Effect of Digitonin on Cellular Division

IV. Interrelation between nucleus and phragmoplast

Abstract

A study of nuclear and phragmoplast association observed in digitonin-treated Allium sativum cells led to a tentative hypothesis that initiation of formation of the phragmoplast-cell wall complex is triggered by a message released by chromosomes of restituting nuclei. A similar theory is applied in an attempt to explain the multiple spindle and phragmoplast systems present in certain PMC's, coenocytic embryos, and non-cellular or nuclear endosperm. Tritiated thymidine and uridine incorporations suggest that digitonin does not interfere with DNA and RNA synthesis. Compounds structurally and functionally related to digitonin did not induce digitonin mitosis.
Acknowledgements: The authors gratefully thank the S.I.U. Office of Research and Projects for financial support and the Merck, Sharp, and Dohme Research Laboratories for purification of digitonin. We also express our sincere gratitude to Drs. Tadashi Hirano and Akio Kushanagi for the valuable assistance granted the senior author during his stay at the Tokyo Metropolitan Isotope Center.