Abstract

MORA, Edith  and  TORO, Marcia. Plant growth stimulation by Burkholderia cepacia, a native rizobacterias of acid soils in venezuelan savannas. Agronomía Trop. [online]. 2007, vol.57, n.2, pp.123-128. ISSN 0002-192X.

The rhizospheres of Galactia jussiaeana and Centrosema venosum native plants of tropical savannas wereanalized to observe the presence of phosphate solubilizing bacterias. Biochemical tests were applied to thebacteria for its characterization and identification. Our results showed that Burkholderia cepacia was the dominant species. Plant growth promotion tests (PGPRcapacity) of the bacteria, seed germination capacity, androot growth promotion were applied to Zea mays (var.Turen). To evaluate germination promotion, inoculatedand non inoculated seeds were set in sterile Petri dishes, and we observed that inoculated seeds germinated100%, while only 71% of non inoculated seedsgerminated. Inoculated radicles were significantivelylonger than those non inoculated. Root length wasmeasured, under sterile conditions and nutritive solution, in plants inoculaed or non inoculated with thebacteria; control condition was the same without bacteria inoculation. After three weeks, inoculated plants showed 28% more root length, higher biomassand foliar concentration of phosphate than those notinoculated. An improvement of availability of phosphate and production of promoting root growthhormones by the bacteria could be influencing theresults. We show out the potential of Burkholderia cepacia, a bacteria native from tropical acid soils, as abiofertilizer.

Keywords : Burkholderia cepacia; plant growthpromoting rhizobacteria (PGPR); biofertilizers; acidsoils.