By this method, basal parts of 12–15 cm length plants with the first pair of leaves were cut off under the water. Cuttings were submerged for 6 h in 50 μg ml−1 IAA stock solution (positive control) and in the bacterial supernatants. As the negative controls, sterile tap water and liquid Czapek media were used. After rinsing the cuttings in the tap water, they were put in a flask with sterile water. The height of the stem with formed roots and number of the roots were measured, and used as the criterion for growth stimulant's activity.