Morphophysiological dormancy in the basal angiosperm order nymphaeales

Emma L. Dalziell, Carol C. Baskin, Jerry M. Baskin, Renee E. Young, Kingsley W. Dixon, David J. Merritt

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

• Background and Aims Substantial evidence supports the hypothesis that morphophysiological dormancy (MPD) is the basal kind of seed dormancy in the angiosperms. However, only physiological dormancy (PD) is reported in seeds of the ANA-grade genus Nymphaea. The primary aim of this study was to determine the kind of dormancy in seeds of six species of Nymphaea from the wet-dry tropics of Australia. • Methods The effects of temperature, light and germination stimulants on germination were tested on multiple collections of seeds of N. immutabilis, N. lukei, N. macrosperma, N. ondinea, N. pubescens and N. violacea. Embryo growth prior to hypocotyl emergence was monitored. • Key Results Germination was generally <10 % after 28 d in control treatments. Germination percentage was highest at 30 or 35 °C for seeds exposed to light and treated with ethylene or in anoxic conditions in sealed vials of water, and it differed significantly between collections of N. lukei, N. macrosperma and N. violacea. Seeds of N. pubescens did not germinate under any of the conditions. Embryo growth (8-37 % in length) occurred before hypocotyl emergence (germination) in seeds of the five species that germinated. • Conclusions Fresh seeds were dormant, and the amount of pregermination embryo growth in seeds of N. lukei and N. immutabilis was relatively small, while in seeds of N. macrosperma, N. ondinea and N. violacea it was relatively large. Thus, seeds of N. lukei and N. immutabilis had PD and those of N. macrosperma, N. ondinea and N. violacea had MPD. Overall, we found that seeds in the most phylogenetically derived clades within Nymphaea have MPD, suggesting that PD is the most likely basal trait within the Nymphaeales. This study also highlights the broad range of dormancy types and germination strategies in the ANA-grade angiosperms.

Original languageEnglish
Pages (from-to)95-106
Number of pages12
JournalAnnals of Botany
Volume123
Issue number1
DOIs
StatePublished - Jan 1 2019

Bibliographical note

Funding Information:
We thank Christine Best, Matthew Barrett, Todd Erickson, Wolfgang Lewandrowski, Myles Menz, Ryan Phillips, Alison Ritchie and Sean Tomlinson for their assistance with fieldwork, and Wolfgang Lewandrowski for his assistance with statistical analysis. We are grateful to a number of landholders, conservation agencies and other groups including the Myers family (particularly Cecelia at Theda Station), Wavelength Nominees (particularly Christine Simpson-Stokes and Stephen Bartlett), the Australian Wildlife Conservancy (Mornington Station and Charnley River) and the staff at Parry Creek Farm and Kakadu National Park for their assistance and allowing access to their properties for field collections. The authors also thank two anonymous reviewers for the comments that improved an earlier version of the manuscript. This work was supported by research grants awarded to E.L.D. from the Friends of Kings Park; The Graduate Women of Western Australia (Mary Walters Bursary); and the ANZ Trustees Holsworth Wildlife Research Endowment. During the research, E.L.D. was supported by an Australian Postgraduate Award and more recently the Australian Research Council (ARC LP160100381).

Publisher Copyright:
© The Author(s) 2018. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.

Keywords

  • Aquatic plants
  • Basal angiosperms
  • Embryo growth
  • Morphophysiological dormancy
  • Nymphaeaceae
  • Physiological dormancy
  • Seed germination
  • Wet-dry tropics

ASJC Scopus subject areas

  • Plant Science

Fingerprint

Dive into the research topics of 'Morphophysiological dormancy in the basal angiosperm order nymphaeales'. Together they form a unique fingerprint.

Cite this