Inherit the wind: evolution of reproductive traits in Cyperaceae

Abstract

Studies about reproductive aspects of angiosperms rarely refer to herbaceous and anemophilous groups. Cyperaceae are cosmopolitan and diverse in terms of sexuality, inflorescence architecture, and pollination modes, such as anemophily, entomophily, and ambophily. Therefore, the evolution of reproductive traits can clarify some questions about the reproductive biology of angiosperms, especially regarding the transitions between biotic and abiotic pollination. This study was designed to investigate the evolution of reproductive traits in Cyperaceae through comparative phylogenetic methods, such as reconstruction of ancestral states and evolutionary correlation. If spicoids in Mapanioideae are indeed inflorescences, the bisexual flower in Cyperaceae would be derived, a rare case in angiosperms. In Cyperoideae, a decrease in the number of flowers and an increase in stamen loss events were observed. This result contradicts the hypothesized increase in reproductive structures in anemophilous species, in which a greater amount of pollen is produced to compensate for the waste generated by wind. Only one correlation was found: between the number of inflorescence branches and the number of reproductive units per inflorescence. Finally, the analyses showed the great diversity of reproductive biology in Cyperaceae and made evident the need to expand the theoretical studies to refine the discovery of correlated traits.