PRODUCTION OF INDOLE-3-ACETIC-ACID DURING GROWTH OF THE RHIZOSPHERE BACTERIA OF THE GENUS PSEUDOMONAS

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 a nalysis and the Gordon-Weber method. The accumulation of IAA exhibited two maxima, in the 9th and 40th hours of cultivation. In both pseudom onad cultures, the first maximum occurred in the exponential phase, an d the second maximum corresponded to the beginning of the stationary g rowth phase. Both maxima of IAA accumulation coincided with decreases in the specific growth rates of the cultures. The stationary-phase cul ture of P. putida 23, as compared to that of P. fluorescens 20, was ch aracterized by greater IAA content, which was retained for a long time .