Distribution of Microtubular Cytoskeletons and Organelle Nucleoids During Microsporogenesis in a 2n Pollen Producer of Hybrid Populus

Abstract The distribution of microtubular cytoskeletons and organelle nucleoids during microsporogenesis in Populus simonii Carr. x P. nigra L. ‘Tongliao’ was studied by indirect immunofluorescence and 4’,6-diamidino-2- phenylindole (DAPI) staining. Our purpose was to reveal the relationship between changes in microtubule and chromosome behavior and cytokinesis and to explain the mechanism of 2n pollen production. We observed stable frequencies of 2n pollen production, ranging from 1.56% to 2.29%, between 2006 and 2008. Moreover, conjoined pollen grains were also observed. Meiotic abnormalities, including univalents, lagging chromosomes and micronuclei, were observed during microsporogenesis. Triads and dyads were also detected in meiotic products. Parallel spindles in metaphase II were unable to fuse, owing to the existence of an organelle band. Regularly, in telophase II, primary phragmoplasts were organized between sister nuclei, and secondary phragmoplasts formed between non-sister nuclei. Cell plates were initiated by centrifugal expansion of phragmoplasts and cytoplasmic infurrowing started at the junctions between the microsporocyte wall and the expanded phragmoplasts. However, a secondary phragmoplast was absent in some microsporocytes. These observations suggest that the occurrence of 2n pollen may result from the partial failure of cytokinesis caused by the absence of secondary phragmoplasts in this hybrid.

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2n GAMETES IN DIPLOID SOLANUM: FREQUENCY AND TYPES OF SPINDLE ABNORMALITIES

Canadian Journal of Genetics and Cytology ◽

10.1139/g82-032 ◽

1982 ◽

Vol 24 (3) ◽

pp. 301-314 ◽

Cited By ~ 31

Author(s):

R. E. Veilleux ◽

N. A. McHale ◽

F. I. Lauer

Keyword(s):

Cross Sections ◽

Meiotic Division ◽

2N Gametes ◽

Anatomical Study ◽

Solanum Phureja ◽

Spindle Orientation ◽

Pollen Production ◽

2N Pollen ◽

Genetic Theory ◽

Parallel Spindles

Cytological disturbances resulting in 2n pollen were examined in four clones of diploid (2x = 24) Solanum phureja Juz. and Buk.; two (148-17 and 127-14) were variable and two (154-1 and B2-11) were consistently high in 2n pollen production. Three types of abnormal spindle orientation were observed at the second meiotic division: fused, tripolar, and parallel spindles (fs, tps, and ps, respectively). All four genotypes had fs. Three had tps, and ps was least frequent, occuring in two genotypes only. Cross-sections of buds revealed that all three abnormalities can occur in adjacent cells of a locule. In all genotypes, fs predominated at high levels of expression of 2n gametes. At lower levels of expression (i.e. less than 60%, which occurred only in 148-17 and 127-14), however, the frequencies of tps and ps increased. In general, there was little evidence for localization of dyads (resulting from fs or ps) or tetrads (resulting from normal divisions) within cross sections of locules, but 52.4% of all tetrads which occurred in a single locule of genotype 127-14 were found in 25% of the locular area. Cross-sections of buds revealed variation in frequency of 2n gametes among anthers (61.7 vs. 5.6% in 148-17) and between locules of an anther (73.1 vs. 90.0% in B2-11). Implications of the anatomical study were applied to current genetic theory regarding the development of 2n gametes in potato species.

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

Silvae Genetica ◽

10.1515/sg-2013-0034 ◽

2013 ◽

Vol 62 (1-6) ◽

pp. 285-291 ◽

Cited By ~ 4

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.

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Meiotic chromosome behavior of Haworthia limifolia

International Journal of Bioassays ◽

10.21746/ijbio.2016.03.009 ◽

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.

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POLLEN PRODUCTION AND DISSEMINATING PROPERTIES OF TRITICALE RELATIVE TO WHEAT

Canadian Journal of Plant Science ◽

10.4141/cjps72-088 ◽

1972 ◽

Vol 52 (4) ◽

pp. 569-574 ◽

Cited By ~ 23

Author(s):

K. C. YEUNG ◽

E. N. LARTER

Keyword(s):

Seed Set ◽

Marker Gene ◽

Pollen Grains ◽

Triticum Aestivum L ◽

Hybrid Seed Production ◽

Pollen Production ◽

Hexaploid Triticale ◽

Anther Length ◽

Anther Extrusion ◽

Wide Range

A study of the pollen production properties of three hexaploid triticale strains (Triticale hexaploide Lart.) showed that their anther length was significantly greater than that of wheat anthers (Triticum aestivum L. em Thell.) and the estimated number of pollen grains per anther ranged from 15,000 to 21,000. In comparison, a total of 8000 grains per anther was estimated for wheat, cult Manitou. Eighty-nine percent anther extrusion occurred in triticale cult Rosner, while Manitou averaged 70% anther extrusion. The period of anthesis of triticale varied according to strain but generally was of longer duration than in Manitou and thereby promoted outcrossing. Using a triticale strain carrying a dominant marker gene, 50% seed-set was obtained at a distance of 12 m leeward of the pollen source; however, a small percentage was still obtained at a distance of 30 m. It would appear from the limited number of triticales used in this study that a wide range of variability exists within this species in its pollen production and disseminating properties. With appropriate selection pressures, strains with an outbreeding habit could be developed for the purpose of hybrid seed production.

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CYTOLOGY OF 2n POLLEN FORMATION IN DIPLOID ALFALFA, MEDICAGO SATIVA

Canadian Journal of Genetics and Cytology ◽

10.1139/g79-057 ◽

1979 ◽

Vol 21 (4) ◽

pp. 525-530 ◽

Cited By ~ 52

Author(s):

Nicholi Vorsa ◽

E. T. Bingham

Keyword(s):

Medicago Sativa ◽

Seed Set ◽

Pollen Grains ◽

Genetic Constitution ◽

2N Pollen ◽

Diploid Parent ◽

2N Gamete ◽

Medicago Sativa L ◽

Pollen Formation ◽

Mother Cells

Four diploid (2x) clones of alfalfa, Medicago sativa L., which produced good seed set when used as male parents in 4x-2x crosses were selected for study. The 2x clones descended from 2x haploids of cultivated 4x alfalfa. Fertility in the 4x-2x cross was due to the production of pollen with the unreduced chromosome number (2n pollen) from the 2x parent. The cytological mechanism of 2n pollen formation was found to be disorientation of spindles at metaphase II in up to 38% of the pollen mother cells. Thus, both n and 2n pollen were produced by all four diploids examined. Normal spindles at metaphase II were oriented such that they defined the poles of a tetrahedron and resulted in normal tetrads in a tetrahedral arrangement. Disoriented spindles were basically parallel to each other and resulted in formation of dyads and occasionally a triad. Dyads developed into two 2n pollen grains; triads developed into one 2n and two n pollen grains. Since both n and 2n pollen grains are produced by the diploids, they can be maintained as diploids or they can be used as male parents in crosses to tetraploids. The genetic constitution of 2n pollen resulting from parallel spindles is similar to that expected after first division restitution of meiosis and much of the heterozygosity of the diploid parent is conserved in the gametes. The 2n gamete mechanism has potential application in germplasm transfer and in maximizing heterozygosity in tetraploid hybrids.

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ATBS1-INTERACTING FACTOR 2 Negatively Modulates Pollen Production and Seed Formation in Arabidopsis

Frontiers in Plant Science ◽

10.3389/fpls.2021.704958 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yoon Kim ◽

Sun-Ho Kim ◽

Dong-Min Shin ◽

Soo-Hwan Kim

Keyword(s):

Pollen Grains ◽

Starch Accumulation ◽

Bhlh Transcription Factor ◽

Pollen Production ◽

Sucrose Transport ◽

Seed Formation ◽

Helix Loop Helix ◽

Knockout Mutants ◽

Auxin Signalling ◽

Genes Encoding

ATBS1-INTERACTING FACTOR 2 (AIF2) is a non-DNA-binding basic-helix-loop-helix (bHLH) transcription factor. Here, we demonstrate that AIF2 negatively modulates brassinosteroid (BR)-induced, BRASSINAZOLE RESISTANT 1 (BZR1)-mediated pollen and seed formation. AIF2-overexpressing Arabidopsis plants (AIF2ox) showed defective pollen grains and seed production while two AIF2 knockout mutants, aif2-1 and aif2-1/aif4-1, displayed opposite phenotypes. Genes encoding BZR1-regulated positive factors of seed size determination (SHB1, IKU1, MINI3) were suppressed in AIF2ox and genes for negative factors (AP2 and ARF2) were enhanced. Surprisingly, BZR1-regulated pollen genes such as SPL, MS1, and TDF1 were aberrantly up-regulated in AIF2ox plants. This stage-independent abnormal expression may lead to a retarded and defective progression of microsporogenesis, producing abnormal tetrad microspores and pollen grains with less-effective pollen tube germination. Auxin plays important roles in proper development of flower and seeds: genes for auxin biosynthesis such as TCPs and YUCCAs as well as for positive auxin signalling such as ARFs were suppressed in AIF2ox flowers. Moreover, lipid biosynthesis- and sucrose transport-related genes were repressed, resulting in impaired starch accumulation. Contrarily, sucrose and BR repressed ectopic accumulation of AIF2, thereby increasing silique length and the number of seeds. Taken together, we propose that AIF2 is negatively involved in pollen development and seed formation, and that sucrose- and BR-induced repression of AIF2 positively promotes pollen production and seed formation in Arabidopsis.

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Morphological diversity of pollen from selected species of the genus Taraxacum, according to their ploidal level

Acta Agrobotanica ◽

10.5586/aa.2008.008 ◽

2012 ◽

Vol 61 (1) ◽

pp. 65-69 ◽

Cited By ~ 2

Author(s):

Jolanta Marciniuk ◽

Anna Rudzińska-Langwald

Keyword(s):

Pollen Grains ◽

Morphological Diversity ◽

Great Variability ◽

2N Pollen ◽

Regular Type ◽

Unknown Number ◽

Species Being ◽

The Way

The study of the morphology of pollen concerned eight species of the genus Taraxacum. Seven types were chosen with a different number of chromosomes belonging to the section Palustria: Taraxacum paucilobum 2n = 3x = 24, T. subdolum 2n = 3x =24, T. subpolonicum 2n =3x = 24, T. vindobonense 2n = 4x = 32, T. trilobifolium 2n = 4x = 32, T. mendax 2n = 5x = 40, T. portentosum 2n =? and one type from the section Obliqua - T. platyglossum 2n =?. Pollen from all the examined species was observed by SEM microscopy. A distinct relation exists between the morphology of pollen and the way of reproduction. Pollen of triploidal species, being compulsory apomicts, is characterized by a great variability of the size and a high percentage of deformed pollen grains. Tetraploids, being optional apomicts, produce regular pollen with a relatively even size. The regular type of pollen in pentaploidal Taraxacum mendax and in species with an unknown number of chromosomes (Taraxacum portentosum and T. platyglossum) suggests that these taxa are optional apomicts.

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A comparison of progeny from diallel crosses of diploid potato with regard to the frequencies of 2n-pollen grains

Euphytica ◽

10.1007/bf00037114 ◽

1995 ◽

Vol 92 (3) ◽

pp. 313-320

Author(s):

Qu Dongyu ◽

Zhu Dewei ◽

M. S. Ramanna ◽

E. Jacobsen

Keyword(s):

Pollen Grains ◽

Diploid Potato ◽

2N Pollen ◽

Diallel Crosses

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A Case of Concurrent MPO-/PR3-Negative ANCA-Associated Glomerulonephritis and Membranous Glomerulopathy

Case Reports in Nephrology ◽

10.1155/2015/316863 ◽

2015 ◽

Vol 2015 ◽

pp. 1-5

Author(s):

Yasuyuki Nakada ◽

Nobuo Tsuboi ◽

Yasuto Takahashi ◽

Hiraku Yoshida ◽

Yoriko Hara ◽

...

Keyword(s):

Renal Biopsy ◽

Indirect Immunofluorescence ◽

Crescentic Glomerulonephritis ◽

Antineutrophil Cytoplasmic Antibody ◽

Basement Membranes ◽

Proteinase 3 ◽

Renal Deterioration ◽

Membranous Glomerulopathy ◽

Immunosorbent Assays ◽

The Relationship

We report a case in which antineutrophil cytoplasmic antibody- (ANCA-) associated glomerulonephritis and membranous glomerulopathy (MGN) were detected concurrently. The patient showed rapidly progressive renal deterioration. A renal biopsy showed crescentic glomerulonephritis, together with marked thickening and spike and bubbling formations in the glomerular basement membranes. Indirect immunofluorescence examination of the patient’s neutrophils showed a perinuclear pattern. Enzyme-linked immunosorbent assays revealed that the ANCA in this case did not target myeloperoxidase (MPO) or proteinase 3 (PR3) but bactericidal-/permeability-increasing protein, elastase, and lysosome. The relationship between these two etiologically distinct entities, MPO-/PR3-negative ANCA-associated glomerulonephritis and MGN, remains unclear.

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Flowering dynamics and pollen production of Laburnum anagyroides Med. under the conditions of south-eastern Poland

Journal of Apicultural Science ◽

10.2478/jas-2013-0021 ◽

2013 ◽

Vol 57 (2) ◽

pp. 103-115 ◽

Cited By ~ 1

Author(s):

Ernest Stawiarz ◽

Anna Wróblewska

Keyword(s):

Pollen Grains ◽

Average Weight ◽

Pollen Production ◽

Full Bloom ◽

Flowering Duration ◽

The Third ◽

Laburnum Anagyroides ◽

Golden Yellow ◽

Single Flower ◽

The Common

Abstract A study on the flowering biology and pollen production of the common laburnum (Laburnum anagyroides Med.) was conducted under the conditions of Lublin during the period 2004 - 2006. The flowering of this species began in the second 10-day period of May and lasted for 2.5 - 4 weeks. The flowers of common laburnum are borne in showy golden-yellow pendulous racemes. They develop successively, starting from the base and moving to the tip of an inflorescence. During the growing season, one shrub produces 800 to 3200 racemes, with 14 to 35 flowers in a single raceme. On average, the flowering duration for a raceme was 12.8 days and 8.7 days for a single flower. Throughout the study years, the shrubs proved to be most attractive in the third 10-day period of May when they reached full bloom. The average weight of pollen produced was 6.08 mg per 10 flowers of Laburnum anagyroides, 14.02 mg per raceme, and 26.0 g per shrub. Pollen grains reached average dimensions of 24.01 μm × 24.26 μm.

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