Solubilização de fosfato por fungos do solo e eficiência de sua inoculação em caupi e milho / Phosphate solubilization by soil fungi and their efficiency in corn and cowpea inoculation

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

16/12/2011

RESUMO

The process of biological nitrogen fixation in leguminous is achieved by bacteria forming nodules possessing the nitrogenase enzyme that are able to catalyze the reduction of molecular nitrogen to ammonia which is assimilated by the plants. Despite the high diversity of the Kingdom Fungi, reports on the solubilization on phosphates by fungi have been restricted to the genera Aspergillus and Penicillium. This is due to the techniques used for isolation that favor fungi with fast sporulation capacity. The synergistic interaction achieved by inoculation of nitrogen fixing bacteria and phosphate solubilizing fungi could promote the plant growth and increase the agricultural production. The objectives of this study were to evaluate the ability of various genera and species of fungi, isolated by filtration and washing of soil particles technique from different land use systems in the Brazilian Amazon, to solubilize calcium phosphate in solid medium; evaluate the influence of selected strains to promote the growth of cowpea cultivar BR17 and maize cultivar BR026 using insoluble phosphorus [P-Ca3(PO4)2] as the sole source of phosphate and evaluate the effectiveness of the co inoculation of two strains of calcium phosphate solubilizing fungi and an unable strain to solubilize calcium phosphate in the PVK agar medium with the Bradyrhizobium strains UFLA03-84 and INPA03-11B to promote the growth of cowpea using insoluble phosphorus as source of phosphate and low concentration of available nitrogen under axenic conditions. We report, the first time, fourteen strains of different genera of saprophytic fungi of the Ascomycota phylum capable of solubilize calcium phosphate in PVK agar medium, the absence of growth inhibition among all fungi strains and the two Bradyrhizobium sp. strains by dual culture technique and the capacity of two strains of phosphate solubilizing fungi and a strain unable to solubilize phosphate to increase the shoot dry matter of the treatments with inoculation significantly (p<0,05) when compared with uninoculated controls.

ASSUNTO(S)

fungos solubilizadores de fosfato fixação biológica de nitrogênio haematonectria ipomoeae pochonia clamydosporia var. catenulata acremonium polychromum bradyrhizobium vigna unguiculata [l.] walp zea mays l. microbiologia agricola nitrogen biological fixation

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