Seed Science Research

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Short Communication

Physical dormancy in the endemic Australian genus Stylobasium, a first report for the family Surianaceae (Fabales)

Jerry M. Baskina1 c1, Carol C. Baskina1a2 and Kingsley W. Dixona3

a1 Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA

a2 Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546-0312, USA

a3 Plant Science Division, Kings Park and Botanic Garden, West Perth, WA 6005, Australia

Article author query

Baskin JM [PubMed]  [Google Scholar]
Baskin CC [PubMed]  [Google Scholar]
Dixon KW [PubMed]  [Google Scholar]


The intact germination unit [seed+endocarp, (‘seed’)] of the two species of the Australian endemic genus Stylobasium (Surianaceae, Fabales) is water impermeable. Thus, the seed does not imbibe water or germinate until the integrity of the endocarp, which contains an outer layer of palisade cells, is disrupted. In this study, intact seeds of S. australe and of S. spathulatum, incubated on a moist substrate (for up to 2 years), did not imbibe water, whereas those that were mechanically scarified (both species), or dipped in boiling water for 30 s (S. spathulatum), imbibed and germinated. Thus, seeds of Stylobasium species have physical dormancy (PY). This is the first report of PY in Surianaceae, making it only the sixteenth family of angiosperms (no gymnosperms) in which this class of seed dormancy has been identified.

(Received April 03 2006)

(Accepted May 31 2006)

Key Words: Fabales; physical seed dormancy; Stylobasium; Surianaceae; water-impermeable endocarp


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