Associação de bactérias diazotróficas na assimilação e transporte de nitrogênio em plantas jovens de seringueira (Hevea spp)

• Ano de defesa: 2011
• Autor(a) principal: Diniz, Patrícia Fabian de Araújo
• Orientador(a): Oliveira, Luiz Edson Mota de
• Banca de defesa: Delu Filho, Nelson, Camargos, Liliane Santos de, Bonome, Lisandro Tomás da Silva
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Lavras
• Programa de Pós-Graduação: Programa de Pós-graduação em Agronomia/Fisiologia Vegetal
• Departamento: Departamento de Biologia
• País: BRASIL
• Palavras-chave em Português: Aminoácidos; Glutamina sintetase; FBN; GABA; Amino acids; Glutamine synthetase
• Área do conhecimento CNPq: Fisiologia Vegetal
• Link de acesso: https://repositorio.ufla.br/handle/1/2696

The use of microorganisms that provide better nutrition of rubber tree can be an alternative to obtain rootstocks early and with reduced use of chemical inputs.This study aimed to promote the isolation and characterization of diazotrophic bacteria associated with rubber trees, seeking to estimate the contribution of these microorganisms on the growth and development of rubber tree seedlings, besides knowing their effects on the enzymatic and biochemical behavior of plants and their influence on nitrogen (N) metabolism, through the analysis of nitrogen compounds in the xylem sap. Four others strains of diazotrophic bacteria from the genus Herbaspirillum, Azospirillum and Burkholderia were also evaluated. For this, treatments consisted of control in low level of N (2mM) and in ideal level of N (8mM), both uninoculated, besides those inoculated and supplemented with 2 mM of N. Nineteen isolated were found in soil samples of rhizosphere from rubber tree. The characterization of the colonies indicated seventeen isolates producing a very elastic mucus, negative gram, rod-shaped cell, immobile and owning two globules of poly-β-hydroxybutyrate, one each end of the rod-shaped cell. The partial sequencing of 16S rDNA gene indicated that five of these isolates belong to the genus Beijerinckia, three belonging to B. indica species and two to B.derxii species, besides one isolated belongs to the genus Bacillus. Bacteria belonging to the genus Beijerinckia were efficient in producing indole-3-acetic acid in the presence of tryptophan. The inoculated plants showed gains in height and diameter of the stems, greater fresh weight of lateral roots, longer length of main root, greater leaf area compared to the control supplemented with 2mM of N. The inoculation promoted the increase in leaf dry matter, shoot dry matter, root dry matter and total dry weight, and higher relative efficiency and high levels of chlorophyll. All bacteria promoted a supply of nitrogen. The analysis of nitrogen compounds transported in xylem sap of the plants, it was concluded that rubber tree translocates, mainly, the amino acids glutamine and GABA to the shoot. Ureides and nitrate were transported in the xylem sap in larger quantities than ammonium in all treatments. A small influence of inoculation on the activity of glutamine synthetase was detected in the roots. In addition, inoculated plants showed higher concentrations of protein and amino acids in leaves.