Abstract

HERNANDEZ-LEAL, Tania I.; CARRION, Gloria  and  HEREDIA, Gabriela. In vitro phosphate solubilization by a strain of Paecilomyces lilacinus (Thom) Samson. Agrociencia [online]. 2011, vol.45, n.8, pp.881-892. ISSN 2521-9766.

Phosphorus is an element with limited availability in the soil, which can be improved by solubilizing fungi of calcium and iron phosphates. Therefore, the objective of this study was to evaluate in vitro the solubilization of phosphate compounds by Paecilomyces lilacinus in solid and liquid culture media. In solid media agar plates were used with each phosphate compound, and a control without phosphates, which were inoculated with spores of the fungus. The halos of solubilization were evaluated and the relative efficiency of solubilization (ERS) was calculated. In tests with liquid media, P. lilacinus was inoculated in culture media with calcium and iron phosphate without agar, in which the soluble phosphorus (P) and pH were quantified. In agar plates with calcium phosphate solubilization halos were observed and ESR was 305 % at 8 d, but in media with iron phosphate halos were not formed. In the liquid medium with calcium phosphate a greater amount of soluble P (71.28 ±7.88 mg L^-1) was obtained compared with the medium with iron phosphate (1.75±0.32 mg L^-1). In the presence of iron phosphate, P. lilacinus immobilized most of the solubilized phosphorus and left a small proportion available. The pH of both culture media decreased in the presence of fungus, which is likely that the main mechanism of solubilization is the production of organic acids.

Keywords : phosphorus; solubilizing fungi; phosphates; Paecilomyces lilacinus.

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