Sites of Protein Synthesis in Nucleoli of Root Meristematic Cells of Allium Cepa As Shown By Radioautography With [3H]Arginine

1967 ◽  
Vol 2 (4) ◽  
pp. 473-480
Author(s):  
L. A. CHOUINARD ◽  
C. P. LEBLOND
Keyword(s):  
Protein Synthesis ◽  
Electron Microscope ◽  
Allium Cepa ◽  
Chase Period ◽  
Meristematic Cells ◽  
Root Meristematic Cells ◽  
Silver Grains

The interphase nucleolus in root meristematic cells of Allium cepa may be divided into four regions, three of which are always present: the fibrillar, granular and lacunar regions, while the fourth or vacuolar region may be missing. The sites of protein synthesis in nucleoli were investigated by means of light and electron-microscope radioautography after a 5-min immersion of the roots in a solution of [3H]arginine. The radioautographs of interphase nucleoli showed many silver grains over both the fibrillar and the granular regions. Occasional silver grains were also recorded over, or close to, the lacunar regions, but none were over the vacuolar regions. A 15-min chase period did not change the radioautographic pattern. It is concluded that the three permanent regions of the interphase nucleoli, namely the fibrillar, the granular and the DNA-containing lacunar regions, are sites of protein synthesis.

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 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.

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.

scholarly journals Effect of water extract from leaves of Nerium oleander L. on mitosis

2015 ◽  
Vol 40 (4) ◽  
pp. 623-631
Author(s):  
J. A. Tarkowska
Keyword(s):  
Electron Microscope ◽  
Allium Cepa ◽  
Mitotic Spindle ◽  
Water Extract ◽  
Water Soluble ◽  
Nerium Oleander ◽  
Root Tips ◽  
Meristematic Cells ◽  
Effect Of Water

The effect of water extract from leaves of <i>Nerium oleander</i> L. on the mitosis in meristematic cells of <i>Allium cepa</i> L. root tips has been studied. Observations were made on the changes during incubation and postincubation. Significant disturbances were observed in the development of the mitotic spindle leading to the formation of polyploid and hypoploid nuclei capable of further division. Substances contained in the water extract, and causing the disturbances, are water soluble glycosides. Introductory observations under an electron microscope indicate that the glycosides desorganize the continuous fibres of the spindle which can be considered as the direct cause of the observed disturbances.

Cytogenetic Responses of Plant Root Meristematic Cells to the Arsenic (III) Contaminated Groundwater in Eastern Parts of Burdwan District, W.B., India

2015 ◽  
Vol 1 (01) ◽  
pp. 79-84
Author(s):  
Abhijit Bandyopadhyay
Keyword(s):  
Mitotic Activity ◽  
Allium Cepa ◽  
Arsenic Concentration ◽  
In Situ Monitoring ◽  
Contaminated Groundwater ◽  
Eastern Region ◽  
Root Cells ◽  
Meristematic Cells ◽  
Allium Cepa L ◽  
Root Meristematic Cells

Both geogenic and anthropogenic activities have resulted in arsenic pollution of groundwater especially in the Eastern region of Burdwan district in West Bengal. Response of Allium cepa L. genetic material to the presence of potential cytotoxic and genotoxic substances in aquatic environment was used to evaluate the arsenic contaminated groundwater-induced genotoxicity and hormesis. For in situ monitoring of the cytotoxicity level, the inhibition of mitosis in root meristematic cells was assayed. To study genotoxicity, micronucleus assay and DNA purity assay (by A260/280 ratio) were used. Treatment for 4 days of newly developed roots of Allium cepa L. with water samples with arsenic content 50 μg L-1 exhibited stimulation in mitotic activity whereas samples with arsenic 1000 μg L-1 showed inhibition of mitotic activity apparently indicating hormesis. Inhibition of mitosis was compared with the concentration dependent increase in generation of reactive oxygen species (ROS), cell death, decrease in activity of antioxidative enzymes (catalase, superoxide dismutase), the absorbance ratio (A260/280) of DNA, or micronuclei in root cells. These findings indicated that contaminated groundwater depending on the magnitude of the arsenic concentration, might either be mitogenic or mitostatic/toxic, which in turn has obvious implications in agriculture and human health.

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