How Does pH Fit in with Oscillating Polar Growth?

Trends Plant Sci. 2018 Jun;23(6):479-489. doi: 10.1016/j.tplants.2018.02.008. Epub 2018 Mar 28.

Abstract

Polar growth in root hairs and pollen tubes is an excellent model for investigating plant cell size regulation. While linear plant growth is historically explained by the acid growth theory, which considers that auxin triggers apoplastic acidification by activating plasma membrane P-type H+-ATPases (AHAs) along with cell wall relaxation over long periods, the apoplastic pH (apopH) regulatory mechanisms are unknown for polar growth. Polar growth is a fast process mediated by rapid oscillations that repeat every ∼20-40s. In this review, we explore a reactive oxygen species (ROS)-dependent mechanism that could generate oscillating apopH gradients in a coordinated manner with growth and Ca2+ oscillations. We propose possible mechanisms by which apopH oscillations are coordinated with polar growth together with ROS and Ca2+ waves.

Keywords: Arabidopsis thaliana; Ca(2+); P-type H(+)-ATPase; apoplastic pH; polar cell expansion; reactive oxygen species.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Arabidopsis / physiology*
  • Calcium / metabolism
  • Cell Differentiation / physiology*
  • Hydrogen-Ion Concentration
  • Plant Roots / growth & development
  • Plant Roots / physiology*
  • Pollen Tube / growth & development
  • Pollen Tube / physiology*
  • Reactive Oxygen Species / metabolism

Substances

  • Reactive Oxygen Species
  • Calcium