The use of colchicine as an indicator of mitotic rate in broad bean root meristems

摘要: 1. Conditions of culture are described, under which the primary roots broad bean seedlings show a constant growth rate and Mitotic Index for limited period time. It was found that diurnal fluctuation in root is eliminated when plumules removed. 2. Experiments with colchicine, acenaphthene.p-diehlorobenzene, α-bromonaphthalene 8-hydroxyquinoline showed colchicine only spindle inhibitor caused marked increases metaphase counts. 3. Three concentrations 0.1, 0.05 0.025%, were to have similar capacities accumulation over treatments from 1 6 hr. duration. With increased durations treatment, concentration differences expressed, weaker being more efficient than stronger ones. The depression duration attributed an inhibitory effect results slowing entry cells into mitosis, i.e. increasing time spent interphase. 4. It required break down spindles organized prior commencement directly dependent on used. For this reason first hour treatment cannot be used determine mitotic rate. 5. The mean number rnetaphases accumulated population 1000 meristematic 30.1 ± 1.3 per hour. Allowing escape 2 c-metaphase interphase, entering thus determined as 32.1 1.6. 6. The parameters cycle. method calculation formulae kinetics cell given. 7. When using technique total cycle 3.9 0.2 24.6 1.5 hr., respectively. shown these values close agreement through use other methods.