Ultrastructural association of the chromatin-containing lacunar spaces with the vacuolar component of the interphase nucleolus in Allium cepa

1982 ◽  
Vol 60 (12) ◽  
pp. 2624-2628 ◽  
Author(s):  
L. A. Chouinard
Keyword(s):  
Granular Material ◽  
Allium Cepa ◽  
Ultrastructural Level ◽  
Observational Evidence ◽  
The Other ◽  
Active Chromatin ◽  
Meristematic Cells ◽  
Fibrillar Material ◽  
Nucleolar Organizing Region ◽  
Root Meristematic Cells

At the ultrastructural level, some of the chromatin-containing lacunar spaces of the interphase nucleolus in root meristematic cells of Allium cepa are seen to be walled off, on one side, by dense-fibrillar material and to be contiguous, on the other side, to electron-transparent areas, of variable sizes and shapes, bordered by dense-granular material continuous with and indistinguishable from the dense-granular component of the nucleolar mass. These electron-transparent areas associated with the lacunar spaces are equated with nucleolar vacuoles since they contain scattered preribosomal-like granules and fibrils and are rimmed by dense-granular material. The relevant observational evidence would be consistent with the view that loops of transcriptionnally active chromatin emanating from the nucleolar organizing region project radially into either only the dense-fibrillar or both the dense-fibrillar and the interior of the electron-transparent vacuolar areas seen to be contiguous to the lacunar spaces in question. In relation to this problem, it is of interest to note that the vacuolar spaces of the interphase nucleolus in Allium cepa occasionally display within their confines discrete masses of fibrillar material, possibly chromatinic in character, and in various states of condensation and configuration.

Ultrastructural association of the chromatin-containing lacunar spaces with the granular component of the interphase nucleolus in Allium cepa

1981 ◽  
Vol 59 (11) ◽  
pp. 2073-2076
Author(s):  
L. A. Chouinard
Keyword(s):  
Granular Material ◽  
Allium Cepa ◽  
Ultrastructural Level ◽  
Dense Fibrillar Component ◽  
Active Chromatin ◽  
Granular Component ◽  
Meristematic Cells ◽  
Partial Association ◽  
Root Meristematic Cells ◽  
Fibrillar Component

At the ultrastructural level, the interphase nucleolus in root meristematic cells of Allium cepa is characterized by the presence of chromatin-containing lacunar spaces associated with the dense-fibrillar component of the nucleolar mass. The present observations reveal that a number of these chromatin-containing lacunar spaces also exhibit partial association with the dense-granular component of the nucleolus. Under the electron microscope, such lacunar spaces are indeed seen to be enclosed or walled off, on one side, by dense-fibrillar material, and on the other side, by dense-granular material continuous with and indistinguishable from the dense-granular component of the nucleolus. The relevant observational evidence would be consistent with the view that loops of transcriptionally active chromatin, emanating from the nucleolar organizing region, project radially into either only the dense-fibrillar or both the dense-fibrillar and the dense-granular material bordering the lacunar spaces in question.

scholarly journals Action of Ponceau 4R (E-124) food dye on root meristematic cells of Allium cepa L.

2015 ◽  
Vol 37 (1) ◽  
pp. 101 ◽  
Author(s):  
Gleuvânia Santana Marques ◽  
Josefa Janaína do Anjos Sousa ◽  
Ana Paula Peron
Keyword(s):  
Allium Cepa ◽  
Meristematic Cells ◽  
Food Dye ◽  
Root Meristematic Cells ◽  
Ponceau 4R

scholarly journals Rooting Induction in Allium cepa for the Study of Mitosis in a Hydroponics System

2020 ◽  
pp. 1-5
Author(s):  
Geovanio Alves da Silva ◽  
Eder Ferreira Arriel ◽  
Mellina Nicácio da Luz ◽  
Valeska Regina Silva Martins ◽  
Elisabeth de Oliveira ◽  
...  
Keyword(s):  
Allium Cepa ◽  
Genetic Information ◽  
Water Source ◽  
The Other ◽  
Root Mass ◽  
Root Number ◽  
Experiment Data ◽  
Hydroponic System ◽  
Meristematic Cells ◽  
System Water

The study of cell division processes is important for the understanding of how genetic information is transmitted from cell to cell and to descendants. To observe the phases of mitosis in meristematic cells of the onion root (Allium cepa), it is necessary to induce the rooting of this bulb that can be influenced by some factors like the type of water and the preparation form of the bulb of the onion for the success of rhizogenesis. In view of the above, the objective was to evaluate the influence of the water source and the opening of holes in the stem of the propagule to induce rooting in a hydroponic system. Two experiments were installed. In the first, one of the treatments was used distilled water and treated water. In the other experiment, three treatments were evaluated (without holes, few holes and a lot of holes in the stem of the bulb). Five days after installation of the first experiment, data were collected on the number of bulbs that gave off roots and this variable was analyzed using the X2 test. In the other test, also at five days, root number and fresh root mass data were obtained and the data were submitted for analysis of variance and the means were compared by the Scott-Knott test. For the induction of rooting in onion bulbs (Allium cepa) in a hydroponic system, water should be used, preferably treated, cleaned and decontaminated. The stem of the onion bulb should receive many perforations to facilitate the absorption of water with the essential nutrients for rooting.

scholarly journals Sodium cacodylate as antimitotic agent

2014 ◽  
Vol 57 (3) ◽  
pp. 329-340
Author(s):  
Jadwiga A. Tarkowska
Keyword(s):  
Allium Cepa ◽  
Mitotic Spindle ◽  
Sodium Cacodylate ◽  
Antimitotic Agent ◽  
Ultrastructural Studies ◽  
Meristematic Cells ◽  
Cacodylate Buffer ◽  
Root Meristematic Cells ◽  
Dividing Cells

The effect of pure sodium cacodylate on dividing cells was studied. The root meristematic cells of <em>Allium cepa</em> L. (the roots were squashed in acetoorcein) and endosperm cells of <em>Haemanthus katherinae</em> Bak. (<em>in vitro</em> observations) were used. Serious disturbances in karyokinesis and cytokinesis were found that led most often to the formation of polyploid or multinucleate (<em>A. cepa</em>) cells. These results point to damage of the mitotic spindle and phragmoplast. Careful use of cacodylate buffer in ultrastructural studies of microtubules is advised.

scholarly journals Incorporation of thymidine into onion root meristematic cell nuclei in presence of hydroxyurea and its role in recovery of mitotic activity

2015 ◽  
Vol 46 (4) ◽  
pp. 701-711
Author(s):  
H. Habdas
Keyword(s):  
S Phase ◽  
The Other ◽  
Cell Nuclei ◽  
Onion Root ◽  
Meristematic Cells ◽  
Hydroxyurea Treatment ◽  
Mitotic Block ◽  
Root Meristematic Cells ◽  
Mitotic Figures ◽  
Root Meristematic Cell

Hydroxyurea treatment of onion roots induced mitotic block which was released by transfer of bulbs to water, and also to some extent by addition of cold or <sup>3</sup>H-thymidine to hydroxyurea solutions. In presence of hydroxyurea there was noted very intense incorporation of <sup>3</sup>H-thymidine into cell nuclei, giving labelling index of 40-70%. However, all the mitotic figures appearing in presence of hydroxyurea and <sup>3</sup>H-thymidine were unlabelled. On the other hand, labelled mitotic figures were obtained when roots incubated with <sup>3</sup>H-thymidine in presence of hydroxyurea had been transferred to water. Incorporation of <sup>3</sup>H-uridine was unaffected by hydroxyurea. The results show that hydroxyurea arrests onion root meristematic cells, either in the S phase and the G<sub>2</sub> phase. Enhanced incorporation of <sup>3</sup>H-thymidine in the presence of hydroxyurea, and release by added thymidine of the mitotic block indicate that hydroxyurea induces in onion root meristematic cells a particular shortage of thymidylate.

scholarly journals A LIGHT AND ELECTRON MICROSCOPE STUDY OF SMALL, SPHERICAL NUCLEAR BODIES IN MERISTEMATIC CELLS OF ALLIUM CEPA, VICIA FABA, AND RAPHANUS SATIVUS

1965 ◽  
Vol 26 (1) ◽  
pp. 1-17 ◽  
Author(s):  
J. G. Lafontaine
Keyword(s):  
Vicia Faba ◽  
Allium Cepa ◽  
Raphanus Sativus ◽  
Ultrastructural Level ◽  
Nuclear Bodies ◽  
Meristematic Cells ◽  
Azure B ◽  
The Common ◽  
Chromosomal Loci ◽  
Common Association

Interphase, preprophase, and prophase nuclei of meristematic cells of Allium cepa, Vicia faba, and Raphanus sativus are characterized by the presence of spherical bodies approximately 1 µ in diameter. These structures are Feulgen-negative but stain metachromatically with azure B, as the nucleolus, following fixation with glutaraldehyde. At the ultrastructural level, they consist predominantly of fibrils estimated to be between 70 and 100 A in diameter which greatly resemble those found within certain zones of the nucleolus in these plant species. Moreover, in Allium cepa, these spherules often exhibit dense particles which are also found within the fibrillar zones of the nucleolus in this species. The observations that the bodies in question are frequently located at the surface of the nucleolus and moreover show cytochemical and ultrastructural similarities with this organelle suggest that they may originate from the nucleolus. However, the common association of the spherules with chromosome strands may indicate instead that these bodies represent extranucleolar ribonucleoprotein materials synthesized by specific chromosomal loci.

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