Physiology, morphology and phenology of seed dormancy break and germination in the endemic Iberian species Narcissus hispanicus (Amaryllidaceae)

Elena Copete, José M. Herranz, Pablo Ferrandis, Carol C. Baskin, Jerry M. Baskin

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

Abstract

Background and Aims Only very few studies have been carried out on seed dormancy/germination in the large monocot genus Narcissus. A primary aim of this study was to determine the kind of seed dormancy in Narcissus hispanicus and relate the dormancy breaking and germination requirements to the field situation. Methods Embryo growth, radicle emergence and shoot growth were studied by subjecting seeds with and without an emerged radicle to different periods of warm, cold or warm plus cold in natural temperatures outdoors and under controlled laboratory conditions. Key Results Mean embryo length in fresh seeds was approx. 1·31 mm, and embryos had to grow to 2·21 mm before radicle emergence. Embryos grew to full size and seeds germinated (radicles emerged) when they were warm stratified for 90 d and then incubated at cool temperatures for 30 d. However, the embryos grew only a little and no seeds germinated when they were incubated at 9/5, 10 or 15/4 °C for 30 d following a moist cold pre-treatment at 5, 9/5 or 10 °C. In the natural habitat of N. hispanicus, seeds are dispersed in late May, the embryo elongates in autumn and radicles emerge (seeds germinate) in early November; however, if the seeds are exposed to low temperatures before embryo growth is completed, they re-enter dormancy (secondary dormancy). The shoot does not emerge until March, after germinated seeds are cold stratified in winter. Conclusions eeds of N. hispanicus have deep simple epicotyl morphophysiological dormancy (MPD), with the dormancy formula C1bB(root) C3(epicotyl). This is the first study on seeds with simple MPD to show that embryos in advanced stages of growth can re-enter dormancy (secondary dormancy).

Original languageEnglish
Pages (from-to)1003-1016
Number of pages14
JournalAnnals of Botany
Volume107
Issue number6
DOIs
StatePublished - May 2011

Bibliographical note

Funding Information:
This work was supported by the PAI07-0088-0300 (‘Creation of a plant germplasm bank of endangered species in the Botanical Garden of Castilla-La Mancha’) and PEII10-0170-1830 (‘Germination ecology of 12 singular and/ or threatened species with morphophysiological dormancy’) projects, supported by the regional Government of Castilla-La Mancha. During the study, E.C.C. held a grant from the regional Government (Consejería de Educación y Ciencia, Junta de Comunidades de Castilla-La Mancha) and the European Social Found. We thank Carlos Guillén for laboratory assistance.

Keywords

  • Dormancy break
  • Narcissus hispanicus
  • embryo growth
  • epicotyl morphophysiological dormancy
  • germination
  • phenology
  • secondary dormancy
  • shoot emergence

ASJC Scopus subject areas

  • Plant Science

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