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Regulation of Mitosis in Living Cells. I. Mitosis under Controlled Conditions
Author(s) -
Jackson Wm. T.
Publication year - 1967
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1967.tb07137.x
Subject(s) - anaphase , mitosis , prophase , nuclear membrane , nucleolus , biology , microbiology and biotechnology , cell cycle , cell , meiosis , genetics , nucleus , gene
A quantitative method has been devised to study mitosis in vitro by phase contrast and polarization microscopy. Mitosis in cell‐wall‐free endosperm cells of Haemanthus kathrinar Baker (the African blood lily) has been divided into 18 arbitrary stages or events. The time course for the various stapes, as well as the percentage of cells that proceed from one stage to another during a four hour observation period, are presented. Cells that were in prophase when selected for study proceeded from nuclear membrane breakdown to melaphase in 60 minutes and remained in melaphase for 30 minutes. Only 13 minutes was required to proceed from onset of anaphase to mid‐anaphasc. Mid‐anaphase provides a clear and precise baseline for determining the time required for succeeding stages to appear. The cell plate made its appearance 40 minutes after mid‐anaphase and was completely formed 20 minutes later. The nuclear membranes also became evident at this latter time and nucleoli were visible 30 minutes later. Thus, the average time for a cell observed initially in prophase to proceed from nuclear membrane breakdown to formation of two daughter cells was just over three hours. A high percentage of cells that were in late prophase or later stages of mitosis at the time of initial observation completed mitosis during the observation period. The effect of the length of time a cell is subjected to experimental conditions upon its subsequent behaviour is assessed. These results form the basis for future studies of the effects of chemicals, particularly herbicides, upon cells in mitosis as observed in vitro by phase contrast and polarization microscopy.