CYTOMIXIS IN POLLEN MOTHER CELLS OF ONONIS (LEGUMINOSAE)

1978 ◽  
Vol 20 (3) ◽  
pp. 383-388 ◽  
Author(s):  
Pierre Morisset
Keyword(s):  
Growth Rates ◽  
Meiotic Prophase ◽  
Flower Bud ◽  
Pollen Mother Cells ◽  
Competition For Space ◽  
Mother Cells

Cytomixis occurred regularly in pollen mother cells (PMCs) of Ononis spinosa L., O. repens L. and O. arvensis L., from early meiotic prophase to telophase II. Usually only a few PMCs were affected in any anther, but occasionally whole anthers showed cytomictic patterns. Cytomixis generally was found at extremities but rarely in the median parts of anthers. Since it appeared to lead to the degeneration of affected PMCs or young microspores, it, therefore, could not give rise to aneuploidy. Cytomixis is interpreted as a pathological abnormality induced by pressure building up within the developing flower bud; it occurred where anthers pressed strongly against each other due to competition for space. It is suggested that uncoordinated growth rates of anthers and floral envelopes could account for intense cytomixis described in hybrids by various authors.

scholarly journals THE EFFECT OF X-RAYS ON CHROMOSOMES IN DIFFERENT STAGES OF MEIOSIS

1935 ◽  
Vol 19 (1) ◽  
pp. 179-198 ◽  
Author(s):  
A. Marshak
Keyword(s):  
Linear Relationship ◽  
Meiotic Prophase ◽  
Sensitive Volume ◽  
X Rays ◽  
Homologous Pairing ◽  
Linkage Mechanism ◽  
Pollen Mother Cells ◽  
X Ray ◽  
Protein Molecules ◽  
Mother Cells

1. Pollen mother cells exposed to low dosages of x-rays at various stages show different frequencies of chromosome abnormalities in the first meiotic anaphase. 2. Maximum frequencies of abnormalities were obtained in buds irradiated in the pachytene stage of the meiotic prophase and in the preceding mitosis. 3. These results are taken to indicate that the x-ray-sensitive portions of the chromonemata are closely approximated in pairs in pachytene and in the early mitotic prophase. The significance of this in relation to non-homologous pairing is indicated. 4. From the nature of the chromosome configurations observed it is concluded that chromonemata are two-parted when they synapse and that a chromonematic division occurs between pachytene and anaphase and during the mitotic prophase. 5. The frequencies of abnormalities show a linear relationship to dosage. 6. The diameter of the sensitive volume of the chromonema is calculated and found to approximate the diameter of some known protein molecules. 7. The linkage mechanism is found to make up about 90 per cent of the total sensitive volume which corresponds with the approximate reduction in length of the chromonema from pachytene to anaphase. 8. The relation of these sensitive volumes to the gene is discussed.

Developmental changes in DNA methylation of pollen mother cells of David lily during meiotic prophase I

2010 ◽  
Vol 44 (5) ◽  
pp. 754-759 ◽  
Author(s):  
Junjun Huang ◽  
Huahua Wang ◽  
Xiaojun Xie ◽  
Huanhuan Gao ◽  
Guangqin Guo
Keyword(s):  
Dna Methylation ◽  
Meiotic Prophase ◽  
Developmental Changes ◽  
Pollen Mother Cells ◽  
Prophase I ◽  
Meiotic Prophase I ◽  
Mother Cells

FINE STRUCTURE OF CHROMOSOME COILING AT MEIOTIC PROPHASE IN RHOEO DISCOLOR

1972 ◽  
Vol 14 (4) ◽  
pp. 801-808 ◽  
Author(s):  
Peter B. Moens
Keyword(s):  
Fine Structure ◽  
Nuclear Envelope ◽  
Meiotic Prophase ◽  
Synaptonemal Complexes ◽  
Pollen Mother Cells ◽  
Mother Cells

Most, if not all of the ends of synaptonemal complexes in Rhoeo discolor pollen mother cells are attached to the nuclear envelope. At least the first 4 μm of complex adjacent to the nuclear envelope is tightly coiled. Since each of the lateral elements is associated with one chromosome it means that the two homologues of the bivalent are relationally coiled in the distal segments.

scholarly journals Cytoplasniic differentiation during microsporogenesis in higher plants

2014 ◽  
Vol 50 (1-2) ◽  
pp. 3-12 ◽  
Author(s):  
H. Dichinnson
Keyword(s):  
Meiotic Prophase ◽  
Messenger Rna ◽  
Higher Plants ◽  
Pollen Mother Cells ◽  
Cytoplasmic Rna ◽  
Low Levels ◽  
Mother Cells ◽  
New Generation

Conspicuous cytoplasmic dedifferentiation in the pollen mother cells takes place early in the meiotic prophase of many plants. This event involves the removal of much of the cytoplasmic RNA. and the differentiation of both plastids and mitochondria to approaching the sole expression of their genomes. Much of the RNA removed from the cytoplasm passes to the nucleoplasm where it is utilised in the construction of a new `generation' of ribusomes. These new ribosomes are incorporated into cytoplasmic `nuclewhich disintegrate in the post-meiotic cytoplasm, restoring its ribosomes to pre-prophase levels. These changes are interpreted as evidence of a process by which the cytoplasm is cleansed of sporophytic control elements, both for the expression of the new gametophytic genome, and in the female cells of higher plants, for transmission to the new generation. The absence of control elements (presumably long-term messenger RNA) from the cytoplasm would result in the dedifferentiation observed in the organelles, and the low levels of reserves in these cells presumably results in characteristically lengthy and unusual redifferentiation of both plastids and mitochondria, once information-carrying molecules again enter the cytosol.

The time and duration of female meiosis in Lilium

1975 ◽  
Vol 188 (1093) ◽  
pp. 459-475 ◽  
Keyword(s):  
Mother Cell ◽  
Embryo Sac ◽  
Female Meiosis ◽  
Flower Bud ◽  
Pollen Mother Cells ◽  
Controlled Conditions ◽  
Mean Temperature ◽  
Mother Cells ◽  
Black Beauty

The time and duration of meiosis in ovules and anthers was estimated in plants of two Lilium hybrids (cultivars ‘Sonata’ and ‘Black Beauty’) grown under controlled conditions. Within each flower bud meiosis did not start in the embryo sac mother cell (e.m.c.) until about the time when meiosis in pollen mother cells (p.m.cs) was ended. In both cultivars meiosis lasted about 50% longer in e.m.cs than in p.m.cs. Thus, at a mean temperature of 20 ± 1 °C meiosis in ‘Sonata’ took 7.5 days in p.m.cs and 10.5 days in e.m.cs, while in ‘Black Beauty’ it took 10.5 days in p.m.cs and 16.0 days in e.m.cs.

scholarly journals Nuclear Compartmentalization in Pollen Mother Cells During Meiotic Prophase

1990 ◽  
pp. 493-497
Author(s):  
M. I. Rodriguez-Garcia ◽  
J. D. Alché ◽  
A. Majewska-Sawka ◽  
M. C. Fernandez ◽  
B. Jassem
Keyword(s):  
Meiotic Prophase ◽  
Pollen Mother Cells ◽  
Mother Cells ◽  
Nuclear Compartmentalization
Sign in / Sign up

Export Citation Format

Share Document