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Abstract(s)
A plant growth-promoting bacterial (PGPB) strain SC2b was isolated from the rhizosphere of
Sedum plumbizincicola grown in lead (Pb)/zinc (Zn) mine soils and characterized as Bacillus
sp. based on (1) morphological and biochemical characteristics and (2) partial 16S ribosomal
DNA sequencing analysis. Strain SC2b exhibited high levels of resistance to cadmium
(Cd) (300 mg/L), Zn (730 mg/L), and Pb (1400 mg/L). This strain also showed various plant
growth-promoting (PGP) features such as utilization of 1-aminocyclopropane-1-carboxylate,
solubilization of phosphate, and production of indole-3-acetic acid and siderophore. The
strain mobilized high concentration of heavy metals from soils and exhibited different
biosorption capacity toward the tested metal ions. Strain SC2b was further assessed for PGP
activity by phytagar assay with a model plant Brassica napus. Inoculation of SC2b increased
the biomass and vigor index of B. napus. Considering such potential, a pot experiment was
conducted to assess the effects of inoculating the metal-resistant PGPB SC2b on growth and
uptake of Cd, Zn and Pb by S. plumbizincicola in metal-contaminated agricultural soils.
Inoculation with SC2b elevated the shoot and root biomass and leaf chlorophyll content of
S. plumbizincicola. Similarly, plants inoculated with SC2b demonstrated markedly higher Cd
and Zn accumulation in the root and shoot system, indicating that SC2b enhanced Cd and
Zn uptake by S. plumbizincicola through metal mobilization or plant-microbial mediated
changes in chemical or biological soil properties. Data demonstrated that the PGPB Bacillus
sp. SC2b might serve as a future biofertilizer and an effective metal mobilizing bioinoculant
for rhizoremediation of metal polluted soils.
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Pedagogical Context
Citation
MA, Ying; OLIVEIRA, Rui; WU, Longhua; LUO, Yongming; RAJKUMAR, Mani; ROCHA, Inês; FREITAS, Helena - Inoculation with metal-mobilizing plant-growth-promoting rhizobacterium bacillus sp. SC2b and its role in rhizoremediation. In 3rd International Congress on Environmental Health (ICEH2014), “Emerging Risks and Challenges on Environment, Health and Safety”, Porto, Portugal, 24-26 September 2014. – In Journal of Toxicology and Environmental Health - Part A: Current Issues. ISSN 1087-2620. Vol. 78, n.º 13-14 (2015), p. 931-944