Pollen Morphology of Six Indonesian Begonia (Begoniaceae) Species

Abstract

Aims: This study aims to determine pollen morphological differences in six Indonesian Begonia species.
 Study Design: All fresh pollen grain of six Indonesian Begonia species were collected using a standard method and observed at SEM (Scanning Electron Microscope) Laboratory.
 Place and Duration of Study: The pollen is collected from Bogor Botanic Gardens, then observed using an SEM in The Museum Zoologicum Laboratory, Research Center for Biology, Indonesian Institute of Sciences (LIPI), on August 2018.
 Methodology: The results of SEM pollen ultrastructure observations were analyzed descriptively by describing images of size, P/E index, aperture, endoaperture, and ornamentation of pollen. The size of pollen morphology is calculated based on the length of the polar axis and the equatorial axis on a micrometer scale. Determination of the shape of pollen can be determined by comparing the length of the polar axis with the equatorial axis.
 Results: All species examined share common pollen grain characters, i.e. isopolar and three zonocolporate. The longest polar axis (P) and equatorial diameter (E) presented by B. puspitae, whereas the shortest of P is shown by B. kudoensis and the shortest of E by B. sudjanae. Only B. hooveriana has prolate – perprolate aperture, whereas other species perprolate. Endoaperture types of B. puspitae, B. sudjanae, and B. hooveriana is lalongate, while the other species is lolongate. The coarsely striate ornamentation forms are presented by B. holosericeoides and B. natunaensis, whereas other species has fine striate ornamentation.
 Conclusion: The size, P/E index, aperture, endoaperture, and ornamentation of pollen are not useful for section classification of six Indonesian Begonia species. Pollen morphology should be incorporated to other characters, such as morphological, cytological, and molecular characters for making delimitation of Begonia species.