With reference to the genetics of Impatiens Balsamina L., Mirabilisjalapa L., and Celosia cristata L., the author described some experimental results in his previous papers (Kanna 1926, 1927, 1929, 1933, 1934). The investigations with special reference to the anthocyanin variegation have been furthered the main results obtained being as follows: 1. With the experimental data for balsam as basis, are described the behavior of three genes for the flower type, ten genes for the flower color, and three for other characters. 2. The white blotches on the petals of balsam are transmitted in inheritance as a recessive character, although its segregating aspect is not simple. 3. Albinism in balsam is segregated as a Mendelian recessive to normal green. 4. The appearance of deficient seedlings is due to gene mutation from dominant to recessive. 5. Two types of fasciation are observed, hereditary and non-hereditary. 6. The haploid chromosome number of balsam is seven. 7. Two linkage groups are established in balsam, including six genes. The s linkage group contains three genes, s, w and d, the p linkage group includes three genes, s, sp, and e, while most of the other genes are independent of one another in their segregations. 8. The pink flower of Celosia is an allelomorph of magenta and yellow, being recessive to the former and dominant to the latter. 9. Genes T, t', t. which are responsible for the stem length in Celosia, constitute a set of triple allelomorphs. 10. Eight mutable genes for the anthocyanin variegation, three in balsam, three in Mirabilis and two in Celasia, were detected. 11. The striped flower of these three plants frequently give rise to monochromatic flowers as owing to mutation from recessive to dominant in their progeny. 12. As the result of mutation from dominant to recessive, the striped strains also throw out some individuals bearing ground-colored flowers that breed true to type. 13. Three genes, self-colored, variegated, and ground-clored, constitute aset of multiple allelomorphs, the genes being constant except the second. 14. Four types of menochromatic bud-variation are observed on the striped balsam. As to the position of the mutated histogens, the plant characteristics are as follows: 15. The striped strain of Celosia frequently bears three kinds of bud-variation, pure magenta (Type A), a mosaic of yellow and magenta in each petal (Type B), and pure magenta (Type C). 16. In Mirabilis, three types of monochromatic bud-variation are observed and their chimerical nature discussed. 17. The intensity of the ground color of the striped strains of balsam changes at times owing to the presence of mutable gene e. 18. The degree of variegation is affected by a modifier v-r in balsam and by m in Mirabilis, resulting in two types of fine and coarse variegations. The two types are transmitted by monohybrid inheritance. 19. Occasionally, owing to mutability of v-r and m bud-variation from coarse to fine variegation are observed in balsam and Mirabilis. 20. The various combinations of eight genes in Mirabilis result in different flower colors with or without variegation. 21. The tricolored Mirabilis, yellow and magenta stripes on white background, carries two mutable genes, ri and ci. 22. Linkage occurs between genes ci and m in Mirabilis. 23. The direction of mutation in allelomorphs is discussed. 24. Mutation generally occurs late in the plant ontogeny. 25. Finally the mutable genes are considered generally in connection with their direction, frequency, position, time of change, the ground color of the striped flowers, and also other contributing factors.
1. The gametic chromosome number 6 (in both male and female) and the somatic number 12 (in male) of Spinacia oleracea were counted in agreement with the previous observations. 2. Cytologically no unequal pair of the chromosomes were observed in both sides of the sexes. 3. An inference was made from the genetic results hitherto reported that the female is homozygous and the male heterozygous for the sex determining factor or factors, namely, the present case suggests the X-Y type of sex determination where X-and Y-chromosomes are morphologically indistinguishable from each other and behave as the autosomes.
The fertilization phenomena in Hynobius retardatus are observed in sections of the eggs, fixed at different intervals after insemination of the spermatozoa. The results are briefly outlined as below: 1) About 1 to 1 1/2 hours after insemination of the spermatozoon the the second polar division is completed, and formation of the second polocyte follows about 1 1/2 to 2 hours after insemination. 2) About 2 1/2 to 3 hours after insemination there is found at the periphery of the egg the already metamorphosed female pronucleus, which moves away from the surface towards the interior of the egg. 3) The spermatozoon enters the egg as early as 15 minutes after insemination and then, within 1 hour, it metamorphoses into the male pronucleus. 4) The conjugation of the male and female pronuclei generally takes place between the 5th and 6th hour after fertilization. They meet at a distance of about 1/4 to 1/3 the egg diameter from the animal pole, along an egg-axis joining the second polocyte with the center of the egg. 5) At the time of the conjugation, both pronuclei are quite similar in their structure, size and staining condition; they are nearly spherical with a smooth nuclear membrane and are filled with colourless nuclear sap. Generally they measure 0.038-0.042mm in diameter. 6) After the two pronuclei meet together, they do not actually fuse, but lie side by side in close contact with the nuclear membrane intact. The maternal and paternal nuclear elements are separated in distinct groups during the stages preparatory to the first cleavage division and the chromosomes are formed independently in each respective nuclear vesicle. 7) In the egg about 7 hours after insemination, the first cleavage spindle is usually found in the process of division.
1. Application of X-rays resulted in 6.39 per cent of sterile rice, and none in the controls. 2. Different responses occur with different exposures as also in the diffetent stages of muturity of the germ track. 3. The induced sterile rice contained 7.18 per cent of mosaics for different degrees of sterility or for fertile and sterile ears. 4. The frequency graph of the percentages of fertile spikelets on sterile rice is a bimodal curve, indicating the characteristic distribution of the genic or chromosomal abnormalities.
The chromosomes of spermatogonia are observed in Hynobius dunni and H. kimurai. In both species the number of chromosomes is fifty-six (56), twenty of which are atelomitic V-shaped and remaining thirty-six are telomitic rod-shaped.
Recent reports of Heitz (1933, '34), Painter (1934), Metz and Gay (1934), Geitler (1934), and others on the morphology of chromosomes in salivary glands of Diptera have greatly attracted our attention and have compelled us to take up the same objects and reexamine their results, especially with regard to the structure of chromosomes. According to the authors above mentioned, the chromosomes found in the salivary glands of Drosophila (Painter, Heitz), Sciara (Metz and Gay), Simulium (Geitler), etc.“show very conspicuous bands or disks of deeply staining material alternating with clearer areas.”Painter tried to determine the position of gene loci in such banded chromosomes and put forward a new map of the chromosomes. The larvae of Lycoria sp. and Drosophila melanogaster (normal; Star Curly; attached-X's (ω/yy)) which are being kept in culture in our laboratory have been dissected in Ringer's solution, tap water or in body fluids and the salivary glands have been treated by the aceto-carmine method and subjected to observation. Sometimes Carnoy's fluid was used before treatment with aceto-carmine. To some preparations Feulgen's nucreal-reaction method was applied. The chromosomes or spiremes seen under the cover-glass which was not so tightly pressed have shown beautifully coloured spiral chromonemata buried in the clearer matrix. The chromosomes in the spireme-nucleus generally show in their matrix chromonemata which we call“secondary chromonemata” (Fig. 2). Such chromosomes as show the secondary chromonemata are found to show coiling again in earlier stages, so that they are seen as larger and thicker chromonemata which we call“primary chromonemata”(Fig. 1). The matrix in which the primary chromonemata were buried seems to have disappeared by becoming continuous with karyolymph. The case that seems to show chromosomes extended artificially as a result of pressure subjected to the cover-glass is shown in Fig. 4 where the spiral condition of secondary chromonemata is fairly clearly recognized. The so-called chromioles are also seen in the secondary chromonema which shows doubleness in places. They may be an initial state of coils of a tertiary chromonema a certain indiation of which is found in secondary chromonemata. The spiral-within-spiral structures of chromosomes was first described by Fujii (1926) in meiotic chromosomes of Tradescantia and this was confirmed by Kuwada (1932) and Kuwada and Nakamura (1933, '34) in their detailed investigations on the same material. The wire-model (Fig. 5) pressed under a plate was compared with the primary and secondary chromonemata pressed under the cover-glass (cf. Fig. 4). The band, disk or ring structure of chromosomes described by several authors may be ascribed to inadequate treatment, to such factors as over-pressure or insufficient staining in making preparations. From the results of observations it may be concluded that the salivary chromosomes of Lycoria (Sciara) and Drosophila used in this investigation show a spiral structure which confirms Kaufmann's results (1931) obtained in the case of Drosophila and that in the earlier stages of nucleus the primary and secondary spiral chromonemata are seen in the chromosomes or spiremes. The existence of a tertiary chromonema in the secondary one has been suggested.