody plant, S. viminalis, and the grassy species, A. capillaris, showed the best results in terms of plant growth and biomass production. The beneficial effects of the phytostabilisation process were maintained at least three years after treatment.


Assuntos
Biodegradação Ambiental , Cobre/toxicidade , Microbiologia do Solo , Poluentes do Solo/toxicidade , Solo/química , Agrostis/crescimento & desenvolvimento , Bactérias/genética , Biomassa , Cobre/farmacocinética , Consórcios Microbianos/genética , Mineração , Raízes de Plantas/química , Raízes de Plantas/microbiologia , Populus/crescimento & desenvolvimento , Salix/crescimento & desenvolvimento , Poluentes do Solo/análise , Poluentes do Solo/farmacocinética , Resíduos Sólidos , Espanha , Especificidade da Espécie
3.
Sci Total Environ ; 548-549: 370-379, 2016 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-26803735

RESUMO

Ni phytomining is a promising technology for Ni recovery from low-grade ores such as ultramafic soils. Metal-hyperaccumulators are good candidates for phytomining due to their extraordinary capacity for Ni accumulation. However, many of these plants produce a low biomass, which makes the use of agronomic techniques for improving their growth necessary. In this study, the Ni hyperaccumulators Alyssum serpyllifolium ssp. lusitanicum, A. serpyllifolium ssp. malacitanum, Alyssum bertolonii and Noccaea goesingense were evaluated for their Ni phytoextraction efficiency from a Ni-rich serpentine soil. Effects of soil inorganic fertilisation (100:100:125kgNPKha(-1)) and soil organic amendment addition (2.5, 5 or 10% compost) on plant growth and Ni accumulation were determined. All soil treatments greatly improved plant growth, but the highest biomass production was generally found after addition of 2.5 or 5% compost (w/w). The most pronounced beneficial effects were observed for N. goesingense. Total Ni phytoextracted from soils was significantly improved using both soil treatments (inorganic and organic), despite the decrease observed in soil Ni availability and shoot Ni concentrations in compost-amended soils. The most promising results were found using intermediate amount of compost, indicating that these types of organic wastes can be incorporated into phytomining systems.


Assuntos
Biodegradação Ambiental , Brassicaceae/metabolismo , Metais/análise , Níquel/análise , Poluentes do Solo/análise , Biomassa , Brassicaceae/química , Solo/química
4.
Int J Phytoremediation ; 18(4): 406-15, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26552496

RESUMO

In this study different bacterial inoculation methods were tested for tobacco plants growing in a mine-soil contaminated with Pb, Zn, and Cd. The inoculation methods evaluated were: seed inoculation, soil inoculation, dual soil inoculation event, and seed+soil inoculation. Each inoculum was added at two bacterial densities (10(6) CFUs mL(-1) and 10(8) CFUs mL(-1)). The objectives were to evaluate whether or not the mode of inoculation or the number of applied microorganisms influences plant response. The most pronounced bacterial-induced effect was found for biomass production, and the soil inoculation treatment (using 10(6) CFUs mL(-1)) led to the highest increase in shoot dry weight yield (up to 45%). Bacterial-induced effects on shoot metal concentrations were less pronounced; although a positive effect was found on shoot Pb concentration when using 10(8) CFUs mL(-1) in the soil inoculation (29% increase) and in the seed+soil inoculation (34% increase). Also shoot Zn concentration increased by 24% after seed inoculation with 10(6) CFUs mL(-1). The best effects on the total metal yield were not correlated with an increasing number of inoculated bacteria. In fact the best results were found after a single soil inoculation using the lower cellular density of 10(6) CFUs mL(-1).


Assuntos
Inoculantes Agrícolas/fisiologia , Rhodococcus/fisiologia , Poluentes do Solo/metabolismo , Tabaco/metabolismo , Tabaco/microbiologia , Inoculantes Agrícolas/crescimento & desenvolvimento , Biodegradação Ambiental , Cádmio/análise , Cádmio/metabolismo , Brotos de Planta/química , Brotos de Planta/metabolismo , Rhodococcus/crescimento & desenvolvimento , Microbiologia do Solo , Poluentes do Solo/análise , Tabaco/química , Tabaco/crescimento & desenvolvimento
5.
Sci Total Environ ; 494-495: 1-8, 2014 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-25016589

RESUMO

The application of plant growth regulators (PGRs) or phytohormones could be an interesting option for stimulating biomass production of hyperaccumulating plants and, consequently, their metal phytoextraction capacity. The effect of exogenous applications of phytohormones (PGR) on the Ni phytoextraction capacity of four Ni hyperaccumulating species (Alyssum corsicum, Alyssum malacitanum, Alyssum murale and Noccaea goesingense) was evaluated. Four different commercially available phytohormones (B, C, K and P) based on gibberellins, cytokinins and auxins were applied to the plant aerial tissues. Each product was applied at three different concentrations (B1-3, C1-3, K1-3 and P1-3). The effect on biomass production was dependent on the species, the PGR type and the concentration at which it was applied. Two of the four products (K and P) consistently increased biomass production compared to untreated control plants in all four plant species. On the other hand, all four products led to a significant increase in the number of branches (and leaves in the case of N. goesingense) of all four species compared to control plants. Application of phytohormones generally led to a reduction in shoot Ni concentration. Nonetheless, in some cases as a consequence of the increase observed in biomass after the application of phytohormones a significant increase in the Ni phytoextraction efficiency was also observed (but this was species- and PGR type-dependent). The results show that PGRs can be successfully used to improve the growth and biomass production of hyperaccumulating species such as Alyssum and Noccaea. However, an increase in biomass did not always lead to a higher Ni removal, and the most effective PGR for increasing Ni removal was the IAA-based product.


Assuntos
Níquel/metabolismo , Desenvolvimento Vegetal/efeitos dos fármacos , Reguladores de Crescimento de Planta/metabolismo , Poluentes do Solo/metabolismo , Biodegradação Ambiental , Níquel/análise , Poluentes do Solo/análise
6.
Int J Phytoremediation ; 15(4): 365-75, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23488002

RESUMO

Recent studies have shown that application of phytohormones to shoots of Alyssum murale increased biomass production but did not increase Ni shoot concentration. Increased biomass and Ni phytoextraction efficiency is useful to achieve economically viable phytomining. The objective of this study was to evaluate the effect of two types of phytohormones on the Ni phytoextraction capacity of four Alyssum species. Two different commercially available phytohormones (Cytokin and Promalin) based on cytokinins and/or gibberellins were applied on shoot biomass of four Ni hyperaccumulating Alyssum species (A. corsicum, A. malacitanum, A. murale, and A. pintodasilvae). Cytokin was applied in two concentrations and promalin in one concentration. The application of phytohormones had no clear positive effect on biomass production, Ni accumulation and Ni phytoextraction efficiency in the studied Alyssum species. A. malacitanum was the only species in which a significantly negative effect of these treatments was observed (in Ni uptake). A slightly positive response to promalin treatment was observed in the biomass production and Ni phytoextraction efficiency of A. corsicum. Although this effect was not significant it does indicate a potential application of these approaches to improve phytoextraction ability. Further studies will be needed to identify the most adequate phytohormone treatment as well as the appropriate concentrations and application times.


Assuntos
Brassicaceae/efeitos dos fármacos , Citocininas/farmacologia , Giberelinas/farmacologia , Metais/metabolismo , Níquel/metabolismo , Reguladores de Crescimento de Planta/farmacologia , Biodegradação Ambiental , Biomassa , Brassicaceae/crescimento & desenvolvimento , Brassicaceae/metabolismo , Metais/análise , Níquel/análise , Oregon , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Solo , Poluentes do Solo/metabolismo
9.
J Hazard Mater ; 217-218: 350-9, 2012 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-22483595

RESUMO

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.


Assuntos
Bactérias/metabolismo , Chumbo/metabolismo , Mineração , Plantas/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Zinco/metabolismo , Plantas/microbiologia
11.
Int J Phytoremediation ; 13 Suppl 1: 229-44, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22046762

RESUMO

Bacterial strains were isolated from the rhizosphere of three populations of the Ni-hyperaccumulator Alyssum serpyllifolium subsp. lusitanicum (A. pintodasilvae; M, S, and L), one population of Ni-hyperaccumulator A. serpyllifolium subsp. malacitanum (A. malacitanum; SB), and one population of the non-hyperaccumulator A. serpyllifolium subsp. serpyllifolium (A. serpyllifolium; SN). Isolates were characterized genotypically by BOX-PCR genomic DNA fingerprinting and comparative sequence analysis of partial 16S rRNA gene, and phenotypically by their Ni tolerance (0-10 mM), presence of plant growth promoting traits (indoleacetic acid (IAA)-, siderophore-, or organic acid-production, and phosphate solubilization) or capacity to produce biosurfactants. Among the collection of rhizobacteria, 84 strains were selected (according to their BOX-PCR profiles and phenotypic characteristics) to assess their ability to modify Ni extractability from Ni-rich (serpentine) soils. Metabolites produced by 13 of the isolates mobilized soil Ni (originating from the rhizosphere of both Ni-hyperaccumulators and non-hyperaccumulator). In contrast, Ni extraction using culture medium filtrates which had supported the growth of 29 strains was significantly reduced. The remaining strains had no effect on Ni mobility. Bacterial induced Ni mobilization was not related to Ni resistance or the phenotypic traits tested. Isolates with potential use in phytoremediation techniques will be further studied in a plant-microorganism-soil system.


Assuntos
Brassicaceae/microbiologia , Níquel/metabolismo , Rhizobiaceae/isolamento & purificação , Rhizobiaceae/metabolismo , Biodegradação Ambiental , Brassicaceae/metabolismo , DNA Ribossômico/química , DNA Ribossômico/genética , Genótipo , Ácidos Indolacéticos , Filogenia , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , RNA Ribossômico 16S/genética , Rhizobiaceae/classificação , Rizosfera , Solo , Poluentes do Solo/metabolismo
14.
Int J Phytoremediation ; 11(6): 525-41, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19810353

RESUMO

In this study we determine culturable microbial densities (total heterotrophs, ammonifiers, amylolytics and cellulolytics) and bacterial resistance to Co, Cr, and Ni in bulk and rhizosphere soils of three populations of the Ni-hyperaccumulator Alyssum serpyllifolium subsp. lusitanicum and the excluder Dactylis glomerata from ultramafic sites (two populations in Northeast (NE) Portugal (Samil (S), Morais (M)) and one population in Northwest (NW) Spain (Melide (L)). The relationship between bioavailable metal concentrations (H2O-soluble) and microbial densities were analysed. Significant differences in microbial densities and metal-resistance were observed between the two species and their three populations. The hyperaccumulator showed higher microbial densities (except cellulolytics) and a greater rhizosphere effect, but this was only observed in S and M populations. These populations of A. serpyllifolium also showed selective enrichment of Ni-tolerant bacteria at the rhizosphere where Ni solubility was enhanced (densities of Ni-resistant bacteria were positively correlated with H2O-soluble Ni). These rhizobacteria could solubilise Ni in the soil and potentially improve phytoextraction strategies.


Assuntos
Brassicaceae/metabolismo , Brassicaceae/microbiologia , Níquel/metabolismo , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Oligoelementos/toxicidade , Biodegradação Ambiental , Monitoramento Ambiental , Sedimentos Geológicos , Níquel/química , Solo/análise , Poluentes do Solo/química , Poluentes do Solo/metabolismo
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