Densidade e ocorrência de microrganismos da Rizosfera de Bauhinia Cheilantha (Bong.) Steud.

Abstract

Soil represents a complex ecosystem in which the relationships and interactions between microorganisms are also complex. Edaphic microorganisms constitute a biological interface with the physical and chemical attributes of the soil, either acting directly in processes such as the mineralization of organic matter or, indirectly, through symbioses such as nitrogen fixation. Bauhinia cheilantha, popularly known as mororó or pata-de-vaca, is a typical legume of the Caatinga. For the Brazilian Northeast, the species under study has a relevant socioeconomic importance, due to its potential as a woody and forage species, being an alternative source of income for the communities, in addition to its ethnopharmacological use, for the production of home remedies. In this sense, the objective was to determine the occurrence and density of microorganisms present in the rhizosphere of the plant “Pata de Vaca” (Bauhinia cheilantha (Bong) Steud) in the semiarid region of Paraiba. The design used for the experiment was completely randomized. Soil samples were collected near the Teacher Training Center (CFP) of the Federal University of Campina Grande – UFCG, Cajazeiras, PB. Sampling was carried out in the surrounding soil and in the rhizosphere of three Bauhinia cheilantha (Bong) Steud plants, with a depth of 0-20 cm in the shape of a target, consisting of three concentric circles (0.5; 1.0 ; 1.5), in which the central point corresponded to the species. The biological attributes evaluated were the analysis of the total density of actinomycetes, bacteria and fungi, being three specific culture media: potato dextrose agar (PDA) plus starch, for the growth of actinomycetes; nutrient agar (NA) for total bacteria and BDA for total fungi, and plating of three dilutions (10-5 10-6 and 10-7). In all samples studied from areas collected from Bauhinia cheilantha (Bong) Steud plants, the presence of actinomycetes, bacteria and fungi were detected, there was no significant effect for the plants and respective areas, and there was a significant effect for microorganisms and for the interaction microorganisms and sampling areas, with greater growth of bacteria and fungi and lesser growth of actinomycetes, mainly in areas of greater influence of the roots. And the highest densities of microorganisms occurred in the surrounding soil samples, that is, 1.5 m radius of the cow's foot, and with less influence of its roots.