Relationships Between Carbon Dioxide Transfer Resistances and Some Physiological and Anatomical Features

When treated with ethylene, mature fruits of the squirting cucumber (Ecballium elaterium (L.) A. Rich) abscind and dehisce prematurely. Abscission of male flowers is also accelerated by ethylene. Visible signs of senescence, a rise in ethylene production, and reduced carbon dioxide production always precede abscission or dehiscence in untreated fruits and flowers. The amounts of diffusible cellulase increase in tissues on both sides of the fruit abscission zone after exposure to ethylene. Anatomical features of this abscission zone are described.The leaves of Ecballium do not abscind although the blade and petiole produce large amounts of ethylene at senescence, nor do they separate when ethylene is supplied. Ethylene treatment of attached fruit peduncles accelerates their rate of elongation in the growing zone below the apical hook. The regulation of growth and abscission in these organs is discussed.

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Electron Cytochemical Study of Carbon Dioxide Laser Effect on Rhesus Monkey Cornea

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010005113x ◽

1974 ◽

Vol 32 ◽

pp. 224-225

Author(s):

K. C. Tsou ◽

J. Morris ◽

P. Shawaluk ◽

B. Stuck ◽

E. Beatrice

Keyword(s):

Carbon Dioxide ◽

Electron Microscope ◽

Rhesus Monkey ◽

Carbon Dioxide Laser ◽

Cytochemical Study ◽

Laser Effect

While much is known regarding the effect of lasers on the retina, little study has been done on the effect of lasers on cornea, because of the limitation of the size of the material. Using a combination of electron microscope and several newly developed cytochemical methods, the effect of laser can now be studied on eye for the purpose of correlating functional and morphological damage. The present paper illustrates such study with CO2 laser on Rhesus monkey.

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The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100068382 ◽

1970 ◽

Vol 28 ◽

pp. 278-279

Author(s):

Charles TurnbiLL ◽

Delbert E. Philpott

Keyword(s):

Electron Microscopy ◽

Carbon Dioxide ◽

Surface Tension ◽

Critical Point ◽

Freeze Drying ◽

Attractive Alternative ◽

Crystal Formation ◽

Critical Point Drying ◽

Time Required ◽

Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

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Mitochondrial Reconstructions Based on Serial Thick Sections and HVEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100115055 ◽

1975 ◽

Vol 33 ◽

pp. 286-287

Author(s):

Jerome J. Paulin

Keyword(s):

Imaging Techniques ◽

Three Dimensional ◽

Posterior Pole ◽

Dimensional Structure ◽

Stereo Imaging ◽

Thin Sections ◽

Anatomical Features ◽

The Past ◽

Cellular Components ◽

Mitochondrial Reticulum

Within the past decade it has become apparent that HVEM offers the biologist a means to explore the three-dimensional structure of cells and/or organelles. Stereo-imaging of thick sections (e.g. 0.25-10 μm) not only reveals anatomical features of cellular components, but also reduces errors of interpretation associated with overlap of structures seen in thick sections. Concomitant with stereo-imaging techniques conventional serial Sectioning methods developed with thin sections have been adopted to serial thick sections (≥ 0.25 μm). Three-dimensional reconstructions of the chondriome of several species of trypanosomatid flagellates have been made from tracings of mitochondrial profiles on cellulose acetate sheets. The sheets are flooded with acetone, gluing them together, and the model sawed from the composite and redrawn.The extensive mitochondrial reticulum can be seen in consecutive thick sections of (0.25 μm thick) Crithidia fasciculata (Figs. 1-2). Profiles of the mitochondrion are distinguishable from the anterior apex of the cell (small arrow, Fig. 1) to the posterior pole (small arrow, Fig. 2).

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