Chromosome Studies on Trillium kamtschaticum Pall. and Its Allies. IX
Chromosome aberrations induced by X-ray treatment
1950 年 16 巻 1 号 p. 37-47
詳細
1950 年 16 巻 1 号 p. 37-47
PMCs of T. kamtschaticum were irradiated at their resting stage, and the following results were obtained.
1) The irradiation leads to the production of both “chromosome” and “chromatid” breaks.
2) The reunion of broken ends occurs between two broken ends as well as between a broken end and a normal end.
3) Broken ends do not often reunite. These free broken ends of chromatids reveal themselves in the next division (that is, in the first pollen mitosis) as paired chromatids which are bridged together at their broken ends.
4) The frequency breaks per chromosome is proportional to the length of whole chromosomes.
5) The frequency of bridges and loops which appear at the first anaphase indicated the ratio of 2 bridges: 1 loop within intra-bivalent aberrations and the ratio of 1:1 in inter-bivalent aberrations. These ratio verify that the mode of disjunction of the paired kinetochores of a bivalent follows the principles of the neo-two plane theory.
