Diversity of epicotyl dormancy among tropical montane forest species in Sri Lanka

Y. S. Athugala, K. M.G.G. Jayasuriya, A. M.T.A. Gunarathne, C. C. Baskin

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Fruiting season of many Sri Lankan tropical montane species is not synchronised and may not occur when conditions are favourable for seedling establishment. We hypothesised that species with different fruiting seasons have different seed dormancy mechanisms to synchronise timing of germination with a favourable season for establishment. Using six species with different fruiting seasons, we tested this hypothesis. Germination and imbibition of intact and manually scarified seeds were studied. Effect of GA3 on germination was examined. Embryo length:seed length (E:S) ratio of freshly matured seeds and of those with a split seed coat was determined. Time taken for radicle and plumule emergence and morphological changes of the embryos were recorded. The radicle emerged from Ardisia missionis, Bheza nitidissima and Gaetnera walkeri seeds within 30 days, whereas it took >30 days in other species. Embryos grew in seeds of B. nitidissima and G. walkeri prior to radicle emergence but not in Microtropis wallichiana, Nothapodytes nimmoniana and Symplocos cochinchinensis. A considerable delay was observed between radicle and plumule emergence in all six species. Warm stratification and/or GA3 promoted germination of all species. All the tested species have epicotyl dormancy. Seeds of B. nitidissima and G. walkeri have non-deep simple morphophysiological epicotyl dormancy, and the other four species have non-deep physiological epicotyl dormancy. Differences in radicle and epicotyl dormancy promote synchronisation of germination to a favourable time for seedling development. Therefore, information on dormancy-breaking and germination requirements of both radicle and epicotyl are needed to determine the kind of dormancy of a particular species.

Original languageEnglish
Pages (from-to)916-925
Number of pages10
JournalPlant Biology
Volume20
Issue number5
DOIs
StatePublished - Sep 2018

Bibliographical note

Funding Information:
We gratefully acknowledge financial support from the Sri Lanka National Research Council (grant No: 11/091).

Publisher Copyright:
© 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands

Keywords

  • Morphophysiological dormancy
  • physiological dormancy
  • seed germination
  • seed morphology
  • seed phylogeny

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Plant Science

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