[Production of indole-3-acetic acid by rhizosphere bacteria of the genus Pseudomonas during the growth process].

The production of indole-3-acetic acid (IAA) by batch cultures of the rhizosphere bacteria Pseudomonas fluorescens 20 and Pseudomonas putida 23, known to stimulate plant growth, was studied by immunoenzymatic analysis and the Gordon-Weber method. The accumulation of IAA exhibited two maxima, in the 9th and 40th hours of cultivation. In both pseudomonad cultures, the first maximum occurred in the exponential phase, and the second maximum corresponded to the beginning of the stationary growth phase. Both maxima of IAA accumulation coincided with decreases in the specific growth rates of the cultures. The stationary-phase culture of P. putida 23, as compared to that of P. fluorescens 20, was characterized by greater IAA content, which was retained for a long time.