METABOLISMO do NITROGÊNIO ASSOCIADO À DEFICIÊNCIA HÍDRICA E SUA RECUPERAÇÃO em GENÓTIPOS DE MILHO
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Data
2002-02-01
Autores
Ferreira, Vilma Marques [UNESP]
Magalhães, Paulo César
Durães, Frederico Ozanan Machado
Oliveira, Luiz Edson Mota de
Purcino, Antonio Álvaro Corsetti
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ISSN da Revista
Título de Volume
Editor
Universidade Federal de Santa Maria (UFSM)
Resumo
O estresse hídrico afeta profundamente o metabolismo celular vegetal. Neste trabalho, objetivou-se quantificar os efeitos da deficiência hídrica e sua recuperação sobre a atividade das enzimas do metabolismo do nitrogênio: redutase do nitrato (RN), glutamina sintetase (GS) e glutamato sintase (GOGAT) e sobre o acúmulo de prolina em plantas dos genótipos de milho BR 2121 e BR 205. O experimento foi conduzido em casa de vegetação, sob o delineamento inteiramente casualizado, com quatro repetições, utilizando-se vasos que continham 14,3kg de solo. Os tratamentos consistiram da combinação dos dois genótipos e quatro intervalos entre irrigações (1, 3, 5 e 7 dias). No dia da avaliação (49 dias após emergência), os tratamentos com intervalos entre 3 e 7 dias, haviam sido irrigados no dia anterior, caracterizando-se portanto como recuperação da deficiência hídrica leve e severa, respectivamente. As extrações e análises foram realizadas utilizando-se a terceira folha basípeta completamente expandida. As atividades das enzimas estudadas não diferiram entre os tratamentos de estresse hídrico, controle e recuperação do estresse moderado, entretanto as plantas sob recuperação do estresse severo apresentaram atividade enzimática superior à das plantas controle. O acúmulo de prolina livre nas folhas aumentou com o estresse hídrico e respondeu à recuperação do estresse apresentando redução. de modo geral, a atividade enzimática e o acúmulo de prolina apresentaram respostas inversas dentro dos tratamentos.
Water stress affects deeply plant cell metabolism. The objective of this work was to quantify the effects of water deficits and its recovery on the performances of nitrogen metabolism enzymes: nitrate reductase (NR), glutamine sintethase (GS) and glutamate sintase (GOGAT) and an accumulation of proline in maize genotypes BR 2121 and BR 205. The trial was carried out in greenhouse, by using pots with 14.3kg of soil. The treatments performed were a combination of two genotypes and four intervals among irrigation (1, 3, 5 and 7 days). on the day in which the treatments were evaluated (49 days after emergency), there was irrigation on the treatments with intervals of 3 and 7 days, therefore those treatments were considered as light and severe recovery of water deficit, respectively. The extractions and analysis were performed by taking the third leaf completely expanded from top to down. The activities of enzymes did not differ among water deficit treatments, control and recovery of severe stress showed higher enzymatic activity than control. The accumulation of free proline in the leaves increased with deficit and responded to recovery of water deficit by reducing its content. In general, the enzimatic activity and the proline accumulation showed inverse answers within treatments.
Water stress affects deeply plant cell metabolism. The objective of this work was to quantify the effects of water deficits and its recovery on the performances of nitrogen metabolism enzymes: nitrate reductase (NR), glutamine sintethase (GS) and glutamate sintase (GOGAT) and an accumulation of proline in maize genotypes BR 2121 and BR 205. The trial was carried out in greenhouse, by using pots with 14.3kg of soil. The treatments performed were a combination of two genotypes and four intervals among irrigation (1, 3, 5 and 7 days). on the day in which the treatments were evaluated (49 days after emergency), there was irrigation on the treatments with intervals of 3 and 7 days, therefore those treatments were considered as light and severe recovery of water deficit, respectively. The extractions and analysis were performed by taking the third leaf completely expanded from top to down. The activities of enzymes did not differ among water deficit treatments, control and recovery of severe stress showed higher enzymatic activity than control. The accumulation of free proline in the leaves increased with deficit and responded to recovery of water deficit by reducing its content. In general, the enzimatic activity and the proline accumulation showed inverse answers within treatments.
Descrição
Palavras-chave
nitrogênio, estresse hídrico, prolina, Redutase do nitrato, GS, GOGAT, nitrogen, water deficit, proline, nitrate reductase, GS, GOGAT
Como citar
Ciência Rural. Universidade Federal de Santa Maria (UFSM), v. 32, n. 1, p. 13-17, 2002.