Physical dormancy in seeds of Dodonaea viscosa (Sapindales, Sapindaceae) from Hawaii

Jerry M. Baskin, Barbara H. Davis, Carol C. Baskin, Sean M. Gleason, Susan Cordell

Research output: Contribution to journalArticlepeer-review

101 Scopus citations

Abstract

Dormancy in seeds of Dodonaea viscosa is due to a water-impermeable seed coat (physical dormancy, PY). Thus, mechanically scarified seeds imbibed water (c. 95% increase in mass) and germinated to high percentages over a wide range of temperature regimes in both white light and darkness, whereas non-scarified seeds did not take up water. Dry heat at 80-160°C and dipping in boiling water for 1-60 s also broke dormancy in a high percentage of the seeds, and continuous far-red light was not inhibitory to germination. However, dry storage in the laboratory for >1 year did not overcome dormancy. Seeds made water-permeable by boiling imbibed water, and thus germinated, at a much slower rate than those made water-permeable by mechanical scarification. We suggest that boiling opened the 'water gap' in the seed coat (not yet described in Sapindaceae but present in other taxa with PY) and that water entered the seed only through this small opening, thereby accounting for the slow rate of imbibition and subsequent germination. Physical dormancy has now been shown to occur in seeds of this polymorphic, worldwide species from Australia, Brazil, Hawaii, Mexico and New Zealand. The low level of dormancy reported for seed lots of D. viscosa in China, India and Pakistan is probably due to collection of seeds before they dried to the critical moisture content for development of water-impermeability of the seed coat. Germination of non-dormant seeds over a wide range of temperatures and in white light, far-red (leaf-canopy shade) light and darkness are part of the germination strategy of D. viscosa and of other taxa whose seeds have PY at maturity.

Original languageEnglish
Pages (from-to)81-90
Number of pages10
JournalSeed Science Research
Volume14
Issue number1
DOIs
StatePublished - Mar 2004

Bibliographical note

Funding Information:
This research was supported by a grant from the Secretariat for Conservation Biology, Honolulu, Hawaii, for studies on seed dormancy and germination of Hawaiian montane species. We thank Mr Teli Xiel, Fujian Provincial Seed Station, Fuzhou, P.R. China, for translating information on seeds of Dodonaea viscosa in Seeds of Woody Plants in China from Chinese to English, and Ms Adriana Sautu, University of Kentucky and The Smithsonian Tropical Research Institute, Republic of Panama, for translating portions of the paper by Rosa and Ferreira from Portuguese to English.

Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.

Keywords

  • Dodonaea
  • Far-red light
  • Germination
  • Heating
  • Imbibition
  • Physical seed dormancy
  • Water gap

ASJC Scopus subject areas

  • Plant Science

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