Skip to Main Content
Secondary dormancy induction and release in Bromus tectorum seeds: The role of temperature, water potential and hydrothermal timeAuthor(s): K. K. Hawkins; P. S. Allen; Susan Meyer
Source: Seed Science Research. doi: 10.1017/S0960258516000258.
Publication Series: Scientific Journal (JRNL)
Station: Rocky Mountain Research Station
View PDF (767.0 KB)
DescriptionSeeds of the winter annual Bromus tectorum lose primary dormancy in summer and are poised to germinate rapidly in the autumn. If rainfall is inadequate, seeds remain ungerminated and may enter secondary dormancy under winter conditions. We quantified conditions under which seeds enter secondary dormancy in the laboratory and field and also examined whether contrasting B. tectorum genotypes responded differently to dormancy induction cues. The study also extends previous hydrothermal time models for primary dormancy loss and germination timing in B. tectorum by using similar models to account for induction and loss of secondary dormancy. Maximum secondary dormancy was achieved in the laboratory after 4 weeks at -1.0 MPa and 5°C. Seeds in the field became increasingly dormant through exposure to temperatures and water potentials in this range, confirming laboratory results. They were released from dormancy through secondary after-ripening the following summer. Different genotypes showed contrasting responses to dormancy induction cues in both laboratory and field. To examine secondary dormancy induction and release in the field in terms of hydrothermal time parameters, we first created a model that allowed mean base water potential (Ψb(50)) to vary while holding other hydrothermal time parameters constant, as in models for primary dormancy loss under dry conditions. The second model allowed all three model parameters to vary through time, to account for changes (e.g. hydrothermal time accumulation) that could occur simultaneously with dormancy induction in imbibed seeds. Shifts in Ψb(50) could explain most changes in dormancy status for seeds retrieved from the field, except during the short period prior to dormancy induction, when hydrothermal time was accumulating. This study illustrates that hydrothermal modelling, and specifically changes in Ψb(50), can be used to characterize secondary dormancy induction and loss in B. tectorum.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationHawkins, K. K.; Allen, P. S.; Meyer, S. E. 2017. Secondary dormancy induction and release in Bromus tectorum seeds: The role of temperature, water potential and hydrothermal time. Seed Science Research. doi: 10.1017/S0960258516000258.
Keywordshydrothermal time model, seed dormancy cycle, seed bank, secondary after-ripening, winter annual
- Induction and release of secondary dormancy under field conditions in Bromus tectorum
- A hydrothermal after-ripening time model for seed dormancy loss in Bromus tectorum L.
- Predicting seed dormancy loss and germination timing for Bromus tectorum in a semi-arid environment using hydrothermal time models
XML: View XML