Skip to main content
Log in

Evidence that hydroxyl radicals mediate auxin-induced extension growth

  • Original Article
  • Published:
Planta Aims and scope Submit manuscript


Reactive oxygen intermediates, i.e. the superoxide radical (\({\rm O}_2^{ \cdot - } \) ), hydrogen peroxide (H2O2) and the hydroxyl radical (\({}^ \cdot {\rm OH}\) ), are generally regarded as harmful products of oxygenic metabolism causing cell damage in plants, animals and microorganisms. However, oxygen radical chemistry may also play a useful role in polymer breakdown leading to wall loosening during extension growth of plant cells controlled by the phytohormone auxin. Backbone cleavage of cell wall polysaccharides can be accomplished in vitro by \({}^ \cdot {\rm OH}\) produced from H2O2 in a Fenton reaction or in a reaction catalyzed by peroxidase supplied with O2 and NADH. Here, we show that coleoptile growth of maize seedlings is accompanied by the release of reactive oxygen intermediates in the cell wall. Auxin promotes release of \({\rm O}_2^{ \cdot - } \) and subsequent generation of \({}^ \cdot {\rm OH}\) when inducing elongation growth. Experimental generation of \({}^ \cdot {\rm OH}\) in the wall causes an increase in wall extensibility in vitro and replaces auxin in inducing growth. Auxin-induced growth can be inhibited by scavengers of \({\rm O}_2^{ \cdot - } \) , H2O2 or \({}^ \cdot {\rm OH}\) , or inhibitors interfering with the formation of these molecules in the cell wall. These results provide the experimental background for a novel hypothesis on the mechanism of plant cell growth in which \({}^ \cdot {\rm OH}\) , produced from \({\rm O}_2^{ \cdot - } \) and H2O2 by cell wall peroxidase, acts as a wall-loosening agent.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

Author information

Authors and Affiliations


Additional information

Electronic Publication

Rights and permissions

Reprints and permissions

About this article

Cite this article

Schopfer, P., Liszkay, A., Bechtold, M. et al. Evidence that hydroxyl radicals mediate auxin-induced extension growth. Planta 214, 821–828 (2002).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: