Electron Microscopy of Silicon Deposits in Foliar Idioblasts of Magnolia Grandiflora

1976 ◽  
Vol 34 ◽  
pp. 374-375
Author(s):  
Michael T. Postek
Keyword(s):  
Electron Microscopy ◽  
Water Loss ◽  
Normal Development ◽  
Magnolia Grandiflora ◽  
Plant Body ◽  
Normal Metabolism ◽  
Hydrated Oxide

Silicon occurs naturally in plants in the form of its hydrated oxide (SiO2.nH2O) commonly called silica. Silica has been shown to be a necessary element in the normal development of many plants, playing an array of roles including strengthening, protection, and reduction of water loss. Deposition of silica in various portions of the plant body, especially the leaves, may also be viewed as a way for the plant to dispose of any excess silica taken up beyond that necessary for normal metabolism.Studies of this “opaline” silica have thus far been limited to species of the Cyperaceae and Gramineae known to possess significant quantities of silica. Within the Magnoliaceae, certain “glistening” idioblast cells at the foliar veinlet termini and vein sheaths of Magnolia grandiflora (1) have been suspected to be siliceous in nature.

Hydraulic segmentation does not protect stems from acute water loss during fire

2021 ◽  
Author(s):  
William A Hoffmann ◽  
Amanda C Rodrigues ◽  
Nicholas Uncles ◽  
Lorenzo Rossi
Keyword(s):  
Water Uptake ◽  
Water Loss ◽  
High Water ◽  
Fire Plume ◽  
Magnolia Grandiflora ◽  
Hydraulic Failure ◽  
Factors Influencing ◽  
Wide Range ◽  
Transport Path ◽  
Measured Water

Abstract The heat plume associated with fire has been hypothesized to cause sufficient water loss from trees to induce embolism and hydraulic failure. However, it is unclear whether the water transport path remains sufficiently intact during scorching or burning of foliage to sustain high water loss. We measured water uptake by branches of Magnolia grandiflora while exposing them to a range of fire intensities, and examined factors influencing continued water uptake after fire. Burning caused a 22-fold mean increase in water uptake, with greatest rates of water loss observed at burn intensities that caused complete consumption of leaves. Such rapid uptake is possible only with steep gradients in water potential, which would likely result in substantial cavitation of xylem and loss of conductivity in intact stems. Water uptake continued after burning was complete, and was greatest following burn intensities that killed leaves but did not consume them. This post-fire uptake was mostly driven by rehydration of the remaining tissues, rather than evaporation from the tissues. Our results indicate that the fire-plume hypothesis can be expanded to include a wide range of burning conditions experienced by plants. High rates of water loss are sustained during burning, even when leaves are killed or completely consumed.

Postnatal Development of the Feline End Bulb of Held

1985 ◽  
Vol 43 ◽  
pp. 492-493
Author(s):  
S. A. Larsen ◽  
George D. Pappas
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Postnatal Development ◽  
Electron Micrographs ◽  
Cochlear Nucleus ◽  
Normal Development ◽  
Computer Assisted ◽  
Anteroventral Cochlear Nucleus ◽  
Adult Cats ◽  
Large Spherical

Maturation of the end bulb of Held (EBH) in the anteroventral cochlear nucleus (AVCN) was studied to determine what degree of plasticity is found in a synapse undergoing maturation, at the same time that the recipient neuron is increasing in size. Although the normal development of the neurons in the cochlear nucleus has been studied by Larsen and Morest, the normal development of the EBH has not been reported at the EM level.The EBH was studied in kittens ranging in age from birth to 60 days postpartum and in adult cats using electron microscopy and Golgi preparations with light microscopy. At selected developmental ages (birth, alternate days starting at the second day of life and extending throughout the first postnatal month, and adult), serial-sectioned electron micrographs of the EBH and its recipient neuron, the large spherical cell (LSC), were traced using computer-assisted morphometry.

Antibacterial Property and Mechanism of Copper Alginate Fiber

2010 ◽  
Vol 152-153 ◽  
pp. 1351-1355
Author(s):  
Yan Wu ◽  
Guang Ting Han ◽  
Ying Gong ◽  
Yuan Ming Zhang ◽  
Yan Zhi Xia ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antibacterial Property ◽  
Copper Ion ◽  
Antibacterial Effects ◽  
Sem Images ◽  
Normal Metabolism ◽  
Alginate Fibers ◽  
Alginate Fiber ◽  
And Staphylococcus Aureus ◽  
Scanning Electron

To apply copper alginate fibers in medical as a new alginate fiber, copper alginate fibers were researched and evaluated against Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus), using antibacterial zone and flash shaking method to analyze anti-bacterial mechanism by the scanning electron microscopy (SEM). The results showed that copper alginate fibers had antibacterial effects, the antibacterial rate against E.coli and S.aureus were 97.4% and 66.2%, respectively; SEM images indicated that bacteria obviously changed after contacting with fibers, the main reason was that copper ion had a damaging effect on pericellular and cell wall. Furthermore, bacterial osmotic pressure was changed and protein synthesis were impeded, and then the normal metabolism of bacteria was destroyed, and finally, bacteria died.

scholarly journals Water Loss: A Nondestructive Indicator of Enhanced Cell Membrane Permeability of Chilling-injured Citrus Fruit

1994 ◽  
Vol 119 (5) ◽  
pp. 983-986 ◽  
Author(s):  
E. Cohen ◽  
B. Shapiro ◽  
Y. Shalom ◽  
J.D. Klein
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Water Loss ◽  
Loss Rate ◽  
Chilling Injury ◽  
Citrus Fruit ◽  
Cell Membrane Permeability ◽  
Citrus Paradisi ◽  
Water Loss Rate ◽  
Scanning Electron

Water loss was found to be a nondestructive indicator before visible symptoms of chilling injury (CI) in cold-stored grapefruit (Citrus paradisi Macf.) and lemon (C. limon L. Burm. f.). The water-loss rate increased significantly after removing the fruit from cold storage and holding at 20C. Scanning electron microscopy revealed large cracks around the stomata. Changes in electrical conductivity of the flavedo tissues, total electrolyte leakage, and K+ or Ca2+ leakage were all inadequate predictors of CI, appearing only after CI was evident.

The effect of chymotrypsin on the development of Dictyostelium discoideum

Development ◽  
1980 ◽  
Vol 57 (1) ◽  
pp. 189-201
Author(s):  
David C. Kilpatrick ◽  
Jerzy A. Schmidt ◽  
John L. Stirling ◽  
John Pacy ◽  
Gareth E. Jones
Keyword(s):  
Electron Microscopy ◽  
Dictyostelium Discoideum ◽  
Normal Development ◽  
Fruiting Bodies ◽  
Con A ◽  
Cellular Slime Mould ◽  
Slime Mould ◽  
Spore Walls ◽  
Cellular Slime ◽  
Vacuolated Cells

Development of the cellular slime mould Dictyostelium discoideum strain NC4, in the presence of α-chymotrypsin (3 mg/ml) is reversibly arrested at the tight aggregate stage (10/12 h). Pronase has a similar effect, but trypsin only retards normal development by about five hours. Normally developing cells are susceptible to α-chymotrypsin if they are transferred into its presence at any time up to the tight aggregate stage (10–12 h). Transfer after this stage does not affect the appearance of fruiting body structures in the normal time (24 h). Electron microscopy showed the ultrastructure of α-chymotrypsin-blocked aggregates after starvation for 24 h to be consistent with a block at 10–12 h of normal development. Poorly developed prespore vacuoles, having thin incomplete walls and a paucity of electrondense material, are present in some cells. No angular vacuolated cells characteristic of stalk cells are visible. Fruiting bodies formed in the presence of a α-chymotrypsin, either as minority structures when the enzyme is added before 10–12 h of normal development, or as the majority structures on later enzyme addition, were found to be abnormal. Normal stalks were formed but the spores were immature. Prespore vacuoles were present, though disrupted, and the cells were not encapsulated by spore walls. The electronegativity of intact slime mould amoebae was significantly reduced, and material containing L-[6-3H]-fucose and [l-14C]leucine was removed from the cell surface on α-chymotrypsin treatment. Few plasma membrane proteins were affected, however, and staining of polyacrylamide gels for glycopeptides using Con A-peroxide binding also showed little change.

Influence of Penicillium frequentans and two of its antibiotics on production of stromata by Monilinia laxa in culture

1989 ◽  
Vol 67 (1) ◽  
pp. 83-87 ◽  
Author(s):  
P. Melgarejo ◽  
A. De Cal ◽  
E. M.-Sagasta
Keyword(s):  
Electron Microscopy ◽  
Normal Development ◽  
Light And Electron Microscopy ◽  
Monilinia Laxa ◽  
Penicillium Frequentans

The influence of an isolate of Penicillium frequentans and two of its antibiotics on the mycelium of Monilinia laxa in culture has been studied using light and electron microscopy. Penicillium frequentans and antibiotic B induced the development of continuous stromata in cultures. Stroma production in colonies exposed to antibiotic A is rhythmic, with alternating zones of normal development of the mycelium. Abundant pycnidium-like structures, within which microconidia of M. laxa were formed, were produced on the induced stromata of cultures exposed to Penicillium and antibiotic A. The presence of melanin-like pigments in normal and induced stromata of M. laxa was also demonstrated and quantified.

Electron Microscopy of Sprouting Seeds

1968 ◽  
Vol 26 ◽  
pp. 88-89
Author(s):  
R. F. W. Pease ◽  
T. L. Hayes
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Survival Rate ◽  
Scanning Electron Microscope ◽  
Allium Cepa ◽  
Water Loss ◽  
Raphanus Sativus ◽  
Control Sample ◽  
Scanning Electron

The examination of living insects in the scanning electron microscope (SEM) was reported in 1966. We now report the examination of living botanical specimens in the SEM. The specimens were the seeds of white sprouting onion (Allium cepa) and of the radish (Raphanus sativus) during the week following germination. The seeds were mounted initially using flour and water and later using a cement (“Elmer's Glue All”). In all cases the natural conductance of the seeds was sufficient to prevent undue charging. 12 onion seeds were examined within three days of placing in moist tissue and again on the three successive days (Figures 1 and 2). The survival rate (5 out of 12) was not significantly lower than in the control sample (about 50% of a large number), however the growth did appear to be retarded and this may have been due to the microscope environment. One notable exception was one seed which was accidentally immersed in the cement with only the sprout uncovered; it is possible that such immersion retarded water loss to the vacuum. The cement subsequently dissolved away as the sprouting seed developed in moist tissue.

scholarly journals Surface structure of Amur region high grade native gold

2021 ◽  
Vol 44 (1) ◽  
pp. 39-47
Author(s):  
S. M. Radomskiy ◽  
V. I. Radomskaya
Keyword(s):  
Electron Microscopy ◽  
Surface Structure ◽  
Oxide Layer ◽  
Native Gold ◽  
Amur Region ◽  
Metallic Gold ◽  
High Grade ◽  
Oxidation Degree ◽  
Oxidation Reduction ◽  
Hydrated Oxide

The purpose of the research is to study the surface structure of high grade gold. The subject of research is gold ore fields in the Amur region. The object of the study is samples of native high grade gold grains from these fields. The study uses the methods of thermodynamics and X-ray electron microscopy. The study results in revealing a multilayer structure of the surface of high grade minerals of the Amur region native gold with the following levels: a boundary layer with zero oxidation degree Au0 in the form of yellow metallic gold; an oxide layer with the oxidation degree Au+1 in the form of purple Au2O; an oxide layer with the oxidation degree Au+3 in the form of a yellow-brown Au2O3; a hydrated oxide layer with the oxidation degree Au+3 in the form of a red-yellow-brown Au(OH)3. The methods of electron microscopy have allowed to identify external surface structures – dense oxide layers of the form of Au2O3 and loose hydrated layers of the form of Au(OH)3, whereas the inner layers of metallic and monovalent gold are not visible. Important thermodynamic characteristics of the presented levels are the values of standard oxidation-reduction potentials (E°), which determine their physicochemical properties: for metallic gold E° = +1.68 V; for the oxide layer with the oxidation degree Au+1 in the form of Au2O – E° = +0.32 V; for the oxide layer with the oxidation degree Au+3 in the form of Au2O3 – E° = +1.36 V; for the hydrated oxide layer with the oxidation degree Au+3 in the form of Au(OH)3 – E° = +0.7 V. The results of the conducted studies indicate that the surface structure has several layers that lower the oxidation-reduction potential, which explains the generation and formation of migratory forms of gold in humid hypergene conditions of natural environment.

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