Morphophysiological dormancy in seeds of six endemic lobelioid shrubs (Campanulaceae) from the montane zone in Hawaii

Carol C. Baskin, Jerry M. Baskin, Alvin Yoshinaga

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The purpose of this study was to investigate seed dormancy breaking and germination requirements of six woody Hawaiian endemic lobelioids (Campanulaceae). Seeds of all species had underdeveloped, physiologically dormant embryos and thus morphophysiological dormancy. Fresh seeds of Clermontia pyrularia Hillebr. and Trematolobelia macrostachys (Hook. & Arnott) A. Zahlbr. did not germinate during 4 weeks of incubation in light at 15/6, 20/10, or 25/15 C, whereas those of Clermontia fauriei H. Lev., Clermontia hawaiiensis (Hillebr.) Rock, Clermontia kakeana Meyen, and Cyanea angustifolia (Cham.) Hillebr. germinated to 61%-85% but only at 25/15 C. Since seeds of the latter four species eventually germinated to 84%-100% when incubated for 12-36 weeks at the three temperature regimes, fresh seeds had conditional dormancy: the physiological component of morphophysiological dormancy was nondeep. Seeds of Trematolobelia macrostachys also came out of dormancy (and germinated to 90%) during 18 weeks of incubation at each of the three temperatures regimes, whereas those of Clermontia pyrularia did so only at 15/6 C. Simulated seasonal temperature variations did not promote dormancy break and germination in any species except Clermontia pyrularia, in which a 12-week incubation period at 25/15 C resulted in 90% germination after seeds were moved to 20/10 C. Seeds of all species had an absolute light requirement for germination except those of Clermontia pyrularia, which germinated to 48% in darkness. Since seeds of the six species only require high temperatures for embryo growth and the breaking of physiological dormancy, they have nondeep simple morphophysiological dormancy.

Original languageEnglish
Pages (from-to)1630-1637
Number of pages8
JournalCanadian Journal of Botany
Volume83
Issue number12
DOIs
StatePublished - Dec 2005

Keywords

  • Campanulaceae
  • Morphophysiological dormancy
  • Seed dormancy
  • Seed germination
  • Tropical montane

ASJC Scopus subject areas

  • Plant Science

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