Effect of phytohormones synthesized by rhizosphere bacteria on plants

• Published in: Prikladnaja biohimija i mikrobiologija Vol. 47; no. 3; p. 302
• Main Authors: Sokolova, M G, Akimova, G P, Vaĭshlia, O B
• Format: Journal Article
• Language: Russian
• Published: Russia (Federation) 01.05.2011
• Subjects: Bacillus megaterium - metabolism; Chromatography, Thin Layer; Cucumis sativus - drug effects; Cucumis sativus - growth & development; Cytokinins - biosynthesis; Cytokinins - pharmacology; Enzyme-Linked Immunosorbent Assay; Indoleacetic Acids - metabolism; Indoleacetic Acids - pharmacology; Plant Growth Regulators - biosynthesis; Plant Growth Regulators - pharmacology; Plant Roots - drug effects; Plant Roots - growth & development; Plant Shoots - drug effects; Plant Shoots - growth & development; Polysaccharides, Bacterial - metabolism; Pseudomonadaceae - metabolism; Rhizosphere; Symbiosis
• ISSN: 0555-1099

New strains of rhizosphere microorganisms Azotobacter chroococcum Az d10, Bacillus megaterium P1-04, and Bacillus mucilaginosus B-1574 were found to be able to synthesize cytokinins (CKs) and indolylacetic acid (IAA). Three forms of CKs-dihydrozeatin riboside, isopentenyl adenosine, and trans-zeatin riboside-were identified, whose ratio was different in the three bacterial cultures. Inoculation of cucumber (Cucumis sativus L.) plants increased the content of CKs and IAA in them by 35.6 and 21.3%, respectively, and also stimulated seed germination and increased the growth rate, the biomass of shoots, the number of lateral roots, and the root hair area, which ensured better plant nutrition. The IAA/CKs ratio shifted during bacterization towards CKs due to increase in the content of riboside forms, which apparently caused growth stimulation.