The breeding system and pollination biology of Sabicea cinerea were studied at "Parque Estadual Dois Irmãos", a fragment of Atlantic forest, in Recife, State of Pernambuco, Brazil, from May/1998 to December/2000. Sabicea cinerea is a vine found in the forest border and which produces flowers throughout the year, with the flowering peak occurring in the dry season (September to February). It presents distylous, actinomorphic, tubular flowers, with white petals. Anthesis begins about 5.00 a.m. nectar production continues until 4.00 p.m.; the daily mean average volume was 8.0 µL and sugar concentration 24%, in both floral morphs. Short-styled (thrum) flowers possess larger corolla and pollen grains in relation to the long-styled (pin) flowers, but there are no differences in the amount of grains between the morphs. Two species of hummingbird visited S. cinerea flowers, Phaethornis ruber, the main pollinator, and Amazilia sp., a nectar thief. Several species of Apidae, Anthophoridae and Halictidae bees, Hesperiidae and Nymphalidae butterflies and Syrphidae flies were also observed visiting Sabicea cinerea flowers. The self-incompatibility of the species was verified through experiments of controlled pollination in field; fruit set was observed only in the intermorph crossings. The occurrence of the sporophytic selfincompatibility was confirmed with the analysis of pollen tubes growth in both floral morphs. The efficiency in pollen transfer among the floral morphs is the main and more important function carried out by the pollinators in order to maintain the S. cinerea populations, mainly because it presents an obligatory xenogamous reproductive system.
heterostyly; hummingbird; pollination biology; Sabicea; self-incompatibility
