Oral morphogenesis during asexual reproduction in Paramecium tetraurelia

Abstract

SUMMARYOral morphogenesis in stock 51 of Paramecium tetraurelia was investigated using the techniques of Chatton-Lwoff and protargol silver impregnation. During the stomatogenesis accompanying divisional morphogenesis a new oral anlage field and endoral kinety are formed and persist throughout the interfission period in both the proter and the opisthe. This previously overlooked fact is important for understanding the developmental origins and significance of the endoral kinety and the oral anlage field. Previously, the kinetosomes constituting the oral anlage field were thought to be formed just prior to the onset of stomatogenesis, being in some way derived from the kinetosomes of the endoral kinety. The demonstration of a permanent anlage field as an integral component of the oral assemblage suggests that the earliest stages of stomatogenesis might best be viewed as temporally controlled surfacing and/or ciliation of pre-existing kinetosomes rather than their de novo synthesis. The endoral kinety would thus have no contributory role in the formation of the anlage field used in the immediately ensuing stomatogenesis.