Seed dormancy and germination of the endangered exceptional Hawaiian lobelioid Brighamia rockii

Dustin Wolkis, Carol C. Baskin, Jerry M. Baskin, Nina Rønsted

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Premise: The Campanulaceae (Lobelioideae) is the Hawaiian plant family with the most endangered and extinct species. Although seeds of Hawaiian lobelioids are desiccation tolerant, the species are exceptional (i.e., they present challenges at various stages of the conventional ex situ conservation chain) due to their generally poor seed survival at the conventional seed-banking temperature (–18°C). Both morphological dormancy (MD) and morphophysiological dormancy (MPD) have been identified in the seeds of other Hawaiian lobelioids; however, the class of dormancy and germination requirements of the Critically Endangered genus Brighamia have not yet been determined. Methods: We measured the embryonic growth in 12-week-old seeds of B. rockii and tested their germination at three temperature regimes (15/5°C, 20/10°C, and 25/15°C) in light and at 25/15°C in darkness. Results: The embryos grew prior to radicle emergence, and the seeds germinated rapidly to high percentages in all tested conditions. Discussion: Whether fresh B. rockii seeds have MD or MPD still needs to be determined; nevertheless, 12-week-old seeds germinated well in light and darkness, and thus the seeds can be used for conservation purposes. Germination in the dark suggests that the species may not form a long-lived soil seed bank in its native habitat.

Original languageEnglish
Article numbere11492
JournalApplications in Plant Sciences
Volume10
Issue number5
DOIs
StatePublished - Sep 1 2022

Bibliographical note

Publisher Copyright:
© 2022 The Authors. Applications in Plant Sciences published by Wiley Periodicals LLC on behalf of Botanical Society of America.

Keywords

  • Brighamia
  • Hawaiian lobelioids
  • critically endangered plants
  • embryo growth
  • ex situ conservation
  • exceptional species

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Plant Science

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