Skip to main content
PMC home page
Plant Physiology logoLink to Plant Physiology
. 1989 Jan;89(1):184–191. doi: 10.1104/pp.89.1.184

Mechanism of Gibberellin-Dependent Stem Elongation in Peas 1

Daniel J Cosgrove 1, Susan A Sovonick-Dunford 1,2
PMCID: PMC1055817  PMID: 11537446

Abstract

Stem elongation in peas (Pisum sativum L.) is under partial control by gibberellins, yet the mechanism of such control is uncertain. In this study, we examined the cellular and physical properties that govern stem elongation, to determine how gibberellins influence pea stem growth. Stem elongation of etiolated seedlings was retarded with uniconozol, a gibberellin synthesis inhibitor, and the growth retardation was reversed by exogenous gibberellin. Using the pressure probe and vapor pressure osmometry, we found little effect of uniconozol and gibberellin on cell turgor pressure or osmotic pressure. In contrast, these treatments had major effects on in vivo stress relaxation, measured by turgor relaxation and pressure-block techniques. Uniconozol-treated plants exhibited reduced wall relaxation (both initial rate and total amount). The results show that growth retardation is effected via a reduction in the wall yield coefficient and an increase in the yield threshold. These effects were largely reversed by exogenous gibberellin. When we measured the mechanical characteristics of the wall by stress/strain (Instron) analysis, we found only minor effects of uniconozol and gibberellin on the plastic compliance. This observation indicates that these agents did not alter wall expansion through effects on the mechanical (viscoelastic) properties of the wall. Our results suggest that wall expansion in peas is better viewed as a chemorheological, rather than a viscoelastic, process.

Full text

PDF
186

Images in this article

186Figure 1
on p.186

Selected References

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

  1. Adams P. A., Montague M. J., Tepfer M., Rayle D. L., Ikuma H., Kaufman P. B. Effect of gibberellic Acid on the plasticity and elasticity of Avena stem segments. Plant Physiol. 1975 Dec;56(6):757–760. doi: 10.1104/pp.56.6.757. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Cleland R., Thompson M. L., Rayle D. L., Purves W. K. Difference in effects of gibberellins and auxins on wall extensibility of cucumber hypocotyls. Nature. 1968 Aug 3;219(5153):510–511. doi: 10.1038/219510a0. [DOI] [PubMed] [Google Scholar]
  3. Cosgrove D. J. Cell wall yield properties of growing tissue : evaluation by in vivo stress relaxation. Plant Physiol. 1985 Jun;78(2):347–356. doi: 10.1104/pp.78.2.347. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Cosgrove D. J., Cleland R. E. Osmotic properties of pea internodes in relation to growth and auxin action. Plant Physiol. 1983 Jun;72(2):332–338. doi: 10.1104/pp.72.2.332. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Cosgrove D. J., Van Volkenburgh E., Cleland R. E. Stress relaxation of cell walls and the yield threshold for growth: demonstration and measurement by micro-pressure probe and psychrometer techniques. Planta. 1984;162(1):46–54. doi: 10.1007/BF00397420. [DOI] [PubMed] [Google Scholar]
  6. Cosgrove D. J. Wall relaxation in growing stems: comparison of four species and assessment of measurement techniques. Planta. 1987;171:266–278. [PubMed] [Google Scholar]
  7. Cosgrove D. Biophysical control of plant cell growth. Annu Rev Plant Physiol. 1986;37:377–405. doi: 10.1146/annurev.pp.37.060186.002113. [DOI] [PubMed] [Google Scholar]
  8. Lockhart J. A. Intracellular Mechanism of Growth Inhibition by Radiant Energy. Plant Physiol. 1960 Jan;35(1):129–135. doi: 10.1104/pp.35.1.129. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Reid J. B. Internode length in pisum: do the internode length genes effect growth in dark-grown plants? Plant Physiol. 1983 Jul;72(3):759–763. doi: 10.1104/pp.72.3.759. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Silk W. K., Jones R. L. Gibberellin response in lettuce hypocotyl sections. Plant Physiol. 1975 Aug;56(2):267–272. doi: 10.1104/pp.56.2.267. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Stuart D. A., Jones R. L. Roles of Extensibility and Turgor in Gibberellin- and Dark-stimulated Growth. Plant Physiol. 1977 Jan;59(1):61–68. doi: 10.1104/pp.59.1.61. [DOI] [PMC free article] [PubMed] [Google Scholar]

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

RESOURCES