Pollen-stigma interference in two gynodioecious species of Lamiaceae with intermediate individuals

Tomás Rodríguez-Riaño, Amots Dafni

Research output: Contribution to journalArticlepeer-review


• Background and Aims: Intermediate individuals (perfect flowers with very high degree of pollen abortion) in a gynodioecious plant species are very rare. A study is made of male-female relationships in each flower type and how floral characters can enhance the avoidance of 'pollen discounting' and 'self-pollination' in two gynodioecious species, Teucrium capitatum and Origanum syriacum. • Methods: The relationship between stigma receptivity and pollen viability was studied in two gynodioecious protandrous species of Lamiaceae, in addition to measuring some floral morphological characters over the life span of the flowers. • Key Results: Three plant types in each species were found: plants bearing hermaphrodite (or male fertile) flowers (MF), female (or male sterile) flowers (MS) and intermediate flowers (INT). Plant types differed in flower size, with MS types being shorter than the other two types. There was no difference in style length among plant types in T. capitatum. Stigma receptivity decayed with floral age and was negative and significantly correlated with pollen viability in the two species, and positive and significantly correlated with style length in O. syriacum but only in MS flowers of T. capitatum. • Conclusions: Reduction in size of floral characters is associated with male sterility, except style length in T. capitatum. MF flowers have two successive reproductive impediments: self-pollination and pollen-stigma interference. In both species, self-pollination is avoided by dichogamy (negative correlation between stigma receptivity and pollen viability), and pollen-stigma interference shows two different patterns: (1) style elongation in O. syriacum is characterized by a significant length increase, final MF dimensions are greater than those of MS dimensions, and style length is positively and significantly correlated with stigma receptivity; and (2) style movement in T. capitatum is characterized by a non-significant increase in style length, final MF floral dimensions are similar to those of MS dimensions, and there is no correlation between style length and stigma receptivity.

Original languageEnglish
Pages (from-to)423-431
Number of pages9
JournalAnnals of Botany
Issue number2
StatePublished - Aug 2007

Bibliographical note

Funding Information:
A postdoctoral grant of the Consejería de Educación y Juventud (Junta de Extremadura) to TRR (Ref. 7–86) is gratefully acknowledged. We thank Prof. R. Claßen-Bockhoff and Prof. S.J. Owens for helpful suggestions and Dr. A. Ortega-Olivencia for thoughtfu1 comments on an earlier draft of this paper.


  • Dichogamy
  • Gynodioecy
  • Lamiaceae
  • Origanum syriacum
  • Pollen discounting
  • Pollen viability
  • Pollen-stigma interference
  • Protandry
  • Stigma receptivity
  • Style elongation
  • Style movement
  • Teucrium capitatum

ASJC Scopus subject areas

  • Plant Science


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