Biologia floral e heterostilia em Vismia Guianensis (Aubl.) choisy (clusiaceae)

Abstract

The floral and reproductive biology of Vistnia guianensis was studied in the Ecological Reserve of “Dois Irmãos”, in Recife (PE), northeastern Brazil, from November/1997 to February/1998. V guianensis is a shrubby species, wherein the flowers, heterostyled of the dimorphic type, are arranged in terminal panicles. The anthesis is diurnal and the flowers last for one day. Nectar volume was about 2,0µl, the sugar concentration varying from 46% to 68% in the two types of flowers. Pollen viability was ca. 93% for both long and short styled-flowers. V guianensis is a self-incompatible species. Only the intermorph pollinations produced fruits (55-65%). Visits by Polybia sp. (Vespidae) and several species of bees were observed to flowers of V. guianensis. Hylaeus sp. (Colletidae), and Augochloropsis sp. (Halictidae) were the most frequent visitors, and were considered, together with Polybia sp., the effective pollinators. Due to the xenogamic reproductive system associated to the heterostylous mechanism, the pollinators have a fundamental role in promoting sexual reproduction in this plant species.