Biodiv Sci ›› 2012, Vol. 20 ›› Issue (3): 280-285.DOI: 10.3724/SP.J.1003.2012.06040

Special Issue: 传粉生物学:理论探讨与初步实践

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Progress in the study of floral symmetry

Jiaokun Li1, Lulu Tang2,*()   

  1. 1 School of Minerals Processing and Bioengineering, Central South University, Changsha 410083
    2 School of Biological Science and Technology, Central South University, Changsha 410013
  • Received:2012-01-30 Accepted:2012-04-10 Online:2012-05-20 Published:2012-05-09
  • Contact: Lulu Tang

Abstract:

Floral symmetry is a classical feature of floral diversity. Actinomorphy and zygomorphy are two main types of floral symmetry in angiosperms. Zygomorphic flowers are thought to have evolved from ancestors whose flowers are actinomorphic. Transition from actinomorphy to zygomorphy has been recognized as a key innovation and is considered crucial in the rapid diversification of angiosperms. In recent years, great progress has been made towards understanding the mechanisms underlying changes in floral symmetry during the evolution of angiosperms in wide-ranging botanical disciplines. Evidence from floral development studies indicates that zygomorphy appears before organ initiation, and persists throughout floral development, or appears later at various stages of development. Reduction, suppression and differential elaboration of floral organs are the major determinants of zygomophy. Floral symmetry is strongly selected by pollinators during the different stages of pollination process. In addition, the tighter flower-pollinator interaction found in zygomorhpic flowers may contribute to increased reproductive success through increased precision in pollen placement on the pollinator’s body. The molecular base of flower symmetry has been explored in core eudicots, and available evidence indicates that CYC-like genes play an important role in the control of zygomorphy. Future prospects in the study of floral symmetry in development biology, pollination biology and molecular genetics are discussed.

Key words: floral symmetry, evolution, development, genetic control