Floral phenology and breeding system of Desmos chinensis (Annonaceae): protogyny and intra-individual floral synchronicity to promote out-crossing

Abstract

The genus Desmos (Annonaceae) consists of 25–30 species of climbers and scandent shrubs, closely related to Dasymaschalon and part of the polyphyletic genus Friesodielsia. Desmos flowers are known to be hermaphroditic with a floral chamber formed by three inner petals, although a comprehensive study of the pollination ecology and breeding system has never been conducted. Floral phenological investigations of Desmos chinensis show that it is protogynous, with a prolonged pistillate phase (ca. 22 hrs), followed by a non-receptive interim phase (ca. 6 hrs) and then a brief staminate phase (ca. 2 hrs). Intra-individual synchrony was observed, with synchronized receptivity of flowers within individuals, and maturation of a new cohort of flowers occurring after 48 hrs, hence limiting opportunities for geitonogamy. Occasional asynchronicity was observed, however, and analysis of inter-simple sequence repeats (ISSR) markers accordingly indicated that Desmos chinensis has a mixed-mating system.