Cytophotometric Studies of Histone and DNA in the Mitotic Cycle of Tulip Endosperm Nuclei

Abstract

In the endosperm of Tulipa Fosteriana seeds 20–30 days after pollination the endospermal pellice at any given time contain an ordered sequence of mitotic phases as they proceeds through the all visible phases of mitotis to postmitotic interphase. This living material is a very convenient experimental model for a study of some nuclear processes during mitotic cycle. Using such pellices fixed by 10% formalin and mounted on the slides the DNA and histone content of interphase nuclei and sets of mitotic chromosomes were estimated by cyto photometry of Feulgen reaction or fast green pH 8.2 staining. It was shown that the duplication of amount of both DNA and histone take place simultaneously during interphase and there is no change of histone amont in the chromosomes during visible stages of mitosis.