Homopolar grafting in Blepharisma japonicum

Abstract

AbstractResults of homoplastic grafting in Blepharisma japonicum v. intermedium are described. The parabiotic homopolar fusion complex of two cells either simply splits into two singlets, or undergoes cell division. In the latter case the division results either in two doublets or in two singlets (proters) and a doublet (opisthe). If one or two of the systems of feeding organelles are removed after parabiotic homopolar fusion of two cells, the fusion complex does not split, but undergoes division. If an almost complete set of feeding organelles is lacking, the division of the graft complex usually results either in a singlet proter and a doublet opisthe or in two doublets. If two complete sets of feeding organelles have been excised from the graft complex, division occurs after the regeneration of the missing organelles, most frequently resulting in two doublets. The same operation on the graft complex with two primordium sites placed very close to each other may result in the regeneration of one normal and one reversed peristome, the latter being to the right of the former. The doublet biotypes derived from the graft complexes with or without further experimental changes usually reproduced true to type. The asymmetric doublet with two peristomes less than 180° apart tends to resorb the left peristome, that is, one with a larger left‐hand somatic area than the other. The asymmetric doublet may also form a third peristome on the right side of the original left peristome. The third peristome is usually of reversed asymmetry. That the appearance of the third primordium site might be due to the presence of the original line of fusion of two components of the doublet, and that the tendency of the original primordium sites to reestablish themselves might give rise to the third one, when the original ones fail to be kept away from one another, are discussed.