Evolution and genetic control of the floral ground plan

Research output: Contribution to journalReview ArticleResearchpeer-review

18 Citations (Scopus)

Abstract

Summary: The floral ground plan is a map of where and when floral organ primordia arise. New results combining the defined phylogeny of flowering plants with extensive character mapping have predicted that the angiosperm ancestor had whorls rather than spirals of floral organs in large numbers, and was bisexual. More confidently, the monocot ancestor likely had three organs in each whorl, whereas the rosid and asterid ancestor (Pentapetalae) had five, with the perianth now divided into sepals and petals. Genetic mechanisms underlying the establishment of the floral ground plan are being deduced using model species, the rosid Arabidopsis, the asterid Antirrhinum, and in grasses such as rice. In this review, evolutionary and genetic conclusions are drawn together, especially considering how known genes may control individual processes in the development and evolution of ground plans. These components include organ phyllotaxis, boundary formation, organ identity, merism (the number or organs per whorl), variation in the form of primordia, organ fusion, intercalary growth, floral symmetry, determinacy and, finally, cases where the distinction between flowers and inflorescences is blurred. It seems likely that new pathways of ground plan evolution, and new signalling mechanisms, will soon be uncovered by integrating morphological and genetic approaches.

Original languageEnglish
Pages (from-to)70-86
Number of pages17
JournalNew Phytologist
Volume220
Issue number1
DOIs
Publication statusPublished - 1 Oct 2018

Keywords

  • angiosperms
  • floral boundaries
  • floral ground plan
  • floral symmetry
  • flower evolution
  • merism
  • phyllotaxy
  • primordia

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