1962 Volume 75 Issue 894 Pages 468-472
(1) If normal eggs of Coccophora Langsdorfii or Fucus evanescens are immersed in 1.6 to 2.0M CaCl2 solution at a stage after their polarity was determined morphologically, dark cytolysis occurs at first in the prospective rhizoid region and then it spreads to the whole region. In Fucus eggs, abnomally, sometimes two or three primary rhizoids are formed. In these eggs, the cytolysis is observed at each region in coincidence with the rhizoid bulgings. If Coccophora eggs are centrifuged at 1, 700 times gravity or higher for one minute and then immersed in the above solution, the cytolysis takes place at the centrifugal end regardless of the prospective rhizoid pole.
(2) It seems that the regional cytolysis with CaCl2 in normal eggs can be attributed to gradients in susceptibility in the cortex of the egg cell for excessive Ca ions, highest at the rhizoid region and they are movable with centrifuging. Nevertheless, the developmental polarity is not always modified.