Podocyst (cnidarians)
The term podocyst (from Greek πούς , genitive: ποδός poús, podos "foot" and κύστις kystis "bladder") denotes an irregularly shaped, lenticular stage within the cnidarians (Cnidaria), which the polyp forms under its foot disk. The podocyst contains embryonic cells that are surrounded by a peridermal covering. The central part of the cells are enriched with yolk-like substances. If the polyp dies or changes its location, a new polyp can later emerge from the podocyst. The path that the polyp travels can be reconstructed on the basis of the podocysts or podocyst sheaths left behind. Podocysts are primarily permanent stages, which in Chrysaora quinquecirrha can be dormant for up to two years. Podocyst formation is also a form of asexual reproduction. One polyp of Rhopilema nomadica produced 14 podocysts within two months, albeit under laboratory conditions. In this species, budding, another common form of asexual reproduction in cnidarians, appears to be rather rare. Presumably, the "mass production" of podocysts contributes to the mass reproduction ("flowers") of some species.
The cysts that are produced by some species (e.g. Catostylus mosaicus ) by the free tips of stolons directly on the surface without the direct action of the polyp are also referred to by some authors as podocysts. However, it is unclear whether these structures are actually homologous with the "real" podocysts that are produced by the polyp's foot disc.
literature
- Mary Needler Arai: The potential importance of podocysts to the formation of scyphozoan blooms: a review. Hydrobiologia, 616: 241-246, Dordrecht 2009 doi : 10.1007 / s10750-008-9588-5
- Bernhard Werner: Cnidaria tribe . In: Textbook of Special Zoology. Volume I: Invertebrates Part 2: Cnidaria, Ctenophora, Mesozoa, Plathelminthes, Nemertini, Entoprocta, Nemathelminthes, Priapulida. 4th completely revised edition, pp. 11–305, Gustav Fischer Verlag, Stuttgart 1984 ISBN 3-437-20261-8
Individual evidence
- ^ RE Black, J. Rosemary T. Enright and Lan-Ping Sung: Activation of the dormant podocysts of Chrysaora quinquecirrha (Scyphozoa) by Removal of the Cyst Covering. Journal of Experimental Zoology, 197 (3): 403-413, New York 2005 ISSN 0022-104X
- ^ A. Lotan, R. Ben-Hillel and Y. Loya: Life cycle of Rhopilema nomadica: a new immigrant scyphomedusan in the Mediterranean. Marine Biology, 112: 237-242, Berlin & Heidelberg 1992 ISSN 0025-3162
- ↑ a b Mary Needler Arai: The potential importance of podocysts to the formation of scyphozoan blooms: a review. Hydrobiologia, 616: 241-246, Dordrecht 2009 doi : 10.1007 / s10750-008-9588-5