No CrossRef data available.
Article contents
Measurement of Total and Osmotic Potentials in Lucerne and Sunflower Tissues using Thermocouple Psychrometers
Published online by Cambridge University Press: 03 April 2017
Summary
The measurement of leaf water and osmotic potential using thermocouple psychrometry was investigated in field grown stands of sunflower and lucerne. For the chamber size and tissue dimensions used, vapour pressure equilibrium was achieved after 4 to 6 h for leaf water and osmotic potential samples. In lucerne, as the time delay between excising the leaf and sealing it in the chamber was increased from 30 s to 8 min, water apparently evaporated from the leaf sample and leaf water and osmotic potential markedly decreased. For routine psychrometer determinations of leaf water and osmotic potential in lucerne (and presumably other species) leaf samples should therefore be sealed in the chambers as quickly as possible to minimize rapid water loss and associated errors in water potential determination. Vapour pressure equilibration for sunflower capitulum and root water and osmotic potential samples was achieved only after 6 and 24 h, respectively.
G. C. Wright y D. M. Whitfield: Medición de los potentiates totales y osmóticos en tejidos de alfalfa y girasol usando psicrómetros termopar.
Resumen
La medición de los potenciales hidrico foliar y osmótico haciendo uso de la psicrometn'a termopar fue estudiada en masas de girasol y alfalfa cultivadas en el campo. Para el tamaño de camera y dimensiones de los tejidos empleados, se logró el equilibrio de la tensión del vapor luego de 4 a 6 h para muestras de potential hidrico foliar y osmótico. En la alfalfa, a medida que se incrementaba la demora entre la excisión de la hoja y su introduction en la camara desde 30 segundos hasta 8 rainutos, el agua aparentemente se evaporaba de la muestra de la hoja, y los potenciales hidrico foliar y osmótico disminuyeron notablemente. Para determinaciones psicrometricas rutinarias del potential hidrico foliar y el osmotico en la alfalfa (y probablemente en otras especies), las muestras foliares deberian por lo tanto introducirse en las camaras cuanto antes para minimizar la pérdida rápida de agua y errores asociados en la deteminación del potential hidrico. El quilibrio de la tension del vapor para el capitulo de girasol y muestras de potential hidrico y osmótico de las rai'ces fue alcanzado sólo después de 6 y 24 horas respectivamente.
- Type
- Research Article
- Information
- Copyright
- Copyright © Cambridge University Press 1988
References
Barrs, H. D. & Kramer, P. J. (1969). Water potential increase in sliced leaf tissue as a cause of error in vapour phase determinations of water potential. Plant Physiology
44:959–964.Google Scholar
Baughn, J. W. & Tanner, C B. (1976). Excision effects on leaf water potential of five herbaceous species. Crop Science
16:184–190.CrossRefGoogle Scholar
Boyer, J. S. (1972). Use of isopiestic technique in thermocouple psychrometry. IIL Application to plants. In Psychrometry in Water Relations Research,
220–223. (Eds R. W, Brown and B. P, Van Haveren). Utah Agricultural Experiment Station, Utah State University.Google Scholar
Brown, P. W. & Tanner, C. B. (1981). Alfalfa water potential measurement: a comparison of the pressure chamber and leaf dewpoint hygrometers. Crop Science
21:240–244.Google Scholar
Brown, P. W. & Tanner, C. B. (1983). Alfalfa osmotic potential: A comparison of the water release curve and frozen-tissue methods. Agronomy Journal
75:91–93.CrossRefGoogle Scholar
Cary, J. W. & Fisher, H. D. (1971). Plant water potential gradients measured in the field by freezing point
Physiologia Plantarum
24:397–402.Google Scholar
Davis, R., Kertlake, R. G. & Ludlow, M. M. (1986). An automatic micro-computer based recording system for a multichannel dewpoint hygrometer used to measure water potential. Tropical Agronomy Technical Memorandum No. 45.
CSIRO, Australia, Division of Tropical Crops and Pasture.Google Scholar
Macnicol, P. K. (1976). Rapid metabolic changes in the wounding response of leaf discs following excision. Plant Physiology
57:80–84.Google Scholar
Millar, B. D. (1974). Improved thermocouple psychrometer for the measurement of plant and soil water potential. IIL Equilibration. Journal of Experimental Botany
25:1070–1084.Google Scholar
Morgan, J. M. (1980). Osmotic adjustment in the spikelets and leaves of wheat. Journal of Experimental Botany
31:655–665.Google Scholar
Nelsen, C E., Safir, G. R. & Hanson, A. D. (1978). Water potential in excised leaf tissue: Comparison of a commercial dew point hygrometer and a thermocouple psychrometer on soybean, wheat and barley. Plant Physiology
61:131–133.Google Scholar
Oosterhuis, D. M. & Walker, S. (1982). Influence of evaporation from the cut edge of excised leaf samples taken for water potential determinations using thermocouple psychrometer. Plant Physiology Supp. 69:16.Google Scholar
Scholander, P. F., Hammel, H. T., Hemmingsen, E. A. & Bradstreet, E. D. (1964). Hydrostatic pressure and osmotic potential in leaves of mangroves and some other plants. Proceedings National Academy of Science
52:119–125.Google Scholar
Sheehy, J. E., Woodward, F. L, Jones, M. B. & Windram, A. (1979). Microclimate, photosynthesis and growth of lucerne (Medicago sativa, L.) L Microclimate and photosynthesis. Annals of Botany
44: 693–707.CrossRefGoogle Scholar
Walker, S., Oosterhuis, D. M. & Savage, M.J. (1983). Field use of screen-cages thermocouple psychrometers in sample chambers. Crop Science
23:627–632. Google Scholar