Planta

, Volume 209, Issue 1, pp 136–142

Involvement of indole-3-acetic acid in the circadian growth of the first internode of Arabidopsis

  • L. Jouve
  • T. Gaspar
  • C. Kevers
  • H. Greppin
  • R. Degli Agosti
Article

DOI: 10.1007/s004250050615

Cite this article as:
Jouve, L., Gaspar, T., Kevers, C. et al. Planta (1999) 209: 136. doi:10.1007/s004250050615

Abstract.

The extension rate of the first inflorescence node of Arabidopsis was measured during light/dark or continuous light exposure and was found to exhibit oscillations which showed a circadian rhythmicity. Decapitation induced a strong inhibition of stem extension. Subsequent application of IAA restored growth and the associated extension–rate oscillations. In addition, IAA treatments, after decapitation, re-established the circadian rhythmicity visible in the intact plants during free run. This indicates that the upper zone of the inflorescence has a major influence on the extension rate of floral stems and implies a role for auxin. Application of N-(1-naphthyl)phthalamic acid, an IAA transport inhibitor, to an intact floral stem inhibited growth and the rhythmicity in the extension rate oscillations, indicating that IAA polar transport may play a role in the dynamics of stem elongation. Furthermore, IAA-aspartate application, after decapitation, did not restore growth and rhythmicity. Nevertheless, biochemical analysis of IAA and IAA-aspartate demonstrated circadian fluctuations of the endogenous levels of both compounds. These observations suggest that IAA metabolism is an essential factor in the regulation of the circadian growth rhythm of Arabidopsis floral stems.

Key words:Arabidopsis Auxin Auxin transport Circadian rhythm Floral stem growth Indole-3-acetic acid aspartate 

Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • L. Jouve
    • 1
  • T. Gaspar
    • 2
  • C. Kevers
    • 2
  • H. Greppin
    • 1
  • R. Degli Agosti
    • 1
  1. 1.Plant Biochemistry and Physiology Laboratory, University of Geneva, 3 place de l'Université, CH-1211 Geneva 4, SwitzerlandCH
  2. 2.Fundamental and Applied Hormonology Laboratory, Institute of Botany B 22, University of Liège-Sart Tilman, B-4000 Liège, BelgiumBE