A number of chromosomes of
Carex podogyna was reported as 2
n=76 by OKUNO (1940), while other two chromosome numbers of 2
n=68 and 2
n=72 have newly been found in the materials used in the present investigation. Reduction divisions of the four plants studied showed that three have 2
n=72 and one has 2
n=68.
Chromosome behavior in meiosis of the plants with 2
n=72 were quite normal, forming regularly 36 bivalents in the first metaphase and 36 chromosomes in both second and the primary pollen nuclear division metaphases (Figs. 1-4). While in meiosis of the plant with 2
n=68 some structural hybridities were found (cf. Table 1, Fig. 5-16). It is premature, however, to discuss the origin of intraspecific aneuploidy of this species until further cytological investigations of many plants as well as related species are carried out. It is suggested, however, that the present intraspecific aneuploid plants may be the derivatives of high polyploidy (cf. TANAKA, 1940d).
Among the pollens of the plant with 2
n=68, an abnormal diploid pollen (Fig. 16) was found, which has two apical nuclei in stead of usual three. Therefore apparently two daughter nuclei of the quartet male nuclei which resulted by the meiotic process seem to survive as the pollen nucleus. This fact probably suggests the possibility that by the doubling or combination of chromosome sets more than one nucleus servive as the pollen nucleus (cf. TANAKA, 1941).
抄録全体を表示