XVI International Botanical Congess

Peridinium volzii and P. inconspicuim are dinoflagellates (Division Pyrrophyta) common in freshwater. Many dinoflagellates exist as motile free-living cells bounded by a complex cellulosic layer. During periods of environmental stress, dinoflagellates will cast off their cellulose plates and form temporary cysts bounded by a sporopollenin wall layer and remain encysted until environmental conditions improve. This study induced cysts and used Light, Fluorescence, Scanning Electron, and Transmission Electron Microscopy to follow the process in the two species. Understanding living dinoflagellates will help us better understand the dinoflagellate fossil record, which is comprised exclusively of cyst forms and is now thought to reach back almost 1,000 million years.