Palinotaxonomia de espécies de Cissus L. (Vitaceae Juss.) ocorrentes no Brasil

Abstract

The pollen grains of 31 Brazilian species of Cissus (Vitaceae) was examined. This is the largest genus of the family, with about 350 taxa. In the neotropics were located 75 species, having its greater representativity in South America with 48 endemic species. In Brazil only the genus Cissus occurs naturally in all states and is represented by 48 species, and can be found in areas of forest, fields, resting and the savannahs. In this study were analyzed 14 informal taxonomic groups with the purpose of describing the pollen morphology and establish if the pollen attributes would be useful to the taxonomy of the group. The botanical material used was obtained from herbarium specimens deposited in Brazilian herbaria. The pollen grains have been treated by the method of lactic acetolysis, being subsequently measured, described, photomicrographed light microscopy, statistical analysis was performed (expressed in tables). For analysis in a scanning electron microscope (SEM), anthers were ruptured and the pollen grains, not acetolysed, spread over a ribbon. Have been characterized as the form, size, the type of aperture, the polarity and the ornamentation of sexine. The pollen grains can be: medium to large, isopolar or heteropolar, oblate spheroidal the prolate, 3-colporate, colpus highly long or long, with a border ornamented or not, granular membrane, presence or absence of operculum; endoaperture lalongate, sometimes showing costae and/or fastigium; the sexine varies from microreticulate, perforate and reticulate. With the results constructed a pollen key in which it was possible to bring together species with similar characters over a subordinate Group. With this research it was concluded that the pollen attributes allowed the distinction of most taxa, except four, confirming the heterogeneity of the genus pollen. It is hoped that this study contributes to a better understanding of the taxonomy of the genus, and provide data for a future phylogeny.