The primary aim of this study was to investigate the effects of seed inoculation with the biocontrol agent Pseudomonas fluorescens strain F113 (producing the antibiotic DAPG) and its modified derivative strain F113G22 (with DAPG production disrupted) on the uptake of nitrogen by pea and wheat plants. Uptake of N by the two plant species was investigated in soil microcosms amended with 15N-labelled fertilisers (urea or ammonium nitrate) or 15N-labelled plant residues. Uptake of fertiliser-N was unaffected by inoculation. However, uptake of N derived from organic residues was enhanced in pea inoculated with either strain. In contrast, uptake of N by wheat was reduced in the presence of either strain F113 or F113G22, suggesting that the effects of these microbial inocula on N-mineralisation in the rhizosphere were dependent on plant species. It was subsequently found that microfaunal populations, especially soil nematodes in the rhizosphere of inoculated pea were significantly larger than those associated with the rhizosphere of non-inoculated controls. In wheat, however, microfaunal populations in the rhizosphere of inoculated plants were lower than those associated with noninoculated controls. These trends were repeated using simple sand microcosms into which soil bacteria and the bacterial-feeding nematode Caenorhabditis elegans were introduced. This suggested that effects on N-mineralisation were mediated by changes in populations of microbial-feeding microfauna. As a possible explanation for the increased nematode populations in the rhizosphere of inoculated pea plants, the nematicidal effects of pea seed exudates on C. elegans were investigated in small-scale sand systems. It was found that exposure to non-inoculated pea seeds reduced the short-term survival of C. elegans as compared to unamended sand, and that survival was greater in the presence of pea seeds inoculated with either strain than non-inoculated seeds, suggesting that nematicidal compounds released by germinating pea seeds were utilised by the P.fluorescens strains. No such effects were observed for wheat.

Made available in DSpace on 2014-06-11T19:35:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-13Bitstream added on 2014-06-13T19:46:25Z : No. of bitstreams: 1 binotti_ffs_dr_ilha.pdf: 5975802 bytes, checksum: 90bef1ffaba7ce8cb7d8049d45949057 (MD5) / O nitrogênio é um nutriente que pode propiciar efeitos benéficos na produtividade, na qualidade química e fisiológica das sementes de feijão. Assim, é de fundamental importância saber qual o momento adequado para sua aplicação e a fonte de N a ser utilizada, além da interação com a prática da inoculação de sementes com Rhizobium spp., em sistema plantio direto. O objetivo do trabalho foi o de estudar o efeito da inoculação de sementes, fontes e modos de aplicação de nitrogênio no desenvolvimento, produtividade, qualidade química e fisiológica de sementes do feijoeiro de inverno no sistema plantio direto em sucessão a milho e Brachiaria. O delineamento experimental foi o de blocos casualizados em esquema fatorial 2x2x8, com quatro repetições. O trabalho foi desenvolvido em Latossolo Vermelho Distrófico argiloso, Selvíria (MS) em dois anos (2006 e 2007) e os tratamentos foram constituídos pela combinação de inoculação de sementes (presença e ausência) com Rhizobium tropici (estirpes SEMIA 4077 + SEMIA 4080), fontes de nitrogênio (uréia – 45% de N e Entec 26® - 26 % de N + 13% de S + inibidor da nitrificação) e modos de aplicação de nitrogênio (testemunha – sem N, 30 dias antes da semeadura – DAS, 15 DAS, semeadura, 15 dias após semeadura no estádio V2 – DASe, 30 DASe no estádio V4, 1/3 Semeadura + 2/3 15 DASe, 1/3 Semeadura + 2/3 30 DASe) na dose de 90 kg ha-1. A uréia é o adubo nitrogenado recomendado para feijoeiro de inverno irrigado, podendo ser aplicado antecipadamente aos 15 DAS ou na semeadura e/ou cobertura. A inoculação propiciou maior teor de carboidratos (açúcares livres e amido) nas sementes, porém, não tem influencia diretamente na qualidade fisiológica e produtividade / Nitrogen is a nutrient that may provide beneficial effects on yield, physiological and chemical quality of common bean seeds. So, it is fundamental importance to know what the right time for its application and the source of N to be used in addition to interaction with the practice of seed inoculation with Rhizobium spp. in no tillage system. The objective of the work was to study the effect of seed inoculation, nitrogen sources and split in the growth, yield, physiological and chemical quality of the common bean seeds in the winter in no tillage system over graminea, in a dystrophic clayey Latosol – Haplustox, MS. The work was carried out in two years (2006 and 2007) in a randomized blocks design using a factorial scheme 2x2x8 and 4 repetitions, constituted by seed inoculation with Rhizobium tropici (presence and absence), two sources of nitrogen (urea - 45% nitrogen and Entec 26® - 26 % de N + 13% de S + DMPP molecules aiming to inhibit nitrification) and eight stadia of nitrogen application (control without N application, 30 days before sowing – DBS, 15 DBS, at sowing – S, 15 days after sowing – DBSe, 30 DBSe, 1/3 S + 2/3 15 DBSe, 1/3 S + 2/3 30 DBSe) at 90 kg ha-1. The urea nitrogen is recommended for irrigated winter common bean and can be applied in advance at 15 DBS or at sowing and/at sidedressing. The inoculation provided higher content of carbohydrates (free sugars and starch) in seeds however, does not directly influence the physiological quality and yield

Resumo: O nitrogênio é um nutriente que pode propiciar efeitos benéficos na produtividade, na qualidade química e fisiológica das sementes de feijão. Assim, é de fundamental importância saber qual o momento adequado para sua aplicação e a fonte de N a ser utilizada, além da interação com a prática da inoculação de sementes com Rhizobium spp., em sistema plantio direto. O objetivo do trabalho foi o de estudar o efeito da inoculação de sementes, fontes e modos de aplicação de nitrogênio no desenvolvimento, produtividade, qualidade química e fisiológica de sementes do feijoeiro de inverno no sistema plantio direto em sucessão a milho e Brachiaria. O delineamento experimental foi o de blocos casualizados em esquema fatorial 2x2x8, com quatro repetições. O trabalho foi desenvolvido em Latossolo Vermelho Distrófico argiloso, Selvíria (MS) em dois anos (2006 e 2007) e os tratamentos foram constituídos pela combinação de inoculação de sementes (presença e ausência) com Rhizobium tropici (estirpes SEMIA 4077 + SEMIA 4080), fontes de nitrogênio (uréia - 45% de N e Entec 26® - 26 % de N + 13% de S + inibidor da nitrificação) e modos de aplicação de nitrogênio (testemunha - sem N, 30 dias antes da semeadura - DAS, 15 DAS, semeadura, 15 dias após semeadura no estádio V2 - DASe, 30 DASe no estádio V4, 1/3 Semeadura + 2/3 15 DASe, 1/3 Semeadura + 2/3 30 DASe) na dose de 90 kg ha-1. A uréia é o adubo nitrogenado recomendado para feijoeiro de inverno irrigado, podendo ser aplicado antecipadamente aos 15 DAS ou na semeadura e/ou cobertura. A inoculação propiciou maior teor de carboidratos (açúcares livres e amido) nas sementes, porém, não tem influencia diretamente na qualidade fisiológica e produtividade / Abstract: Nitrogen is a nutrient that may provide beneficial effects on yield, physiological and chemical quality of common bean seeds. So, it is fundamental importance to know what the right time for its application and the source of N to be used in addition to interaction with the practice of seed inoculation with Rhizobium spp. in no tillage system. The objective of the work was to study the effect of seed inoculation, nitrogen sources and split in the growth, yield, physiological and chemical quality of the common bean seeds in the winter in no tillage system over graminea, in a dystrophic clayey Latosol - Haplustox, MS. The work was carried out in two years (2006 and 2007) in a randomized blocks design using a factorial scheme 2x2x8 and 4 repetitions, constituted by seed inoculation with Rhizobium tropici (presence and absence), two sources of nitrogen (urea - 45% nitrogen and Entec 26® - 26 % de N + 13% de S + DMPP molecules aiming to inhibit nitrification) and eight stadia of nitrogen application (control without N application, 30 days before sowing - DBS, 15 DBS, at sowing - S, 15 days after sowing - DBSe, 30 DBSe, 1/3 S + 2/3 15 DBSe, 1/3 S + 2/3 30 DBSe) at 90 kg ha-1. The urea nitrogen is recommended for irrigated winter common bean and can be applied in advance at 15 DBS or at sowing and/at sidedressing. The inoculation provided higher content of carbohydrates (free sugars and starch) in seeds however, does not directly influence the physiological quality and yield / Orientador: Orivaldo Arf / Coorientador: Salatiér Buzetti / Banca: Marco Eustaquio de Sa / Banca: Kuniko Iwamoto Haga / Banca: Leandro Borges Lemos / Banca: Neli Cristina Belmiro dos Santos / Doutor