Evaluación de cepas de Bacillus spp. como microorganismos promotores del crecimiento vegetal (PGPR) en brócoli (Brassica oleracea) y lechuga (Lactuca sativa).

Abstract

The promotion of plant growth by PGPR occurs in two ways, the first is the synthesis of growth regulating substances, such as gibberellins and auxins, the fixation of atmospheric nitrogen and the solubilization of phosphates and the second is through the biological control of pathogens. Several strains of Bacillus, such as B. subtilis, B. megaterium, B. licheniformis and B. pumilus, have stood out in the aforementioned characteristics. Through laboratory tests it was proved that strains of Bacillus licheniformis (BL) and Bacillus megaterium (CT11) have the capacity to fix nitrogen, produce auxins at concentrations of 11.4050 ± 0.0879 and 8.9040 ± 0.4550 ppm respectively and solubilize phosphates in concentrations of 41.7501 ± 1.7302 and 43.2257 ± 0.0799 ppm respectively. The field evaluation was carried out by means of an experimental DCA design in broccoli and lettuce pylons. In lettuce, 26.7 % more height was obtained compared to the control with treatment 2, treatments 2 and 4 increased the percentage of germination, treatment 3 positively influenced the conditions of photosystem II, and treatment 4 increased the dry matter content. For broccoli, 13.72 % more height was obtained compared to the control with treatment 2 and treatment 2 increased the dry matter content. The weight and length of the root increased significantly compared to the control in the treatments for the two horticultural species.