Advertisement

Planta

, Volume 126, Issue 3, pp 259–267 | Cite as

Some evidence for the existence of turgor pressure gradients in the sieve tubes of willow

  • S. Rogers
  • A. J. Peel
Article

Summary

Sieve tube sap was collected either from the severed stylets of Tuberolachnus salignus (Gmelin) or via incisions made into the phloem of small willow trees or potted cuttings. Measurements of the osmotic potential (O.P.) of sap samples showed a gradient to exist in the presumed direction of assimilate transport, ie from apex to base of the stem.

In most experiments samples of phloem tissue were taken after the collection of sieve tube sap, the water potential of these pieces of tissue being measured in a psychometer. Although a water potential gradient existed in the opposite sense to the O.P. gradient in the sap (lowest water potential at the apex of the stem), the difference between O.P. and W.P. indicated the turgor of the sieve tubes to be higher at the apex than at the base of the stem. The magnitude of the turgor gradient measured in this way lay between 0.5 and 2.7 atm m-1.

In other experiments severed stylets only were used to determine whether a hydrostatic gradient can exist in willow sieve tubes. After measurement of flow rates from stylets sited at the apex and base of willow stems, the Poiseuille expression was used to calculate the pressure at the point of stylet puncture. These experiments gave values for the pressure gradient (in the presumed direction of assimilate flow) of between 1.9 and 4.7 atm m-1.

Keywords

Pressure Gradient Water Potential Willow Experiment Sample Osmotic Potential 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Abbreviation

O.P.

osmotic potential

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Crafts, A. S., Crisp, C. E.: Phloem transport in plants. San Francisco: Freeman 1971Google Scholar
  2. Curtis, O. F., Schofield, H. T.: A comparison of osmotic concentrations of supplying and receiving tissues and its bearing on the Münch hypothesis of the translocation mechanism. Amer. J. Bot. 20, 502–512 (1933)Google Scholar
  3. Dixon, H. H., Gibbon, M. W.: Bast sap in plants. Nature (Lond.) 130, 661–662 (1932)Google Scholar
  4. Hammel, H. T.: Measurement of turgor pressure and its gradient in the phloem of oak. Plant Physiol. (Lancaster) 43, 1042–1048 (1968)Google Scholar
  5. Horwitz, L.: Some simplified mathematical treatments of translocation in plants. Plant Physiol. (Lancaster) 33, 81–93 (1958)Google Scholar
  6. Huber, B., Schmidt, E., Jahnel, H.: Untersuchungen über den Assimilatstrom. Tharandt. Forstl. Jb. 88, 1017–1050 (1937)Google Scholar
  7. Kaufmann, M. R., Kramer, P. J.: Phloem water relations and translocation. Plant Physiol. (Lancaster). 42, 191–194 (1967)Google Scholar
  8. Milburn, J. A.: Phloem transport in Ricinus: concentration gradients between source and sink. Planta (Berl.) 117, 303–319 (1974)Google Scholar
  9. Mittler, T. E.: Studies on the feeding and nutrition of Tuberolachnus salignus (Gmelin). Ph. D. Thesis University of Cambridge (1954)Google Scholar
  10. Münch, E.: Die Stoffbewegungen in der Pflanze. Jena: Fischer 1930Google Scholar
  11. Peel, A. J.: Studies on the physiology of the sieve tube in higher plants. Ph. D. Thesis University of Nottingham (1959).Google Scholar
  12. Pfeiffer, M.: Die Verteilung der osmotischen Werte im Baum im Hinblick auf die Münchsche Druckstromtheorie. Flora 132, 1–47 (1937)Google Scholar
  13. Spanner, D. C.: The Peltier effect and its use in the measurement of suction pressure. J. exp. Bot. 2, 145–168 (1951)Google Scholar
  14. Tingley, M. A.: Concentration gradients in plant exudates with reference to the mechanism of translocation. Amer. J. Bot. 31, 30–38 (1944)Google Scholar
  15. Waister, P. D.: Equipment for measuring water stress in leaves. University of Nottingham, Department of Horticulture, Miscellaneous Publication No. 15 (1963)Google Scholar
  16. Weatherley, P. E., Johnson, R. P. C.: The form and function of the sieve tube. A problem in reconciliation. Int. Rev. Cytol. 24, 149–192 (1968)PubMedGoogle Scholar
  17. Weatherly, P. E., Peel, A. J., Hill, G. P.: Studies on the physiology of the sieve tube. Preliminary experiments using aphid mouthparts. J. exp. Bot. 10, 1–16 (1959)Google Scholar
  18. Zimmermann, M. H.: Translocation of organic substances in trees. II. On the translocation mechanism in the phloem of white ash. Plant Physiol. (Lancaster) 32, 399–404 (1957)Google Scholar

Copyright information

© Springer-Verlag 1975

Authors and Affiliations

  • S. Rogers
    • 1
  • A. J. Peel
    • 1
  1. 1.Department of Plant BiologyThe UniversityHullUK

Personalised recommendations