Growth of rhizobacteria tolerant towards lead and mercury and the plantgrowth promoting activities
2011
Nor Idaya Yatim | Alia Najiah Lokman | Ainon Hamzah
The objectives of this study were to characterize the growth of rhizobacterial isolates in various concentrations of lead (Pb) and mercury (Hg), and to determine their plant growth promoting (PGP) activities. A total of eight bacteria isolates; SF-S1-4, SF-S1-5, SF-S1-7, SF-S1-8, SF-S1-18, SF-S1-19, SF-S1-60 and SF-S1-61, that have been isolated from oil-contaminated sludge farm were grown in various concentrations of Pb and Hg in a minimal salt medium (MSM). Isolates were also tested for minimum inhibitory concentration (MIC) towards other types of heavy metals including cadmium (Cd), copper (Cu), zinc (Zn), cobalt (Co) and arsenate (As), and their PGP activities such as production of indole-3-acetic acid (IAA), hydrogen cyanide, ammonium (NH₃) and phosphate solubilization were also determined. The growth of all bacterial isolates in MSM was decreased when the concentration of Pb and Hg increased up to 1000 ppm and 1 ppm, respectively. Isolate SF-S1-5 showed the lowest reduction in the number of cells up to 400 ppm of Pb and 0.6 ppm of Hg. All isolates showed heptametal-tolerance pattern with MIC value in between 100 to 800 ppm for Cd, Cu, Co, Zn, Pb and As, but for Hg was at a lower concentration (30 to 40 ppm). All isolates capable of producing at least two of the PGP activities and isolate SF-S1-5 is the most potential as PGPR since it showed positive results for all tests.
Show more [+] Less [-]AGROVOC Keywords
Bibliographic information
This bibliographic record has been provided by Universiti Putra Malaysia