Comparative Pollen Viability and Pollen Tube Growth of two Endemic Philippine Etlingera (Zingiberaceae, Alpinioideae)

The pollen viability and pollen tube growth of Etlingera dalican and Etlingera philippinensis (Zingiberaceae) were examined from fresh samples under the light microscope (LM) and scanning electron microscope (SEM). Pollen measurements were 68-75μm (E. dalican) and 60-65μm (E. philippinensis), having spheroidal shape for hydrated pollen and irregularly-shape for dry pollen for both species. E. dalican pollen has greenish-yellow color while that of E. philippinensis is greenish. Both species had inaperturate pollen but differ in their ornamentation which is gemmate in E. dalican while psilate in E. philippinensis. E. dalican has 88.56% pollen viability while E. philippinensis has only 40.69%. The rate of pollen tube growth was faster (17.75 μm per day) in E. dalican than E. philippinensis (8.17 μm per day). The possible pollinators observed for the two species were butterflies of the genus Catopsilia, ants and flies. Additional information on the inflorescence and flower description of the two species are herein presented.