Chromosome Studies in Hyacinthus orientalis L.

Naithani, S. P.

doi:10.1093/oxfordjournals.aob.a083467

Cited by 15 publications

(7 citation statements)

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“…Several authors (Kaufmann, l926a;Koshy, 193? ;Naithani, 1937;Kuwada, 1939) have suggested that the chromatids (of mitosis) are twisted at the time of their inception.…”

Section: Discussionmentioning

confidence: 99%

“…-18 - Kato, 1935Kuwada, 1938Kaufmann, 1931Taylor, 1931Smith, 1932Hoare, 1934Stebbins, 1935Shinke, 1934' Naithani, 1937Chandler et al, 1937Koshy, 1937McClintock, 1938 Huskins & Smith, 1935Wilson & Huskins, 1939 Hunter {unpub.) Shimakura, 193?…”

Section: Theories Of Spiralizationmentioning

confidence: 99%

“…(Other evidence in the literature for double intertwining or interlocking anaphase chromatids has already been mentioned p.20). In contrast to those authors \Vho consider that relational coiling is an active process, several investigators attribute relational coiling to the plane of cleavage being such that the resultant balf-chromatids, or chromonemata, are relationally coiled at their inception (Kaufmann, 1926a;Koshy, 1937;Naithani, 1937;Kuwada, 1939).…”

Section: Theories Of Spiralizationmentioning

confidence: 99%

“…•rable IV Bonnevie, 1908Bonnevie, 1908 Mobr, 1914 White, 194-0 Hsu-Siang, 1932Koshy, 1933Dar1ington, 1936Sax, 1936Sax, 1936Koshy, 1937Naithani, 1937 Huskins & Hunter, '3? Wilson, 1939 Wilson & Hus:kins, '39 Upcott, Husted, 1936Nebel, 1939bCleveland, 1938 As to the consistency of coiling in chromosomes or parts of chromosomes, there has been considerable controversy.…”

Section: From a Study Of Relic And Relational Coiling Inmentioning

confidence: 99%

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STUDIES ON THE CHROMOSOME SPIRALIZATION CYCLE INTRILLIUM

Sparrow¹,

Huskins²,

Wilson³

1941

Can. J. Res.

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Studies of the major, relic, and relational coils and of chromosome, chromatid, and chromonema length changes in meiotic, microspore, and root tip chromosomes of Trillium erectum L. and T. grandiflorum Salisb. have led to the following conclusions:—Elongation of the chromonema occurs between early diakinesis and first anaphase and between second anaphase and microspore prophase. Contraction occurs between zygotene and early diakinesis, between first and second anaphase, and during microspore prophase. Chromonema elongation between early diakinesis and anaphase is associated with the formation of the major coil and its transition into the relic coil of the microspore prophase is accompanied by a further elongation. The tertiary split results in the half-chromatids being associated in the form of a plectonemic spiral, which persists as such to microspore prophase. The gyres of the plectonemic relic coil become partially straightened out to form a relational coil, whose twists are in the same direction as their antecedent relic coils. During microspore prophase some relational twists are apparently eliminated at intrabrachial changes of direction, others by contraction and untwisting of the chromatids.Changes of direction fall into three categories: (1) those associated with attachments, (2) those associated with chiasmata, and (3) the remainder, the frequency of which is proportional to the number of gyres. Intrabrachial changes of direction are more numerous in microspore prophase than in root tip chromosomes, presumably because Factor (2) is inoperative in the latter. There are very few data that could possibly be taken to indicate that chromosomes may have an inherent directional pattern of coiling.To the tentative hypothesis of Wilson and Huskins that the major coil of meiosis is formed by an elongation of the chromonema within a restricted space, the pellicle, the following may be added: the half-chromatids at metaphase are wound in the form of a plectonemic spiral. The straightening out of this spiral results in the relationally twisted chromatids of microspore prophase. These twists are eliminated both by cancellation at the points at which changes of direction have occurred in the major coil and also by contraction and untwisting of the chromatids.

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“…Several authors (Kaufmann, l926a;Koshy, 193? ;Naithani, 1937;Kuwada, 1939) have suggested that the chromatids (of mitosis) are twisted at the time of their inception.…”

Section: Discussionmentioning

confidence: 99%

Section: Theories Of Spiralizationmentioning

confidence: 99%

Section: Theories Of Spiralizationmentioning

confidence: 99%

Section: From a Study Of Relic And Relational Coiling Inmentioning

confidence: 99%

See 2 more Smart Citations

STUDIES ON THE CHROMOSOME SPIRALIZATION CYCLE INTRILLIUM

Sparrow¹,

Huskins²,

Wilson³

1941

Can. J. Res.

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“…Bei einigen ausgepragt typisch "partiell-heterochromatischen" Objekten mit "euchromatischen" Chromosomenenden geringerer Heterochromasie konnen diese infolge del' Darstellungstechnik als scheinbar glatte unstrukturierte Faden erscheinen. So fanden sich im spaten Pachytan von Laya elegans (SCHERZ 1957) (DARLINGTON 1935;NAITHANI 1937;STRAUB 1938;DARLINGTON and UPCOTT 1939;COLEMAN and HILLARY 1941;SWANSON 1942;LINNERT 1955 u. a.…”

Section: Materials Und Methodeunclassified

35. Paul Eberle: Cytologische Untersuchungen an Gesneriaceen II. Die Verkürzung eu‐ und heterochromatischer Chromosomenabschnitte vom Pachytän bis zur Metaphase‐I*

1957

Berichte der Deutschen Botanischen Gesellschaft

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Zusammenfassung . Die Chromosomenverkürzung einiger Gesneriaceen wurde vom späten Pachytän bis zur Diakinese bzw. Metaphase‐I gemessen. Bis zur Metaphase‐I verkürzen sich die Gesamtchromosomen auf 1/16 bis 1/27 ihrer Pachytänwerte; die „heterochromatischen” Abschnitte sind hierbei bis zur Diakinese mit 1/6 bis 1/9, die „euchromatischen” Chromosomenenden mit 1/10 bis 1/23 beteiligt. . Sowohl die „heterochromatischen” Chromosomenabschnitte als auch die „euchromatischen” Enden dieser „partiell‐heterochromatischen” Objekte besitzen dieselbe Längsgliederung in wenige μ lange tatsächlich euchromatische und heterochromtaische Segmente wie die sogenannten „total euchromatischen” Chromosomen. Die Strukturunterschiede der erwähnten Chromosomen bzw. größeren Chromosomenabschnitte sind nur durch ein unterschiedliches Mengenverhältnis dieser eu‐ und heterochromatischen Chromosomenanteile bedingt. . Dieses unterschiedliche Mengenverhältnis und die im späten Leptotän beginnende Chromosomenspiralisation sind die Hauptursache für die den genannten Chromosomen bzw. Chromosomenabschnitten eigenen Verkürzungswerte; diese ab spätem Pachytän gewonnenen Meßwerte umfassen nämlich nur einen Teil der zur Chromosomenverkürzung führenden Spiralisation. . Das Heterochromatin ist Ausgangsort der gesamten, sowohl die heterochromatischen als auch die euchromatischen Segmente umfassenden Chromosomenspiralisation; dessen Menge bestimmt das Außmaß sowie den Beginn der Spiralisation und damit die Endwerte der Chromosomenkontraktion.

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The Behavior of Meiotic Prophase Chromosomes as Revealed Through the Use of High Temperatures

Swanson

1943

American J of Botany

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Chromosome Studies in Hyacinthus orientalis L.

Cited by 15 publications

References 0 publications

STUDIES ON THE CHROMOSOME SPIRALIZATION CYCLE INTRILLIUM

STUDIES ON THE CHROMOSOME SPIRALIZATION CYCLE INTRILLIUM

35. Paul Eberle: Cytologische Untersuchungen an Gesneriaceen II. Die Verkürzung eu‐ und heterochromatischer Chromosomenabschnitte vom Pachytän bis zur Metaphase‐I*

The Behavior of Meiotic Prophase Chromosomes as Revealed Through the Use of High Temperatures

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