U1 snRNP components are present in the vegetative and generative nuclei of the pollen grain

1995 ◽  
Vol 8 (6) ◽  
Author(s):  
IlonaI. Concha ◽  
Jorge Mansilla ◽  
Magaly Riveros ◽  
LuisO. Burzio
Keyword(s):  
Pollen Grain ◽  
U1 Snrnp ◽  
Generative Nuclei

The Formation of the Generative Cell in the Pollen Grain of Endymion Non-Scriptus (L)

1968 ◽  
Vol 3 (4) ◽  
pp. 573-578
Author(s):  
R. E. ANGOLD
Keyword(s):  
Cell Wall ◽  
Somatic Cells ◽  
Generative Cell ◽  
Cell Plate ◽  
Pollen Grain ◽  
Generative Nucleus ◽  
A Cell ◽  
Generative Nuclei

The generative cell wall in the pollen grain of Endymion non-scriptus is formed, as in somatic cells, from a cell plate between the vegetative and generative nuclei. This wall curves around the generative nucleus, and fuses with the intine to enclose the generative cell. The generative cell is subsequently freed from the intine by the constriction of the generative cell wall between the generative nucleus and the intine.

scholarly journals Morbid mitosis and the activity of inert chromosomes in sorghum

1941 ◽  
Vol 130 (859) ◽  
pp. 127-150 ◽  
Keyword(s):  
Structural Changes ◽  
Wild Population ◽  
Specific Effect ◽  
Pollen Grains ◽  
Variable Number ◽  
Pollen Grain ◽  
Vegetative Nucleus ◽  
In The Wild ◽  
Primary Division ◽  
Generative Nuclei

Sorghum purpureo-sericeum has five paris of active, A , chromosomes and a variable number of extra, B , chromosomes in equilibrium in the wild population (Janaki-Ammal 1940; and table 7). The B -chromosomes vary in structure within and between plants owing to frequent spontaneous changes, including misdivision of the centromere. One is an iso-chromosome. The B 's are sex-limited so far as that is possible in a plant: they are confined to the germ track owing to loss by lagging elsewhere. They are lost in the radicle before seed ripening and in the shoot tissues as they reach maturity. Only in the anthers and ovaries are they regularly maintained. B -chromosomes pair with one another at meiosis when homologous, and the two arms of the iso-chromosome form chiasmata with one another. Pollen grains of plus plants (with extra B 's) have extra divisions of the vegetative nucleus rapidly following the primary division. The first pollen grain division is delayed by the presence of B -chromosomes. Its course is always normal. At the second division the B 's always pass to the generative pole undivided and so double its dose. When only two generative nuclei are formed, one or both may produce sperm. Three, four or five generative nuclei, however, kill the pollen grain. The extra divisions are thus malignant. The B -chromosomes as usual are heterochromatic. They have an abnormal nucleic acid cycle. Their action on the cells, containing them is non-specific and cumulative, and their apparently specific effect in stimulating mitosis in the pollen grains is possibly due to these being the only cells that contain them whose mitosis and growth are normally limited. Spontaneous structural changes in heterochromatic chromosomes are frequent at mitosis in plants and animals. Such changes could evidently establish malignant propensities in somatic cells by stimulating recurrent mitosis.

scholarly journals Nondisjunction and unequal spindle organization accompany the drive of Aegilops speltoides B chromosomes

2019 ◽  
Author(s):  
DanDan Wu ◽  
Alevtina Ruban ◽  
Jörg Fuchs ◽  
Jiri Macas ◽  
Petr Novák ◽  
...  
Keyword(s):  
Pollen Grain ◽  
Cellular Mechanism ◽  
B Chromosomes ◽  
Aegilops Speltoides ◽  
Mendelian Segregation ◽  
Flow Cytometric ◽  
Sister Chromatids ◽  
Insight Into ◽  
Generative Nuclei ◽  
Quantitative Flow

AbstractSupernumerary B chromosomes (Bs), which are often preferentially inherited, deviating from usual Mendelian segregation. This chromosome drive is one of the most important features of Bs. Here we analyzed the drive mechanism of Aegilops speltoides Bs and provide direct insight into its cellular mechanism. Comparative genomics resulted in the identification of the tandem repeat AesTR-183 of Ae. speltoides Bs, which also can be found on the Bs of Ae. mutica and rye, was used to track Bs during microgametogenesis. Nondisjunction of CENH3-positive, tubulin interacting B sister chromatids and an asymmetric spindle during first pollen grain mitosis are likely components of the accumulation process. A quantitative flow cytometric approach revealed, that independent on the number of Bs present in the mother plant Bs accumulate in the generative nuclei with more than 93%. Nine of eleven tested (peri)centromeric repeats were shared by A and B chromosomes. A common origin of the drive process in Poaceae is likely.

scholarly journals RADIOAUTOGRAPHIC LOCALIZATION OF DEOXYTHYMIDINE TRIPHOSPHATE IN TRADESCANTIA POLLEN GRAINS DURING DNA SYNTHESIS

1968 ◽  
Vol 38 (3) ◽  
pp. 509-514 ◽  
Author(s):  
S. T. Takats
Keyword(s):  
Acetic Acid ◽  
Dna Synthesis ◽  
Generative Cell ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Ethanol Acetic Acid ◽  
Dry Emulsion ◽  
Generative Nuclei

Tradescantia pollen grains, isolated during the period of DNA synthesis in the generative cell, accumulate deoxythymidine triphosphate (dTTP)-3H after incubation with thymidine-3H in the presence of millimolar deoxyadenosine. Most of this dTTP-3H was found to resist extraction by the fixative, cold ethanol-acetic acid, and its location was investigated by radioautography with thin, dry emulsion. Substantial binding of dTTP-3H occurred as an artifact; but when nuclei were isolated from the fixed pollen grains by sonication, it was found that they were differentially labeled: generative nuclei contained dTTP-3H, vegetative nuclei did not. This observation is discussed and is interpreted as evidence supporting the idea that thymidine is phosphorylated only in the generative cell of the pollen grain.

scholarly journals Ultrastructural transformations of nuclei in differentiating Hyacirlthus orientalis L. pollen grain cells

2014 ◽  
Vol 56 (4) ◽  
pp. 667-685 ◽  
Author(s):  
Elżbieta Bednarska ◽  
Alicja Górska-Brylass
Keyword(s):  
Protein Synthesis ◽  
Structural Changes ◽  
Pollen Grain ◽  
Pollen Maturation ◽  
Rna And Protein Synthesis ◽  
Hyacinthus Orientalis ◽  
Generative Nuclei

The ultrastructure of the pollen nuclei was studied during pollen maturation in <em>Hyacinthus orientalis</em> L., in which both pollen cells go through full interphase (G<sub>1</sub> S, G<sub>2</sub>). The particular stages of interphase, however, do not proceed simultaneously in the vegetative and generative nuclei. The ultrastructural transformations of both pollen nuclei were analysed with reference to the dynamics of variations in the level of RNA and protein synthesis, investigated earlier. A distinction is drawn between the structural changes common for both nuclei, linked immanently with the interphase and the transformations connected with the differentiation of pollen cells.

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