Comparative plant growth promoting traits and distribution of rhizobacteria associated with heavy metals in contaminated soils

Abstract

ABSTRACT:The heavy metals at high concentration are generally toxic to the plants for their metabolism and growth; therefore, interactions among metals, rhizosphere microbes and plants have attracted attention because of the biotechnological potential of microorganisms for metal removal directly from contaminated soils or the possible transference of them to the plants. The aim of this study was to compare the relationships between the physiological in vitro characteristics of rhizobacteria isolated from plant metal accumulators and their distribution relating with the heavy metals content in contaminated soils. The results of this study showed that the heavy metals present in the rhizosphere of the plant species analyzed, decrease the microbial biomass and content of heavy metals caused a different distribution of rhizobacteria found. Gram negative rhizobacteria (90 %) and gram positive rhizobacteria (10 %) were isolated; all of them are metal-resistant rhizobacteria and 50 % of the isolated rhizobacteria possess both traits: higher indol acetic acid and siderophore producers. The inoculation with these rhizosphere microorganisms that possess metal-tolerating ability and plant growth promoting activities, can be recommended with a practical importance for both metal-contaminated environment and plant growth promotion.

Phytoremediation of soil contaminated by heavy oil with plants colonized by mycorrhizal fungi

“…Although this biotechnology has strong potential, the injected bacteria (bioaugmentation) might compete with native species and change the native ecological system. By contrast, phytoremediation technology uses the plant mechanisms and associated rhizosphere effects in the absorption, degradation, and stabilization of soil pollutants (Liste and Prutz 2006;Melo et al 2011).…”

Effect of Phytohormones and Rhizobacteria on Ephitelantha micromeris Callus Growth

“…strain C2, was isolated by Melo et al, (2011), from the rhizosphere of Sporobolus indicus L. R. Br., grown in a metal contaminated soils located in Villa de la Paz in the state of San Luis Potosí, México and categorized by its in vitro production of indole acetic acid (IAA) according to Khalid et al, (2004) as higher producer with 18.7 to 25 μg/mL.…”

Comparison in Growth Parameters of the Bacterization Effect on Axonopus affinis Seeds and EDTA against Cadmium

“…strain Sp7E isolated from the rhizosphere of Viguiera dentata (Cav.) Spreng, by Melo et al, (2011). Bacterial inoculum was obtained from the rhizobacteria strain cultured on plates with LuriaBertani (LB) agar medium for 48 h at 28°C.…”