IMPACT OF INTRODUCED PSEUDOMONAS FLUORESCENS MUTANTS ON INDIGENOUS RHIZOSPHERE MICROFLORA OF BEAN

摘要

Mutants of pseudomonas fluorescens were used for inoculation of bean (Phaseolus vulgaris L.) at different growth stages to assess their impact on indigenous culturable heterotrophic bacteria in the rhizoshere. Survival of inoculants, changes in numbers of the indigenous bacteria and their physiological state, and microbial community structures were determined using a simple agar plating method. The results showed that survival of introduced P. fluorescens mutants varied according to the growth stage of bean inoculated. However, overall, the mutants survived better in the rhizoshere with time, when they were inoculated on seeds. In contrast to some authors, the effect of mutants introduced was observed in the case of indigenous bacterial numbers and microbial community structures. Overal, no significant treatment effect was observed, when changes n values of kinetic parameters of colony formation were considered. Generally, cfu numbers, physiological state and community structure of indigenous microflora in the rhizoshere were depended on the effect of the interaction between the inoculants, the time after the introduction and the growth stage of plant.