Bactérias diazotróficas em mudas de bananeira

Abstract

The objective of this work was to select strains of diazotrophic bacteria associated with banana plants and to determine micropropagated plantlet-growth-promotion by their inoculation with diazotrophs. Isolates of Herbaspirillum-Yike and Burkholderia cepacia related bacteria were inoculated in plantlets of banana cv. Prata Ana and the cultivar Caipira. Plantlets of banana cv. Prata Anã grown in vitro on a poor nitrogen substrate presented higher fresh weight when Herbaspirillum-\\\s.t bacteria were used as inoculum, while the banana cv. Caipira grew better with the inoculation of Burkholderia cepacia related bacteria. Nevertheless, plants of the cultivar Caipira cultivated in plastic bags filled with sand and vermiculite (1:2) and supplied with Hoagland's solution containing 5 mg L-1 of N grew faster with the inoculation of Herbaspirillum-like and Burkholderia cepacia related bacteria. This effect was similar to 50 mg L-1 of N fertilizer added to the positive control. However, the control plants showed higher N content in their shoots when compared to bacterial inoculated plants. This work constitutes the first announcement of banana plant-growth-promotion by diazotrophic bacteria.