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Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2021-05-03T01:24:50Z No. of bitstreams: 1 2017 - Liliandra Barreto Em?dio Gomes.pdf: 1047441 bytes, checksum: 7018d83464c9630d4d9240a716992d2d (MD5) Made available in DSpace on 2021-05-03T01:24:50Z (GMT). No. of bitstreams: 1 2017 - Liliandra Barreto Em?dio Gomes.pdf: 1047441 bytes, checksum: 7018d83464c9630d4d9240a716992d2d (MD5) Previous issue date: 2017-03-30 Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior, CAPES, Brasil. The use of diazotrophic plant growth promoter Azospirillum brasilense stands out as a sustainable alternative in reducing the application of N in pastures, presenting potential for the reduction of degradation levels. The objective of this study was to evaluate the effects of inoculation of strain Sp 245 of Azospirillum brasilense on different genotypes of Brachiaria. For that, experiments were carried out under greenhouse conditions and in laboratories at Embrapa Agrobiologia (Serop?dica-RJ). Fourteen cultivars of the Brachiaria genus were studied: B. brizantha (Marand?, Xara?s, Paiagu?s, Piat? and B140); B. decumbens cv. Basilisk; B. humidicola (Comum, Tupi, H47 and Llanero); B. ruziziensis and hybrids (H331, Mulato and Mulato II) with or without the application of the turfous inoculant containing the strain Sp 245 of Azospirillum brasilense at different times of cuts. The experimental design was a randomized complete block design with five replications. The results obtained in greenhouse, regarding the biomass production and accumulation of N in the aerial part, allowed the selection of the cultivars Marand?, Basilisk and the hybrid Mulato II for the conduction of two experiments where the development of the root system of the plants Through the software WinRhizo and the identification of the bacterium inside the plant using the strain Sp 245 of Azospirillum brasilense marked with a fluorescent green protein (GFP). With the results obtained, it was verified that the strain Sp 245 promoted an increase of biomass in the different cultivars of Brachiaria, highlighting the cultivars Mulato II, Ruziziensis and Basilisk. The root development of the cultivars Marand?, Basilisk and Mulato II was favored by the inoculation, with better development for all variables analyzed. The contribution of FBN varied for each genotype and as a function of the cutting season and the inoculation of the Sp 245 strain was able to contribute up to 16% at 60 days of sowing and 20% at 180 days of the N accumulated by the plant through the FBN. The use of the Sp 245 strain of Azospirillum brasilense marked with green fluorescent protein (GFP) allowed to differentiate the bacteria inoculated experimentally from those pre-existing in the plant and to confirm the presence of this in the intercellular spaces of the roots of the hybrid Mulato II and B. decumbens cv . Basilisk after ten days of inoculation. Therefore, the analyzes showed that the inoculation of the Brachiaria seeds contributed to the better plant development, increasing the root system and favoring the accumulation of N through the FBN. A utiliza??o da bact?ria diazotr?fica promotora de crescimento vegetal Azospirillum brasilense destaca-se como uma alternativa sustent?vel na redu??o da aplica??o de N em pastagens, apresentando potencial para a redu??o dos n?veis de degrada??o. O objetivo desse estudo foi avaliar os efeitos da inocula??o da estirpe Sp 245 de Azospirillum brasilense em diferentes gen?tipos de Brachiaria. Para tal foram conduzidos experimentos em casa de vegeta??o e em laborat?rios na Embrapa Agrobiologia (Serop?dica-RJ). Foram estudados quatorze cultivares do g?nero Brachiaria, sendo: B. brizantha (Marand?, Xara?s, Paiagu?s, Piat? e B140); B. decumbens cv. Basilisk; B. humidicola (Comum, Tupi, H47 e Llanero); B. ruziziensis e h?bridos (H331, Mulato e Mulato II) com ou sem a aplica??o do inoculante turfoso contendo a estirpe Sp 245 de Azospirillum brasilense em diferentes ?pocas de cortes. O delineamento experimental foi de blocos ao acaso com cinco repeti??es. Os resultados obtidos em casa de vegeta??o, quanto a produ??o de biomassa e ac?mulo de N na parte a?rea, permitiram a sele??o das cultivares Marand?, Basilisk e do h?brido Mulato II para a condu??o de dois experimentos onde foram analisados o desenvolvimento do sistema radicular das plantas atrav?s do software WinRhizo e a identifica??o da bact?ria dentro da planta com a utiliza??o da estirpe Sp 245 de Azospirillum brasilense marcada com uma prote?na verde fluorescente (GFP). Com os resultados obtidos, verificou-se que a estirpe Sp 245 promoveu um incremento de biomassa nas diferentes cultivares de Brachiaria com destaque para as cultivares Mulato II, Ruziziensis e Basilisk. O desenvolvimento radicular das cultivares Marand?, Basilisk e Mulato II foi favorecido pela inocula??o, com melhor desenvolvimento para todas as vari?veis analisadas. A contribui??o da FBN variou para cada gen?tipo e em fun??o da ?poca de corte e a inocula??o da estirpe Sp 245 foi capaz de contribuir com at? 16% aos 60 dias de semeadura e 20% aos 180 dias, do N acumulado pela planta atrav?s da FBN. O uso da estirpe Sp 245 de Azospirillum brasilense marcada com a prote?na verde fluorescente (GFP) permitiu diferenciar as bact?rias inoculadas experimentalmente daquelas pr?-existentes na planta e confirmar a presen?a desta nos espa?os intercelulares das ra?zes do h?brido Mulato II e da B. decumbens cv. Basilisk ap?s dez dias de inocula??o. Portanto, as an?lises mostraram que a inocula??o das sementes de Brachiaria contribuiu para o melhor desenvolvimento vegetal, aumentando o sistema radicular e favorecendo o ac?mulo de N atrav?s da FBN.