A new type of specialized morphophysiological dormancy and seed storage behaviour in Hydatellaceae, an early-divergent angiosperm family

Renee E. Tuckett, David J. Merritt, Paula J. Rudall, Fiona Hay, Stephen D. Hopper, Carol C. Baskin, Jerry M. Baskin, Julia Tratt, Kingsley W. Dixon

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Background and Aims: Recent phylogenetic analysis has placed the aquatic family Hydatellaceae as an early-divergent angiosperm. Understanding seed dormancy, germination and desiccation tolerance of Hydatellaceae will facilitate ex situ conservation and advance hypotheses regarding angiosperm evolution. Methods: Seed germination experiments were completed on three species of south-west Australian Hydatellaceae, Trithuria austinensis, T. bibracteata and T. submersa, to test the effects of temperature, light, germination stimulant and storage. Seeds were sectioned to examine embryo growth during germination in T. austinensis and T. submersa. Key Results: Some embryo growth and cell division in T. austinensis and T. submersa occurred prior to the emergence of an undifferentiated embryo from the seed coat ('germination'). Embryo differentiation occurred later, following further growth and a 3- to 4-fold increase in the number of cells. The time taken to achieve 50 of maximum germination for seeds on water agar was 50, 35 and 37 d for T. austinensis, T bibracteata and T. submersa, respectively. Conclusions: Seeds of Hydatellaceae have a new kind of specialized morphophysiological dormancy in which neither root nor shoot differentiates until after the embryo emerges from the seed coat. Seed biology is discussed in relation to early angiosperm evolution, together with ex situ conservation of this phylogenetically significant group.

Original languageEnglish
Pages (from-to)1053-1061
Number of pages9
JournalAnnals of Botany
Volume105
Issue number6
DOIs
StatePublished - Jun 2010

Bibliographical note

Funding Information:
This work was supported by the University of Western Australia and the Millennium Seed Bank Project, Kew. In addition, R. E. T. received a post-graduate scholarship from the ANZ Trustees Foundation-Holsworth Wildlife Research Endowment and the Australian Federation of University Women (WA) Inc. D. J. M. was supported by the Botanic Gardens and Parks Authority – Alcoa of Australia Limited Seed Conservation Partnership. This research was conducted under the auspices of the Millennium Seed Bank Project, Kew, which is supported by the UK Millennium Commission, the Wellcome Trust and Orange plc.

Keywords

  • Desiccation
  • Embryo
  • Evolution
  • Hydatellaceae
  • Morphophysiological dormancy
  • Seed
  • Trithuria austinensis
  • Trithuria bibracteata
  • Trithuria submersa

ASJC Scopus subject areas

  • Plant Science

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