Meiotic abnormalities of Vaccinium ashei × Vaccinium darrowi hybrids

1984 ◽  
Vol 26 (2) ◽  
pp. 146-151 ◽  
Author(s):  
R. G. Goldy ◽  
P. M. Lyrene
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
Interspecific Hybridization ◽  
Unreduced Gametes ◽  
Meiotic Abnormalities ◽  
Vaccinium Ashei ◽  
Nucleolar Organizing Regions ◽  
Vaccinium Darrowi ◽  
Mother Cells ◽  
Base Chromosome Number

Meiosis was studied in pollen mother cells of three Vaccinium ashei (2n = 6x = 72) × Vaccinium darrowi (2n = 2x = 24) hybrids. Numerous irregularities were found, including 60 somatic chromosomes instead of the expected 48, two synezetic knots, two nucleolar organizing regions, lagging chromosomes at anaphase I and II, nonassociating chromosomes, meiotic asynchrony, micronuclei at telophase I and II, misaligned spindles, extra nucleoli, increased percentage of unreduced gametes, incomplete tetrads, and polyspory. Lagging chromosomes at anaphase I did not appear as univalents, but as bivalents. This suggests a base chromosome number for Vaccinium of x = 6, not x = 12.Key words: Vaccinium ashei, rabbiteye blueberry, Vaccinium darrowi, interspecific hybridization, cytogenetics, meiosis.

Persisting demibivalents: a unique meiotic behaviour in Cuscuta babylonica Choisy

Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 63-66 ◽  
Author(s):  
Batia Pazy ◽  
Uzi Plitmann
Keyword(s):  
Key Words ◽  
Chromosome Segregation ◽  
Meiotic Behaviour ◽  
Chromosome Behaviour ◽  
Chromosome Movement ◽  
Pollen Mother Cells ◽  
Key Words Meiosis ◽  
Mother Cells ◽  
Telomeric Association

Idiosyncratic chromosome behaviour during meiosis was found in pollen mother cells of Cuscuta babylonica Choisy, a thread-like holoparasitic herb. Its main features are among the following: (i) telomeric association between homologues through most stages of the process, which leads to persisting chromatid bivalents (= "demibivalents"); (ii) uncommon chromosome segregation in first and second anaphase; and (iii) prolonged intensified heterochromatinization. Although "regular" in its own way, this process leads to the formation of unviable products. Its further investigation might contribute to our understanding of the role of the spindle and chromosome movement in the ordinary process of meiosis. Key words: meiosis (abnormal), persisting demibivalents, Cuscuta babylonica.

scholarly journals A taxonomic revision of the genus Cleome L. (Capparaceae) in Bangladesh

1970 ◽  
Vol 14 (1) ◽  
pp. 25-36
Author(s):  
Hosne Ara ◽  
Bushra Khan ◽  
Md. Mansur-ul-Kadir Mia
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
Geographical Distribution ◽  
Taxonomic Revision ◽  
Economic Importance ◽  
Plant Taxon

The available record of the genus Cleome L. for Bangladesh has been updated in this paper and includes C. diffusa, C. gynandra, C. hassleriana, C. rutidosperma and C. viscosa. The updating has been done in case of nomenclature with important synonyms, local names, description of the taxa along with illustrations, flowering and fruiting times, ecological notes, specimens examined and their geographical distribution. For identification of the species, a dichotomous bracketed key has been added in this paper. Information on chromosome number and economic importance have also been provided where available. Key words: Cleome, Taxonomic revision, Capparaceae, Bangladesh DOI: 10.3329/bjpt.v14i1.520 Bangladesh J. Plant Taxon. 14(1): 25-36, 2007 (June)

scholarly journals B chromosome in Plantago lagopus Linnaeus, 1753 shows preferential transmission and accumulation through unusual processes

2017 ◽  
Vol 11 (2) ◽  
pp. 375-392 ◽  
Author(s):  
Manoj K. Dhar ◽  
Gurmeet Kour ◽  
Sanjana Kaul
Keyword(s):  
B Chromosome ◽  
Unreduced Gametes ◽  
Molecular Techniques ◽  
Root Tip ◽  
Genetic Constitution ◽  
Preferential Transmission ◽  
Female Sex ◽  
Process Formation ◽  
Plantago Lagopus ◽  
Mother Cells

Plantagolagopus is a diploid (2n = 2x =12) weed belonging to family Plantaginaceae. We reported a novel B chromosome in this species composed of 5S and 45S ribosomal DNA and other repetitive elements. In the present work, presence of B chromosome(s) was confirmed through FISH on root tip and pollen mother cells. Several experiments were done to determine the transmission of B chromosome through male and female sex tracks. Progenies derived from the reciprocal crosses between plants with (1B) and without (0B) B chromosomes were studied. The frequency of B chromosome bearing plants was significantly higher than expected, in the progeny of 1B female × 0B male. Thus, the B chromosome seems to have preferential transmission through the female sex track, which may be due to meiotic drive. One of the most intriguing aspects of the present study was the recovery of plants having more chromosomes than the standard complement of 12 chromosomes. Such plants were isolated from the progenies of B chromosome carrying plants. The origin of these plants can be explained on the basis of a two step process; formation of unreduced gametes in 1B plants and fusion of unreduced gametes with the normal gametes or other unreduced gametes. Several molecular techniques were used which unequivocally confirmed similar genetic constitution of 1B (parent) and plants with higher number of chromosomes.

Cytogenetic studies of leafy spurge, Euphorbia esula, and its allies (Euphorbiaceae)

1988 ◽  
Vol 66 (11) ◽  
pp. 2247-2257 ◽  
Author(s):  
A. E. Stahevitch ◽  
C. W. Crompton ◽  
W. A. Wojtas
Keyword(s):  
Seed Germination ◽  
Chromosome Number ◽  
Natural Populations ◽  
Leafy Spurge ◽  
Euphorbia Esula ◽  
Meiotic Abnormalities ◽  
Stability Studies ◽  
Polymorphic Species ◽  
Cytogenetic Studies ◽  
Euphorbia Cyparissias

Cytological and cytogenetic studies were carried out on populations of leafy spurge (Euphorbia esula L. s.l.) and its allies primarily from North America but also from Europe. Chromosome numbers were determined for 126 samples of E. esula, 11 of E. cyparissias L., 1 of the hybrid (E. ×pseudoesula Schur) between these two species, and 1 of E. agraria Bieb. All plants of E. esula were hexaploid. Of the total, 125 leafy spurge accessions had a chromosome number of n = 30; 1 of n = 25++. Very few meiotic abnormalities were observed. Euphorbia cyparissias was primarily tetraploid (n = 20), although occasional diploids (n = 10) were encountered. Tetraploids were fertile; diploids were sterile. The hybrid between the two foregoing species had a chromosome number of n = 25, indicating that the E. cyparissias parent was a tetraploid; meiosis in the hybrid was abnormal. Euphorbia agraria was found to have a gametic number of n = 20, which is the first chromosome number determination for this species; meiosis was normal. Artificial crosses were made successfully between 31 accessions of leafy spurge. Seed germination of the F1 progeny slightly exceeded that reported for natural populations, and meiosis was normal. Pollen stability studies were carried out on herbarium material. Stainability was 100% for most of the samples studied. Extensive pollen size polymorphism was found. It is suggested that this phenomenon supports the hypothesis that E. esula is of allopolyploid origin. No cytological or cytogenetic basis was found for considering the leafy spurge accessions examined in this study as other than as a single, albeit somewhat polymorphic, species.

Meiotic chromosome behaviour in Cenchrus ciliaris

Bothalia ◽  
1998 ◽  
Vol 28 (1) ◽  
pp. 83-90 ◽  
Author(s):  
N. C. Visser ◽  
J. J. Spies
Keyword(s):  
Chromosome Number ◽  
Meiotic Chromosome ◽  
Basic Chromosome Number ◽  
Chromosome Behaviour ◽  
Meiotic Abnormalities ◽  
Single Specimen ◽  
Cenchrus Ciliaris ◽  
Basic Chromosome ◽  
Single Genome ◽  
Meiotic Irregularities

A basic chromosome number of x = 9 has been confirmed for Cenchrus ciliaris L. Polyploidy is common and levels vary from tetraploid to hexaploid. Aneuploidv is reported for a single specimen, where two chromosomes of a single genome were lost. Various meiotic irregularities were observed. The highest incidence of meiotic abnormalities was observed in the pentaploid specimens. This was attributed to their uneven polyploid level All specimens varied from segmental alloploid to alloploid.

Changes in DNA content and chromosome number during spermatogenesis in the gall midge Monarthropalpus buxi (Cecidomyiidae, Diptera)

Genome ◽  
1992 ◽  
Vol 35 (2) ◽  
pp. 244-250 ◽  
Author(s):  
B. Jazdowska-Zagrodzinska ◽  
R. Dallai ◽  
C. A. Redi
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
Meiotic Division ◽  
Dna Content ◽  
Germ Line ◽  
Gall Midge ◽  
Key Words Dna ◽  
Further Development

In this paper we analyze the course of spermatogenesis in Monarthropalpus buxi. The first meiotic division occurs without any chromosomes pairing. As a result one spermatocyte II appears from which two sperms originate, and one residual cell, which does not undergo any further division. We found variations in chromosome number and DNA content between germ line cells of different individuals. Such variations were observed in the spermatocytes I and II, and in the sperms. In contrast, the residual cells, which did not take part in further development, always had the same DNA content and constantly inherited 20 chromosomes: 4 constituting one haploid set of the somatic type (S chromosomes) and 16 of the germ line limited type (E chromosomes).Key words: DNA content, chromosome number, Cecidomyiidae, germ line, spermatogenesis.

Karyotypes of Leptarrhena and Tanakaea (Saxifragaceae)

1984 ◽  
Vol 62 (4) ◽  
pp. 671-673 ◽  
Author(s):  
Douglas E. Soltis
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Chromosomal Evolution ◽  
Conservative Nature ◽  
Chromosomal Data ◽  
Base Chromosome Number ◽  
Flavonoid Chemistry

In an attempt to clarify subtribal relationships in tribe Saxifrageae, chromosome numbers and karyotypes were determined for the two species comprising subtribe Leptarrheninae: Leptarrhena pyrolifolia and Tanakaea radicans. In both species 2n = 14, a common chromosome number throughout Saxifrageae. The two species have distinctive karyotypes that appear to differ in the centromeric positions of three pairs of chromosomes. These findings, in conjunction with earlier studies, demonstrate that genera of Saxifrageae often differ karyotypically. Leptarrhena exhibits considerable karyotypic similarity to genera of subtribe Saxifraginae characterized by a base chromosome number of x = 7. Chromosomal data, therefore, do not clearly differentiate subtribes Saxifraginae and Leptarrheninae. This observation is in agreement with evidence from paly-nology and flavonoid chemistry. Karyotypic studies continue to demonstrate the conservative nature of chromosomal evolution in tribe Saxifrageae.

scholarly journals Karyotype analysis with orcein and CMA in two species of Alocasia (Schott) G. Don (Araceae)

1970 ◽  
Vol 40 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Syeda Sharmeen Sultana ◽  
Hosne Ara ◽  
Sheikh Shamimul Alam
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
Karyotype Analysis ◽  
Chromosome Complement ◽  
Taxonomic Status ◽  
The Other ◽  
First Report ◽  
Total Length ◽  
Internet Information ◽  
Chromosomal Length

Alocasia fallax Schott and A. odora (Roxb.) Koch (Araceae) were investigated cytogenetically to confirm their taxonomic status. There is no report of 2n chromosome number for A. fallax in the available literature and internet information. Therefore the 2n chromosome number (2n = 28) found in this study is probably the first report for A. fallax. Alocasia odora showed exactly double 2n chromosome number (2n = 56) from A. fallax. In addition to chromosome number, the other karyotypic features of A. odora were exactly double for that of A. fallax. The centromeric formulae of A. fallax was 24 m + 4 sm whereas it is just double in A. odora. Total length of 2n chromosome complement of A. odora (62.58 μm) was almost double to A. fallax. The range of chromosomal length of the two species was almost same. Moreover, A. odora plant is much taller than A. fallax. All of these data suggests that A. odora might be an autotetraploid of A. fallax which in course of evolution had undergone some changes in GC-rich repeats. Key words: Alocasia; CMA; Karyotype analysis DOI: http://dx.doi.org/10.3329/bjb.v40i1.7998 Bangladesh J. Bot. 40(1): 53-56, 2011 (June)

Variation in pollen wall ultrastructure in New World Senecioneae (Asteraceae), with special reference to Packera

1997 ◽  
Vol 75 (5) ◽  
pp. 730-735 ◽  
Author(s):  
J. F. Bain ◽  
B. S. Tyson ◽  
D. F. Bray
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chromosome Number ◽  
Special Reference ◽  
New World ◽  
Pollen Wall ◽  
Wall Structure ◽  
Transmission Electron ◽  
Wall Ultrastructure ◽  
Base Chromosome Number

The structure of the pollen wall as revealed by transmission electron microscopy is presented for 34 species representing two subtribes and 12 genera of New World Senecioneae. The genus Packera (=aureoid Senecio), with the exception of Packera zimapanica, is characterized by the helianthoid wall structure. In light of these results, the disposition of the latter species requires review. The genera Robinsonecio and Telanthophora of the subtribe Tussilagininae also possess helianthoid pollen. All other taxa surveyed have senecioid pollen. So far as known no taxa exist within the tribe Senecioneae with a base chromosome number of n = 20 and helianthoid pollen. This suggests that the evolution of Packera may have involved hybridization between members of the two subtribes Senecionineae and Tussilagininae. Key words: Asteraceae, Packera, Senecioneae, pollen, TEM, systematics.

scholarly journals Cytomixis and Associated Meiotic Abnormalities in Pollen Mother Cells of Chlorophytum tuberosum (Roxb.) Baker

CYTOLOGIA ◽  
2013 ◽  
Vol 78 (2) ◽  
pp. 157-162 ◽  
Author(s):  
Gopal Dev Mandal ◽  
Asis Kumar Nandi ◽  
Anath Bandhu Das
Keyword(s):  
Meiotic Abnormalities ◽  
Pollen Mother Cells ◽  
Mother Cells
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