BUD SEPARATION IN HYDRA OLIGACTIS

¹ Department of Biology, Cleveland State University, Cleveland, Ohio 44115

Bud detachment with peduncle and basal disc formation distinguishes the asexual reproductive products of Hydra from the secondary axes of colonial coelenterates. This bud individuation was examined in Hydra oligactis using three approaches. Isolation experiments showed that parental body column could enhance hypostomal tissue's development of peduncle and basal disc. This established that the parental body column has a role in bud detachment. Grafting procedures used distal budding to indicate ability to direct bud separation. In bud formation and separation from the most distal surface of a subhypostomally amputated parental animal, the budding region of the parental body column was both necessary and sufficient for individuation. Cell quantification studies revealed a combination of three cellular characteristics in regions directing distal budding: a small proportion of nerve cells, a "big" interstitial-cell/epithelial cell ratio considerably < 1, and an interstitial-cell derivative/epithelial cell ratio of < 0.50.