Data/hora: 21/06/2024 12:07:17

Biblioteca(s): | Embrapa Mandioca e Fruticultura.
Data corrente: | 13/12/2005
Data da última atualização: | 13/12/2005
Autoria: | GOMES, M. de M. de A.; LAGÔA, A. M. M. A.; MEDINA, C. L.; MACHADO, E. C. M.; MACHADO, M. A.
Afiliação: | Universidade Estadual do Norte Fluminense.
Título: | Interactions between leaf water potential, stomatal conductance and abscisic acid content of orange trees submitted to drought stress.
Ano de publicação: | 2004
Fonte/Imprenta: | Brazilian Journal of Plant Physiology, Londrina, v. 16, n. 3, p.155-161, sep./dec. 2004.
ISSN: | 1677-0420
Idioma: | Inglês
Conteúdo: | Thirty-month-old 'Pêra' orange trees grafted on 'Rangpur' lemon trees grown in 100 L pots were submitted to water stress by the suspension of irrigation. CO2 assimilation (A), transpiration (E) and conductance (gs) values declined from the seventh day of stress, although the leaf water potential at 6:00 a.m. (Ypd) and at 2:00 p.m. (Y2) began to decline from the fifth day of water deficiency. The CO2 intercellular concentration (Ci) of water- stressed plants increased from the seventh day, reaching a maximum concentration on the day of most severe stress. The carboxylation efficiency, as revealed by the ratio A/Ci was low on this day and did not show the same values of non-stressed plants even after ten days of rewatering. After five days of rewatering only Ypd and Y2 were similar to control plants while A, E and gs were still different. When Y2 decreases, there was a trend for increasing abscisic acid (ABA) concentration in the leaves. Similarly, stomatal conductance was found to decrease as a function of decreasing Y2.ABA accumulation and stomatal closure occurred when Y2 was lower than -1.0MPa. Water stress in 'Pera' orange trees increased abscisic acid content with consequent stomatal closure and decreased Y2 values.
Palavras-Chave: | gas exchanges.
Thesagro: | Citrus Sinensis.
Thesaurus Nal: | abscisic acid; water stress.
Categoria do assunto: | --
Registro original: | Embrapa Mandioca e Fruticultura (CNPMF)
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