Chin J Plant Ecol ›› 2014, Vol. 38 ›› Issue (1): 76-90.DOI: 10.3724/SP.J.1258.2014.00008

• Research Articles • Previous Articles     Next Articles

Gynomonoecy in angiosperms: phylogeny, sex expression and evolutionary significance

Jannathan MAMUT, TAN Dun-Yan*()   

  1. Xinjiang Key Laboratory of Grassland Resources and Ecology & Ministry of Education Key Laboratory for Western Arid Region Grassland Resources and Ecology, College of Grassland and Environment Sciences, Xinjiang Agricultural University, ürümqi 830052, China
  • Received:2013-11-14 Accepted:2013-12-19 Online:2014-11-14 Published:2014-01-15
  • Contact: TAN Dun-Yan

Abstract:

Gynomonoecy is the mode of sex expression in which female and bisexual flowers occur on the same plants; it is an important step in the evolution of monoecy from hermaphroditism in angiosperms. The sexual system of gynomonoecy is considered to play several important roles, including reducing herbivore damage to pistils, reducing inbreeding depression by favoring out-crossing and pollen-pistil interference, enhancing the flexibility of resource allocation to male and female functions in two flower types, and attracting pollinators. According to the classification of APG III system, gynomonoecy occurs in about 23 families in angiosperms including Lactoridaceae in magnoliids, Araceae and Poaceae in monocots, and Asteraceae, Amaranthaceae, Lamiaceae and other families in eudicots. Gynomonoecy is most common in Asteraceae. Female and bisexual flowers from different gynomonoecious taxa show diversified sex expressions, such as their position in inflorescence, morphs, size and flowering time. These traits are regulated not only by genetic factors, but also by resource availability (e.g., nutrition, light, temperature, and moisture conditions). Because reports on gynomonoecy in China are rare, this paper emphasizes our analysis and summary of the phylogeny of gynomonoecious taxa and their evolution in angiosperm and the relationship between their sex expression and environmental conditions. In addition, five hypotheses on the evolutionary significance of gynomonoecy are introduced and evaluated in this paper. Finally, we discuss prospects for further research in this topical area. Our purpose is to provide a theoretical framework for research on evolutionary patterns and mechanisms of gynomonoecy for angiosperms in China.

Key words: angiosperms, evolutionary significance, gynomonoecy, phylogeny, sex expression, sexual systems