Thematic Article

Journal of Plant Growth Regulation

, Volume 24, Issue 4, pp 285-295

Open Access This content is freely available online to anyone, anywhere at any time.

Long-distance ABA Signaling and Its Relation to Other Signaling Pathways in the Detection of Soil Drying and the Mediation of the Plant’s Response to Drought

  • William J. DaviesAffiliated withLancaster Environment Centre, Lancaster University
  • , Guzel KudoyarovaAffiliated withUfa Science Centre, Russian Academy of Sciences
  • , Wolfram HartungAffiliated withJulius von Sachs Institut fur Biowissenschaften der Universitat Lehrstuhl Botanik 1

Abstract

In this article we review evidence for a variety of long-distance signaling pathways involving hormones and nutrient ions moving in the xylem sap. We argue that ABA has a central role to play, at least in root-to-shoot drought stress signaling and the regulation of functioning, growth, and development of plants in drying soil. We also stress the importance of changes in the pH of the leaf cell apoplast as influenced both by edaphic and climatic variation, as a regulator of shoot growth and functioning, and we show how changes in xylem and apoplastic pH can affect the way in which ABA regulates stomatal behavior and growth. The sensitivity to drought of the pH/ABA sensing and signaling mechanism is emphasized. This allows regulation of plant growth, development and functioning, and particularly shoot water status, as distinct from stress lesions in growth and other processes as a reaction to perturbations such as soil drying.

Keywords

Long-distance drought signaling Abscisic acid Ethylene Cytokinin pH Deficit irrigation Water use efficiency (WUE)