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.

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 Structure and Mode of Formation of the Nucleolus in Meristematic Cells of Vicia faba and Allium cepa

1958 ◽  
Vol 4 (6) ◽  
pp. 777-784 ◽  
Author(s):  
J. G. Lafontaine
Keyword(s):  
Vicia Faba ◽  
Allium Cepa ◽  
Mitotic Cycle ◽  
Outer Cortex ◽  
Distinctive Character ◽  
Small Bodies ◽  
Meristematic Cells ◽  
Late Anaphase ◽  
Character Evidence ◽  
Dense Substance

Interphase nucleoli from Vicia faba and Allium cepa meristematic cells are roughly classified into two categories: (a) those that commonly show a rather homogeneous texture (except for small light spaces of various sizes) and frequently contain dense particles 140 A in diameter; (b) those found more frequently in Vicia characterized by a very sharp boundary between a dense outer cortex and a much lighter central core. The dense particles are not found in such nucleoli. In Allium the boundary is more irregular and dense particles are sometimes observed in the outer layer. Many nucleoli show a structure intermediate between these two types. They are characterized by a gradient of increasing density from the center to the periphery and occasionally contain dense 140 A granules. During interphase, certain nucleoli are closely associated with segments of chromatin strands which undoubtedly represent nucleolar organizing regions. The dense 140 A granules are followed during the mitotic cycle. In Allium, they are first seen in loose clusters between arms of late anaphase chromosomes where they become more concentrated in early telophase. The substance within which they are scattered slowly increases in density during that time until finally, the particles are limited to small bodies of distinctive character. Evidence is presented suggesting that these small prenucleolar bodies fuse during telophase to give rise to the mature interphase nucleoli. Similar events are described in Vicia material except that a coating of dense substance appears around telophase chromosomes before the formation of prenucleolar bodies.

The preprophase band: possible involvement in the formation of the cell wall

1976 ◽  
Vol 22 (2) ◽  
pp. 403-411 ◽  
Author(s):  
M.J. Packard ◽  
S.M. Stack
Keyword(s):  
Cell Wall ◽  
Allium Cepa ◽  
Cell Walls ◽  
Preprophase Band ◽  
Adjacent Cell ◽  
Root Tips ◽  
Meristematic Cells ◽  
Narrow Region ◽  
The Matrix

Numerous vesicles were observed among the microtubules of the “preprophase” band in prophase cells from root tips of Allium cepa. The content of these vesicles looks similar to the matrix of adjacent cell walls, and these vesicles often appear to be involved in exocytosis. In addition, the cell walls perpendicular to the plane of (beneath) the preprophase band are often differentially thickened compared to the walls lying parallel to the plane of the band. Our interpretation of these observations is that the preprophase band may direct or channel vesicles containing precursors of the cell wall to localized regions of wall synthesis. The incorporation of constituents of the cell wall into a narrow region defined by the position of the preprophase band may be a mechanism that ensures unidirecitonal growth of meristematic cells.

scholarly journals Antiproliferative effect of the hydroalcoholic extract of Hymenaea stigonocarpa Mart. ex Hayne (Fabaceae, Caesalpinioideae) on the meristematic cells of Allium cepa L. roots

Biotemas ◽  
2014 ◽  
Vol 28 (1) ◽  
pp. 45 ◽  
Author(s):  
Layana Menezes da Silva ◽  
Ana Paula Peron ◽  
Francisco Ronielson da Silva Carvalho ◽  
Livia Martins ◽  
Iana Felício Bantim Calou ◽  
...  
Keyword(s):  
Allium Cepa ◽  
Antiproliferative Effect ◽  
Hydroalcoholic Extract ◽  
Meristematic Cells ◽  
Allium Cepa L

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.

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