scholarly journals Effect of methotrexate on the ultrastructure of Alliurn ceps L. and Haemanthus albiflos Jacq. roots cultured under anaerobic conditions

2014 ◽  
Vol 50 (4) ◽  
pp. 557-561 ◽  
Author(s):  
Maria Podbielkowska

Changes were found in the cell structure of the root meristems of <em>Haemanthus albiflos</em> and <em>Allium cepa</em> treated with methotrexate, an oncostatic preparation of the antimetabolite group. Root culture was conducted under anaerorbic conditions to induce In this way glycolysis typical for neoplastic cells. In <em>Haemanthus</em>, where the glycolytilc process runs normally, hypertrophy of the rough ER membranes noted correlated with the presence of numerous mitochondria and dictyasames with changed Structure. In <em>Allium</em> cells, where the glycalytic process runs with the participation of alliin, methotrexate did not evoke development of ER membranes. The structure of mitochondria and dictyosomes was similar as that in the root meristem of <em>Haemanthus</em>. In both studied objects thickening of the cell wall was noted.

Revista CERES ◽  
2016 ◽  
Vol 63 (5) ◽  
pp. 646-652
Author(s):  
Magda Andréia Tessmer ◽  
Beatriz Appezzato-da-Glória ◽  
Ricardo Alfredo Kluge

ABSTRACT ʻGiomboʼ is one of most cultivated persimmon cultivars in Brazil. It is a late-harvest cultivar and requires treatment for astringency removal. The aim of this study was to evaluate the efficiency of ethanol and the effect of harvest time on reducing astringency, physicochemical and anatomical characteristics of 'Giombo' persimmon. Two experiments were carried out, one in each growing season, with five treatments corresponding to exposure to 1.70 mL kg-1ethanol for 0, 12, 24, 36 and 48 hours. At the end of the growing season (2011) the fruits achieved the astringency index and levels of soluble tannins suitable for consumption in 24 hours, and at the beginning of the growing season (2012) in 36 hours, indicating that the efficiency of the treatment is related to harvest time and ethanol exposure time. Astringency removal with ethanol affects the cell structure with accumulation of substances inside the cells and in intercellular spaces, resulting in the degradation of the parenchyma cell wall. To avoid such damage and maintain fruit quality, it is recommended the combination of low ethanol doses with less ethanol exposure time.


1976 ◽  
Vol 22 (2) ◽  
pp. 403-411 ◽  
Author(s):  
M.J. Packard ◽  
S.M. Stack

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.


2009 ◽  
Vol 15 ◽  
pp. 83-88 ◽  
Author(s):  
Prabhakar Bhatta ◽  
S. R. Sakya

The mitotic activity and chromosomal behaviour was observed in four different concentrations of magnesium sulphate at four different duration of treatment using Allium cepa as a biological system. Mito-inhibitory effect of the compound was observed in higher concentration. The compound was capable of producing various chromosomal abnormalities indicating the cytostatic and clastogenic properties of magnesium sulphate. Key words: Allium cepa, magnesium sulphate, mitotic index, phase indices.doi: 10.3126/eco.v15i0.1947 ECOPRINT 15: 83-88, 2008


2019 ◽  
pp. 71-78

EFECTOS DEL SORBATO DE POTASIO A DIFERENTES CONCENTRACIONES y TIEmPO DE ExPOSICIóN SOBRE EL CICLO CELULAR y EL mATERIAL GENÉTICO EN mERISTEmOS RADICULARES DE AllIuM CEPA l. (CEBOLLA) EFFECT OF POTASSIUm SORBATE AT DIFFERENT CONCENTRATIONS AND ExPOSURE TImE ON THE CELL CyCLE AND THE GENETIC mATERIAL IN ROOT mERISTEmS OF AllIuM CEPA l “ONION” Joselyne Quispe, José Saldaña, Tony Verde y Shirley Valderrama Universidad Nacional de Trujillo, Trujillo,Perú DOI: https://doi.org/10.33017/RevECIPeru2010.0011/ RESUMEN Con el propósito de determinar el efecto del Sorbato de Potasio sobre el ciclo celular en meristemos radiculares de Allium cepa L. “cebolla” se establecieron tres grupos experimentales que se expusieron a las soluciones de Sorbato de Potasio en concentraciones de 0.5, 1 y 2 g/L; por 6, 7 y 8 horas cada una y un grupo control. Luego se realizó la respectiva coloración en Orceína acética al 2% de acuerdo a la técnica de Tjio y Levan, observándose con el microscopio compuesto un total de 1500 células meristemáticas en cada uno de los tratamientos. Los resultados aplicando tratamiento después de 8 horas de exposición a la concentración de 2 g/L mostraron una disminución del índice mitótico de 11.26 %, mientras que se incrementó el índice profásico en 95.57 %. Se produjeron también alteraciones como rupturas cromosómicas, puentes anafásicos y células binucleadas. Las pruebas y análisis de varianza, mostraron diferencias significativas entre los diferentes tratamientos, confirmado mediante la prueba de comparación múltiple de promedios de Duncan. Se evidencia un probable efecto genotóxico en el material genético por el Sorbato de Potasio y una alteración en el ciclo celular de los meristemos de A. cepa L.; así mismo, se comprueba la función de biosensor de A. cepa L. en el estudio de sustancias que puedan afectar el ciclo celular. Palabras clave: Allium cepa, Sorbato de Potasio, Índice Mitótico, Alteración del material genético, Puentes anafásicos, Rupturas cromosómicas, Células binucleadas. ABSTRACT In order to determine the effect of Potassium Sorbate on the cell cycle in root meristems of Allium cepa L. “onion” set three experimental groups were exposed to solutions of Potassium Sorbate at concentrations of 0.5, 1 and 2g /l, for 6, 7 and 8 hours each and a control group. Later the respective color in 2% Acetic orcein according to the technique of Tjio and Levan, observed with the compound microscope a total of 1500 meristematic cells in each of the treatments. The appropriate treatment results after 8 hours of exposure to the concentration of 2 g / L showed a decrease in mitotic index of 11.26%, while it increased the rate at 95.57% prophasic index. There were also alterations as chromosome breaks, anaphasic bridges and binucleated cells. The tests and analysis of variance showed significant differences between the different treatments, as confirmed by multiple comparison test of Duncan averages. It shows a probable genotoxic effect in the genetic material by Potassium Sorbate and an alteration in the cell cycle of meristems of A. cepa L., likewise, is found biosensor function of A. cepa L. in the study of substances that may affect the cell cycle. Keywords: Allium cepa, Potassium Sorbate, Mitotic index, Abnormal genetic material, Chromosomal breaks, Anafasic bridges, Binucleated cells.


Mutagenesis ◽  
1997 ◽  
Vol 12 (4) ◽  
pp. 265-269 ◽  
Author(s):  
Samanta S. Khora ◽  
Kamal K. Panda ◽  
Brahma B. Panda

2020 ◽  
Vol 188 ◽  
pp. 109786
Author(s):  
Arvind Kumar ◽  
Shalinder Kaur ◽  
Shikha Chandel ◽  
Harminder Pal Singh ◽  
Daizy Rani Batish ◽  
...  

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 938 ◽  
Author(s):  
Wu ◽  
Wu ◽  
Shi ◽  
Chen ◽  
Wang ◽  
...  

In this study, the microstructure and mechanical properties of poplar (Populus tomentosa) catkin fibers (PCFs) were investigated using field emission scanning electron microscope, atomic force microscopy (AFM), X-ray diffraction, and nanoindentation methods. Experimental results indicated that PCFs had a thin-wall cell structure with a large cell lumen and the hollow part of the cell wall took up 80 percent of the whole cell wall. The average diameters of the fiber and cell lumen, and the cell wall thickness were 5.2, 4.2, and 0.5 µm, respectively. The crystallinity of fibers was 32%. The AFM images showed that the orientation of microfibrils in cell walls was irregular and their average diameters were almost between 20.6–20.8 nm after being treated with 2 and 5 wt.% potassium hydroxide (KOH), respectively. According to the test of nanoindentation, the average longitudinal-reduced elastic modulus of the PCF S2 layer was 5.28 GPa and the hardness was 0.25 GPa.


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