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Registro Completo |
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Biblioteca(s): |
Embrapa Trigo. |
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Data corrente: |
10/01/2010 |
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Data da última atualização: |
10/01/2010 |
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Autoria: |
MARQUES, J. Q. de A. |
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Título: |
Conservação do solo. |
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Ano de publicação: |
1960 |
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Fonte/Imprenta: |
O Observador Econômico e Financeiro, n. 291, 9 p., maio 1960. |
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Idioma: |
Português |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 00298naa a2200109 a 4500
001 1828236
005 2010-01-10
008 1960 bl --- 0-- u #d
100 1 $aMARQUES, J. Q. de A.
245 $aConservação do solo.
260 $c1960
773 $tO Observador Econômico e Financeiro$gn. 291, 9 p., maio 1960.
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Embrapa Trigo (CNPT) |
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 | 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
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Biblioteca(s): |
Embrapa Milho e Sorgo. |
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Data corrente: |
06/03/2003 |
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Data da última atualização: |
07/06/2018 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Autoria: |
PURCINO, A. A. C.; ALVES, V. M. C.; PARENTONI, S. N.; BELELE, C. L.; LOGUERCIO, L. L. |
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Afiliação: |
ANTONIO ALVARO CORSETTI PURCINO, CNPMS; VERA MARIA CARVALHO ALVES, CNPMS; SIDNEY NETTO PARENTONI, CNPMS. |
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Título: |
Aluminum effects of nitrogen uptake and nitrogen assimilating enzymes in maize genotypes with contra tolerance to aluminum toxicity. |
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Ano de publicação: |
2003 |
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Fonte/Imprenta: |
Journal of Plant Nutriton, New York, v. 26, n. 1, p. 31-61, 2003. |
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Idioma: |
Inglês |
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Conteúdo: |
The objective of this study was to investigate the effect of aluminum (Al) on NO3- and NH4+ uptake and on activity/expression of the N- assimilating enzymes glutamine synthetase (GS1, GS2, and GSr isoforms, EC 6.3.1.2), glutamate synthase (NADH- GOGAT, EC 1.4.7.14; ferredoxin- GOGAT, EC 1.4.7.1), and glutamate dehydrogenase (GDH, EC 1.4.1.2) of maize (Zea mays L.) genotypes contrasting in tolerance to Al toxicity. Seeds were germinated on paper towels, screened for uniformity and allowed to grow for 5-6 d in a modified Steinberg nutrient solution, pH 5.5, in a glasshouse, under natural light. Immediately after transference to a growth chamber (12 h photoperiod, 26°C ± 0.5/18°C ± 0.9 day/night temperature, 72% RH and 540 µ Em-2 s-1 quantum flux density) Al stress was imposed by lowering pH to 4.5 and addition of 166 µmoles L-1 AlCl3. Control plants were grown in the same nutrient solution without Al, pH 4.5. Aluminum inhibited NO3- and NH4+ uptake and decreased shoot dry matter yield in all genotypes used in this investigation. Irrespective of their tolerance to Al toxicity, Al- treated plants had less nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), and sulfur (S) in their leaves. In roots, Al treatment did not affect dry matter weight but decreased accumulation of N, Ca, and Mg. Phosphorus and potassium (K) tended to accumulate in roots of Al- treated plants, suggesting that Al inhibited P translocation to the leaves. In roots, Al induced anaplerotic GDH and phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) activities, but inhibited GS activity. Moreover, in the apex (0-5 mm) and in the 6-15 mm segment of the elongation zone of most genotypes, Al tended to inhibit expression of GSr and favor expression of GS1. This increase in GS1 expression concomitantly with decreased N uptake and elevated deaminating GDH activity are indicative of metabolic changes usually associated with plant senescence. In leaves, Al did not influence GOGAT and GS activities and expression of GS isoforms suggesting it does not disturb assimilation of nitrogenous compounds translocated from roots to leaves. Nonetheless, lower leaf PEPC activity suggests that Al intoxicated plants had lower CO2- fixation rates. The inverse effect of Al treatment on the activities of GDH and PEPC in roots and leaves, indicates that whereas increased activities in roots were induced by stress related stimuli, decreased activities in leaves were caused by a reduced nitrogen supply to the leaves. Because the earliest effects observed in this investigation appeared only after 24 h of exposure to Al and were similar in both tolerant and sensitive genotypes, it is concluded that the changes observed in N uptake and assimilation into plant amino acids were downstream of the initial, primary Al toxicity event. MenosThe objective of this study was to investigate the effect of aluminum (Al) on NO3- and NH4+ uptake and on activity/expression of the N- assimilating enzymes glutamine synthetase (GS1, GS2, and GSr isoforms, EC 6.3.1.2), glutamate synthase (NADH- GOGAT, EC 1.4.7.14; ferredoxin- GOGAT, EC 1.4.7.1), and glutamate dehydrogenase (GDH, EC 1.4.1.2) of maize (Zea mays L.) genotypes contrasting in tolerance to Al toxicity. Seeds were germinated on paper towels, screened for uniformity and allowed to grow for 5-6 d in a modified Steinberg nutrient solution, pH 5.5, in a glasshouse, under natural light. Immediately after transference to a growth chamber (12 h photoperiod, 26°C ± 0.5/18°C ± 0.9 day/night temperature, 72% RH and 540 µ Em-2 s-1 quantum flux density) Al stress was imposed by lowering pH to 4.5 and addition of 166 µmoles L-1 AlCl3. Control plants were grown in the same nutrient solution without Al, pH 4.5. Aluminum inhibited NO3- and NH4+ uptake and decreased shoot dry matter yield in all genotypes used in this investigation. Irrespective of their tolerance to Al toxicity, Al- treated plants had less nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), and sulfur (S) in their leaves. In roots, Al treatment did not affect dry matter weight but decreased accumulation of N, Ca, and Mg. Phosphorus and potassium (K) tended to accumulate in roots of Al- treated plants, suggesting that Al inhibited P translocation to the leaves. In roots, Al induced anaplerotic GDH and phos... Mostrar Tudo |
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Thesagro: |
Alumínio; Milho. |
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Categoria do assunto: |
S Ciências Biológicas |
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Marc: |
LEADER 03449naa a2200193 a 4500
001 1486649
005 2018-06-07
008 2003 bl uuuu u00u1 u #d
100 1 $aPURCINO, A. A. C.
245 $aAluminum effects of nitrogen uptake and nitrogen assimilating enzymes in maize genotypes with contra tolerance to aluminum toxicity.$h[electronic resource]
260 $c2003
520 $aThe objective of this study was to investigate the effect of aluminum (Al) on NO3- and NH4+ uptake and on activity/expression of the N- assimilating enzymes glutamine synthetase (GS1, GS2, and GSr isoforms, EC 6.3.1.2), glutamate synthase (NADH- GOGAT, EC 1.4.7.14; ferredoxin- GOGAT, EC 1.4.7.1), and glutamate dehydrogenase (GDH, EC 1.4.1.2) of maize (Zea mays L.) genotypes contrasting in tolerance to Al toxicity. Seeds were germinated on paper towels, screened for uniformity and allowed to grow for 5-6 d in a modified Steinberg nutrient solution, pH 5.5, in a glasshouse, under natural light. Immediately after transference to a growth chamber (12 h photoperiod, 26°C ± 0.5/18°C ± 0.9 day/night temperature, 72% RH and 540 µ Em-2 s-1 quantum flux density) Al stress was imposed by lowering pH to 4.5 and addition of 166 µmoles L-1 AlCl3. Control plants were grown in the same nutrient solution without Al, pH 4.5. Aluminum inhibited NO3- and NH4+ uptake and decreased shoot dry matter yield in all genotypes used in this investigation. Irrespective of their tolerance to Al toxicity, Al- treated plants had less nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), and sulfur (S) in their leaves. In roots, Al treatment did not affect dry matter weight but decreased accumulation of N, Ca, and Mg. Phosphorus and potassium (K) tended to accumulate in roots of Al- treated plants, suggesting that Al inhibited P translocation to the leaves. In roots, Al induced anaplerotic GDH and phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) activities, but inhibited GS activity. Moreover, in the apex (0-5 mm) and in the 6-15 mm segment of the elongation zone of most genotypes, Al tended to inhibit expression of GSr and favor expression of GS1. This increase in GS1 expression concomitantly with decreased N uptake and elevated deaminating GDH activity are indicative of metabolic changes usually associated with plant senescence. In leaves, Al did not influence GOGAT and GS activities and expression of GS isoforms suggesting it does not disturb assimilation of nitrogenous compounds translocated from roots to leaves. Nonetheless, lower leaf PEPC activity suggests that Al intoxicated plants had lower CO2- fixation rates. The inverse effect of Al treatment on the activities of GDH and PEPC in roots and leaves, indicates that whereas increased activities in roots were induced by stress related stimuli, decreased activities in leaves were caused by a reduced nitrogen supply to the leaves. Because the earliest effects observed in this investigation appeared only after 24 h of exposure to Al and were similar in both tolerant and sensitive genotypes, it is concluded that the changes observed in N uptake and assimilation into plant amino acids were downstream of the initial, primary Al toxicity event.
650 $aAlumínio
650 $aMilho
700 1 $aALVES, V. M. C.
700 1 $aPARENTONI, S. N.
700 1 $aBELELE, C. L.
700 1 $aLOGUERCIO, L. L.
773 $tJournal of Plant Nutriton, New York$gv. 26, n. 1, p. 31-61, 2003.
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