Data/hora: 21/06/2024 22:55:52

Biblioteca(s): | Embrapa Pantanal.
Data corrente: | 04/05/2001
Data da última atualização: | 30/03/2017
Autoria: | WISTUBA, N.; REICH, R.; WAGNER, H. J.; ZHU, J. J.; SCHNEIDER, H.; BENTRUP, F. W.; HAASE, A.; ZIMMERMANN, U.
Título: | Xylem flow and its driving forces in a tropical liana: concomitant flow-sensitive NMR imaging and pressure probe measurements.
Ano de publicação: | 2000
Fonte/Imprenta: | Plant Biology, v.2, n.6, p.579-582, 2000.
Idioma: | Inglês
Conteúdo: | Flow-sensitive NMR imaging and pressure probe techniques were used for measuring xylem water flow and its driving forces (i.e., xylem pressure as well as cell turgor and osmotic pressure gradients) in a tropical liana, Epipremnun aureum. Selection of tall specimens allowed continuous and simultaneous measurements of all parameters at various distances from the root under diurnally changing environmental conditions. Well hydrated plants exhibited exactly linearly correlated dynamics changes in xylem tension and flow velocity. Concomitant multiple-probe insertions along the plant shoot revealed xylem and turgor pressure gradients with changing magnitudes due to environmental changes and plant orientation (upright, apex-down, or horizontal). The data suggest that in upright and - to a lesser extent - in horizontal plants the transpirational water loss by the cells towards the apex during the day is not fully compensated by water uptake throught the night. Thus, longitudinal cellular osmotic pressure gradients exist. Due to the tight hydraulic coupling of the xylem and the tissue cells these gradients represent (besides the transpiration-induced tension in the xylem) an additional tension component for anti-gravitional water movement from the roots throught the vessels to the apex.
Palavras-Chave: | Cell osmotic; Diurnal change; NMR; Plant; Tropical liana; Xylem flow.
Thesagro: | Planta.
Categoria do assunto: | --
Registro original: | Embrapa Pantanal (CPAP)
Exemplares: | CPAP - (48959-1) - ADC - SP - PP - SP16249 -  - 16249 - DIS