Growth promotion of eucalyptus seedling mediated by bacteria auxin producers

Abstract

It has been growing the search for cultural techniques in plant growth promotion, especially by the use of growth regulators, aiming the increase of productivity or improve the quality of seedlings of forest species. In this study was evaluate the effect of bacterial strains producing indole acetic acid (IAA) in growth promotion of Eucalyptus urograndis seedlings, H13 and I144 clones. Thirth two bacterial strains selected previously by the auxin production capacity under laboratory conditions were used in this study, which were inoculated by aerial spraying and evaluated the plant height, root length and fresh weight of shoot and root system, 112 days after cutting. For the I144 clone it was found that B2, B4, B5, B6 and S6 bacterial strains increased efficiently the fresh root weight in the range of 43.7% to 53.8%. In the case H13 clone the S9 straindecreased the biomass production of aerial part of plants by 50%, as well as S4, S6, S7, S9, B8 and B11 strains, decreasing the root biomass of plants in order of 35.7 to 64.3%.