Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

Self-incompatibility in Senecio squalidus L. (Asteraceae)

SIMON J. HISCOCK
Annals of Botany
Vol. 85, Supplement A: Pollen-Stigma Interactions (March 2000), pp. 181-190
Published by: Oxford University Press
Stable URL: http://www.jstor.org/stable/42770684
Page Count: 10
  • Download ($42.00)
  • Cite this Item
Self-incompatibility in Senecio squalidus L. (Asteraceae)
Preview not available

Abstract

The Asteraceae, one of the largest families of flowering plants, shows an extreme diversity of breeding systems with many species having a pronounced flexibility in breeding strategy—a factor thought to be crucial to the success of this family in colonizing most major biogeographical regions. Despite self-incompatibility (SI) being the most common mode of outcrossing in the Asteraceae, there have been few detailed studies of SI within this family. This paper discusses the SI system operating in Senecio squalidus (Oxford ragwort), an invasive alien species that has colonized most parts of the UK within the last 150 years. In S. squalidus, SI is sporophytic and controlled by a single multiallelic S locus. Preliminary findings suggest that UK populations contain few S alleles. Pseudo self-compatibility (PSC) has been found to operate in S. squalidus and leads to total or partial loss of S-specific discrimination as females, though pollen S function is unaffected. Exceptional compatible and semi-compatible crosses in normally incompatible groups suggest that a cryptic gametophytic element (the G gene) can influence the outcome of certain crosses. It is suggested that PSC, mediated by modifier loci unlinked to the S locus, together with the apparent activity of a G gene in determining SI, may have provided flexibility in the SI system of S. squalidus that was crucial to its success as a colonist. Basic aspects of the cell biology of the pollen-stigma interaction during compatible and incompatible pollinations in S. squalidus are discussed in the light of previous studies of species in the Asteraceae and Brassicaceae.

Page Thumbnails

  • Thumbnail: Page 
[181]
    [181]
  • Thumbnail: Page 
182
    182
  • Thumbnail: Page 
183
    183
  • Thumbnail: Page 
184
    184
  • Thumbnail: Page 
185
    185
  • Thumbnail: Page 
186
    186
  • Thumbnail: Page 
187
    187
  • Thumbnail: Page 
188
    188
  • Thumbnail: Page 
189
    189
  • Thumbnail: Page 
190
    190