Planta

, Volume 223, Issue 3, pp 604–612

Interactions between ethylene, gibberellin and abscisic acid regulate emergence and growth rate of adventitious roots in deepwater rice

Original Article

DOI: 10.1007/s00425-005-0111-1

Cite this article as:
Steffens, B., Wang, J. & Sauter, M. Planta (2006) 223: 604. doi:10.1007/s00425-005-0111-1

Abstract

Growth of adventitious roots is induced in deepwater rice (Oryza sativa L.) when plants become submerged. Ethylene which accumulates in flooded plant parts is responsible for root growth induction. Gibberellin (GA) is ineffective on its own but acts in a synergistic manner together with ethylene to promote the number of penetrating roots and the growth rate of emerged roots. Studies with the GA biosynthesis inhibitor paclobutrazol revealed that root emergence was dependent on GA activity. Abscisic acid (ABA) acted as a competitive inhibitor of GA activity. Root growth rate on the other hand was dependent on GA concentration and ABA acted as a potent inhibitor possibly of GA but also of ethylene signaling. The results indicated that root emergence and elongation are distinct phases of adventitious root growth that are regulated through different networking between ethylene, GA and ABA signaling pathways. Adventitious root emergence must be coordinated with programmed death of epidermal cells which cover root primordia. Epidermal cell death is also controlled by ethylene, GA and ABA albeit with cell-type specific cross-talk. Different interactions between the same hormones may be a means to ensure proper timing of cell death and root emergence and to adjust the growth rate of emerged adventitious roots.

Keywords

Abscisic acid Adventitious roots Ethylene Gibberellic acid Growth Oryza sativa L. 

Abbreviations

ABA

Abscisic acid

GA

Gibberellic acid

NBD

Norbornadiene (bicyclo[2.2.1]hepta-2,5-diene)

PAC

Paclobutrazol

PCD

Programmed cell death

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Bianka Steffens
    • 1
  • Jinxiang Wang
    • 2
  • Margret Sauter
    • 1
  1. 1.Botanisches InstitutUniversität KielKielGermany
  2. 2.Laboratory of Plant Nutritional Genetics, Root Biology CenterSouth China Agricultural University24098 Kiel GuangzhouChina

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