scholarly journals Facilitated transport of Mn2+ in sycamore (Acer pseudoplatanus) cells and excised maize root tips. A comparative 31P n.m.r. study in vivo

1988 ◽  
Vol 252 (2) ◽  
pp. 401-408 ◽  
Author(s):  
C Roby ◽  
R Bligny ◽  
R Douce ◽  
S I Tu ◽  
P E Pfeffer
Keyword(s):  
Metal Ion ◽  
Plasma Membranes ◽  
Maize Root ◽  
Root Tip ◽  
Acer Pseudoplatanus ◽  
Relative Distribution ◽  
Root Tips ◽  
Root Cells ◽  
Hypoxic Conditions

Movement of paramagnetic Mn2+ into sycamore (Acer pseudoplatanus) cells has been indirectly examined by observing the line broadening exhibited in its 31P n.m.r. spectra. Mn2+ was observed to pass into the vacuole, while exhibiting a very minor accumulation in the cytoplasm. With time, gradual leakage of phosphate from the vacuole to the cytoplasm was observed along with an increase in glucose-6-phosphate. Anoxia did not appear to affect the relative distribution of Mn2+ in the cytoplasm and vacuole. Under hypoxic conditions restriction of almost all movement of Mn2+ across the plasmalemma as well as the tonoplast was observed. In contrast, maize root tips showed entry and complete complexation of nucleotide triphosphate by Mn2+ during hypoxia. The rate of passage of Mn2+ across the tonoplast in both sycamore and maize root cells is approximately the same. However, the rates of facilitated movement across the respective plasma membranes appear to differ. More rapid movement of Mn2+ across the plasmalemma in maize root tip cells allows a gradual build-up of metal ion in the cytoplasm prior to its diffusion across the tonoplast. Sycamore cells undergo a slower uptake of Mn2+ into their cytoplasms (comparable with the rate of diffusion through the tonoplast), so little or no observable accumulation of Mn2+ is observed in this compartment.

Location of fucosyl transferases in the membrane system of maize root cells

1979 ◽  
Vol 40 (1) ◽  
pp. 235-244
Author(s):  
J.R. Green ◽  
D.H. Northcote
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Sucrose Gradient ◽  
Maize Root ◽  
Transferase Activity ◽  
Root Tips ◽  
Root Cells ◽  
Discontinuous Sucrose Gradient

There are two fucosyl transferase activities present within the endomembranes of the cells of maize root-tips. One transfers fucose to polyprenyl phosphate and occurs in the endoplasmic reticulum, the second transfers fucose probably to polysaccharide or glycoprotein. In order to show an association of this second fucosyl transferase activity with the endoplasmic reticulum as well as the Golgi apparatus, a method of fractionating the membranes in a discontinuous sucrose gradient was used. Membranes were prepared in the presence of Mg2+, which maintained the attachment of ribosomes to the endoplasmic reticulum, and also in the presence of EDTA, which removed most of the ribosome complex. This caused a shift in density of these membranes. Two types of experiments were carried out; either maize roots were incubated in L-[1-3H]fucose and then membranes prepared and the amount of polymer synthesized in vivo determined or isolated membranes were incubated with GDP-L-[U-14C]fucose in vitro and the amount of polymer synthesized was found. The results showed that the Golgi apparatus had the highest amount of this fucosyl transferase activity, but there was a significant amount of activity associated with the endoplasmic reticulum and the latter was shifted in the sucrose gradient depending on the conditions used.

scholarly journals The Endoplasmic Reticulum and the Golgi Structures in Maize Root Cells

1959 ◽  
Vol 5 (3) ◽  
pp. 501-506 ◽  
Author(s):  
W. Gordon Whaley ◽  
Hilton H. Mollenhauer ◽  
Joyce E. Kephart
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Electron Microscope ◽  
Nuclear Envelope ◽  
Epoxy Resin ◽  
Maize Root ◽  
Root Tips ◽  
Animal Cells ◽  
Root Cells ◽  
Vesicular Structure

Maize root tips were fixed in potassium permanganate, embedded in epoxy resin, sectioned to show silver interference color, and studied with the electron microscope. All the cells were seen to contain an endoplasmic reticulum and apparently independent Golgi structures. The endoplasmic reticulum is demonstrated as a membrane-bounded, vesicular structure comparable in many aspects to that of several types of animal cells. With the treatment used here the membranes appear smooth surfaced. The endoplasmic reticulum is continuous with the nuclear envelope and, by contact at least, with structures passing through the cell wall. The nuclear envelope is characterized by discontinuities, as previously reported for animal cells. The reticula of adjacent cells seem to be in contact at or through the plasmodesmata. Because of these contacts the endoplasmic reticulum of a given cell appears to be part of an intercellular system. The Golgi structures appear as stacks of platelet-vesicles which apparently may, under certain conditions, produce small vesicles around their edges. Their form changes markedly with development of the cell.

scholarly journals Cytogenetic impact of sodium chloride stress on root cells of Vigna radiata L. seedlings

2020 ◽  
Vol 45 (2) ◽  
Author(s):  
Jabeen Farheen ◽  
Simeen Mansoor
Keyword(s):  
Mitotic Division ◽  
Root Tip ◽  
Ecological Problem ◽  
Root Tips ◽  
Root Cells ◽  
Nacl Concentration ◽  
Seedling Roots ◽  
Metaphase Stage ◽  
Tip Cells ◽  
Root Tip Cells

AbstractObjectivesThe high salinization stress to seedling is the substantial ecological problem in the ongoing era. It negatively influences the growth that retard mitotic division by enhancing aberrations in nuclear chromatin. In the light of these views, the current work was designed to investigate the response of Vigna seedlings root tip cells to the presence of NaCl ions.Materials and methodsNM-92 and NM19-19 seeds were imbibed separately in distilled water for 24 h and allowed to grow into 0, 50, 150, 250, and 350 mM NaCl solution for 24 h. Excised root tips were stained, and slides were scored at 100× objective for the mitotic index (MI) and chromosomal aberrations.ResultsOur data demonstrated that as NaCl molarity increased, the MI was declined along with various chromatin abnormalities. The 150 mM of NaCl showed more lagging (69%) of chromosomes during anaphase in NM19-19. The highest stickiness at metaphase stage (68%) was found in 250 mM NaCl in variety NM19-19. However, both varieties were differed non-significantly for c-mitosis that was recorded 99% at 350 mM NaCl concentration.ConclusionsThe NaCl ions toxicity induced various cytological anomalies in seedling roots that adversely affect the growth of Vigna seedlings.

Cell synchronization and isolation of metaphase chromosomes from maize (Zea mays L.) root tips for flow cytometric analysis and sorting

Genome ◽  
1996 ◽  
Vol 39 (4) ◽  
pp. 697-703 ◽  
Author(s):  
Jai-Heon Lee ◽  
K. Arumuganathan ◽  
S. M. Kaeppler ◽  
C. M. Papa ◽  
H. F. Kaeppler
Keyword(s):  
Cell Cycle ◽  
Flow Cytometric Analysis ◽  
Maize Root ◽  
Root Tip ◽  
Root Tips ◽  
Chromosome Sorting ◽  
Synthesis Inhibitor ◽  
Metaphase Chromosomes ◽  
Flow Karyotype ◽  
Flow Cytometric

Accumulation of cells containing metaphase chromosomes is an important step in cytological analyses and chromosome sorting procedures. The goal of this research was to optimize treatment parameters to synchronize the cell cycle of maize root tip meristem cells. Levels of hydroxyurea, a DNA synthesis inhibitor, were assessed for their utility in accumulating cells at the G1 phase of the cell cycle. Trifluralin, amiprophos-methyl, and colchicine were used to accumulate cells containing metaphase chromosomes upon release from hydroxyurea inhibition. Optimal mitotic indices were achieved by treating seedlings with 5 mM hydroxyurea for 18 h, incubating for 1 h without chemical treatment to release the hydroxyurea block, and then treating emerging roots with 1 μM trifluralin for 4 h. The mitotic index of synchronized maize root tips was over 70%. Uniformity of synchronization depended upon selection of seeds with emerging radicles that were similar in length at the time of treatment. Suspensions of intact chromosomes were prepared by a simple slicing procedure. The chromosome preparations were found to be suitable for flow cytometric characterization and sorting. Chromosome peaks of the observed flow karyotype resembled the predicted flow karyotype calculated on the basis of maize chromosome size. Key words : flow karyotype, hydroxyurea, plant chromosome sorting, trifluralin.

Changes in lipid composition of oat root membranes as a function of water-deficit stress

1985 ◽  
Vol 63 (2) ◽  
pp. 77-84 ◽  
Author(s):  
C. Liljenberg ◽  
M. Kates
Keyword(s):  
Fatty Acids ◽  
Plasma Membrane ◽  
Water Deficit ◽  
Lipid Composition ◽  
Membrane Fraction ◽  
Plasma Membranes ◽  
Root Tip ◽  
Water Deficit Stress ◽  
Root Cells ◽  
Steryl Esters

The effect of repeated water-deficit stress on the lipid composition of root cells from 5-day-old oat (Avena sativa L. cv. Seger) seedlings was studied. The content of total acyl lipids was found to decrease with increasing degree of water-deficit stress, owing largely to decreases in free fatty acids, triglycerides, phosphatidylethanolamine (PE), wax esters, steryl esters, and acylated steryl glycosides. Major polar lipids both in total root cells and in the plasma membrane enriched fraction, as well as the microsomal membrane fraction, were PE, phosphatidylcholine (PC), digalactosyldiacylglycerol (DGDG), monogalactosyldiacylglycerol (MGDG), and polyglycolipid. Decreases in the degree of unsaturation of the fatty acids as a funtion of increased water-deficit stress were observed for the MGDG and polyglycolipid components of total root cells and for the MGDG, DGDG, and polyglycolipid of the plasma membrane fraction. Electron microscopy showed that stressed root tip cells had much smoother plasma membranes than those of control unstressed root cells. These results suggest that root cells of oat seedlings respond to water-deficit stress by reducing the total plasma membrane mass and degree of lipid fluidity, which would reduce the water permeability of the plasma membranes and help maintain cell turgidity.

scholarly journals Rhizophagy Cycle: An Oxidative Process in Plants for Nutrient Extraction from Symbiotic Microbes

2018 ◽  
Vol 6 (3) ◽  
pp. 95 ◽  
Author(s):  
James White ◽  
Kathryn Kingsley ◽  
Satish Verma ◽  
Kurt Kowalski
Keyword(s):  
Cell Walls ◽  
Plasma Membranes ◽  
Reactive Oxygen ◽  
Root Tip ◽  
Free Living ◽  
Root Cells ◽  
Cell Plasma ◽  
Cell Shapes ◽  
Bacteria And Fungi ◽  
Nutrient Extraction

In this paper, we describe a mechanism for the transfer of nutrients from symbiotic microbes (bacteria and fungi) to host plant roots that we term the ‘rhizophagy cycle.’ In the rhizophagy cycle, microbes alternate between a root intracellular endophytic phase and a free-living soil phase. Microbes acquire soil nutrients in the free-living soil phase; nutrients are extracted through exposure to host-produced reactive oxygen in the intracellular endophytic phase. We conducted experiments on several seed-vectored microbes in several host species. We found that initially the symbiotic microbes grow on the rhizoplane in the exudate zone adjacent the root meristem. Microbes enter root tip meristem cells—locating within the periplasmic spaces between cell wall and plasma membrane. In the periplasmic spaces of root cells, microbes convert to wall-less protoplast forms. As root cells mature, microbes continue to be subjected to reactive oxygen (superoxide) produced by NADPH oxidases (NOX) on the root cell plasma membranes. Reactive oxygen degrades some of the intracellular microbes, also likely inducing electrolyte leakage from microbes—effectively extracting nutrients from microbes. Surviving bacteria in root epidermal cells trigger root hair elongation and as hairs elongate bacteria exit at the hair tips, reforming cell walls and cell shapes as microbes emerge into the rhizosphere where they may obtain additional nutrients. Precisely what nutrients are transferred through rhizophagy or how important this process is for nutrient acquisition is still unknown.

scholarly journals Polyprenyl phosphate sugars synthesized during slime-polysaccharide production by membranes of the root-cap cells of maize (Zea mays)

1979 ◽  
Vol 178 (3) ◽  
pp. 661-671 ◽  
Author(s):  
J R Green ◽  
D H Northcote
Keyword(s):  
Endoplasmic Reticulum ◽  
Zea Mays ◽  
Neutral Lipids ◽  
Root Tip ◽  
Synthetase Activity ◽  
Root Tips ◽  
Maize Roots ◽  
Glucose Derivatives

Two types of experiments were carried out; either maize roots were incubated in L-[1-3H]fucose or membranes were prepared from root tips and these were incubated with GDP-L-[U-14C]fucose or UDP-D-[U-4C]glucose. The radioactively labelled lipids that were synthesized in vivo and in vitro were extracted and separated into polar and neutral components. The polar lipids had the characteristics of polyprenyl phosphate and diphosphate fucose or glucose derivatives, and the neutral lipids of sterol glycosides (fucose or glucose). A partial separation of the glycolipid synthetase reactions was achieved. Membranes were fractionated into material that sedimented at 20,000g and 100,000g. Most of the polar glycolipid synthetase activity (for the incorporation of both fucose and glucose) was located in the 100,000 g pellet, and this activity was probably located in the endoplasmic reticulum. The neutral lipid, which contained fucose, was synthesized mainly by membranes of the 20,000g pellet, and the activity was probably associated with the dictyosomes, whereas the neutral glucolipids were synthesized by all the membrane fractions. It is suggested that the polar (polyprenyl) lipids labelled with fucose could act as possible intermediates during the synthesis of the glycoproteins and slime in the root tip.

Effects of Cytochalasin B on the Golgi Apparatus of Maize Root Cells

1975 ◽  
Vol 33 ◽  
pp. 576-577
Author(s):  
H. H. Mollenhauer ◽  
D. J. Morrè
Keyword(s):  
Golgi Apparatus ◽  
Cell Surface ◽  
Cytochalasin B ◽  
Zea Mays L ◽  
Distribution Patterns ◽  
Maize Root ◽  
Secretory Vesicles ◽  
Root Tips ◽  
Root Cells ◽  
M 14

Seedlings of maize (Zea mays L.) var. WF-9 X M-14 were exposed to cytochalasin B for 1/2, 1, and 2 hr at concentrations of 0, 10, and 100 ppm. The root tips were then fixed for electron microscopy and the epidermal and outer cap cells examined for changes in dictyosome form, intercisternal fibers or secretory vesicles.Cytochalasin B did not cause significant changes in dictyosome form (Fig. 1) or intercisternal fibers. However, it did induce alterations in the distribution patterns of Golgi apparatus-derived secretory vesicles.In epidermal and outer cap cells of the maize root, following cytochalasin B treatment, secretory vesicles accumulated within the central portions of the cytoplasm in those regions occupied by Golgi apparatus (Fig. 2, 3). Cytoplasmic regions along the cell surface were devoid of secretory vesicles, and very few vesicles were found at the cell surface (Fig. 2, 3). We interpret these findings to mean that secretory vesicles formed by the Golgi apparatus did not move to the cell surface, but accumulated at or near their sites of origin following treatment with cytochalasin B.

Ultrastructural localization of acid phosphatase activity in root tips by the p-(acetoxymercuric) aniline diazotate reagent and a comparison with a Gomori procedure

1977 ◽  
Vol 26 (1) ◽  
pp. 19-29
Author(s):  
P. Stewart ◽  
D. Pitt
Keyword(s):  
Acid Phosphatase ◽  
Mung Bean ◽  
Subcellular Location ◽  
Ultrastructural Localization ◽  
Lead Salt ◽  
Precipitation Method ◽  
Root Tip ◽  
Root Tips ◽  
Root Cells ◽  
Post Coupling

The localization of acid phosphatase was studied in root tip cells of pea and mung bean by use of a heavy metal azo-dye technique. Diazotized p-(acetoxymercuric) aniline in a post-coupling procedure, using naphthol AS-BI phosphate as substrate, yielded a fine particulate reaction product within vacuoles, intercellular spaces, multivesicular bodies and at various sites throughout the cytoplasm of pea root cells and differentiating mung bean protoxylem cells. An ultrastructural comparison with a modified Gomori lead-salt precipitation method revealed differences in the subcellular location of beta-glycerophosphatase and naphthol AS-BI phosphatase. The distribution of acid phosphatases within plant meristematic cells is discussed.

scholarly journals Comparative Studies on Cellular Behaviour of Carnation (Dianthus caryophyllusLinn. cv. Grenadin) GrownIn VivoandIn Vitrofor Early Detection of Somaclonal Variation

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Jamilah Syafawati Yaacob ◽  
Rosna Mat Taha ◽  
Arash Khorasani Esmaeili
Keyword(s):  
Somaclonal Variation ◽  
Ploidy Level ◽  
Dianthus Caryophyllus ◽  
Nuclear Dna Content ◽  
Culture Period ◽  
Root Tip ◽  
Root Cells ◽  
The Mean

The present study deals with the cytological investigations on the meristematic root cells of carnation (Dianthus caryophyllusLinn.) grownin vivoandin vitro. Cellular parameters including the mitotic index (MI), chromosome count, ploidy level (nuclear DNA content), mean cell and nuclear areas, and cell doubling time (Cdt) were determined from the 2 mm root tip segments of this species. The MI value decreased when cells were transferred fromin vivotoin vitroconditions, perhaps due to early adaptations of the cells to thein vitroenvironment. The mean chromosome number was generally stable (2n=2x=30) throughout the 6-month culture period, indicating no occurrence of early somaclonal variation. Following the transfer to thein vitroenvironment, a significant increase was recorded for mean cell and nuclear areas, from 26.59 ± 0.09 μm2to 35.66 ± 0.10 μm2and 142.90 ± 0.59 μm2to 165.05 ± 0.58 μm2, respectively. However, the mean cell and nuclear areas ofin vitrogrownD. caryophylluswere unstable and fluctuated throughout the tissue culture period, possibly due to organogenesis or rhizogenesis. Ploidy level analysis revealed thatD. caryophyllusroot cells contained high percentage of polyploid cells when grownin vivoand maintained high throughout the 6-month culture period.

Sign in / Sign up

Export Citation Format

Share Document