Longitudinal Stolon Pulsations in the Colonial Hydroid Dynamena pumila (Linnaeus, 1758)

Abstract

It is established via time-lapse video microscopy that the zone of longitudinal extension of the stolon coenosarc in the colonial hydroid Dynamena pumila can extend over two interstitial sites (modules). The stretching occurs in the form of oscillations with a period corresponding to the growth pulsations of the stolon tip. Consequently, the growth zone is not restricted to one stolon module, and the main condition for longitudinal growth of the coenosarc appears to be the stretching created by the advancing growth tip, not only by the increasing number of cells in the growth zone, as the main cause of coenosarc elongation.