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Registros recuperados : 82 | |
7. | | GOEDERT, C. O. Temperatura do planossolo em Pelotas, Rio Grande do Sul. Pesquisa Agropecuária Brasileira, Rio de Janeiro, v. 6, p. 9-16, 1971. (Agronomia, 4). Título em inglês: Planosol temperature in Pelotas, Rio Grande do Sul, Brazil.
A partir do v. 3(1968) é constituída de duas partes: Série Agronomia e Série Veterinária, publicadas também separadamente. Biblioteca(s): Embrapa Unidades Centrais. |
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Registros recuperados : 82 | |
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| Acesso ao texto completo restrito à biblioteca da Embrapa Recursos Genéticos e Biotecnologia. Para informações adicionais entre em contato com cenargen.biblioteca@embrapa.br. |
Registro Completo
Biblioteca(s): |
Embrapa Recursos Genéticos e Biotecnologia. |
Data corrente: |
22/07/1991 |
Data da última atualização: |
04/07/2005 |
Autoria: |
GOEDERT, C. O. |
Afiliação: |
EMBRAPA/CENARGEN. |
Título: |
Seed dormancy of tropical forage grasses and implications for the conservation of genetic resources. |
Ano de publicação: |
1984 |
Fonte/Imprenta: |
Reading : University of Reading, 1984. |
Páginas: |
190p. |
Descrição Física: |
Tese Doutorado. |
Idioma: |
Inglês |
Conteúdo: |
Investigation are described on the characteristics of tropical grass seeds affect their management, particularly in genebanks. Five tropical forage grass species were selected for study Brachiaria humidicola, Brachiaria decumbens, Panicum maximum, Paspalum guenoarum and Andropogon gayanus. It is shown that germination tests currently provide the best basis for monitoring viability. However two problems are particularly prevalent in tropical grasses which hinder the interpretation of germination tests; first, freshly harvested seeds often show low purity (i.e. a high proportion of immature and empty spikelets); and secondly, many of the true seeds often show pronounced dormancy (i.e. though viable they are incapable of germination without special stimuli). Investigation of the purity problems showed that in can be overcome with the use of X-ray equipament, but other methods are unreliable. Investigation of the dormancy problem led to the conclusion that advantage needs to be taken of the interaction of several dormancy-breaking agents. It is shown that simultaneous use of three of these are specially valuable alternating-temperatures, linght and nitrate ions. In particular it is important to define the optimum characteristics of alternative-temperature regimes for maximum stimulation of germination. Techniques for doing this were developed using a two-way temperature-gradient plate. Amplitude and thermoperiod were both shown to be particularly important attributes and, although the optima for each species investigated differed in detail, in no case did any optimum diverge far from a regime in which seeds were subjected to diurnal cycles of 20h at 15o and 4h at 35oC in the presence of 10-2 M KNO3 and intermittent illumination. The significance of these and other experimental results are discussed in relation to seed physiology and to the problems of the management of seed accessions in genebanks for genetic conservation. MenosInvestigation are described on the characteristics of tropical grass seeds affect their management, particularly in genebanks. Five tropical forage grass species were selected for study Brachiaria humidicola, Brachiaria decumbens, Panicum maximum, Paspalum guenoarum and Andropogon gayanus. It is shown that germination tests currently provide the best basis for monitoring viability. However two problems are particularly prevalent in tropical grasses which hinder the interpretation of germination tests; first, freshly harvested seeds often show low purity (i.e. a high proportion of immature and empty spikelets); and secondly, many of the true seeds often show pronounced dormancy (i.e. though viable they are incapable of germination without special stimuli). Investigation of the purity problems showed that in can be overcome with the use of X-ray equipament, but other methods are unreliable. Investigation of the dormancy problem led to the conclusion that advantage needs to be taken of the interaction of several dormancy-breaking agents. It is shown that simultaneous use of three of these are specially valuable alternating-temperatures, linght and nitrate ions. In particular it is important to define the optimum characteristics of alternative-temperature regimes for maximum stimulation of germination. Techniques for doing this were developed using a two-way temperature-gradient plate. Amplitude and thermoperiod were both shown to be particularly important attributes and, althou... Mostrar Tudo |
Palavras-Chave: |
Forrageira; Genetic conservation; Genetic resource; Gramineas forrageiras tropicais; Grass; Pastagem tropical; Regiao Tropical; Seed; Seed physiology; Sementes; Tropical forage grasses; Tropical pasture. |
Thesagro: |
Agricultura; Agronomia; Conservação; Dormência; Germinação; Horticultura; Pastagem; Planta Forrageira; Recurso Genético; Semente. |
Thesaurus NAL: |
agriculture; agronomy; dormancy; forage; germination; seeds; storage. |
Categoria do assunto: |
-- |
Marc: |
LEADER 03177nam a2200469 a 4500 001 1163573 005 2005-07-04 008 1984 bl uuuu m 00u1 u #d 100 1 $aGOEDERT, C. O. 245 $aSeed dormancy of tropical forage grasses and implications for the conservation of genetic resources. 260 $aReading : University of Reading$c1984 300 $a190p.$cTese Doutorado. 520 $aInvestigation are described on the characteristics of tropical grass seeds affect their management, particularly in genebanks. Five tropical forage grass species were selected for study Brachiaria humidicola, Brachiaria decumbens, Panicum maximum, Paspalum guenoarum and Andropogon gayanus. It is shown that germination tests currently provide the best basis for monitoring viability. However two problems are particularly prevalent in tropical grasses which hinder the interpretation of germination tests; first, freshly harvested seeds often show low purity (i.e. a high proportion of immature and empty spikelets); and secondly, many of the true seeds often show pronounced dormancy (i.e. though viable they are incapable of germination without special stimuli). Investigation of the purity problems showed that in can be overcome with the use of X-ray equipament, but other methods are unreliable. Investigation of the dormancy problem led to the conclusion that advantage needs to be taken of the interaction of several dormancy-breaking agents. It is shown that simultaneous use of three of these are specially valuable alternating-temperatures, linght and nitrate ions. In particular it is important to define the optimum characteristics of alternative-temperature regimes for maximum stimulation of germination. Techniques for doing this were developed using a two-way temperature-gradient plate. Amplitude and thermoperiod were both shown to be particularly important attributes and, although the optima for each species investigated differed in detail, in no case did any optimum diverge far from a regime in which seeds were subjected to diurnal cycles of 20h at 15o and 4h at 35oC in the presence of 10-2 M KNO3 and intermittent illumination. The significance of these and other experimental results are discussed in relation to seed physiology and to the problems of the management of seed accessions in genebanks for genetic conservation. 650 $aagriculture 650 $aagronomy 650 $adormancy 650 $aforage 650 $agermination 650 $aseeds 650 $astorage 650 $aAgricultura 650 $aAgronomia 650 $aConservação 650 $aDormência 650 $aGerminação 650 $aHorticultura 650 $aPastagem 650 $aPlanta Forrageira 650 $aRecurso Genético 650 $aSemente 653 $aForrageira 653 $aGenetic conservation 653 $aGenetic resource 653 $aGramineas forrageiras tropicais 653 $aGrass 653 $aPastagem tropical 653 $aRegiao Tropical 653 $aSeed 653 $aSeed physiology 653 $aSementes 653 $aTropical forage grasses 653 $aTropical pasture
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