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Le rôle de la taille et de la nutrition dans le déterminisme de la gemmulation chez les Spongillides

par Rasmont, Raymond
Référence Developmental biology, 8, 3, page (243-271)
Publication Publié, 1963-12

Article révisé par les pairs

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Résumé :

Small freshwater sponges of the species Ephydatia fluviatilis were cultivated in petri dishes, on a diet consisting of killed bacteria. They were investigated with respect to their gemmulation speed. This speed depends in a complex way on the number of gemmules from which the individual sponges have hatched, and on the nature and quantity of the diet they are fed. The hatching of a gemmule within a sponge already differentiated accelerates its gemmulation. However, this in vivo hatching is possible only in particular conditions. The sponge exerts an inhibitory influence on the hatching of any live gemmule it contains, the strength of this inhibition depending on the physiological state of the sponge. The following hypotheses can be suggested as a tentative explanation of the observed facts: (a) The onset of gemmulation would be related to the accumulation within the sponge of some kind of blastogenic material. (b) The triggering itself of the formation of gemmules would be performed by an inducer able to diffuse within the sponge and even from one sponge to another. (c) Inhibition by the sponge of the hatching of gemmules it contains would also be exerted by means of a diffusible agent, perhaps identical with the gemmulation inducer itself. The agreement between these hypotheses and the experimental and ecological data is discussed. © 1963.