The Japanese Journal of Genetics

Comparative studies on the panicle development in normal and dwarf types of rice plant

Kane NAKAYAMA

1940 Volume 16 Issue 4 Pages 139-148
Published: 1940
Released on J-STAGE: April 04, 2007

DOIhttps://doi.org/10.1266/jjg.16.139

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The panicles of rice plant grow very slowly in the dwarf types AAbb, aaBB and aabb as well as in the normal type AABB till about thirty-seven days after the sowing, and there is practically no difference between their sizes in any types before this stage of development.
In fourty-four days after the sowing, the panicles of two larger types AABB and AAbb begin actively to develope and differentiate the branch primordia of the first order. In the other types aaBB and aabb any apparent change is not yet to be found.
The branches of the second order in panicles appear in all types in about fifty days after the sowing.
On these branches the primordia of lemma and palea are formed in the larger types AABB and AAbb, but not yet in the dwarfs aaBB and aabb.
In the following ten days, a perfect set of the flower organs, viz. stamen, filament, pistil, ovule, and lodicule is formed. The length of panicles in this stage of development is apparently larger in the types AABB and AAbb than in those of aaBB and aabb, but the flower size developed at the top of panicles is nearly equal to each other in plants of all genotypes concerned. The fact shows that the longitudinal growth of panicle is controlled at an early stage of development by the dwarf genes, while the eventual difference in flower size among the different types may only appear when the most active growth of glumes proceeds.
It is concluded that so far as the early stages of development concerned, the length of panicles in larger types is caused by the more active cell divisions and the more advanced development of cells so formed and not by the larger dimensions of cells.

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Tetraploid PMCs of Rhoeo induced by low temperature treatment

Toshio AKEMINE

1940 Volume 16 Issue 4 Pages 149-154
Published: 1940
Released on J-STAGE: April 04, 2007

DOIhttps://doi.org/10.1266/jjg.16.149

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In the winter of 1937, pots of Rhoeo discolor Hance were transfered from the green house (23°C) to the place of 2°C for four hours and then were put back again. Two weeks after treatment, some anthers were found to contain a considerable number of tetraploid PMCs mixed among the normal diploid ones. The chromosome configurations were studied by one 'diakinesis' (Fig. 6) and nine MI (Figs. 2-4 and 7-15) PMCs. They involved univalents, ring bivalents, chains of three or more chromosomes, rings of 4 chromosomes and polyvalents bearing triple terminal chiasmata. They are all similar to those demonstrated by Seitz (1935) in tetraploid Oenothera species. These 4x-PMCs are ascribed to be due to the failure of cytokinesis at the last mitosis in the archesporial tissues which were affected by influence of low temperature treatments. The chromosome configurations observed favor the assumption that Rhoeo is an interchange heterozygote as has been hitherto inferred only from ring configurations.

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Genetical studies of the lady-bird beetle, Harmonia axyridis PALLAS. (Report IV)

Yasusi HOSINO

1940 Volume 16 Issue 4 Pages 155-163
Published: 1940
Released on J-STAGE: April 04, 2007

DOIhttps://doi.org/10.1266/jjg.16.155

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In this report two more rare pattern types: aulica (Fig. 1-a, b) and gutta (new name proposed by Prof. T. Komai) (Fig. 1-f, g, h) are dealt with. Both of these are due to the factors (P^Au=factor for aulica, P^G=factor for gutta) belonging to the same allelomorphic series as conspicua, transversifascia, spectabilis, axyridis, forficula and succinea and behave as dominants to succinea.
The heterozygote of axyridis and aulica (P^AP^Au) (Fig. 1-c) and the heterozygote of forficula and aulica (P^FP^Au) (Fig. 1-d) can be distinguished as such from homozygotes. The heterozygote of transversifascia and aulica (P^TP^Au) may be distinguished from transversifascia in that the spot has a concavity on the antero-median side (Fig. 1-e), though in some cases the heterozygote of transversifascia and aulica shows the same appenrance as transversifascia. The distinction between the heterozygote of gutta and axyridis (P^GP^A) and the heterozygote of conspicus and axridis (P^CP^A) and that between the heterozygote of gutta and forficula (P^GP^F) and the heterozygote of conspicua and forficula (P^CP^F) can often made by the fact that the spot is provided with an accessory speck on its antero-median corner, though the speck may be missing in some cases (see Report II, Fig. 1-l, m and Report III, Fig. 1-e). The heterozygote of conspicua and aulica (P^CP^Au), the heterozygote of conspicua and gutta (P^CP^G), the heterozygote of gutta and spectabilis (P^GP^S), the heterozygote of gutta and transversifascia (P^GP^T) and the heterozygote of gutta and aulica (P^GP^Au) can not be distinguished from conspicua; the heterozygote of spectabilis and aulica (P^SP^Au) may shows the same appearance as spectabilis.

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On the chromosome numbers in the genus Carex

Shun OKUNO

1940 Volume 16 Issue 4 Pages 164-170
Published: 1940
Released on J-STAGE: April 04, 2007

DOIhttps://doi.org/10.1266/jjg.16.164

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In the present study, the somatic chromosome numbers of about 40 species of the genus Carex have been determined (Table 1). In this Table the chromosome numbers are arranged in the systematic order adopted by Kükenthal. Twenty different chromosome numbers have been found as follows, 30, 34, 36, 38, 42, 48, 52, 54, 56, 60, 62, 64, 66, 68, 70, 74, 76, 78, 84 and 90 (Figs. 1-39). These numbers cannot be generally arranged in a series of multiples, but it is noteworthy that the polyploid relation has been observed in C. multifolia and C. stenantha, namely, 2n=30 and 60 in the former (Figs. 18-19), 2n=34 and 68 in the latter (Figs. 27-28) and that aneuploidy has also been found in C. conica, 2n=34, 38 and 42 (Figs. 16-17). As a rule, the chromosome shape is spherical or elliptical. And the chromosome decreases generally in size as their number increases. In C. pilosa, two individuals having the different chromosome numbers (n=32 and 57) have been detected and it is a very interesting fact that their meiotic chromosomes show the secondary association of different types, namely, in the individual of 32 chromosomes, each two bivalents associate generally with each other and in that of 57 chromosomes, each three bivalents associate together (Figs. 44-45). Such pairing in the genus Carex has not been hitherto reported by any investigator.

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Studies on the experimental production of fasciation in buckwheat by the treatment of seeds with heteroauxin solution

Yoshito YAMASAKI

1940 Volume 16 Issue 4 Pages 171-175
Published: 1940
Released on J-STAGE: April 04, 2007

DOIhttps://doi.org/10.1266/jjg.16.171

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This paper deals with the fasciation experimentaly produced in buckwheat (Tochigi No. 1) by the treatment of seeds with the aqueous solution of heteroauxin.
1. In Experiment I, air dry seeds were soaked in 0.1% heteroauxin solution for 60, 50, 40, 30, 20 and 10 hours (Exp. I-A_??_F); in Experiment II, germinated seeds (having a seminal root of about 2_??_4mm long) were immersed in the same solution as in Exp. I for 40, 30, 20, 10 and 5 hours (Exp. II-A_??_E). In both experiments, the seeds treated with the solution were washed with water, and sown in the field to observe the effects of the treatment. In Experiment III, the germinated seeds, similar to those used in Exp. II, were injected with 0.1% heteroauxin solution at the top, and they were sown immediately without washing. In these experiments, the seed germination and the seeds soaking in the chemical were carried out in a thermostat kept at 25°C.
2. In these experiments, abnormal plants with two opposite leaves on the second node (the one above the cotyledon-node) were met with in very high proportions. Such abnormal plants were classified into 4 types (cf. Table 1), In Exps. I and II, the proportions of the abnormal plants to the total seedlings increased with the length of treatment. In Exp. I, the abnormalities other than (a) type were observed more frequently than in Exps. II and III.
In the cases where the seeds were treated for 40 and 30 hours, Exp. I shows higher ratios of abnormal plants than Exp. II, but in the case where the seeds were treated for 10 hours Exp. II shows higher ratio of abnormal plants than Exp. I; in the case of 20 hours no difference was observed between those experiments.
3. Fasciation occurs in some of the branches grown on the second node of the abnormal plants (Fig. 1). Fasciation is not observed in the branches produced on the successive normal node of the abnormal individuals. It was not observed also in the normal plants. Thus fasciation is always accompanied by the abnormalities.
From the facts represented in Table 2, it seems that the condition which induces fasciation also produces the abnormalities. In Exp. III, fasciation was not met with at all. It seems that the fasciation shows a tendency to appears somewhat more frequently in the abnormal individuals belonging to (b), (c) and (d) types than in that of (a) type.

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A historical review on the methods for the demonstration of the Golgi apparatus

Siro TARAO

1940 Volume 16 Issue 4 Pages 176-189
Published: 1940
Released on J-STAGE: April 04, 2007

DOIhttps://doi.org/10.1266/jjg.16.176

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