Espectro polínico de própolis produzidas no Nordeste do Brasil: contribuição das Fabaceae

Abstract

Propolis is a mixture of resin, wax, oils, and pollen grains produced by the honeybee Apis mellifera L. from different plant parts, being used to fill gaps within beehives thus functioning as thermal isolation and protecting the colonies against natural invaders. The propolis compounds originate from three sources: exudates of plants collected by bees, substances secreted by the metabolism of bees and substances that are introduced usually by wind during the preparation of propolis. The composition rates and chemical diversity of propolis varies according to the regions where it is produced. Therefore, the main goal of this work was to characterize the botanical origin based on the pollen spectrum of 26 samples of propolis (green, red and brown) from northeastern Brazil, with emphasis in the analysis of the family Fabaceae once this is a representative group in regional flora, being useful to infer distinct phytophysiognomies. In order to identify the botanical origin of the propolis, the samples were treated chemically and washing in absolute alcohol, and the pollen sediment were analyzed, and pollen types were identified and counted according with their ocurrence in the samples. Pollen types identification was done with comparison with literature reports, palynological atlas and pollen library of the Laboratory of Vegetal Micromorphology at the UniversidadeEstadual de Feira de Santana. We found 196 pollen types related to 123 genera and 47 botanical families. The family Fabaceae accounted for 49 pollen types, being present in all propolis samples. Moreover, 34% of pollen types with frequency more than 50% belong to this family, being Mimosa pudicathe most frequent pollen type among samples (84.62 %). This family contributed with a range of four to 78% of the pollen spectrum of the propolis samples. The similarity analysis revealed groups of propolis samples that shared pollen types associated to taxa useful for apiculture. These groups were composed with propolis of the three colors types, what pointed to the lack of pollen identity of the propolissamples.