ABSTRACT: High yields obtained from soybean [Glycine max (L.) Merrill], and consequent profits, are related to efficient symbiosis of soybean with nitrogen fixing bacteria of the Bradyrhizobium genus. Inoculation with strains belonging to the Bradyrhizobium japonicum, B. elkanii, and B. diazofficiens species, approved by the Brazilian Ministry of Agriculture (MAPA), is a common practice for this crop. However, variations in the composition of inoculants can change the quality of the product. The aim of this study was to genetically identify […]

ABSTRACT Legume-rhizobia symbiosis is a cross-kingdom association that results in large amounts of nitrogen incorporated in food webs. For the Brazilian semi-arid region, data on genetic variability and symbiotic efficiency of Papilionoidae rhizobial communities are very scarce. The aim of this study was to evaluate the genetic variability and the symbiotic efficiency of eight rhizobial isolates obtained from “mulungu” (Erythrina velutina Willd.) nodules. For 16S rRNA gene sequencing, the genomic DNA was extracted using a commercial kit, amplified with universal […]

The process of biological nitrogen fixation (BNF), performed by symbiotic nitrogen fixing bacteria with legume species, commonly known as α and β rhizobia, provides high sustainability for the ecosystems. Its management as a biotechnology is well succeeded for improving crop yields. A remarkable example of this success is the inoculation of Brazilian soybeans with Bradyrhizobium strains. Rhizobia produce a wide diversity of chemical structures of exopolysaccharides (EPS). Although the role of EPS is relatively well studied in the process of […]

A field experiment was conducted at Crato – Ceará to study how green manuring affects nodulation and yield of cowpea (Vigna unguiculata (L.) Walp) which received different inoculation treatments. The experiment was conducted under a randomized block design, split-split-plot arrangement with four replicates. Treatments were green manures for the main plot, nitrogen sources for the split-plot and bi-weekly plant samplings for the split-split-plot. The green manures under study were pearl millet – Pennisetum americanum; velvet beans – Stizolobium aterrimum; or […]

Mining activities promote severe environmental degradation in many parts of the world, and revegetation techniques with diverse plant species have been used for rehabilitation of these areas. Studies on the occurrence, efficiency and diversity of key microbial groups such as leguminosae-nodulating, nitrogen fixing bacteria (LNNFB) are essential because they are involved in nutrient cycling processes and, therefore, to the sustainability of these areas. Aiming to evaluate the efficiency and phenotypic diversity of LNNFB, soil samples were collected from different bauxite […]

The leguminous tree Anadenanthera peregrina var. falcata (angico-do-cerrado) forms symbiotic associations with nitrogen fixing bacteria (rhizobia) and arbuscular mycorrhizal fungi. The aim of this study was the evaluation of the influence of rhizobial and arbuscular mycorrhizal inoculation on the initial growth of angico-do-cerrado plants, in autoclaved and non-autoclaved soil with and without inoculations. The experiment was carried out in a greenhouse using mycorrhized roots of maize and a mixture of rhizobial isolates as inocula. Plant growth was positively affected by […]

An experiment was carried out at the Soil Science Department of Federal University of Lavras (MG), from November/1999 to January/2000, aiming to evaluate the survival of strain and isolates of rhizobia, in heavy metal contaminated soil.The possible relationship between rhizobia tolerance in culture medium and its survival in contaminated soil was also verified.From a group of 60strains/isolates tested at a previous study for metal tolerance in YMA medium, two out of the most tolerant microorganisms [BR-4406 (strain recommended as inoculant […]

Two experiments were carried out at the Soil Science Department of the Federal University of Lavras (MG), to assess the tolerance to heavy metals “in vitro” of inoculant strains (I), and isolates from both heavy metals contaminated soil (ICS) and uncontaminated soil (IUS) of Bradyrhizobium from Enterolobium contortisiliquum and Acacia mangium and of Azorhizobium from Sesbania virgata. In the first experiment ten strains and, or, isolates of each plant species, were tested in YMA media modified by addition of biological […]

Although periodically flooded ecosystems represent 25% of the total Amazon area, they contribute to 75% of timber production. Both periodically flooded and upland ecosystems are greatly diverse in species belonging to Leguminosae family. Some of these species are currently exploited, but the economic potential of the vast majority has been overlooked. The knowledge of the plant growth characteristics of these species under nursery conditions is the first step to understand their biology and establish artificial woodlands in deforested areas. This […]