Nodulation and symbiotic nitrogen fixation in barbatimão plants (Striphnodendron adstringens)

Abstract

Nitrogen is a vitally important macronutrient for all plants. Its absorption takes place only through more reactive forms such as nitrate and ammonium since plants alone are not capable of absorbing atmospheric nitrogen (N2). However, some plants, such as a large part of the Fabaceae family, are capable of establishing symbiotic relationships with certain bacteria that allow them to be absorbed as a way to meet their needs. The barbatimão (Striphnodendron adstringens) is an example of one of these plants, it is known today that a certain variety of symbionts is able to modulate the genus Stryphnodendron, however, it is not known specifically which ones, nor the efficiency of these relationships in the case of S. astringents. Therefore, the present study aims to obtain results regarding different strains of rhizobia able to modulate other legumes, such as Mimosa caesalpineaefolia and Enterolobium sp. (among others), and which ones will be able to modulate the barbatimão and be more efficient regarding the production and fixation of nitrogen by the plant and consequently in the growth of these plants. Barbatimão seeds will be used, which will be germinated and cultivated in their native soil (Cerrado) and vermiculite, in 2-liter pots where they will be inoculated with the selected rhizobia. The plants will be grown and maintained for about 90 days (after germination) and during this period some growth measurements will be analyzed. At the end of the experiment, growth analyses such as total biomass, height, leaf area, number, and mass of nodules, as well as biochemical analyses such as total proteins, total free amino acids, ureides, and total nitrogen will be performed. From these analyses, it is expected to observe different responses regarding the growth and symbiotic nitrogen fixation in the barbatimão, among the different strains of rhizobia that will be used, and furthermore select the most efficient strain in the process of symbiotic nitrogen fixation in this plant species. (AU)