Summary
Hydra is a unique epigenetic system where simultaneous existence of stability and lability in its cells is encountered. The two terminal ends of the hypostome and basal disc have been designated as unipotentials, in between these two points the area is bipotential, i. e. it can form either basal disc or hypostome.
The dynamic state of instability in hydra has been explained on the assumption that in case of a developmental urgency the mid equipotential system can transform into either or both kinds of unipotential through the action of some inhibitory complex.
Hypostome as a developmental centre is more powerful than its counter centre namely the basal disc.
Similar content being viewed by others
Literature
Barth, L. G.: The determination of the regenerating hydranth in tubularia. Physiol. Zool.17, 355–365 (1944).
Berrill, N. J.: Growth, development and pattern. San Francisco: F. W. H. Freeman & Co. 1961.
Burt, D. R. R.: The capacity of different regions ofPelmatohydra oligactis Pall. to form the head or foot. J. Exp. Zool.68, 59–93 (1934).
Child, C. M.: Patterns and problems of development. Chicago: University of Chicago Press 1941.
Mookerjee, S.: Dual capacity of differentiation of the middle piece in hydra. Naturwissenschaften49, 356–357 (1962).
—, andA. Sinha: Regionally in the inductive power of hydra tentacle. J. Exp. Zool.141, 379–390 (1959).
—, andS. Sanyal: Nature of cellular integration in hydra. Proc. Zool. Soc. Cal.15, 119–127 (1962).
Rose, S. M.: Specific inhibition during differentiation. Ann. N. Y. Acad. Sci.60, 1136–1159 (1955).
Sanyal, S.: Organiser problem in hydra. Naturwissenschaften11, 263–264 (1960).
Sinha, A. K.: Experimental determination of polarity in hydra. Wilhelm Roux' Arch. Entwickl.-Mech. Org.157, 101–116 (1966).
Tardent, P., andH. Eymann: Experimentelle Untersuchungen über den regenerationshemmenden Faktor von Tubularia. Wilhelm Roux' Arch. Entwickl.- Mech. Org.151, 1–37 (1959).
Turning, A. M.: The chemical basis of morphogenesis. Phil. Trans. Roy. Soc. London, B237, 37–72 (1954).
Weiss, P.: The cell in development. Laboratory investigation. New York: Paul B. Hoeber Inc. 1959.
—, andL. Kavaneu: A model of growth and growth control in mathematical terms. J. gen. Physiol.47, 1 (1957).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mookerjee, S., Sinha, A. System of stability and lability in hydra. W. Roux' Archiv f. Entwicklungsmechanik 158, 331–340 (1967). https://doi.org/10.1007/BF00573403
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00573403