Cytological, Morphological and Geographical Studies on the Differentiation of Species of Kalimeris in Japan II

Kalimeris pinnatifida

Abstract

1. Kalimeris pinnatifida, the sole diploid species (2n=18) known in the genus, is endemic to northern and central Honshu, Japan. The author investigated external morphology and ecological preference of the species in its natural habitats. Detailed cytologial and morphological studies were made on sampled clones grown in the experimental garden.
2. As a roadside plant, K. pinnatifida showed little variation in ecological preference. Although its external morphology was highly variable in certain characters, the pattern of variation was not changed throughout the species range so far investigated.
3. It was cytologically stable as a diploid species, being regular in meiosis and constant in metaphase karyotype as well as in chromosome number.
4. Its metaphase karyotype was characterized with a secondary constriction on the short arms of the largest chromosome pair and relatively little difference in length and in the position of primary constrictions among the constituent chromosomes. The position of the primary constrictions was either median or submedian.
5. Karyotype analysis was made in detail at prometaphase, as well. Differentiation in terms of stainability was recognized within and between the chromosomes. Using this as a marker point, it was ascertained that each chromosome of complements had different structural characteristics. There was, however, a general tendency that the centric region of a chromosome was stronger in stainability than the distal regions.
6. During mitotic prometaphase to metaphase, the differentiated regions of a chromosome showed differential contraction which seemed almost inversely proportional to the intensity of stainability at prometaphase of respective regions. An increase in stainability accompanied to the contraction, making the whole length of chromosome arms uniform in stainability at metaphase.