| |
|
|
| Registros recuperados : 11 | |
| Registros recuperados : 11 | |
|
|
|
 | Acesso ao texto completo restrito à biblioteca da Embrapa Milho e Sorgo. Para informações adicionais entre em contato com cnpms.biblioteca@embrapa.br. |
Registro Completo
|
Biblioteca(s): |
Embrapa Milho e Sorgo. |
|
Data corrente: |
02/09/1998 |
|
Data da última atualização: |
13/07/2018 |
|
Tipo da produção científica: |
Artigo em Periódico Indexado |
|
Autoria: |
PURCINO, A. A. C.; ARELLANO, C.; ATHWAL, G. S.; HUBER, S. C. |
|
Afiliação: |
ANTONIO ALVARO CORSETTI PURCINO, CNPMS. |
|
Título: |
Nitrate effect on carbon and nitrogen assimilating enzymes of maize hybrids representing seven eras of breeding. |
|
Ano de publicação: |
1998 |
|
Fonte/Imprenta: |
Maydica, Bergamo, v. 43, n. 2, p. 83-94, 1998. |
|
Idioma: |
Inglês |
|
Conteúdo: |
The objective of this study was to determine possible differences in the carbon and nitrogen metabolism of 14 maize era hybrids released since 1930. Plants fed 1.6 mM N03- had nitrate reductase activity (NRA) comparable to plants fed 16 mM N03- but did not sustain maximum NRA, and had reduced growth. Nitrate reductase (NR) and sucrose phosphate synthase (SPS) activities were not related to year of hybrid release. However, the activation states of NR under low nitrate, and of SPS under high nitrate increased up to 1970 and then leveled off. This suggests a trend towards increased efficiency for both No3- reduction in low nitrate plants, and sucrose synthesis in high nitrate plants. Chloroplastic glutamine synthetase (GS2) protein did not respond to NO3- supply and was not related to year of hybrid release. However, cytosolic glutamine synthetase (GS1) protein was higher in low nitrate plants compared to high nitrate plants. Furthermore, in low nitrate plants, GS1 protein correlated negatively to NRA indicating that its role was to remobilize N compounds Phosphoenophyruvate carboxylase (PEPC) activity responded to increased No3- supply and increased up to 1970's declining thereafter. In most hybrids, PEPC specific activity (activity mg-1 protein .s-1) was higher in the high nitrate plants. The specific activities of NR, SPS and glutamate dehydrogenase (GDH) tended to be lower in high nitrate plants, although SPS and GDH activities, expressed on a g fresh weight basis, responded to increased nitrate supply. These observations support the hypothesis that PEPC protein is preferentially increased during the estabhishment of the C4 syndrome GDH activity declined over the last 70 years in the low nitrate plants. A negative correlation was found between GDH specific activity and GS2 protein in the high nitrate plants. When trends in enzyme activity were examined over time, it was observed that from the 1930's to the 1970's breeding for increased grain yield indirectly selected plants with increased PEPC activity and more activated NR and SPS. This trend was not observed in hybrids released during the 1930's and 1990's, indicating thar increments in grain yield observed during these last two decades were not due to additional enhancements in nitrate reduction, primary carbon fixation and sucrose metabolism. MenosThe objective of this study was to determine possible differences in the carbon and nitrogen metabolism of 14 maize era hybrids released since 1930. Plants fed 1.6 mM N03- had nitrate reductase activity (NRA) comparable to plants fed 16 mM N03- but did not sustain maximum NRA, and had reduced growth. Nitrate reductase (NR) and sucrose phosphate synthase (SPS) activities were not related to year of hybrid release. However, the activation states of NR under low nitrate, and of SPS under high nitrate increased up to 1970 and then leveled off. This suggests a trend towards increased efficiency for both No3- reduction in low nitrate plants, and sucrose synthesis in high nitrate plants. Chloroplastic glutamine synthetase (GS2) protein did not respond to NO3- supply and was not related to year of hybrid release. However, cytosolic glutamine synthetase (GS1) protein was higher in low nitrate plants compared to high nitrate plants. Furthermore, in low nitrate plants, GS1 protein correlated negatively to NRA indicating that its role was to remobilize N compounds Phosphoenophyruvate carboxylase (PEPC) activity responded to increased No3- supply and increased up to 1970's declining thereafter. In most hybrids, PEPC specific activity (activity mg-1 protein .s-1) was higher in the high nitrate plants. The specific activities of NR, SPS and glutamate dehydrogenase (GDH) tended to be lower in high nitrate plants, although SPS and GDH activities, expressed on a g fresh weight basis, responde... Mostrar Tudo |
|
Palavras-Chave: |
Maize; Nitrate. |
|
Thesagro: |
Carbono; Melhoramento; Milho; Nitrato; Nitrogênio; Zea Mays. |
|
Thesaurus NAL: |
breeding; carbon; metabolism; nitrogen. |
|
Categoria do assunto: |
S Ciências Biológicas |
|
Marc: |
LEADER 03133naa a2200301 a 4500
001 1480503
005 2018-07-13
008 1998 bl uuuu u00u1 u #d
100 1 $aPURCINO, A. A. C.
245 $aNitrate effect on carbon and nitrogen assimilating enzymes of maize hybrids representing seven eras of breeding.$h[electronic resource]
260 $c1998
520 $aThe objective of this study was to determine possible differences in the carbon and nitrogen metabolism of 14 maize era hybrids released since 1930. Plants fed 1.6 mM N03- had nitrate reductase activity (NRA) comparable to plants fed 16 mM N03- but did not sustain maximum NRA, and had reduced growth. Nitrate reductase (NR) and sucrose phosphate synthase (SPS) activities were not related to year of hybrid release. However, the activation states of NR under low nitrate, and of SPS under high nitrate increased up to 1970 and then leveled off. This suggests a trend towards increased efficiency for both No3- reduction in low nitrate plants, and sucrose synthesis in high nitrate plants. Chloroplastic glutamine synthetase (GS2) protein did not respond to NO3- supply and was not related to year of hybrid release. However, cytosolic glutamine synthetase (GS1) protein was higher in low nitrate plants compared to high nitrate plants. Furthermore, in low nitrate plants, GS1 protein correlated negatively to NRA indicating that its role was to remobilize N compounds Phosphoenophyruvate carboxylase (PEPC) activity responded to increased No3- supply and increased up to 1970's declining thereafter. In most hybrids, PEPC specific activity (activity mg-1 protein .s-1) was higher in the high nitrate plants. The specific activities of NR, SPS and glutamate dehydrogenase (GDH) tended to be lower in high nitrate plants, although SPS and GDH activities, expressed on a g fresh weight basis, responded to increased nitrate supply. These observations support the hypothesis that PEPC protein is preferentially increased during the estabhishment of the C4 syndrome GDH activity declined over the last 70 years in the low nitrate plants. A negative correlation was found between GDH specific activity and GS2 protein in the high nitrate plants. When trends in enzyme activity were examined over time, it was observed that from the 1930's to the 1970's breeding for increased grain yield indirectly selected plants with increased PEPC activity and more activated NR and SPS. This trend was not observed in hybrids released during the 1930's and 1990's, indicating thar increments in grain yield observed during these last two decades were not due to additional enhancements in nitrate reduction, primary carbon fixation and sucrose metabolism.
650 $abreeding
650 $acarbon
650 $ametabolism
650 $anitrogen
650 $aCarbono
650 $aMelhoramento
650 $aMilho
650 $aNitrato
650 $aNitrogênio
650 $aZea Mays
653 $aMaize
653 $aNitrate
700 1 $aARELLANO, C.
700 1 $aATHWAL, G. S.
700 1 $aHUBER, S. C.
773 $tMaydica, Bergamo$gv. 43, n. 2, p. 83-94, 1998.
Download
Esconder MarcMostrar Marc Completo |
|
Registro original: |
Embrapa Milho e Sorgo (CNPMS) |
|
|
Biblioteca |
ID |
Origem |
Tipo/Formato |
Classificação |
Cutter |
Registro |
Volume |
Status |
Fechar
|
| Nenhum registro encontrado para a expressão de busca informada. |
|
|
