Evaluation of the ability of rhizosphere isolates to solubilize low-soluble Zn under in-vitro conditions and their ability to supply Zn to maize

In this study, the effect of potent zinc solubilizing bacteria on zinc supply of single cross cultivar 704 was evaluated.

Isolation of bacteria from rhizospheres of maize, wheat and sunflower was performed in different cities of East Azerbaijan province. The experiment was performed in two phases in vitro and in a greenhouse in a completely randomized statistical design with three replications.

A total of 20 bacterial isolates were obtained from the rhizosphere of the studied plants. In qualitative evaluation, the results showed that ZP13 isolates in zinc phosphate source, ZO11 in zinc oxide source and ZC10 in zinc carbonate source with HD / CD ratio with 1.74, 1.68 and 1.61, respectively, had the highest solubility. In quantitative evaluation of zinc solubility, ZP13 isolate (24.64 mg / L), ZC10 isolate in zinc carbonate (19.48 mg / L) and ZO11 isolate in zinc oxide (26.54 mg / L) had the highest solubility. The two isolates ZO11 and ZO14 in comparison with the negative control treatment led to an increase in zinc uptake of 179.7 and 62.37% in the root and 155.1 and 110.6% in the shoot part of maize, respectively. Identification of isolates ZO11 and ZO14 showed that they belong to Acinetobacter calcoaceticus and Agromyces italicus, respectively.

According to the results of this experiment, the potential of rhizobacteria of different plants can be used to provide the zinc required by plants as a healthy and eco-friendly solution.