scholarly journals Colchicine induced manifestation of abnormal male meiosis and 2n pollen in Trachyspermum ammi (L.) Sprague (Apiaceae)

Caryologia ◽  
2021 ◽  
Author(s):  
Harshita Dwivedi
Keyword(s):  
Morphological Analysis ◽  
Male Meiosis ◽  
Unreduced Gametes ◽  
2N Pollen ◽  
Cytological Analysis ◽  
Cytological Investigation ◽  
Drug Induced ◽  
Meiotic Restitution ◽  
Trachyspermum Ammi ◽  
Meiotic Aberrations

Unreduced gametes are the key source for the natural polyploidization in plants, but process of its formation is very low in nature. Meiotic mutants are second source for the formation of 2n pollen. In this cytological investigation, the meiotic aberrations and its impact on post-meiotic products were analysed in autotetraploid Trachyspermum ammi (L.) Sprague (4n=36). The seedlings of T. ammi (L.) Sprague were treated with 3 different concentrations of colchicine (0.2, 0.4 and 0.5%, w/v) for 3 different durations. Six polyploid plants were induced which was confirmed on the basis of cytological analysis. Colchicine, an anti-microtubular drug induced different meiotic and post-meiotic abnormalities such as chromosomal bridges, lagging chromosomes, scattering, precocious, fragments, dyads, triads, and polyads. The formation of several abnormal sporads clearly signifies the meiotic restitution. The tendency of univalents to scattered in the cytoplasm at metaphase was identified as a peculiar aberration asynapsis. Pollen variability and fusion of pollen walls was reported and pollen fertility was calculated. The morphological analysis of the pollen allowed us to confirm the occurrence of 2n pollen.

scholarly journals Meiotic restitution mechanisms involved in the formation of 2n pollen in Agave tequilana Weber and Agave angustifolia Haw

SpringerPlus ◽  
2012 ◽  
Vol 1 (1) ◽  
pp. 17 ◽  
Author(s):  
Víctor Gómez-Rodríguez ◽  
Benjamín Rodríguez-Garay ◽  
Rodrigo Barba-Gonzalez
Keyword(s):  
Agave Tequilana ◽  
2N Pollen ◽  
Meiotic Restitution ◽  
Agave Angustifolia

Meiotic aberrations during 2n pollen formation in Begonia

Heredity ◽  
2009 ◽  
Vol 104 (2) ◽  
pp. 215-223 ◽  
Author(s):  
A Dewitte ◽  
T Eeckhaut ◽  
J Van Huylenbroeck ◽  
E Van Bockstaele
Keyword(s):  
2N Pollen ◽  
Pollen Formation ◽  
Meiotic Aberrations

scholarly journals Karyotype Reorganization in Wheat–Rye Hybrids Obtained via Unreduced Gametes: Is There a Limit to the Chromosome Number in Triticale?

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2052
Author(s):  
Olga G. Silkova ◽  
Yulia N. Ivanova ◽  
Dina B. Loginova ◽  
Lilia A. Solovey ◽  
Elena A. Sycheva ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Unreduced Gametes ◽  
Frequency Of Occurrence ◽  
Robertsonian Translocations ◽  
Meiotic Restitution ◽  
Group 3 ◽  
Group 2 ◽  
Few Data ◽  
Diploid Gametes ◽  
Group 1

To date, few data have been accumulated on the contribution of meiotic restitution to the formation of Triticum aestivum hybrid karyotypes. In this study, based on FISH and C-banding, karyotype reorganization was observed in three groups of F5 wheat–rye hybrids 1R(1A) × R. Aberrations, including aneuploidy, telocentrics, and Robertsonian translocations, were detected in all groups. Some of the Group 1 plants and all of the Group 2 plants only had a 4R4R pair (in addition to 1R1R), which was either added or substituted for its homeolog in ABD subgenomes. In about 82% of meiocytes, 4R4R formed bivalents, which indicates its competitiveness. The rest of the Group 1 plants had 2R and 7R chromosomes in addition to 1R1R. Group 3 retained all their rye chromosomes, with a small aneuploidy on the wheat chromosomes. A feature of the meiosis in the Group 3 plants was asynchronous cell division and omission of the second division. Diploid gametes did not form because of the significant disturbances during gametogenesis. As a result, the frequency of occurrence of the formed dyads was negatively correlated (r = −0.73) with the seed sets. Thus, meiotic restitution in the 8n triticale does not contribute to fertility or increased ploidy in subsequent generations.

Anther culture of a 2n pollen producing clone of Solanum phureja Juz. &Buk.

1985 ◽  
Vol 27 (5) ◽  
pp. 559-564 ◽  
Author(s):  
R. E. Veilleux ◽  
J. Booze-Daniels ◽  
E. Pehu
Keyword(s):  
Anther Culture ◽  
Polyacrylamide Gel Electrophoresis ◽  
Pollen Grains ◽  
Unreduced Gametes ◽  
Solanum Phureja ◽  
2N Pollen ◽  
Regenerated Plants ◽  
Series Of Experiments ◽  
Pollen Formation ◽  
First And Second Generation

In a series of experiments, a total of 95 plants were regenerated from culture of 1416 anthers of a single genotype (PP5) of Solanum phureja that expressed a variable frequency of 2n pollen by the genetic equivalent of first division restitution. The regenerated plants included 29 monoploids (2n = x = 12), 58 diploids (2n = 2x = 24) and 8 tetraploids (2n = 4x = 48). Monoploids carrying the potential for 2n pollen formation are central to the development of a breeding scheme to construct highly heterozygous diplandroids. Segregation of tuber flesh color and tuber protein bands revealed by polyacrylamide gel electrophoresis in first and second generation anther-derived diploid plants provided evidence for both embryogenesis of 2n pollen as well as doubling of monoploid genomes as sources of anther-derived diploids. Because of variation for the same genetic markers in anther-derived tetraploids, sources other than embryogenesis of doubly restituted (4n) pollen grains were implied. An enhanced response to anther culture was noted in some anther-derived dihaploids.Key words: unreduced gametes, potato, anther culture, diplandroid, monoploid.

Cytological analysis of the male meiosis inPeriplaneta americana

1959 ◽  
Vol 56 (2) ◽  
pp. 281-287 ◽  
Author(s):  
G. P. Sharma ◽  
Ram Parshad ◽  
Prem Sehgal
Keyword(s):  
Male Meiosis ◽  
Cytological Analysis

scholarly journals Cloning and Expression of Omission of Second Division-like Genes from Carnation

2017 ◽  
Vol 142 (6) ◽  
pp. 425-433
Author(s):  
Xuhong Zhou ◽  
Xijun Mo ◽  
Yalian Jiang ◽  
Hao Zhang ◽  
Rongpei Yu ◽  
...  
Keyword(s):  
Expression Patterns ◽  
Dianthus Caryophyllus ◽  
Male Meiosis ◽  
Cloning And Expression ◽  
Ovary Development ◽  
Pcr Analysis ◽  
2N Pollen ◽  
Potential Applications ◽  
High Level ◽  
Stage 1

The omission of second division gene (OSD1) gene plays a fundamental role in meiosis and is associated with 2n gamete formation in Arabidopsis thaliana. The objective of this work was to unravel the mechanisms leading to 2n pollen production, and isolate and analyze the expression patterns of OSD-like (OSDL) genes in carnation (Dianthus caryophyllus). We found an absence of the second meiotic division caused the formation of 2n pollen. Three homoeologous genes were cloned and labeled as OSDLa, OSDLb, and OSDLc in a diploid carnation. The cDNAs were 1180 bp for OSDLa, 1288 bp for OSDLb, and 971 bp for OSDLc. A strong similarity was found between the amino sequences of OSDLb and OSDLc. An evident feature of OSDLs proteins is the presence of D-box and MR-tail domains; however, the GxEN/KEN-box domain, which is distinct among the other plant proteins was absent. Quantitative real time polymerase chain reaction (qRT-PCR) analysis showed that OSDL genes maintain continuous expression in buds and other tissues. OSDLa has the highest expression in buds of 1.1–1.2 cm long (stage 2), and OSDLb has a high level of expression in buds of 0.9–1.0 cm long (stage 1) and stage 2 buds and ovary tissues in three carnation cultivars. The expression level of OSDLc was highest in ovaries. These expression patterns strongly suggest that OSDLs in carnation involve male meiosis and ovary development. These findings can have potential applications in fundamental polyploidization research and plant breeding programs in carnation.

scholarly journals Occurrence and cytological mechanism of numerically unreduced pollen in diploid Populus euphratica

2013 ◽  
Vol 62 (1-6) ◽  
pp. 285-291 ◽  
Author(s):  
Pingdong Zhang ◽  
Xiangyang Kang
Keyword(s):  
Indirect Immunofluorescence ◽  
Populus Euphratica ◽  
Unreduced Gametes ◽  
2N Pollen ◽  
Tetrad Stage ◽  
Division Plane ◽  
Parallel Spindles ◽  
Chromosome Staining ◽  
Mother Cells ◽  
Cytological Mechanism

AbstractUnreduced gametes are the driving force for the polyploidizaiton of plants in nature, and are also an important tool for breeding of triploid individuals. The final heterozygosity of a 2n pollen grain depends on the cytological mechanism behind 2n pollen formation. In this study, meiotic abnormalities were analysed using fluorescent chromosome staining and indirect immunofluorescence during the microsporogenesis of 18 genotypes of diploid P. euphratica Oliv. (2n = 2x = 38). Among the 18 genotypes, 16 genotypes produce 2n pollen and two genotypes produce only normal n pollen. In all 2n pollen producers, we found that the first meiotic division was normal but that the second division was characterized by frequent abnormal spindle orientation (parallel, tripolar, and fused spindles) and premature cytokinesis. The parallel, fused spindles and premature cytokinesis were considered to be leading dyad formation, and tripolar spindles seemed to be causing triad formation at the tetrad stage. There was a higher frequency of parallel spindles than other spindle forms, but no significant correlations between parallel spindles and dyads were observed. However, a significant association (r = 0.68, P < 0.05) between the tripolar spindles and dyads was found. In some Microspore mother cells (MMCs), an indirect immunofluorescence examination of meiosis II revealed that the parallel spindles led to the gathering of one or two non-sister groups of chromosomes, causing an incorporation of RMSs from two daughter nuclei. Therefore, the incorporated RMSs established two nuclear cytoplasmic domains for the control of division plane, resulting in either triad or dyad formation.

A CYTOGENETICAL ANALYSIS OF STERILE MUTANTS IN CAENORHABDITIS ELEGANS

1980 ◽  
Vol 22 (3) ◽  
pp. 391-403 ◽  
Author(s):  
Nicole Mounier ◽  
Jean Brun
Keyword(s):  
Caenorhabditis Elegans ◽  
Oocyte Maturation ◽  
Chromosome Pairing ◽  
Male Meiosis ◽  
Cytological Analysis ◽  
Wild Type ◽  
Nematode Caenorhabditis Elegans ◽  
The Third ◽  
Homozygous Mutant ◽  
Cytogenetical Analysis

The regulation of gametogenesis in the hermaphrodite and proterandrous nematode Caenorhabditis elegans is introduced here through the analysis of nonconditional sterile mutants. To investigate the mechanisms which allow the two gametogenetic phases to succeed each other in the same ovotestis, three mutants were studied cytogenetically. Two of the mutants exhibit only the spermatocyte phase and the third shows a greatly reduced and disturbed oogenesis. These three mutations all produce large decreases in ovotestis size and gonocyte number. Each of the three is monofactorial, recessive, autosomal and independent. Homozygous mutant males are also sterile. The gametogenesis phases which could be disturbed by mutation were determined by cytological analysis of the ovotestis of 12 other sterile strains. These phases occur during mitotic divisions of the genital primordium, zygotene chromosome pairing, male meiosis and spermiogenesis, oogenesis induction and oocyte maturation. These steps of gametogenesis need a wild-type genie activity to occur normally. It appears that spermatogenesis and oogenesis are two genetically independent processes, and that oogenesis is rather autonomous and its induction would depend on a hormonal factor.

scholarly journals Meiotic Aberrations Leading To Aneuploidy In Cauliflower (Brassica Oleracea L. var. Botrytis)

2021 ◽  
Author(s):  
Xianwen Ji ◽  
Cilia Lelivelt ◽  
Erik Wijnker ◽  
Hans de Jong
Keyword(s):  
Brassica Oleracea ◽  
Chromosome Pairing ◽  
Tandem Repeats ◽  
Chiasma Formation ◽  
Male Meiosis ◽  
Genetic And Environmental Factors ◽  
Mother Cells ◽  
Selection Of ◽  
Meiotic Aberrations ◽  
Metaphase I

Abstract Aneuploid cauliflower plants (Brassica oleracea L. var. botrytis) display abnormal curd phenotypes causing serious commercial problems in offspring populations. Despite extensive breeding efforts, selection of genotypes producing euploid gametes remains unsuccessful due to unknown genetic and environmental factors. To reveal the origin of aneuploid gametes, we analyzed chromosome pairing, chiasma formation and chromosome segregation in pollen mother cells of selected cauliflower genotypes. To this end we compared different genotypes exhibiting Low with < 5%, Moderate with 5-10% and High with > 10% aberrant offspring. Microscopic observations revealed regular chromosome pairing at pachytene. However, cells at diakinesis and metaphase I showed variable numbers of univalents, suggesting that chiasma formation during meiotic prophase is incomplete or disrupted and results in a partial desynaptic phenotype. Cells at anaphase I – telophase II exhibited various degrees of unbalanced chromosome numbers explaining the aneuploid offspring. Immunofluorescence probed with an MLH1 antibody demonstrated fluorescent foci in all genotypes, but their lower numbers do not correspond to the putative sites of chiasmata. Interchromosomal connections between chromosomes and bivalents are common at diakinesis and metaphase I, and they contain centromeric and 45S rDNA tandem repeats, but such threads seemed not to affect proper disjoin of the half bivalents at anaphase I. Moreover, male meiosis in the arabidopsis APETALA1/ CAULIFLOWER double mutant with the typical cauliflower phenotype did show interchromosomal connections, but there were no indications for partial desynapsis. We now hypothesize that the occurrence of desynapsis in cauliflower is a developmental out-of-phase phenomenon partially or completely controlled by genes involved in flower and curd development.

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