Data/hora: 02/06/2024 11:46:30

Biblioteca(s): | Embrapa Meio Norte / UEP-Parnaíba.
Data corrente: | 04/04/1995
Data da última atualização: | 04/04/1995
Autoria: | MEYER, W. S.; REICOSKY, D. C.
Título: | Enclosing leaves for water potential measurement and its effect on interpreting soil-induced water stress.
Ano de publicação: | 1985
Fonte/Imprenta: | Agricultural and Forest Meteorology, v. 35, p. 187-192, 1985.
Idioma: | Inglês
Conteúdo: | Accurate measurement of leaf xylem pressure potential (x exp) is needed to interpret plant water deficit effects in the field. Recent work has shown that values of x exp obtained from exposed leaves differ markedly from leaves enclosed immediately prior to excision. The present study was conducted to compare the effect of using values from exposed (x exp) and enclosed (x enc) leaves in the calculation of the soil-induced component of plant water stress. The pressure chamber technique was modified by using a sealing compound around the petiole and a laminated aluminium foil and polyethylene envelope to enclose a leaf beginning a few seconds prior to excision until the reading was completed one or two minutes later. The data showed that, as the air vapor pressure deficit (AVPD) increased, the absolute difference between x exp and x enc increased. When AVPD=4k Pa, this difference was 0.8 MPa. The soil-induced component of the leaf pressure potential of cotton (Gossypium hirsutum L.) can be underestimated in absolute magnitude by up to 44% if x exp values are used in the calculation. Removing this error by using x enc values subsequently improves both the discriminating ability of the plant water stress index proposed by Idso et al. (1982) and the accuracy of the estimate of the soil-induced component of leaf xylem pressure potential.
Palavras-Chave: | Estresse hídrico.
Thesagro: | Irrigação; Potencial Hídrico; Solo.
Categoria do assunto: | --
Registro original: | Embrapa Meio Norte / UEP-Parnaíba (CPAMN-UEPP)
Exemplares: | CPAMN-UEPP - (3885-1) - EMB - SP - -- - SP 054/1988 -  - 1988.00054 - DIS