贻贝棘尾虫镜像骈体横切后前后切块再分别左右对折的实验

EXPERIMENTS OF FOLDING LEFT AND RIGHT HALVES OF THE ANTERIOR AND POSTERIOR HALVES AFTER TRANSVERSELY CUTTING THE DOUBLET IN MIRROR-IMAGE DOUBLET OF STYLONYCHIA MYTILUS

将贻贝棘尾虫镜像骈体横断后 ,再将前后切块的左右半细胞做对折骈接。前半部分切块对折后有 67%成为左右镜像对称骈体 ;有 33 %形成末端对末端的镜像骈体 ,最后分开成为一正常虫体和一具有反向口围带的单体虫。后半部分切块对折后基本上全部形成左右镜像对称骈体。这一事实可用位置值的添加理论来解释。但也显示出预存的缘棘毛在确定形成左右镜像对称骈体或末端对末端的镜像骈体中所起的重要作用。

In this work,doublets were produced by a created cell graft method.They were feed with Chilomonas in Pringsheim's fluid.This experiment was done with steel needle under microscope.Put the doublet in diethylaminoethyl cellulose to slow down its activity.After the mirror image doublet of Stylonychia mytilus was transversby cub, the left half parts of each section was folded 180° to against the right half part.Then to dispose the re operated cell masses on different growth stage with osmium tetroxide and protargol. The results exhibited that 67 per cent of re operated anterior masses re generated into mirror image doublets and 33 per cent became end to end mirror image doublets which then separated into two single cells.Hence the ciliary pattern in one cell was normal,and the other was reversed.All of the re operated posterior masses regenerate into mirror image doublets.These results can be explained by the positional value adding theory, but the pre existing structure——the marginal cirri also play an important role during regeneration of each type.