Abstract
1. The pattern and distribution of chromosome aberrations induced by mitomycin C were compared between Vicia faba which possesses heterochromatic regions and Tradescantia paludosa lacking visible heterochromatin in all the chromosomes, using meristematic cells of their roots.
2. Mitomycin C produced chromatid-type aberrations in both Vicia and Tyadescantia. The frequency of aberrations was higher in Vicia than Tradescantia. The distribution of aberrations was found to be nonrandom with a marked excess of breaks in some heterochromatic regions of Sb-chromosomes in Vicia and at some segments of submetacentric chromosomes in Tradescantia.
3. The mechanism of action of mitomycin C and the possible reasons for these localized effects were discussed.
