Rizobactérias promovem o crescimento de feijoeiro-comum e de milho por diferentes processos / Rhizobacteria promote growth of common bean and maize by different processes

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

02/12/2011

RESUMO

Plant Growth Promoting Rhizobacteria (PGPR) promote the growth of legumes and non-legume plants enhancing their nutrition, mainly of nitrogen and phosphorus. For this purpose, these bacteria make use of mechanisms such as solubilization of insoluble inorganic phosphate, plant growth hormone production and biological fixation of nitrogen in the rhizosphere, in addition to other mechanisms. The work was intended to investigate the effect of the co-inoculation of CIAT 899T, strain aproved by MAPA (Ministério da Agricultura, Pecuária e Abastecimento Ministry of Agricultue and Supply) as an inoculant for the bean plant crop with strains of Burkholderia fungorum (UFLA 04-226, UFLA 04-217, UFLA 04-155, UFLA 04-232) Burkholderia sp. (UFLA 04-234) and Azospirillum brasilense (BR 11001T), selected in a previous screening as potential candidates. Also there was the ability of strains with the potential to solubilize insoluble inorganic phosphate in vitro to promote the growth of common bean and corn under different conditions. In axenic conditions, the co-inoculation of strain CIAT 899T with strain UFLA 04-155 increased the dry matter fo the nodules and of the shoot, content of P, Mg, Cu and Fe in relation to the plant inoculated only with CIAT 899T. However, in soil, UFLA 04-155 provided significant increase of the above-cited parameters, and further the content of K, Ca, S and Zn, stimulating the native community of rhizobes in a significant way as compared with the non-inoculated plant. These results point out, for the first time, the potential of Burkholderia fungorum to promote the growth of common bean plant either co-inoculated or not with CIAT 899T. Under axenic conditions, both UFLA 04-155 and UFLA 04-21, applied jointly with insoluble calcium phosphate (P-Ca) were capable of increasing the shoot dry matter of the common bean plant in relation to the plant which was given only P-Ca, but the increase was not caused by the solubilization mechanism. But in soil, those two strains, more UFLA 04-233, promoted the growth of the corn by the solubilization of natural phosphate 45 days after planting. The solubilization mechanism of insoluble phosphate utilized by these strains was probably the one of release of 2-ketogluconic acid and also of oxalic acid. Those acids were identified and quantified among the acids studied in HPLC. These results point out that Burkholderia sp. UFLA 04-21 may be a potential canditate for the development of biofertilizer applicable into corn crop.

ASSUNTO(S)

rizobactérias promotoras de crescimento burkholderia zea mays phaseolus vulgaris microbiologia agricola growth-promoting rhizobacteria

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