Pollen types of Sapindaceae from Brazilian forest fragments: apertural variation

Abstract

Morphological variations in angiosperm pollen grains may aid in the differentiation of families, genera and species. Sapindaceae pollen morphology holds promise for the recognition of taxa of this cosmopolitan family, which is well distributed in tropical regions and possesses great morphological diversity. This study presents the pollen morphology of 23 native Brazilian species of Sapindaceae from forest fragments in the state of Sao Paulo, Brazil. The aim was to identify pollen types in order to expand the morphological knowledge of the analyzed species and contribute to the taxonomy and conservation of the family. Pollen grains were acetolysed, measured and photographed using light and scanning electron microscopy. Qualitative data were described for three pollen types, while quantitative data were analyzed by descriptive and multivariate statistics. The pollen grains are monads, isopolar or heteropolar, small to medium in size, peroblate to oblate-spheroidal and with a subcircular to quadrangular amb. Variation in the type of the apertures [3-porate, 3-(4)-colporate, 3-syncolporate or 3-parasyncolporate] allowed the analyzed genera to be separated into three pollen types. Furthermore, differences in ornamentation (psilate, rugulate, striate, microreticulate, reticulate) delimit species within the established pollen types.