Lead translocation and localization in Allium cepa roots

1987 ◽  
Vol 65 (9) ◽  
pp. 1851-1860 ◽  
Author(s):  
Małgorzata Wierzbicka
Keyword(s):  
Allium Cepa ◽  
Cell Walls ◽  
Middle Lamella ◽  
Root Surface ◽  
Root Tip ◽  
Meristematic Zone ◽  
Ultrastructural Studies ◽  
Lead Salts ◽  
Allium Cepa L ◽  
Lead Translocation

Based on autoradiographic (210Pb) and ultrastructural studies, it was determined that lead is taken up from solution with the same intensity along the length of Allium cepa L. roots. As expected, the rate of uptake is dependent on the lead concentration and exposure time of the roots to lead salts. Lead takes about 80 min to penetrate radially through consecutive root tip layers in the meristematic zone. Lead is first deposited on the root surface, and then is translocated radially through the middle lamella (apoplast) of root cap cells. The lead reaches protoderm cells and meristematic cells of the hypodermis, where it penetrates into the symplast. Lead passes through consecutive ground meristem tissue layers at the rate of 1 cell layer/5 min. Its deposition in the ground meristem tissue is surprisingly nonuniform. It is deposited uniformly in the first six layers, but in the deeper (7th to 10th) layers, lead deposits are encountered in intercellular spaces and the middle lamellae, then in the cell walls near the plasmalemma, and finally in vacuoles.

scholarly journals Domain-specific and cell type-specific localization of two types of cell wall matrix polysaccharides in the clover root tip.

1992 ◽  
Vol 118 (2) ◽  
pp. 467-479 ◽  
Author(s):  
M A Lynch ◽  
L A Staehelin
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cellular Differentiation ◽  
Cortical Cell ◽  
Middle Lamella ◽  
Root Cap ◽  
Root Tip ◽  
Cortical Cells ◽  
Peripheral Cell ◽  
Clover Root

Using immunocytochemical techniques and antibodies that specifically recognize xyloglucan (anti-XG), polygalacturonic acid/rhamnogalacturonan I (anti-PGA/RG-I), and methylesterified pectins (JIM 7), we have shown that these polysaccharides are differentially synthesized and localized during cell development and differentiation in the clover root tip. In cortical cells XG epitopes are present at a threefold greater density in the newly formed cross walls than in the older longitudinal walls, and PGA/RG-I epitopes are detected solely in the expanded middle lamella of cortical cell corners, even after pretreatment of sections with pectinmethylesterase to uncover masked epitopes. These results suggest that in cortical cells XG and PGA/RG-I are differentially localized not only to particular wall domains, but also to particular cell walls. In contrast to their nonoverlapping distribution in cortical cells, XG epitopes and PGA/RG-I epitopes largely colocalize in the epidermal cell walls. The results also demonstrate that the middle lamella of the longitudinal walls shared by epidermal cells and by epidermal and cortical cells constitutes a barrier to the diffusion of cell wall and mucilage molecules. Synthesis of XG and PGA/RG-I epitope-containing polysaccharides also varies during cellular differentiation in the root cap. The differentiation of gravitropic columella cells into mucilage-secreting peripheral cells is marked by a dramatic increase in the synthesis and secretion of molecules containing XG and PGA/RG-I epitopes. In contrast, JIM 7 epitopes are present at abundant levels in columella cell walls, but are not detectable in peripheral cell walls or in secreted mucilage. There were also changes in the cisternal labeling of the Golgi stacks during cellular differentiation in the root tip. Whereas PGA/RG-I epitopes are detected primarily in cis- and medial Golgi cisternae in cortical cells (Moore, P. J., K. M. M. Swords, M. A. Lynch, and L. A. Staehelin. 1991. J. Cell Biol. 112:589-602), they are localized predominantly in the trans-Golgi cisternae and the trans-Golgi network in epidermal and peripheral root cap cells. These observations suggest that during cellular differentiation the plant Golgi apparatus can be both structurally and functionally reorganized.

scholarly journals Effect of Ferrous Gluconate on Chromosomal Abnormality Index of Allium Cepa Root Tip

2021 ◽  
Vol 9 (4) ◽  
pp. 755-758
Author(s):  
Nergis Kaya
Keyword(s):  
Allium Cepa ◽  
Chromosomal Aberration ◽  
Chromosomal Abnormality ◽  
Genotoxic Effect ◽  
Root Tip ◽  
Control Group ◽  
Root Tips ◽  
Ferrous Gluconate ◽  
Allium Cepa L ◽  
Abnormality Index

In completed research, ferrous gluconate -a food additive- used to preserve black color to prevent discoloration during storage in ripe black olives, and Allium cepa L. species. A. cepa L. roots were treated with different doses of ferrous gluconate. The effective concentration EC50 (0.068 g/l) was determined. A. cepa root tips were treated with EC50/2 (0.034 g/l), EC50 (0.068 g/l), 2XEC50 (0.136 g/l) dose for 24, 48, 72 hours, and afterward, the root tips were prepared for observation under the light microscope according to the method of preparing mitotic preparation. Chromosomal abnormality index (CAI) and genotoxic effect of ferrous gluconate in A. cepa root tip cells were determined. Repeated measurement ANOVA and TUKEY multiple comparison tests were used to investigate the effect of time and dose together on genotoxicity. C-mitosis, polyploidy, polar shifting in anaphase, polar shifting in telophase, equatorial plate shifting, laggard chromosome was observed by microscope. The highest CAI (70.16±4.85) was observed at 72h for 2XEC50 dose. Chromosomal aberration is also observed in control group. While the most common chromosomal aberration is determined as C-mitosis; The least observed chromosomal aberration is determined as polyploidy. Research results revealed that ferrous gluconate has a genotoxic effect on the root tip of A. cepa.

scholarly journals Effect of triazophos on mitotic activity and chromosomal behavior in root meristems of Allium cepa L.

2010 ◽  
Vol 6 ◽  
pp. 4-7 ◽  
Author(s):  
Archana Pandey ◽  
Shyam R Sakya
Keyword(s):  
Mitotic Activity ◽  
Allium Cepa ◽  
Root Meristem ◽  
Plant Science ◽  
Root Tip ◽  
Allium Cepa L ◽  
Meristematic Region ◽  
Cellular Abnormalities ◽  
Tip Cells ◽  
Root Tip Cells

Effect of triazophos (an organophosphorous insecticide) on mitotic activity and chromosomal behavior in the meristematic region of root tip cells of Allium cepa L. was assessed. The insecticide showed mitotic depression and positive chromo-toxic effects. Abnormalities, such as stickiness, plasmolysed cells, equatorial plate shifting, polar shifting, irregular chromosome arrangement, precocious arms formation, bridge formation, C-metaphase, fragmentation of chromosomes, unequal cytokinesis, diagonal cytokinesis, delayed cytokinesis and formation of binucleated cells, were recorded in the chemically pretreated root meristem. Key-words: chromosomal and cellular abnormalities; cytotoxic effect; mitotic index; phase indices.DOI: 10.3126/botor.v6i0.2903 Botanica Orientalis - Journal of Plant Science (2009) 6: 4-7

scholarly journals Cytogenetic effect of crude aqueous extract from leaf of Lycium barbarum on root tip of Allium cepa L.

2008 ◽  
Vol 5 (4) ◽  
pp. 492-499
Author(s):  
Baghdad Science Journal
Keyword(s):  
Mitotic Index ◽  
Chromosome Aberration ◽  
Allium Cepa ◽  
Aqueous Extract ◽  
Sublethal Effect ◽  
Root Tip ◽  
Lycium Barbarum ◽  
Phase Index ◽  
Allium Cepa L ◽  
Crude Aqueous Extract

This study was carried out to investigate the cytogenetic effects of crude aqueous extract of Lycium barbarum on the roots tip of Allium cepa Using three concentration 125, 25, 50 mg/ ml for 2, 4, 6 hours treatment periods.This study were included some cytogenetic analysis such as mitotic index , phase index and chromosome aberration. The data showed that the treatment with 50mg/ml for 6huors led to reduce the mitotic index less than 50% . This reduction considered to have toxic and sublethal effect . These results revealed mutagenic potency by inducing differents type of chromosome aberration.

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