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An exploratory study of phosphorus-solubilizing bacteria in two habitats associated with Cedrela Montana Moritz ex Turcz

Abstract:

The availability of phosphorus (P) in the earth's crust is limited by the chemical composition of the soil, and by anthropogenic factors in disturbed environments. Only 0.1% of P is available to be absorbed directly by plants, positive interaction with phosphorus solubilizing bacteria (PSB) is required to convert P insoluble to its soluble form and make it available to plants. Although this association is of great importance, there is little information over presence on BSF in tree species from Andean montane forests. The objective of this research was to identify the presence of BSF in the rhizosphere of two individuals of Andean cedar (Cedrela Montana), from the secondary forest (BS) and grassland zone (ZP), located in Intag (north of the Western Cordillera of Ecuador). A total of three samples were collected from the soil of each rhizosphere, which was enriched with tricalcium phosphate, and cultured in NBRIP selective medium to determinate the presence of BSF. We obtained 54 BS isolates and 46 ZP isolates, with phosphorus solubilization capacity. The BS-5, BS-6, and ZP-10 reached the highest phosphate solubilization indices, with values of 4.63, 2.75, and 2.08. The results suggest that BSF, from rhizospheric soil of C. Montana, is present in both habitats (BS and ZP), where we found promising isolates; however, those from BS showed a greater solubilizing capacity of inorganic phosphorus. The information obtained in this study will serve as the basis for the future development of specific bioinoculants that allow the propagation of Andean cedar under greenhouse conditions.