Abstract

Information on microbial production of cytokinins and their effect on plant growth are limited. Therefore, the objective of the present study was to investigate cytokinins production by Pseudomonas sp., a major component of rhizobacteria with multiform and diverse activities, which enhance plant growth by synthesizing various secondary metabolites. In the present investigations, thirty Pseudomonas isolates were isolated from the rhizosphere of Pyrus and Malus and were screened for cytokinins production (50 to 210 μg/ml). Four strains viz PN-4-SAN, PN-10-SAN, AN-2-NAG and AN-4-NAG were selected on the basis of their higher cytokinins production. The maximum cytokinins production was observed at 72h incubation period in nutrient broth at pH 7.0 under shaken condition at 28°C. Cytokinins were extracted, purified and evaluated by thin layer chromatography and specific bioassay method.

Key words: Cytokinins, plant growth promoting rhizobacteria (PGPR), Pseudomonas sp., thin layer chromatography, radish cotyledon bioassay.