Abstract

Development of polyad grain of Calliandra haematocephala Hassk. Was studied. Electron microscopy technique preparation was adapted for this study. That is, pre-fix in glutaraldehyde, post-fix in osmium tetraoxide, dehydrate in acetone, embed in plastics, cut with ultramicrotone, thick section (1μ thick) stained with methylene blue-azure II, examine under light microscope. Different developmental stages, namely, undifferentiated, one-, two-, four-, five-, six-, and eight-celled stages were revealed. Each nuclear division is followed immediately by cytokinensis which is common in Monocotyledons and also found in this species. Sporopollenin starts adding on the surface when 4-celled stage is reached (wall formation). Although cell plate has already separated two dayghter cells away but sporopolleninous wall had not appeared at that time. Longitudinally, there can be several octads formed from each locule, however, horizontally there is only one expected at the same level. In other words, there was only one pollen mother cell exisiting at the initiation stage. Accompanying events, such as tapetal layer (development and disintegration), and reinforcement of endothecial cells are also reported.