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Unusual Aspects of Meiotic and Postmeiotic Chromosomes of Gasteria

Hsu-Chuan Tuan
Botanical Gazette
Vol. 92, No. 1 (Sep., 1931), pp. 45-65
Stable URL: http://www.jstor.org/stable/2471295
Page Count: 23
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Unusual Aspects of Meiotic and Postmeiotic Chromosomes of Gasteria
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Abstract

1. Behavior of normal reduction chromosomes of Gasteria as described by Taylor is cited and summarized. 2. Three types of abnormal meiotic and postmeiotic chromosomes of the same plant are described. One type, represented by closely coiled second metaphase chromosomes, is directly derived from the heterotypic chromosomes by an omission of the first interphase and second prophase. The other type, represented by giant headed chromosomes, is derived from the first metaphase chromosomes through a partial telophasic disorganization. The third type, represented by heavily constricted chromosomes in binucleated cells, is derived from the first metaphase chromosomes through a short lived interphase and breakdown of the nuclear membrane. The constrictions are much exaggerated and resemble the satellites in the somatic chromosomes. 3. The spiral which is involved in the structure of these types is single through the omission of the first interphase and second prophase. 4. Formation of third division chromosomes and 8-celled groups is described. This condition is thus far unique in higher plants. 5. Abnormal diakinetic chromosomes and chromosomes at other stages are able to assume a false resting stage after a brief process of disintegration of the chromatic material. 6. A nucleolus was seen in nuclei with fully developed chromosomes; it was not converted into any of the chromosomal appendages.

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