| Author Title Journal |
Okada YK, Sugino H (1934) Transplantation experiments in Planaria gonocaphala Duges. I. Proc Imp Acad Tokyo 10(1-2): 37-40; 107-110 |
Abstract / Notes
The body of P. gonocephala shows quite different physiological specialization according to different levels, especially between the extremely anterior and posterior parts. For example, when a small portion of these regions is transplanted into the middle of the other regions and a subsequent cut of the host is made as the case may be at the anterior or posterior level of the graft, the fate of regeneration of the remaining part always depends upon the original specialization, i.e., the polarity of the transplanted pieces, if the latter be not of a considerable size, can be negligible. In both cases of transplantation of small pieces and union of 2 large parts of the body no proliferation of new tissue is found between 2 surfaces of the same or a very similar specialization. Accordingly there is no regeneration of new organs in such a union except reorganization of the old. But between 2 surfaces of different specialization new tissue always appears more or less and there is regeneration of new organs. It is of no consequence whether 2 components of the union are in normal or reversed orientation to each other. With respect to the development of the pharynx, it is highly important that 2 different parts of the body, namely one before and one behind the original pharynx, should be jointed together. The fact that new pharnyx or pharynges are induced by an implantation of the ganglionic portion of the head into the pharyngeal or postpharyngeal region would be nothing more than a method of bringing 2 parts of highly different specialization together and does not seem to depend upon the special activity of the ganglionic elements contained. New pharynges can be equally well induced by transplanting the non-ganglionic prepharyngeal portion into the postpharyngeal regions| Home page -- (Main hierarchy) |