Impact of native phosphate solubilizing bacteria on the growth and development of radish (Raphanus sativus L.) plants

This work was aimed at evaluating the activity of native phosphate solubilizing bacteria on growth and development of radish (Raphanus sativus L.) plants. Bacteria were isolated from the Departament of Sucre (Colombia) soil using selective media (NBRIP), further identifi ed by macroscopic and microscopic observation and biochemically characterized using the API System. Their ability to solublize phosphate was then evaluated using the vanadomolybdate acid phosphate colorimetric method. The microorganisms of the highest phosphate solubilizing capacity (Enterobacter sp. and Klebsiella sp.) were multiplied up to concentrations of 106, 107 and 108 c.f.u./mL and then evaluated on radish seeds. Eight treatments were used including witness control and commercial control. Biometric variables, root length, leaf area and dry weight, for treatments T5 (biopreparation with Klebsiella sp., 107 c.f.u./mL) and T1 (biopreparation with Enterobacter sp.,106 u.f.c./mL) were statistically higher than the control treatment. In addition, no signifi cant differences regarding dry weight were found with respect to T7 (chemical fertilizer). The growth and development of radish plants were improved in treatments inoculated with bacteria when compared to controls, confi rming the positive effect of phosphate solubilizing activity of the native strains.