Received 31 January 1989. Accepted 13 May 1991.
PHAGOTROPHY IN THE FRESHWATER, PHOTOSYNTHETIC DINOFLAGELLATE AMPHIDINIUM CRYOPHILUM1
Article first published online: 27 OCT 2004
Journal of Phycology
Volume 27, Issue 5, pages 600–609, October 1991
How to Cite
Wilcox, L. W. and Wedemayer, G. J. (1991), PHAGOTROPHY IN THE FRESHWATER, PHOTOSYNTHETIC DINOFLAGELLATE AMPHIDINIUM CRYOPHILUM. Journal of Phycology, 27: 600–609. doi: 10.1111/j.0022-3646.1991.00600.x
We thank Dr. Linda Graham for her assistance and suggestions and Drs. Gary Floyd and John West for comments on the manuscript.
- Issue published online: 27 OCT 2004
- Article first published online: 27 OCT 2004
- Amphidinium cryophilum;
The cold-water, photosynthetic dinoflagellate Amphidinium cryophilum Wedemayer, Wilcox & Graham feeds phagotrophically on other dinoflagellate species. Food is ingested through a feeding tube, termed here the “phagopod,” which extends from the antapex. The peduncle of this organism plays no observable role in the feeding process. The phagopod is essentially a hollow cylinder composed electron-opaque material that is possibly deposited on a membrane. No Amphidinium cytoplasmic components, including microtubules or other cytoskeletal elements, were observed in the phagopod. Prefeeding cells aggregate, in small clumps near prey organisms with their phagopods extended. Eventually some cells commence feeding, first inserting the phagopod through the prey cell-covering and then slowly, over a period of 10 min or more, drawing cytoplasm through the phagopod and into a nascent food vacuole. Both light and electron microscopy suggest that one or more prey cell amphiesmal membranes remain intact during the feeding process. Upon completion of feeding, the Amphidinium cell swims off with a prominent food vacuole in the hypocone, leaving at least part of the phagopod attached to the prey cell. Phagotrophy in A. cryophilum seems to vary with light intensity. At low light intensities, cells feed phagotrophically and are nearly colorless, whereas at high light levels they feed much less frequently, if at all, and are brightly pigmented.