Resistance to Nickel and Cadmium in Indigenous and Non-indigenous Plant Growth Promoting Rhizobacteria (PGPR) in Contaminated Soils



The purposes of this research were to the evaluation of resistance to nickel and cadmium in 52 indigenous and non-indigenous strains of contaminated soils and a study of growth promoting characteristics of some resistant isolates. Resistance test at three levels of cadmium (0, 100, 200 mg l-1) and five levels of nickel (0, 250, 500, 750, 1000 mg l-1) in the framework of a completely randomized design of three replications was conducted. Indole acetic acid producing ability, production of ACC- deaminase enzyme and siderophore, solubilization of organic and inorganic non-soluble phosphate were determined as plant growth promoting characteristics. The results showed, from 52 strains, 10 strains (19.2%) were resistant to high levels of nickel and cadmium. From amongst ten strains, two isolates 105 and 109 were not only the most resistant to nickel and cadmium but also had some plant growth promoting characteristics.