Skip to main content
PMC home page
Plant Physiology logoLink to Plant Physiology
. 1996 Mar;110(3):1007–1016. doi: 10.1104/pp.110.3.1007

Osmoregulation by Oat Coleoptile Protoplasts (Effect of Auxin).

C P Keller 1, E Van Volkenburgh 1
PMCID: PMC157801  PMID: 12226237

Abstract

The effect of auxin on the physiology of protoplasts from growing oat (Avena sativa L.) coleoptiles was investigated. Protoplasts, isolated iso-osmotically from peeled oat coleoptile segments, were found to swell steadily over many hours. Incubated in 1 mM CaCl2, 10 mM KCl, 10 mM 2-(morpholino)ethanesulfonic acid/1,3-bis-[tris(hydroxymethyl)methylamino]propane, pH 6.5, and mannitol to 300 milliosmolal, protoplasts swelled 28.9% [plus or minus] 2.0 (standard error) after 6 h. Addition of 10 [mu]M indoleacetic acid (IAA) increased swelling to 41.1% [plus or minus] 2.1 (standard error) after 6 h. Swelling (in the absence of IAA) was partially dependent on K+ in the bath medium, whereas auxin-induced swelling was entirely dependent on K+. Replacement of mannitol in the bath by Glc increased swelling (in the absence of IAA) and eliminated auxin-induced swelling. Swelling with or without IAA was inhibited by osmotic shock and was completely reversed by 0.1 mM NaN3. Sodium orthovanadate, applied at 0.5 mM, only gradually inhibited swelling under various conditions but was most effective with protoplasts prepared from tissue preincubated in vanadate. Our data are interpreted to suggest that IAA increases the conductance of the plasma membrane to K+.

Full Text

The Full Text of this article is available as a PDF (1.6 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Amodeo G., Srivastava A., Zeiger E. Vanadate inhibits blue light-stimulated swelling of vicia guard cell protoplasts. Plant Physiol. 1992 Nov;100(3):1567–1570. doi: 10.1104/pp.100.3.1567. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. COCKING E. C. Action of growth substances, chelating agents and antibiotics on isolated root protoplasts. Nature. 1962 Mar 10;193:998–999. doi: 10.1038/193998a0. [DOI] [PubMed] [Google Scholar]
  3. Cleland R. E., Prins H. B., Harper J. R., Higinbotham N. Rapid Hormone-induced Hyperpolarization of the Oat Coleoptile Transmembrane Potential. Plant Physiol. 1977 Mar;59(3):395–397. doi: 10.1104/pp.59.3.395. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Hohl M., Schopfer P. Water Relations of Growing Maize Coleoptiles : Comparison between Mannitol and Polyethylene Glycol 6000 as External Osmotica for Adjusting Turgor Pressure. Plant Physiol. 1991 Mar;95(3):716–722. doi: 10.1104/pp.95.3.716. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Ketchum K. A., Shrier A., Poole R. J. Characterization of potassium-dependent currents in protoplasts of corn suspension cells. Plant Physiol. 1989 Apr;89(4):1184–1192. doi: 10.1104/pp.89.4.1184. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Kim H. Y., Coté G. G., Crain R. C. Potassium Channels in Samanea saman Protoplasts Controlled by Phytochrome and the Biological Clock. Science. 1993 May 14;260(5110):960–962. doi: 10.1126/science.260.5110.960. [DOI] [PubMed] [Google Scholar]
  7. Löbler M., Klämbt D. Auxin-binding protein from coleoptile membranes of corn (Zea mays L.). I. Purification by immunological methods and characterization. J Biol Chem. 1985 Aug 15;260(17):9848–9853. [PubMed] [Google Scholar]
  8. Lüthen H., Bigdon M., Böttger M. Reexamination of the Acid growth theory of auxin action. Plant Physiol. 1990 Jul;93(3):931–939. doi: 10.1104/pp.93.3.931. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Rayle D. L., Cleland R. E. The Acid Growth Theory of auxin-induced cell elongation is alive and well. Plant Physiol. 1992 Aug;99(4):1271–1274. doi: 10.1104/pp.99.4.1271. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Rubinstein B. Effect of pH and Auxin on Chloride Uptake into Avena Coleoptile Cells. Plant Physiol. 1974 Dec;54(6):835–839. doi: 10.1104/pp.54.6.835. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Rubinstein B. Osmotic Shock Inhibits Auxin-stimulated Acidification and Growth. Plant Physiol. 1977 Mar;59(3):369–371. doi: 10.1104/pp.59.3.369. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Ruesink A. W., Thimann K. V. Protoplasts from the Avena coleoptile. Proc Natl Acad Sci U S A. 1965 Jul;54(1):56–64. doi: 10.1073/pnas.54.1.56. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Senn A. P., Goldsmith M. H. Regulation of electrogenic proton pumping by auxin and fusicoccin as related to the growth of Avena coleoptiles. Plant Physiol. 1988 Sep;88(1):131–138. doi: 10.1104/pp.88.1.131. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Stevenson T. T., Cleland R. E. Osmoregulation in the Avena coleoptile in relation to auxin and growth. Plant Physiol. 1981 Apr;67(4):749–753. doi: 10.1104/pp.67.4.749. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Thiel G., Blatt M. R., Fricker M. D., White I. R., Millner P. Modulation of K+ channels in Vicia stomatal guard cells by peptide homologs to the auxin-binding protein C terminus. Proc Natl Acad Sci U S A. 1993 Dec 15;90(24):11493–11497. doi: 10.1073/pnas.90.24.11493. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES