Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-04-18T20:10:31Z No. of bitstreams: 1 2010 - Cec?lia de Souza Ant?nio.pdf: 1613209 bytes, checksum: e560fdd88ef8707b79c6d4b0120730ec (MD5) / Made available in DSpace on 2017-04-18T20:10:31Z (GMT). No. of bitstreams: 1 2010 - Cec?lia de Souza Ant?nio.pdf: 1613209 bytes, checksum: e560fdd88ef8707b79c6d4b0120730ec (MD5) Previous issue date: 2010-04-20 / CAPES / The sugar cane is one of the major agricultural products in Brazil. The crop is able to associate with diazotrophic bacteria (fix nitrogen from the air), that may be located inside the plant tissue (entophytic). The diazotrophic bacteria are capable of promoting growth of sugar cane by means of biological nitrogen fixation (BNF) or production of hormones. But little is known about populations of these bacteria present in sugar cane. This work aimed to study diversity of the population and identify the isolates by molecular and physiological methods, as well as to assess the effectiveness of some isolates to promote plant growth of sugar cane in the field. In solid potato media, there were observed the formation of seven groups, with 95% of similarity, showing the great colonies morphology variation. Many isolates showed similar characteristics to the genus Gluconacetobacter, when analyzed in semi-solid LGI-P media and solid Potato-P and LGI-P media. Two isolates were most efficient in the endolar synthesis with production over 49 ?g/mL. All isolates were classified as Gram negative. Of the 36 isolates, 27.5% were similar to the standard strain RB 11366 (Burkholderia tropica), 45% to BR 11281 strain (Gluconacetobacter diazotrophicus) and 5% to the other patterns BR 11335 (Herbaspirillum seropedicae), BR 11504 (Herbaspirillum rubrisubalbicans) and BR 11145 (Azospirillum amazonense). Through the comparison of the sequencing of 16S rDNA with the NCBI GenBank isolate 215 was identified as belonging to species Gluconacetobacter diazotrophicus, the 179-1a belonging to Burkholderia tropica and the isolated 151-B, 211-A, and 219 to the gender Burkholderia. The inoculated strains 160-1 and 215 promoted an increase in the straw dry biomass (up to 0.7 Mg ha-1) and total nitrogen of flag leaf (above 69,7 kg ha-1), respectively in the tested varieties RB 72454 and RB 918,639. Only the 160-1 isolate was able to promote increase in biomass in the RB 867515 variety. Stalk yield was higher for the variety RB 918639 with 191.96 Mg ha-1. / A cana-de-a??car ? um dos principais produtos agr?colas do Brasil. A cultura ? capaz de se associar as bact?rias diazotr?ficas (fixam nitrog?nio do ar), que podem estar no interior do tecido da planta (endof?ticas). As bact?rias diazotr?ficas endof?ticas s?o capazes de promover o crescimento da cana-de-a??car por meio da fixa??o biol?gica do nitrog?nio (FBN) ou pela produ??o de fitorm?nios. Mas pouco se conhece sobre as popula??es presentes destas bact?rias em cana-de-a??car. O presente trabalho visou estudar a diversidade da popula??o e identificar estes isolados, atrav?s de m?todos moleculares e fisiol?gicos, assim como avaliar a efici?ncia de alguns isolados na promo??o de crescimento vegetal de plantas de cana-de-a??car no campo. Foi observada em meio s?lido Batata, com 95% de similaridade, a forma??o de sete grupos mostrando a grande varia??o morfol?gica de col?nias neste meio testado. Muitos isolados apresentaram caracter?sticas similares ao g?nero Gluconacetobacter, quando analisados em meio semi-s?lido LGI-P e s?lido Batata-P e LGI-P. Dois isolados foram mais eficientes na s?ntese de ind?les com produ??es acima de 49 ?g/mL. Todos os isolados foram classificados como Gram negativos. Dos 36 isolados avaliados, 27,5% foram semelhantes ? estirpe padr?o RB 11366 (Burkholderia tropica); 45% a BR 11281 (Gluconacetobacter diazotrophicus) e 5% aos demais padr?es BR 11335 (Herbaspirillum seropedicae), BR 11504 (Herbaspirillum rubrisubalbicans) e BR 11145 (Azospirillum amazonense). Atrav?s da compara??o do seq?enciamento do gene 16S rDNA com o NCBI GenBank o isolado 215 foi identificado com pertencente a esp?cie de Gluconacetobacter diazotrophicus , o 179-1A com pertencente a esp?cie Burkholderia tropica e os isolados 151-B, 211-A e 219 ao g?nero Burkholderia. As estirpes 160-1 e 215 inoculadas promoveram aumento na produ??o de biomassa seca da palha (acima de 0,7 Mg.ha-1) e nitrog?nio total da folha bandeira (acima de 69,7 kg.ha-1), respectivamente nas variedades RB 72454 e RB 918639 testadas. Apenas o isolado 160-1 foi capaz de promover um aumento de biomassa seca na variedade RB 867515. A produ??o de colmos foi maior para a variedade RB918639 com 191,96 Mg.ha-1.