Biologia reprodutiva de Geonoma Brevispatha Barb. Rodr. (Arecaceae) em área de mata de galeria inundável em Uberlândia-MG

Abstract

Geonoma brevispatha is a palm tree with clonal growth and restricted to flooded habitats, borders of rivers and streams. The aim of this work was to study its reproductive biology in an inundable gallery forest, in Uberlândia, MG in the period from April 2004 to December 2005. The species bloomed from April to November 2004 with larger intensity of opening of the flowers in September. The largest production of fruits happened between October and December 2004, coinciding with the rainy season. The flowers are of wine color, are diclinous, protandrous, and present strong scent. The flowers are arranged in triads (two staminate flowers and one central pistillate flower). Only the pistillate flowers produce nectar. The anthesis happens about 8:00 a.m. The pistillate flower is smaller than the staminate and it lasts from two to four days, while the staminate lasts one day. The pollen viability rate for flowers in pre-anthesis was 84.3% and 95.9% to open flowers. The stigma receptivity occurs from the button phase. The medium number of flowers for inflorescences was of 2192.8 ± 1184.1 of staminate flowers and 1129.5 ± 571.4 of pistillate flowers. It doesn t have overlapping between pistillate and staminate flowers in the same inflorescence and nor in the same plant, and thus characterizes the functional dioecy. Apomixis was not found in this species. The reproductive success was larger in the crossed pollination. The main pollinators were flies of the families Muscidae and Sarcophagidae. Bees and beetles were considered as occasional pollinators.