Planta

, Volume 219, Issue 5, pp 847–855

Dormancy of Arabidopsis seeds and barley grains can be broken by nitric oxide

  • Paul C. Bethke
  • Frank Gubler
  • John V. Jacobsen
  • Russell L. Jones
Original Article

DOI: 10.1007/s00425-004-1282-x

Cite this article as:
Bethke, P.C., Gubler, F., Jacobsen, J.V. et al. Planta (2004) 219: 847. doi:10.1007/s00425-004-1282-x

Abstract

Seeds of Arabidopsis thaliana (L.) Heynh. and grains of barley (Hordeum vulgare L.) were used to characterize the affects of nitric oxide (NO) on seed dormancy. Seeds of the C24 and Col-1 ecotypes of Arabidopsis are almost completely dormant when freshly harvested, but dormancy was broken by stratification for 3 days at 4°C or by imbibition of seeds with the NO donor sodium nitroprusside (SNP). This effect of SNP on dormancy of Arabidopsis seeds was concentration dependent. SNP concentrations as low as 25 μM reduced dormancy and stimulated germination, but SNP at 250 μM or more impaired seedling development, including root growth, and inhibited germination. Dormancy was also reduced when Arabidopsis seeds were exposed to gasses that are generated by solutions of SNP. Nitrate and nitrite, two other oxides of nitrogen, reduced the dormancy of Arabidopsis seeds, but much higher concentrations of these were required compared to SNP. Furthermore, the kinetics of germination were slower for seeds imbibed with either nitrate or nitrite than for seeds imbibed with SNP. Although seeds imbibed with SNP had reduced dormancy, seeds imbibed with SNP and abscisic acid (ABA) remained strongly dormant. This may indicate that the effects of ABA action on germination are downstream of NO action. The NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3 oxide (cPTIO) strengthened dormancy of unstratified and briefly stratified Arabidopsis seeds. Dormancy of three cultivars of barley was also reduced by SNP. Furthermore, dormancy in barley grain was strengthened by imbibition of grain with cPTIO. The data presented here support the conclusion that NO is a potent dormancy breaking agent for seeds and grains. Experiments with the NO scavenger suggest that NO is an endogenous regulator of seed dormancy.

Keywords

Abscisic acidArabidopsisDormancyGerminationNitric oxideStratification

Abbreviations

ABA

Abscisic acid

cPTIO

2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3 oxide

GA

Gibberellin

SNP

Sodium nitroprusside

NOx

Gaseous oxides of nitrogen

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Paul C. Bethke
    • 1
  • Frank Gubler
    • 2
  • John V. Jacobsen
    • 2
  • Russell L. Jones
    • 1
  1. 1.Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyUSA
  2. 2.CSIRO Division of Plant IndustryCanberra CityAustralia