The haploid chromosome numbers of the following have been determined for the first time:-Capparis zeylanica Linn.=20. Cadaba indica Lamk.=18. Maerua arenaria Hook. f & Thomp.=10. Secondary association is reported in Capparis zeylanica and the previous finding that the primary basic number of the family 7 is supported by observations made herein. Evidence is found to show that polyploidy as well as structural changes of chromosomes have played an important part in the evolution of the species. The association of 4 bivalents is interpreted on this basis. Secondary association and its limitations as the sole factor in determining ancestral homology are discussed in the light of the present findings and of the data gathered previously on other genera of this family. Some general remarks are made on the distribution of chromosome numbers in this family and a tentative scheme formulated to show the phylogenetic evolution of some of the important genera.
1. The bathing of the protoplasm of slime molds in various salts and acids, or the injection of these into protoplasm, brings about the formation of rhythmic bands through the precipitation of protoplasmic proteins. 2. Both the hydrogen ion and the ions of heavy metals produce banded precipitates in protoplasm . 3. The periodic precipitation of concentric rings in protoplasm bears a striking resemblance to the Liesegang phenomenon. 4. The more rapid entrance of solutes at certain restricted and isolated points of the plasmodium indicates pronounced differentiation in the permeability of the surface.
1) There are considerable variations in fertility and karyotypes of Crepidiastrixeris denticulato-platpphiilla Kitamura collected at Aburatubo near Misaki (Fig. 3-18). 2) The number of florets and involucre scales per head was counted. The fertility was determined directly by the ratio of the number of ripe achenes to that of florets. The plants with 11 florets have the highest fertility (Table 2). These plants seem to be different in some way from the F1 hybrids which have 9 florets. 3) The number of involucre scales is much more stable than the number of florets (Table 3). This character shows incomplete dominance and seems to be conditioned by the polymeric genes like many other quantity characters. 4) One hypoploid (monosomic) form (Fig. 3), one with diploid-tetraploid chimera (Figs. 14 and 15) and one tetraploid form (Figs. 18, 20 and 21). But these tetraploid plants seem, to be of secondary occurrence after transplantation into the experimental garden from the mild climate of the coastal region. 5) Meiotic divisions of some plants were studied. Pairing and separation of chromosomes proceed fairly regularly. In the tetraploid plants also a regular formation of tetravalents was observed (Figs. 23-25). The writer wishes to thank Prof. Y. Sinoto of the Tokyo Imperial University under whose direction and guidance these investigations have been undertaken, and also Prof. VI. Eri of the Marine Biological Station of the Tokyo Imperial University, who facilitated him to collect the plants used in the present work.
Das Verhalten der achromatischen Figur wurde bei der somatischen Mitose der jungen Prothalliumzellen von Osiniwda japonica THUNB. in vivo untersucht. Aus den Lebendbeobachtungen ergibt sich, daß weder das Verschwinden der Kernwandung am Ende der Prophase noch das Vermischungsvermögen der Kernflüssigkeit mit dem Zytoplasma beim Auftreten der Metaphasespindel stattfinden, daß sich die Wandung des Prophasekernes dabei kontinuierlich zu derjenigen des Atraktosoms and weiter zu derjenigen des Phragmoplasten verändert, and daß sich das als Grundsubstanz der achromatischen Figur aus der Karyolymphe entstandene Atraktoplasma hinsichtlich seiner Gestalt and seiner Funktion vom Zytoplasma sich abgrenzend als ein abgeschlossener Körper vcrhält. Die Scheidewandanlage entwickelt sich im Phragmoplasten zentrifugal, die feste Scheidewand jedoch durch Mitwirkung des Zytoplasmawandbelags der Mutterzelle zentripetal, wobei die Scheidewandbildung bei stark vakuolisierten großen Prothalliumzellen von der einen Seite der Mutterzellwand zu einer anderen fortschreitet. Nach der Bildung der Zellplatte degeneriert der Phragmoplast durch Zytoplasmatisierung der sich an der Bildung der Scheidewandanlage nicht beteiligten Phragmoplastsubstanz. Zum Schluß möchte ich hinzufügen, daß ich der Japanischen Gesellschaft zur FÖrderung der Zytologie für die finanzielle Unterstützung dieser Arbeit zu großem Dank verpflichtet bin.
1) It is pointed out that the kinetochore is subjected to variable effects under different treatments and this has caused much serious confusion in terminology of this cell organ. The writer prefers the term “kinetochore” for this organ rather than the other current name “centromere”, because it proved to be not of such a chromomeric nature as the latter name implies. 2) The kinetochore is a compound body consisting of the chromonematic thread (=the kinetonema) which is persistent throughout the division and of the matrix surrounding it which develops fully at metaphase. 3) The behavior of the kinetonema is just the same as that of the rest of the chromonema (=the genonema), viz., in pairing, in opening-out, in separation of the daughter halves and in the development of the matrix, excepting that the genonema is always precocious in behavior as contrasted with the kinetonema under usual conditions. 4) The origin of the so-called “Zugfasern” is inferred to be such as previously advocated by Belar; they arise from the kinetochore toward the pole and not in the reverse direction.
1. Statistically significant differences were found among nineteen plants of Lolium peieuee L. in total number of chiasmata, number of terminal chiasmata, and number of open bivalents per microsporocyte. The chiasma frequency was not correlated with the terminalization coefficient. 2. The percentage of metaphase I sporocytes showing univalents varied from zero to 9.7 in the different plants. The range in percentage of metaphase I sporocytes showing non-orientated bivalent and loosely attached bivalents was 1.3 to 14.8 percent and 1.0 to 32.0 percent, respectively. 3. Statistically significant negative correlation coefficients were obtained (1) between total chiasma frequency and percentage of metaphase I sporocytes having univalents and (2) between both total and terminal chiasma frequency and percentage of sporocytes having loosely attached bivalents. Percentage of sporocytes with non-orientated bivalents was not correlated with chiasma frequency. The terminalization coefficient was not correlated with metaphase I univalents. non-orientated bivalents, or loosely attached bivalents. 4. In one plant, CT 405, 41.6 percent of the anaphase I sporo-cytes had one or more lagging univalents, a maximum of six occurring in one sporocyte. In the remaining plants, the percentage of sporocytes showing laggards varied from zero to 2.5. The lagging univalents divided equationally in all observed cases. 5. The percentages of metaphase I sporocytes with univalents and with loosely attached bivalents were correlated with frequency of lagging univalents at anaphase I when the data for CT 405 were not included in the calculations. Apparently most of the laggards in this plant arose from some source other than these two. 6. The numbers of chromosomes were determined in the two groups at anaphase I in 633 sporocytes in which lagging chromosomes did not occur and in all cases seven chromosomes were seen in each group. 7. The data on frequency of micronuclei in the sporocytes at interphase I indicated that a majority of the daughter half chromosomes from anaphase I laggards were included in the daughter nuclei. 8. The percentage of quartets with one or more micronuclei in one or more of the four cells ranged from zero to 30.0 percent in eighteen plants. Apparently lagging and dividing univalents at anaphase I were important in producing micronuclei in the quartets both as a result of failure of the daughter half chromosomes to reach the poles in the first division and their inability to move normally in the second division. 9. In ten of the plants, the number of micronuclei per 100 quartets varied from 26.7 to 71.4 percent of the expected number calculated on the assumption that all daughter half chromosomes from anaphase I laggards formed micronuclei. No micronuclei were expected in one plant and none was obtained. In the remaining six plants, the number of micronuclei exceeded the calculated. One plant had about three times as many as expected. These results suggested that micronuclei were produced in certain plants from some source in addition to lagging univalents at anaphase I. 10. This conclusion was supported by the occurrence in seven plants of types of quartets, based on number and position of micronuclei, which were not expected on the assumption that all micronuclei were formed from daughter half chromosomes derived from lagging and dividing univalents at anaphase I. 11. The presence of dicentric bridges and acentric fragments at anaphase I, interphase I, and in the quartets indicated that thirteen of the nineteen plants were heterozygous for inversions. 12. Rare aneuplofd sporocytes in one plant and a tetr aploid sporocyte in another plant suggested occasional irregularities in premeiotic divisions. 13. Percentage of normal appearing pollen varied from 21.2 to 95.7 percent in eleven plants.
In the present paper the configuration assumed by the chromonema in chiasma loops and chromatid bridges was studied, with an aim to ascertain how the chromonema coiling in such arms both ends of which are fixed differs from the previous findings on free arms whose distal end is free and to touch in this way of comparison the problem of the mechanism of spiralisation. Observations on these “fixed” strands have shown that:- 1) When they are below a certain limit of length, they are not able to assume regular cylindrical spirals, but take merely wavy corrugated configurations. In “free” strands no such a conditions is met with. 2) Sometimes each of the paired chromatids is subjected to independent coiling. In free arms of the normal chromosomes such irregularity in coiling is never met with, the paired chromatids always forming a single fused spiral. 3) The spiral configurations assumed by these, when they are relatively long, are characterized by a profound increase in frequency of reversals in coiling direction as contrasted with the case of free strands previously studied. 4) In these strands the spiral of the balanced type (Fig. la) occurs predominantly; especially in the true terminal chiasma loops, the configurations are always of this type. From these findings and other sources of evidence previously presented it has been inferred that:- 1) Pairing of the homologues takes place after the leptotene threads completed the untwisting of the relic twists; they conjugate thereafter side-by-side in one, limited pairing surface of each; the four strands which are to separate two-by-two at diplotene lie thus essentially parallel. 2) “Free” strands are able to rotate in spiralisation and consequently the parallel arrangement of the paired chromatids can be converted into the twisted orientation in spirals, that is, the relational spiral, while in “fixed” strands their freedom of rotation is prevented and therefore the paired chromatids take more complicated configurations as the present paper has shown. In the latter, the paired strands will assume either a relational spiral in the form of a balanced spiral or a parallel one in the form of an unbalanced spiral. 3) For what determines the pitch and the regularity of the spiral in metaphase chromosomes the following three factors are considerable: (a) the space delimited by the matrix, (b) the elasticity of the chromonema and (c) the electrical charges to be accepted by the chromonema at metaphase plate which determine at the same time the external chromosome mechanics. These are responsible for the formation of the major as well as the minor spiral.
Some fine structures of chromosomes which are not rendered visible by other methods, are shown to exist in the preparations made by the maceration method used in the present investigation. Each anaphase chromosome is composed of two chromatids (half-chromosomes) each of which contains a chromonema spiral or spirals. The two chromatids may twist around each other to a greater or less degree. During telophase and interphase the chromonema remains in the coiled state, although the coiling is renderec somewhat irregular. At the commencement of prophase the chro. monemata of each individual chromosome seem to draw close together. In the following stage the chromonema spirals are converted to regularly coiled major spirals in which the new or minor coiling is in progress, as the result of which the prophasic chromosome changes, such as the straightening out of the old spirals, and the thickening and shortening of the chromosome, take place. Gradually each chromosome develops a visible longitudinal split.
In der vorliegenden Untersuchung habe ich bei den fünf gesunden Hoden, welche aus fünf Hingerichteten im lebendfrischen Zustand entnommen wurden, die Zytoplasmakomponente der Spermatogonien, Spermatozyten and Riesenzellen eingehend erforscht. Die wichtigen Ergebnisse sind im folgenden angegeben. 1) Die Spermatogonien liegen auf der Membrana propria der Samenkanälchen. Das Zytoplasma ist hell uncl grob wabig; der rundliche Kern von etwa 6-8.5μ Größe sieht dunkel and homogen aus. Das Kernkörperchen kommt in der Regel mehrfach and häufig auf der Kernmembran vor. Der Golgiapparat ist von “diffuser Form”; die einzelnen Apparatelemente, welche aus dem osmiophilen Externum and osmiophoben Internum zusammengesetzt sind, sind perinukleär angeordnet. Die Mitochondrien sind grob granulär, finden sich mit den Apparatelementen beimengt in der perinukleären schmalen Zytoplasmazone. 2) Die ausgewachsenen Spermatozyten befinden sich in der Regel von der Membrana propria nach innen entfernt. Das Zytoplasma ist dicht and homogen gebaut. Der Kern von etwa 8.5-9.5μ Größe enthält in der Nähe der Mitte einen großen Nukleolus. Der Golgiapparat ist von “komplexer Form, ” stellt auf einem Pol des Kerns einen rundlichen oder kappenförmigen Körper dar, welche im Innern ein rundliches Idiozom mit Zentralkörperchen beherbergt (Golgi-Idiozom-Komplex). Außer diesem Hauptgolgiapparat treten oft in menschlichen Spermatozyten 1-2 akzessorische Golgiapparate auf. Die Mitochondrien sind fein granulär and im großen ganzen diffus im Zytoplasma verteilt. 3) Auf der Membrana propria oder davon nach innen etwas entfernt kommen kleine Zellen mit einem rundlichen Kern von etwa 6-6.5μ Größe vor, welche den kleinen Spermatogonien ähnlich aussehen. Durch die gewöhnlichen histologischen Beobachtungen kann man kaum entscheiden, ob these Zellen zu den Spermatogonien oder Spermatozyten zuzu echnen seien. In diesen Zellen ist der Golgiapparat nicht mehr der diffusen Form; die Apparatelemente sammeln sich auf einem Pol des Kerns in eine kappenartige Figur an and beginnen miteinander zusammenzufließen, um einen komplexen Körper wie der Golgiapparat der ausgewachsenen Spermatozyten zu bilden. Die Mitochondrien sind fein granulär and im ganzen Zytoplasma zerstreut verteilt. Aus obigen zytologischen Befunden kann man mit Sicherheit sagen, daß these Zellen die jungsten Spermatozyten vertreten, welche durch die letzte Spermatogonienteilung gebildet worden sind. Man kann bei diesen Zellen den Übergang der Spermatogonien zu Spermatozyten genau verfolgen. Der Golgiapparat von komplexer Form ist also aus den Apparatelementen der diffusen Form zusammengesetzt, obwohl man darin kaum mehr die einzelnen Apparatelemente unterscheiden kann. Aus dieser Schlußfolgerung kann man umgekehrt sagen, daß die Apparatelemente die Bausteine oder Struktureinheiten des Golgiapparates seien. 4) In den Samenkanälchen des menschlichen Hodens kommen physiologisch nicht selten die Riesenzellen vor. Riesenzellen, welche nach den Beschaffenheiten des Kerns and Zytoplasma wahrscheinlich zu den Spermatogonien zuzurechnen sein dürfen, liegen immer auf der Membrana propria. Der Golgiapparat and die Mitochondrien solcher Zellen sind ganz gleich beschaffen wie bei den gewöhnlichen Spermatogonien. Daraus konnte ich feststellen, daß these Riesenzellen nichts anders als die Riesenspermatogonien sind. Sie werden wieder in einkernige and mehrkernige Riesenzellen eingeteilt. Die Größe des Kerns der einkernigen Riesenzellen beträgt 9.5-16μ. Die Kernzahl der mehrkernigen Riesenzellen ist 2-6. Außer den Riesenspermatogonien kommen im Samenepithel Riesenspermatozyten vor, welche einkernig oder zweikernig sind.
1. In the F1 plants of P. bracteata×P. lateritium some characters were intermediate between those of the parent plants, but many other characters of the male parent, lateiitium, dominated over those of the female parent, bracteata. 2. The chromosome number of the parent plants was the same, but their sizes were different; the chromosomes in lateritium being generally smaller than those of bracteata. The chromosome number in the F1 plants was 2n=14, just the sum of the gametic chromosome number in the parent plants. The variation in chromosome sizes was greater than either of those of the parent plants. 3. In the meiosis of the F1 plants there were found more than 3 pairs, sometimes 5 pairs of gemini, some of them being unequal and others separating early in the later prophase and behaving like univalents. Many univalents, probably the just mentioned, proceeded earlier than the bivalents into the poles, though their distribution was at random as we see usually in the non-splitting univalents in the 1st meiotic division. Generally 3, sometimes 2, bivalents formed an equatorial plate after many univalents had gone into the poles, and followed them after separation or without separation of partners. Simultaneously when the bivalents were at the equator few univalents were found in the periphery of the equatorial region; the latter has passed into the poles without splitting. 4. The cytokinesis generally occurred after the 1st meiotic division, though often it was incomplete. Several irregularities in the division were observed. Second division was rather regular, but due to the irregular behaviours in the 1st division very few good pollen grains were produced. The F1 plants were highly sterile even when they were back-crossed with healthy pollen grains of the parent plants. 5. Traction fibers were observed clearly especially in the aceto-carmine smear materials. The univalents were connected with one pole by the traction fibers which may play the role of the movement of the univalents without aid from any other additional forces, e.g. the “Stemmkorper”, which was considered by BELAR as a separator of the daughter chromosome groups toward the poles. The writer's sincere thanks are due to Prof. K. FUJII for his kind advice in the course of this study. The expence of carrying out the present work was partly defrayed out of a grant from the Science Research Fund of the Department of Education to which her thanks are also due.
1. The nucleus of the vegetative cells of Saccharomyces cerevisiae is composed of a central deeply stained large karyosome, with a narrow hyaline zone around it, and an external membrane. The form of the karyosome is generally spherical, but sometimes it is irregular. It sometimes showed a granular structure in the case of treatment with ferments such as takadiastase. Small granules are often found around the nucleus. 2. The nucleus and also some granules are stained by the Feulgen nucleal reaction. 3. The nucleus undergoes mitosis. The resting nucleus becomes transformed into thick threads which become 4 chromosomes. The latter divide in the atractosome (spindle) to form two daughter nuclei. 4. After mitosis one of the newly formed daughter nuclei, taking on a dumbbell shape, travels through the isthmus into the bud, while the other one remains in the mother cell as its nucleus.