Persistent occurrence of meiotic abnormalities in a new hexaploid cytotype of Thalictrum foetidum from Indian cold deserts

Biologia ◽  
2011 ◽  
Vol 66 (3) ◽  
Author(s):  
Vijay Singhal ◽  
Pawan Rana ◽  
Puneet Kumar ◽  
Dalvir Kaur
Keyword(s):  
Meiotic Chromosome ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Plant Size ◽  
Pollen Sterility ◽  
Male Meiosis ◽  
Meiotic Abnormalities ◽  
Leaf Pubescence ◽  
Karyotypic Analysis ◽  
In The Wild

AbstractThalictrum foetidum L. (Ranunculaceae), a morphologically variable and widely distributed species of temperate and alpine Himalayas is worked out cytologically for the first time from India. Earlier studies from outside India were restricted to chromosome counts and karyotypic analysis. We studied the male meiosis, microsporogenesis and pollen viability in the wild accessions from the cold deserts of Lahaul-Spiti, Kinnaur and Pangi Valley of Himachal Pradesh. Present cytomorphological surveys in the species record the existence of two distinct morphotypes involving plant size; colour and size of leaf/leaflet; dentation of leaflet lobes; and degree of leaf pubescence. All the accessions in the two morphovariants share the same meiotic chromosome number (n = 21) and adds a new intraspecific hexaploid cytotype. The accessions show the phenomenon of cytomixis involving transfer of chromatin material among proximate pollen mother cells (PMCs) and associated meiotic abnormalities like, out of plate bivalents, interchromosomal connections, and laggards, bridges and micronuclei at anaphases/telophases. Microsporogenesis results into abnormal sporads (tetrads with micronuclei, dyads, triads and polyads). The products of such sporads resulted into some pollen sterility and pollen grains of heterogeneous sizes. The persistent occurrence of phenomenon of cytomixis and associated meiotic abnormalities and consequently pollen sterility and pollen grains of heterogeneous sizes in the hexaploid cytotype of T. foetidum seems to be under some genetic factors associated with the genome.

scholarly journals Meiotic behaviour and pollen fertility of F1, F2 and BC1 progenies of Iris dichotoma and I. domestica

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wenji Xu ◽  
Gangjun Luo ◽  
Xiaoyin Lian ◽  
Fengyang Yu ◽  
Yang Zheng ◽  
...  
Keyword(s):  
Pollen Fertility ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Male Meiosis ◽  
Meiotic Behaviour ◽  
Interspecific Hybridisation ◽  
Meiotic Abnormalities ◽  
Chromosome Bridges ◽  
First Time ◽  
Spindle Fibres

Abstract Pollen characteristics are very important for Iris interspecific hybridisation. In this study, the pollen viability and male meiosis were studied in yellow-flowered Iris dichotoma (Y2), I. domestica (S3) and their hybrids F1, F2 and BC1 (BC1-Y and BC1-S). The BC1-Y hybrids showed higher pollen viability than that of F1, F2 and BC1-S hybrids, which were between I. dichotoma (26.1%) and I. domestica (35.1%). Two sterile hybrids, F2-1 and BC1-S-1, exhibited more meiotic abnormalities (57.3% and 58.7%) than other individuals. During the first meiotic division, a diffuse diplotene stage was observed for the first time in the genus Iris. The meiotic abnormalities included non-congressed chromosomes, chromosome bridges, lagging chromosomes, unequal division, abnormally oriented spindle fibres, nonsynchronous division and polyad, and resulted in reduced pollen fertility. The relatively high frequency of 2n pollen grains was found in hybrids of BC1-Y-2, BC1-Y-1, BC1-S-2, BC1-S-3 and BC1-S-4. Our research provides a new resource for meiotic behaviour and pollen fertility of the genus Iris.

Meiotic chromosome behavior of Haworthia limifolia

2016 ◽  
Vol 5 (03) ◽  
pp. 4902
Author(s):  
Afrin Nazli ◽  
Kamini Kumar*
Keyword(s):  
Genetic Recombination ◽  
Meiotic Chromosome ◽  
Pollen Sterility ◽  
Meiotic Abnormalities ◽  
Chromosome Behavior ◽  
The Family ◽  
Medicinal Properties ◽  
Fruit Formation ◽  
Meiosis I ◽  
Chromosomal Behaviour

Haworthia limifolia is a xerophytic plant belonging to the family Liliaceae and is indigenous to Africa. It is use extensively for its medicinal properties like antibacterial, antifungal properties and used for the treatment of sores, superficial burns, as a blood purifier and to promote pregnancy in women and cattles. In present investigation chromosomal behaviour of H. limifolia in meiosis was studied. In diplotene stage chiasmata was observed showing the possibilities of genetic recombination. Chromosome clumps were observed in diakinesis indicating sticky nature of chromosomes. Meiotic abnormalities like stickiness, precocious movement, formation of bridges and laggards were also reported in both meiosis I and II. A fairly high percentage of pollen sterility that is 73.41% was recorded resulting in failure of fruit formation. This plant could be designated as facultative apomict (Swanson, 1957) as the only means of reproduction found was asexual or vegetative.

scholarly journals Abnormal Microspore Development Leads to Pollen Abortion in a Seedless Mutant of ‘Ougan’ Mandarin (Citrus suavissima Hort. ex Tanaka)

2007 ◽  
Vol 132 (6) ◽  
pp. 777-782 ◽  
Author(s):  
Zhiyong Hu ◽  
Min Zhang ◽  
Qigen Wen ◽  
Jie Wei ◽  
Hualin Yi ◽  
...  
Keyword(s):  
Pollen Viability ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Mature Pollen ◽  
Abnormal Development ◽  
Microspore Development ◽  
Wild Type ◽  
Pollen Abortion ◽  
Tetrad Stage ◽  
In The Wild

Seedlessness is of commercial importance in citrus (Citrus L.). Seedless ‘Ougan’ mandarin (C. suavissima) was selected from a bud sport mutation that occurred in ‘Ougan’ mandarin. We analyzed their pollen viability through KI-I2 and FDA staining, and examined the anthers of wild-type (seedy) and seedless mutant ‘Ougan’ mandarin using histological and cytochemical methods to characterize the process of pollen development. No pollen fertility was detected in this mutant. Pollen abortion in anthers of the mutant occurred at the tetrad stage of microspore development, and almost all the tetrads were abnormal. The mutant had heterogeneous microspore populations, including monads, dyads, triads, tetrads, and polyads in the same microsporangium. Pollen grain number per anther of the mutant was 21.9% less than the wild type. Morphology of mature pollen grains using SEM showed that the shape of mature pollen grains from both wild type and mutant is similar, but the microsporangia of the latter contained pollen grains of more variable sizes. At the early mature pollen grain stage, abundant starch grains and lipids appeared in the wild type's pollen, but fewer amounts were observed in the mutant. Moreover, the tapetal cells of the wild type accumulated lipids, but not those of the mutant. Results indicated that the abnormal development of the microspore led to pollen abortion in the mutant, and this could be the reason for its seedlessness. However, the genetic reasons for the aberrant tetrads are not clear and are under investigation.

scholarly journals Quantitative methods in microscopy to assess pollen viability in different plant taxa

2020 ◽  
Vol 33 (3-4) ◽  
pp. 205-219
Author(s):  
Lorenzo Ascari ◽  
Cristina Novara ◽  
Virginia Dusio ◽  
Ludovica Oddi ◽  
Consolata Siniscalco
Keyword(s):  
Statistical Power ◽  
Quantitative Methods ◽  
Pollen Viability ◽  
Crop Improvement ◽  
Pollen Grains ◽  
Pollen Sterility ◽  
Pollen Grain ◽  
Automated Image Analysis ◽  
Future Research ◽  
Sterile Pollen

AbstractHigh-quality pollen is a prerequisite for plant reproductive success. Pollen viability and sterility can be routinely assessed using common stains and manual microscope examination, but with low overall statistical power. Current automated methods are primarily directed towards the analysis of pollen sterility, and high throughput solutions for both pollen viability and sterility evaluation are needed that will be consistent with emerging biotechnological strategies for crop improvement. Our goal is to refine established labelling procedures for pollen, based on the combination of fluorescein (FDA) and propidium iodide (PI), and to develop automated solutions for accurately assessing pollen grain images and classifying them for quality. We used open-source software programs (CellProfiler, CellProfiler Analyst, Fiji and R) for analysis of images collected from 10 pollen taxa labelled using FDA/PI. After correcting for image background noise, pollen grain images were examined for quality employing thresholding and segmentation. Supervised and unsupervised classification of per-object features was employed for the identification of viable, dead and sterile pollen. The combination of FDA and PI dyes was able to differentiate between viable, dead and sterile pollen in all the analysed taxa. Automated image analysis and classification significantly increased the statistical power of the pollen viability assay, identifying more than 75,000 pollen grains with high accuracy (R2 = 0.99) when compared to classical manual counting. Overall, we provide a comprehensive set of methodologies as baseline for the automated assessment of pollen viability using fluorescence microscopy, which can be combined with manual and mechanized imaging systems in fundamental and applied research on plant biology. We also supply the complete set of pollen images (the FDA/PI pollen dataset) to the scientific community for future research.

scholarly journals The Arabidopsis ATK1 gene is required for spindle morphogenesis in male meiosis

Development ◽  
2002 ◽  
Vol 129 (10) ◽  
pp. 2401-2409
Author(s):  
Changbin Chen ◽  
Adam Marcus ◽  
Wuxing Li ◽  
Yi Hu ◽  
Jean-Philippe Vielle Calzada ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Meiotic Chromosome ◽  
Male Meiosis ◽  
Wild Type ◽  
Isolation And Characterization ◽  
In The Wild ◽  
Mitosis And Meiosis ◽  
Mutant Male ◽  
Metaphase I

The spindle plays a central role in chromosome segregation during mitosis and meiosis. In particular, various kinesins are thought to play crucial roles in spindle structure and function in both mitosis and meiosis of fungi and animals. A group of putative kinesins has been previously identified in Arabidopsis, called ATK1-ATK4 (previously known as KATA-KATD), but their in vivo functions have not been tested with genetic studies. We report here the isolation and characterization of a mutant, atk1-1, which has a defective ATK1 gene. The atk1-1 mutant was identified in a collection of Ds transposon insertion lines by its reduced fertility. Reciprocal crosses between the atk1-1 mutant and wild type showed that only male fertility was reduced, not female fertility. Molecular analyses, including revertant studies, indicated that the Ds insertion in the ATK1 gene was responsible for the fertility defect. Light microscopy revealed that, in the atk1-1 mutant, male meiosis was defective, producing an abnormal number of microspores of variable sizes. Further cytological studies indicated that meiotic chromosome segregation and spindle organization were both abnormal in the mutant. Specifically, the atk1-1 mutant male meiotic cells had spindles that were broad, unfocused and multi-axial at the poles at metaphase I, unlike the typical fusiform bipolar spindle found in the wild-type metaphase I cells. Therefore, the ATK1 gene plays a crucial role in spindle morphogenesis in male Arabidopsis meiosis.

scholarly journals Viability, production and morphology of pollen grains for different species in the genus Manihot (Euphorbiaceae)

2012 ◽  
Vol 26 (2) ◽  
pp. 350-356 ◽  
Author(s):  
Lívia de Jesus Vieira ◽  
Taliane Leila Soares ◽  
Mônica Lanzoni Rossi ◽  
Alfredo Augusto Cunha Alves ◽  
Francisco de Assis Ribeiro dos Santos ◽  
...  
Keyword(s):  
Pollen Viability ◽  
Pollen Grains ◽  
In Vitro Tests ◽  
Average Production ◽  
In Vivo Tests ◽  
In The Wild ◽  
Wild Accessions ◽  
Floral Bud

The objective of this work was to characterize the viability, production and morphology of pollen for different species in the genus Manihot. Floral buds from Manihot accessions were collected from two germplasm banks at Embrapa Cassava & Fruits. The viability of the pollen was assessed via colorimetric, in vitro and in vivo assays. The diameter of the pollen grains was determined by measuring the transversal length of the grain. The experimental design was entirely randomized. Studies on pollen ultrastructure were performed via scanning electron microscopy. Pollen viability was high in the colorimetric tests and intermediate in vivo tests; there was no germination in the in vitro tests. The average production for all accessions was 1,253 pollen grains per floral bud. The size of the pollen grains varied from 132 to 163 µm in the wild accessions, and 129 to 146 µm in the cultivated accessions. The pollen grains for all accessions were very large, apolar, spherical as well as inaperturate, with an exine ornamented with pila organized in a Croton pattern. The wild accessions, in general, produced more and larger pollen grains compared with the cultivated accessions.

scholarly journals Reduced fertility caused by meiotic defects and micronuclei formation during microsporogenesis in xBrassicoraphanus

2021 ◽  
Author(s):  
Hosub Shin ◽  
Hye Rang Park ◽  
Jeong Eun Park ◽  
Seung Hwa Yu ◽  
Gibum Yi ◽  
...  
Keyword(s):  
Driving Forces ◽  
Meiotic Chromosome ◽  
Pollen Viability ◽  
Hybrid Sterility ◽  
Pollen Sterility ◽  
Plant Evolution ◽  
Unbalanced Gamete ◽  
Meiotic Chromosomes ◽  
Genomic Study ◽  
Successive Generations

Abstract Background Hybridization and polyploidization events are important driving forces in plant evolution. Allopolyploids formed between different species can be naturally or artificially created but often suffer from genetic instability and infertility in successive generations. xBrassicoraphanus is an intergeneric allopolyploid obtained from a cross between Brassica rapa and Raphanus sativus, providing a useful resource for genetic and genomic study in hybrid species. Objective The current study aims to understand the cause of hybrid sterility and pollen abnormality in different lines of synthetic xBrassicoraphanus from the cytogenetic perspective. Methods Alexander staining was used to assess the pollen viability. Cytogenetic analysis was employed to monitor meiotic chromosome behaviors in pollen mother cells (PMCs). Origins of parental chromosomes in xBrassicoraphanus meiocytes were determined by genome in situ hybridization analysis. Results The xBrassicoraphanus lines BB#4 and BB#6 showed high rates of seed abortion and pollen deformation. Abnormal chromosome behaviors were observed in their PMCs, frequently forming univalents and inter-chromosomal bridges during meiosis. A positive correlation also exists between meiotic defects and the formation of micronuclei, which is conceivably responsible for unbalanced gamete production and pollen sterility. Conclusion These results suggest that unequal segregation of meiotic chromosomes, due in part to non-homologous interactions, is responsible for micronuclei and unbalanced gamete formation, eventually leading to pollen degeneration and inferior fertility in unstable xBrassicoraphanus lines.

scholarly journals Meiotic Studies in Some Species of Tribe Cichorieae (Asteraceae) from Western Himalayas

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Raghbir Chand Gupta ◽  
Henna Goyal ◽  
Vijay Singh ◽  
Rajesh Kumar Goel
Keyword(s):  
Chromosome Number ◽  
Pollen Viability ◽  
Intraspecific Variability ◽  
Pollen Grains ◽  
Early Prophase ◽  
Western Himalayas ◽  
Meiotic Abnormalities ◽  
Unreduced Pollen ◽  
Chromosome Stickiness ◽  
First Time

The present paper deals with meiotic studies in 15 species belonging to 6 genera of the tribe Cichorieae from various localities of Western Himalayas. The chromosome number has been reported for the first time inHieracium crocatum(2n=10) andLactuca lessertiana(2n=2x=16). Further, intraspecific variability has been reported for the first time inH. umbellatum(2n=2x=10and2n=6x=54),Tragopogon dubius(2n=2x=14and2n=4x=28), andT. gracilis(2n=2x=14). The chromosome report of2n=2x=10inYoungia tenuifoliais made for the first time in India. Maximum numbers of the populations show laggards, chromosome stickiness, and cytomixis from early prophase to telophase-II, leading to the formation of aneuploid cells or meiocytes with double chromosome number. Such meiotic abnormalities produce unreduced pollen grains and the reduced pollen viability.

scholarly journals A Duplicated Copy of the Meiotic Gene ZIP4 Preserves up to 50% Pollen Viability and Grain Number in Polyploid Wheat

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 290
Author(s):  
Abdul Kader Alabdullah ◽  
Graham Moore ◽  
Azahara C. Martín
Keyword(s):  
Pollen Viability ◽  
Pollen Grains ◽  
Wheat Chromosome ◽  
Grain Number ◽  
Meiotic Gene ◽  
Chromosome 5B ◽  
Mutant Pollen ◽  
Female Gametogenesis ◽  
Chromosome 3B

Although most flowering plants are polyploid, little is known of how the meiotic process evolves after polyploidisation to stabilise and preserve fertility. On wheat polyploidisation, the major meiotic gene ZIP4 on chromosome 3B duplicated onto 5B and diverged (TaZIP4-B2). TaZIP4-B2 was recently shown to promote homologous pairing, synapsis and crossover, and suppress homoeologous crossover. We therefore suspected that these meiotic stabilising effects could be important for preserving wheat fertility. A CRISPR Tazip4-B2 mutant was exploited to assess the contribution of the 5B duplicated ZIP4 copy in maintaining pollen viability and grain setting. Analysis demonstrated abnormalities in 56% of meiocytes in the Tazip4-B2 mutant, with micronuclei in 50% of tetrads, reduced size in 48% of pollen grains and a near 50% reduction in grain number. Further studies showed that most of the reduced grain number occurred when Tazip4-B2 mutant plants were pollinated with the less viable Tazip4-B2 mutant pollen rather than with wild type pollen, suggesting that the stabilising effect of TaZIP4-B2 on meiosis has a greater consequence in subsequent male, rather than female gametogenesis. These studies reveal the extraordinary value of the wheat chromosome 5B TaZIP4-B2 duplication to agriculture and human nutrition. Future studies should further investigate the role of TaZIP4-B2 on female fertility and assess whether different TaZIP4-B2 alleles exhibit variable effects on meiotic stabilisation and/or resistance to temperature change.

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