Cytological Studies on Sciaphila japonica, MAK

I. On Chromosome Contributions to Cytology and Genetics from the Departments of Plant-Morphology and of Genetics, Botanical Institue, Faculty of Science, Tokyo Imperial University, No. 44

Abstract

1. The haploid number of chromosomes counted in the pollen-and embryosac-mother-cells of Sciaphila japonica is twenty-four and the diploid number in somatic cells is fourty-eight. In an endosperm nucleus a triploid number of chromosomes, namely seventy-two, can be enumerated.
2. The size difference among the chromosomes is conspicuous.
3. The pairing of chromosomes is recognized.
4. The shape of chromosomes in metaphase is generally rod-shaped. The large gemini and certain intermediate gemini are somewhat constricted in the middle. Sometimes they are V-shaped. In somatic and endosperm cells, the large chromosomes and the intermediate ones have a band-like shape generally indicating their double nature preparatory to their anaphasic separation.
5. The position of arrangement of large gemini and large univalent chromosomes in a nuclear plate is generally peripheral, while the intermediate ones take the position at the periphery or among the small ones.
6. It is supposed that S. japonica is probably a tetraploid plant.