Journals Proceedings

Abstract

Pseudomonas sp. PDMZnCd2003 is a plant growth-promoting bacteria (PGPB) that was isolated from Zn/Cd contaminated soil. This research aims to study the characteristics of the Zn/Cd resistance and plant growth promoting properties of Pseudomonas sp.PDMZnCd2003 under Zn/Cd stress. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods were carried out to evaluate the lowest concentrations of Zn and/or Cd that inhibited and killed the bacterium. The MIC concentrations for Zn, Cd, Zn plus Cd and fixed Cd plus Zn were 150 mg l-1, 70 mg l-1, 60/60 mg l-1 and 20/150 mg l-1, respectively. The MBC concentrations for Cd were 300 mg l-1, while the bacterial growth recovered from treatment with 400 mg l-1 of Zn, 100/100 mg l-1 of Zn plus Cd, and 20/2000 mg l-1 of fixed Cd plus Zn. The growth tended to decrease under Zn/Cd stress, however, the plant growth properties of IAA production, N2 fixation and P solubilisation remained under Zn plus Cd at 20/20 mg l-1. Due to the Zn-Cd resistance and plant growth promoting properties under heavy metal stresses, the results demonstrate that Pseudomonas sp. ZnCd2003 should be used as a biofertilizer to promote plant growth in a Zn/Cd phytoremediation process.