KARYOLOGICAL STUDIES IN AMORPHOPHALLUS CAMPANULATUS

1970 ◽  
Vol 12 (1) ◽  
pp. 187-196 ◽  
Author(s):  
R. Krishnan ◽  
M. L. Magoon ◽  
K. Vijaya Bai
Keyword(s):  
Differential Staining ◽  
Root Tip ◽  
Pollen Mitosis ◽  
General Morphology ◽  
Chromosomal Complement ◽  
Morphological Criteria ◽  
Two Stages ◽  
Haploid Complement

Karyomorphological studies of Amorphophallus campanulatus Blume (Araceae) were pursued at pachytene and at root tip and pollen mitotic metaphases. The haploid complement (n = 14) at root and pollen mitoses could be categorized under six types including two nucleolar chromosomes. The karyotypes at these two stages were in agreement except for the relative lengths of one of the nucleolar chromosomes. The chromosomes at prophase of pollen mitosis and pachytene were characterized by differential staining. The two nucleolar chromosomes at pollen mitosis and pachytene were similar in general morphology and length relationships. Adopting suitable morphological criteria, the haploid chromosomal complement is identified. Based on this data and other considerations, a polyploid origin for this species was suggested and the urgent need for a comprehensive cytological survey of this genus is stressed.

The Relationship Between Chromosome Volume and Dna Content in Unsquashed Metaphase Cells of Barley, Hordeum Vulgare Cv. Tuleen 346

1982 ◽  
Vol 56 (1) ◽  
pp. 101-111
Author(s):  
M. D. BENNETT ◽  
J. B. SMITH ◽  
J. P. WARD ◽  
R. A. FINCH
Keyword(s):  
Hordeum Vulgare ◽  
Dna Content ◽  
Root Tip ◽  
Hordeum Vulgare L ◽  
Reciprocal Translocations ◽  
Morphological Criteria ◽  
Relative Dna Content ◽  
Sole Criterion ◽  
Mother Cells ◽  
Diploid Cells

The present work used haploid and diploid cells of barley, Hordeum vulgare L. cv. Tuleen 346 (2n = 2x = 14), which has three reciprocal translocations. All seven chromosomes of the haploid set are distinguishable using morphological criteria in Feulgen-stained root-tip squashes seen in the light microscope, as are five of the bivalents at diakinesis. The relative DNA content per bivalent was estimated in pollen mother cells at diakinesis. The results showed that all seven chromosomes or bivalents of Tuleen 346 can be identified using relative DNA content as sole criterion. The absolute and relative volumes of the seven chromosomes were estimated from electron micrographs of serial sections of unsquashed root-tip cells of a haploid. The results show that, using relative chromosome volume as sole criterion, it is highly probable that all seven chromosomes in single unsquashed cells of Tuleen 346 can be correctly identified. Consequently, teats for various non-random spatial arrangements of chromosomes in unsquashed cells of Tuleen 346 using this character to identify the chromosomes should be feasible. There was a very highly significant positive relationship (r>0.99) between relative chromosome volume and mean relative DNA content per chromosome for each cell examined at metaphase of mitosis or meiosis. Thus, some mechanism ensures that the degree of condensation of all seven chromosomes within a cell is usually very similar in Tuleen 346, despite its grossly abnormal karyotype.

THE CHROMOSOMAL COMPLEMENT OF THE YELLOW-CHEEKED VOLE: Microtus xanthognathus (Leach)

1974 ◽  
Vol 16 (2) ◽  
pp. 267-272 ◽  
Author(s):  
V. R. Rausch ◽  
R. L. Rausch
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
Medium Size ◽  
Fundamental Number ◽  
Chromosomal Number ◽  
Chromosomal Complement ◽  
History Of ◽  
Haploid Complement

The karyotype of Microtus xanthognathus (Leach) is described, based on material from one female and one male vole. The diploid chromosomal number was found to be 54, and the fundamental number 62. The metacentric X-chromosome was of medium size and averaged 6.6% of the haploid complement. The designated Y-chromosome was near acrocentric. The specific distinction of M. xanthognathus and Microtus chrotorrhinus (Miller) was confirmed by the recognition of major differences in karyotype and differences in fundamental number. The distributional history of M. xanthognathus is briefly discussed.

scholarly journals In vitro Induction of Banana Autotetraploids by Colchicine Treatment of Micropropagated Diploids

1992 ◽  
Vol 40 (6) ◽  
pp. 887 ◽  
Author(s):  
SD Hamill ◽  
MK Smith ◽  
WA Dodd
Keyword(s):  
In Vitro Selection ◽  
Morphological Characteristics ◽  
Colchicine Treatment ◽  
Shoot Tips ◽  
Cell Permeability ◽  
Root Tip ◽  
Optimum Treatment ◽  
Morphological Criteria ◽  
In Vitro Induction

Alternative breeding strategies, based on colchicine-induced autotetraploids, have been proposed as a means of introducing disease resistance into banana breeding programs. This paper describes techniques for the in vitro induction of banana autotetraploids by the use of colchicine on cultured explants. The technique can be readily applied and large numbers of autotetraploids produced. The optimum treatment involved immersing shoot tips in a 0-5% w/v colchicine solution for 2 h under aseptic conditions. Dimethyl sulfoxide (DMSO) was applied with the colchicine treatments to increase cell permeability and so absorption of colchicine, resulting in the optimum treatment unchanged at 0-5% colchicine, but including the addition of 2% v/v DMSO. Of the shoot tips treated over 30% were induced to the autotetraploid level. Methods for in vitro selection of induced tetraploids from treated diploid plantlets were also developed. Tetraploid plants were more robust with thicker pseudostems, roots and broader leaves than diploids and they could be selected on these morphological characteristics. Mean stomatal lengths of diploid banana plants growing in vitro were significantly smaller (16-0 mum) than the tetraploids (26.9 mum) and were used as a more reliable indicator of ploidy than morphological criteria alone. A root tip squash technique using carbol fuchsin was developed for positive confirmation of ploidy change by chromosome counts- Although chimerism and reversion to the diploid form occurred, it was not considered a problem because of the large number of autotetraploids induced. Stable autotetraploids were recovered and established in the field and were characterised by their large, drooping leaves and thick pseudostems. They have retained these characteristics for more than 3 years in the field.

Chromosome pairing failure in an intersectional amphiploid of Bromus altissimus × B. arvensis

1985 ◽  
Vol 27 (6) ◽  
pp. 705-709 ◽  
Author(s):  
K. C. Armstrong
Keyword(s):  
Chromosome Pairing ◽  
Embryo Culture ◽  
Differential Staining ◽  
Root Tip ◽  
Giemsa Banding ◽  
Homologous Pairing ◽  
Hybrid Nature ◽  
Tip Cells ◽  
Root Tip Cells

An intersectional F1 hybrid between Bromus arvensis and B. altissimus was made with the aid of embryo culture. The hybrid nature of the F1 and the amphiploid were confirmed by karyotyping root-tip cells. Following Giemsa banding, the chromosomes of B. arvensis stained darker than those of B. altissimus. Very little chromosome pairing was observed in the F1 hybrid (11.60 I + 1.08 II + 0.10 III). Chromosome pairing in the amphiploid (2n = 28) varied from almost complete pairing to very little pairing in different samples. The chromosome pairing indicated that very little homology exists between the genomes of B. altissimus and B. arvensis. Pairing failure in the amphiploid may result from the action of pairing control genes which are strong enough to prevent homologous pairing but which are variable in expression because of a sensitivity to endogenous and exogenous factors.Key words: Bromus, amphiploid, chromosome pairing, differential staining.

DETERMINATION OF CELL CYCLE IN PLANTS USING BrdU-FPG

1980 ◽  
Vol 22 (2) ◽  
pp. 305-308 ◽  
Author(s):  
Kirby J. Evans ◽  
W. Gary Filion
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Cycle Time ◽  
Differential Staining ◽  
Root Tip ◽  
Cell Cycle Time ◽  
Sister Chromatids ◽  
Vicia Faba L ◽  
Established Cell

The BrdU-FPG method for differential staining of sister chromatids was employed to estimate the cell cycle time in two plants species. The protocol is based upon the ability to differentiate cytologically between chromosomes which have completed two or three DNA synthesis phases. Vicia faba L. which has a well established cell cycle time was used to verify the technique. Utilizing this method the cell cycle time of Zebrina pendula Schnizl. root tip meristem cells was determined to be 17.0 hours.

The spatial order of chromosomes in root-tip metaphases of Aegilops umbellulata

1983 ◽  
Vol 218 (1211) ◽  
pp. 225-239 ◽  
Keyword(s):  
Electron Micrographs ◽  
Computer Analysis ◽  
Spatial Association ◽  
Metaphase Plate ◽  
Three Dimensions ◽  
Root Tip ◽  
Thin Sections ◽  
Homologous Chromosomes ◽  
Aegilops Umbellulata ◽  
Morphological Criteria

Twelve root-tip metaphase cells of the diploid grass Aegilops umbellulata Zhuk. (2 n = 2 x = 14) were reconstructed in three dimensions from electron micrographs of serial thin sections. In ten of these cells each individual chromosome in the nuclei was identified by morphological criteria. No evidence for somatic association of centromeres of homologous chromosomes was found. However, with use of computer analysis, evidence was found suggesting: (i) that the centromeres are not arranged randomly on the metaphase plate but are ordered in two haploid sets; and (ii) that the order within each set is that predicted by a model based on spatial association of pairs of corresponding arms of most similar size on heterologous chromosomes.

Altered Fine Structure of B Lymphocytes Correlated with Defective Terminal Differentiation

1973 ◽  
Vol 31 ◽  
pp. 386-387
Author(s):  
Dale E. Bockman ◽  
L. Y. Frank Wu ◽  
Alexander R. Lawton ◽  
Max D. Cooper
Keyword(s):  
Immune Deficiency ◽  
B Lymphocytes ◽  
Plasma Cells ◽  
Present Report ◽  
Specific Antigen ◽  
Terminal Differentiation ◽  
Second Stage ◽  
Two Stages ◽  
Deficiency Diseases ◽  
Cell Line Generation

B-lymphocytes normally synthesize small amounts of immunoglobulin, some of which is incorporated into the cell membrane where it serves as receptor of antigen. These cells, on contact with specific antigen, proliferate and differentiate to plasma cells which synthesize and secrete large quantities of immunoglobulin. The two stages of differentiation of this cell line (generation of B-lymphocytes and antigen-driven maturation to plasma cells) are clearly separable during ontogeny and in some immune deficiency diseases. The present report describes morphologic aberrations of B-lymphocytes in two diseases in which second stage differentiation is defective.

A Study of the Ultrastructure of Visual Cell Outer Segment Membranes, Using a Water-Miscible Embedding Medium and Differential Staining

1972 ◽  
Vol 30 ◽  
pp. 50-51
Author(s):  
Anthony J. Godfrey
Keyword(s):  
Outer Segment ◽  
Protein Denaturation ◽  
Uranyl Acetate ◽  
Differential Staining ◽  
Visual Cell ◽  
Lead Citrate ◽  
Chick Retina ◽  
Dark Staining ◽  
Embedding Medium ◽  
The Individual

Aldehyde-fixed chick retina was embedded in a water-containing resin of glutaraldehyde and urea, without dehydration. The loss of lipids and other soluble tissue components, which is severe in routine methods involving dehydration, was thereby minimized. Osmium tetroxide post-fixation was not used, lessening the amount of protein denaturation which occurred. Ultrathin sections were stained with 1, uranyl acetate and lead citrate, 2, silicotungstic acid, or 3, osmium vapor, prior to electron microscope examination of visual cell outer segment ultrastructure, at magnifications up to 800,000.Sections stained with uranyl acetate and lead citrate (Fig. 1) showed that the individual disc membranes consisted of a central lipid core about 78Å thick in which dark-staining 40Å masses appeared to be embedded from either side.

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