1. |
Karyotype and Chiasma Frequency in the Indian Hedgehog,Hemiechinus Auritus Collaris |
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Caryologia,
Volume 28,
Issue 2,
1975,
Page 149-156
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摘要:
The karyotype ofHemiechinus auritus collarisconsists of 48 chromosomes comprising 16 pairs of submetacentric, 5 pairs of metacentric, 2 pairs of « minute » metacentric and a pair of metacentric sex chromosomes, X and Y.
ISSN:0008-7114
DOI:10.1080/00087114.1975.10796605
出版商:Taylor & Francis
年代:1975
数据来源: Taylor
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2. |
The Formation of Hypertrophied Nuclei in the Endosperm ofAllium CepaL. |
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Caryologia,
Volume 28,
Issue 2,
1975,
Page 157-162
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摘要:
The development of the endosperm inAllium cepaconforms to the free-nuclear type. The cytoplasm of the endosperm at the caecal region is denser, rich in RNA and proteins but low in diffused polysaccharides. There are more triploid nuclei per unit area in this region than elsewhere. The small cells of the hypostase are rich in RNA and proteins. This may well result from the high rate of perfusion of nutrients through the hypostase at this time.
ISSN:0008-7114
DOI:10.1080/00087114.1975.10796606
出版商:Taylor & Francis
年代:1975
数据来源: Taylor
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3. |
Cytological Action of Pederin During the Cleavage of the Newt Egg |
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Caryologia,
Volume 28,
Issue 2,
1975,
Page 163-180
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摘要:
Pederin (10−4M and 2.10−4″M), acting on the cleaving eggs ofTriturus helveticusRaz., does not prevent or arrest cleavage before mitosis. It dissociates the achromatic apparatus from the nuclei, inducing achromosomic mitoses, but does not destroy either the spindle or the asters. Disfunction of kinetochores results in aberrant polar chromosomes not being included in the equatorial plate (so-called three groups metaphase) and aberrant caryomeres.
ISSN:0008-7114
DOI:10.1080/00087114.1975.10796607
出版商:Taylor & Francis
年代:1975
数据来源: Taylor
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4. |
Chromosome Studies inParamphistomum CerviZeder 1970 (Trematoda: Digenea—Paramphistomidae) |
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Caryologia,
Volume 28,
Issue 2,
1975,
Page 181-186
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摘要:
The chromosome number ofParamphistomum cervihas been established for the first time from spermatogonial metaphases and meiotic stages as 2n= 14. The karyotype and the idiogram have been provided. The results are discussed in the light of the available literature concerning other species possessing the same chromosome numbers.
ISSN:0008-7114
DOI:10.1080/00087114.1975.10796608
出版商:Taylor & Francis
年代:1975
数据来源: Taylor
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5. |
Contribution a L'Etude Cytotaxonomique desRumex—I. Le GenreRumexL.Sensu Stricto |
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Caryologia,
Volume 28,
Issue 2,
1975,
Page 187-201
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摘要:
Le caryotype de 33 espèces du genreRumex sensu strictoa été étudié. Pour sept de ces espèces, le nombre chromosomique n'était pas connu. Il s'agit deR. angustifolius(2n= 20),R. rupestris(2n=20),R. fennicus(2n=40),R. Bequaertiï(2n=40),R. Skottsber-gii(2n=60),R. rhodesius(2n=60),R. Kerneri(2n=80) etR. densiflorus(2n=100).
ISSN:0008-7114
DOI:10.1080/00087114.1975.10796609
出版商:Taylor & Francis
年代:1975
数据来源: Taylor
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6. |
Contribution a L'Etude Cytotaxonomique desRumex—II. Le GenreBucephalophoraPau |
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Caryologia,
Volume 28,
Issue 2,
1975,
Page 203-206
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摘要:
Le caryotype deBucephalophora aculeata(L.) Pau (2n=16) a été étudié en détail.
ISSN:0008-7114
DOI:10.1080/00087114.1975.10796610
出版商:Taylor & Francis
年代:1975
数据来源: Taylor
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7. |
Variations Interphasiques de la Teneur en DNA et du Volume Nucleaires du Zygote dePetunia Hybrida—Consequences Metaboliques |
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Caryologia,
Volume 28,
Issue 2,
1975,
Page 207-224
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摘要:
L'étude des variations de la teneur en DNA et du volume des noyaux des zygotes dePetunia hybridamet en évidence un certain nombre de caractéristiques particulières. On observe au début de la phase G1une synthèse de DNA, métabolique par hypothèse, de 0,66 C. Après une période de stabilisation, l'ensemble du DNA présent dans le noyau est repliqué pendant la phase S qui dure environ 28 heures à 20oC pour la population des zygotes du niveau ovulaire considéré. Cette période S correspond à une longueur d'ovules comprise entre 450 et 520 μm. Une partie du DNA métabolique se trouve apparemment détruite pendant la phase G2. Les éléments recueillis permettent d'estimer la durée moyenne du cycle total d'une zygote 111 heures pour une durée de S de 4,6 heures. La détermination de la teneur en DNA des noyaux méristématiques du Pétunia (2C≃9, l pg) autorise, à titre de comparaison, une estimation des durées correspondantes dans les méristèmes radiculaires des 13 et 4,4 heures respectivement. On notera également que le volume du noyau des zygotes évolue d'une façon sensiblement parallèle à sa teneur en DNA. La discussion permet d'établir une relation étroite entre le volume des noyaux et leur teneur en matière sèche. Ceci conduit à émettre pour le zygote l'hypothèse d'une absence ou d'une faible intensité des synthèses qui ne concernent pas la replication du DNA et l'organisation des chromosomes.
ISSN:0008-7114
DOI:10.1080/00087114.1975.10796611
出版商:Taylor & Francis
年代:1975
数据来源: Taylor
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8. |
Cyclic Changes of Histones/DNA Ratio in Differentiating Nuclei of Metaxylem Cell Linein Allium Cepa Root Tip |
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Caryologia,
Volume 28,
Issue 2,
1975,
Page 225-228
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摘要:
Cytophotometric analysis of the nuclear DNA and histones content were carried out in procambial cells with develop into metaxylem inAllium ceparoot tip. The collected data indicate that histones/DNA ratio is not constant. It is in fact highest during the endoreduplication process (stages 1 and 4), decreases in extrasynthesis of nucleolus associated DNA (stages 2 and 5) and reaches its lowest values during extra DNA release (stages 3 and 6).
ISSN:0008-7114
DOI:10.1080/00087114.1975.10796612
出版商:Taylor & Francis
年代:1975
数据来源: Taylor
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9. |
Is there a Podostemum type of Embryo Sac in the GenusFarmeria? |
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Caryologia,
Volume 28,
Issue 2,
1975,
Page 229-235
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摘要:
The development of the female gametophyte inFarmeria indicais of the Apinagia type, form B of BATTAGLIA. Ontogeny of the embryo sac does not justify the existence of an antipodal cell. The present study supports the opinion that there is no Podostemum type of embryo sac in members of Podostemaceae. The term « Nucellar Plasmodium » has been proposed for the so-called pseudo-embryo sac.
ISSN:0008-7114
DOI:10.1080/00087114.1975.10796613
出版商:Taylor & Francis
年代:1975
数据来源: Taylor
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10. |
Inheritance of the Nucleolar Trisome inZea MaysL. |
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Caryologia,
Volume 28,
Issue 2,
1975,
Page 237-250
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摘要:
Trisomie inheritance of the nucleolar chromosome (chromosome 6) in maize is the object of this investigation. The meiotic behaviour of the three chromosome 6 units was observed in microsporocytes, while the female progeny of trisomie individuals was examined in root tips. The outcome of this analysis suggests that meiotic losses of a supernumerary chromosome 6 do not explain, alone, the failure of trisomic types to reach the theoretical frequency of 50% of the progeny. Post-meiotic losses, at the expense ofn +1 spores and/or 2n+ 1 zygotes or embryos may therefore contribute to this failure. The same conclusion is reached by analysing the microspore quartets with regard to their nucleolar make-up. The frequency of a peculiar quartet showing two spores with two nucleoli in diagonal position suggests that the daughter units originating from pre-division of univalents have a tendency to be included in telophase nuclei of the second meiotic division, instead of being lost. A difference found regarding the size of nucleoli in spores with one or two nucleolar organizers suggests that these regions are not autonomous or independent of each other, but somewhat regulated by the cell's needs.
ISSN:0008-7114
DOI:10.1080/00087114.1975.10796614
出版商:Taylor & Francis
年代:1975
数据来源: Taylor
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