[Study of the stability of morphogenetic substances in Acetabularia]

It was shown by means of interspecific transplantation that the morphogenetic substances in the A. crenulata cytoplasm kept their ability to determine the species specific morphogenesis in the A. mediterranea fragments during not less than 30 days. The isolation of the A. crenulata cytoplasm from the cell resulted in the complete inactivation of morphogenetic substances within 2--3 hrs. The removal of chloroplasts from the injected cytoplasm did not change its morphogenetic activity. The cytoplasm treatment by exogenous ribonuclease accelerated the inactivation of morphogenetic substances; this suggests its ribonucleic nature.