Nitric oxide gas stimulates germination of dormant Arabidopsis seeds: Use of a flow-through apparatus for delivery of nitric oxide

Igor G.L. Libourel, Paul C. Bethke, Roberto De Michele, Russell L. Jones

Research output: Contribution to journalArticlepeer-review

67 Scopus citations

Abstract

Nitric oxide (NO) is a gaseous free radical that reacts with O2 in air and aqueous solution. NO donors have been widely used to circumvent the difficulties inherent in working with a reactive gas, but NO donors do not deliver NO at a constant rate for prolonged periods of time. Furthermore, some of the most commonly used NO donors produce additional, bioactive decomposition products. We designed and built an apparatus that allowed for the precise mixing of gaseous NO with air and the delivery of gas through sample vials at fixed rates. This experimental setup has the added advantage that continuous flow of gas over the sample reduces the buildup of volatile breakdown products. To show that this experimental setup was suitable for studies on the dormancy and germination of Arabidopsis thaliana seeds, we introduced vapors from water or sodium nitroprusside (SNP) into the gas stream. Seeds remained dormant when treated with water vapor, but gases generated by SNP increased germination to 90%. When pure NO was mixed with air and passed over dormant seeds, ∼30% of the seeds germinated. Because nitrite accumulates in aqueous solutions exposed to NO gas, we measured the accumulation of nitrite under our experimental conditions and found that it did not exceed 100 μM. Nitrite or nitrate at concentrations of up to 500 μM did not increase germination of C24 ecotype Arabidopsis seeds to more than 10%. These data support the hypothesis that NO participates in the loss of Arabidopsis seed dormancy, and they show that for some dormant seeds, exposure to exogenous NO is sufficient to trigger germination.

Original languageEnglish (US)
Pages (from-to)813-820
Number of pages8
JournalPlanta
Volume223
Issue number4
DOIs
StatePublished - Mar 2006

Bibliographical note

Funding Information:
Acknowledgements This work was supported by grants from the NSF and the College of Natural Resources, Division of Agricultural and Natural Resources, University of California. The authors thank Prof. M.A. Marletta for making his NO meter available to us, and E.R. Derbyshire for technical assistance. The authors also thank R.C. Cohen for aiding the construction of the flow-through setup with materials and expertise.

Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.

Keywords

  • Arabidopsis
  • C-PTIO
  • Cyanide
  • Nitric oxide
  • SNP
  • Seed dormancy

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