フークス科藻類の発生力学XVII.

Abstract

Eggs of Coccophora Langsdorfii was ultracentrifuged just after fertilization at 25, 000 times gravity for five minutes. As a result, the following was discovered.(1) The intracellular materials are stratified into at least five layers. Arranged in order from the centripetal end, they are: the oil cap, the transparent layer of free water, the plastids and nucleus layer, the hyaline cytoplasm layer, and the granules layer.(2) When the centrifuged egg is immersed in distilled water, or in hypotonic sea water below 30per cent in concentration, the granules stratified in the centrifugal zone are darkened in color and the darkening begins at or near the centrifugal end and then spreads towards the centripetal side, then the plasmoptysis occurs in the centrifugal half. This indicates that the water permeability is highest at the centrifugal end.(3) When the centrifuged egg is immersed in the solution of the starfish toxin at or over 10-4 in concentration, the plasma membrane is destroyed in the subcentripetal zone surrounding the layer of hyaline cytoplasm. This indicates that a certain differentiation in susceptibility to starfish toxin has taken place in the plasma membrane or the cortical layer with the centrifugation. That is, the cortical layer including the plasma membrane is also movable by centrifuging, though the movement is invalid in determining the polarity axis.