Low-temperature Scanning Electron Microscopy and Physical-Chemical investigations of leaf surface characteristics

Plant protection agents (often incorrectly referred to as ‘pesticides’) mostly are targeted at plant surfaces either to protect them against pathogens and parasites or to destroy the treated plants in the case of herbicides. Many times, more than one species of plants are involved, that respond differently to such applications.In any of the cases cited, a thorough knowledge of the leaf surface characteristics may help to explain desired or undesirable effects. Also the wetting properties of a spray applied to plants will likely influence the performance of the active ingredient involved. It is obvious that only the use of a whole array of different methods will allow an interpretation or a prediction of effects caused by the application of plant protection sprays.To get well preserved epicuticular wax structures of leaf surfaces we used low-temperature scanning electron microscopy (LTSEM). Fresh cut samples were immediatly frozen in liquid nitrogen, transferred into a Balzers SCU 020 cryopreparation unit attached to an SEM Cambridge Mk II A.

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Intracellular structures of rapid frozen biological samples observed by high-resolution low-temperature Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100155657 ◽

1989 ◽

Vol 47 ◽

pp. 736-737

Author(s):

T. Inoué ◽

H. Koike

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Low Temperature ◽

Liquid Nitrogen ◽

Specimen Preparation ◽

Chemical Fixation ◽

Brown Adipose ◽

Critical Point Drying ◽

Temperature Scanning ◽

Scanning Electron

Low temperature scanning electron microscopy (LTSEM) is useful to avoid artifacts such as deformation and extraction, because specimens are not subjected to chemical fixation, dehydration and critical-point drying. Since Echlin et al developed a LTSEM, many techniques and instruments have been reported for observing frozen materials. However, intracellular structures such as mitochondria and endoplasmic reticulum have been unobservable by the method because of the low resolving power and inadequate specimen preparation methods. Recently, we developed a low temperature SEM that attained high resolutions. In this study, we introduce highly magnified images obtained by the newly developed LTSEM, especially intracellular structures which have been rapidly frozen without chemical fixation.[Specimen preparations] Mouse pancreas and brown adipose tissues (BAT) were used as materials. After the tissues were removed and cut into small pieces, the specimen was placed on a cryo-tip and rapidly frozen in liquid propane using a rapid freezing apparatus (Eiko Engineering Co. Ltd., Japan). After the tips were mounted on the specimen stage of a precooled cryo-holder, the surface of the specimen was manually fractured by a razor blade in liquid nitrogen. The cryo-holder was then inserted into the specimen chamber of the SEM (ISI DS-130), and specimens were observed at the accelerating voltages of 5-8 kV. At first the surface was slightly covered with frost, but intracellular structures were gradually revealed as the frost began to sublimate. Gold was then coated on the specimen surface while tilting the holder at 45-90°. The holder was connected to a liquid nitrogen reservoir by means of a copper braid to maintain low temperature.

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Criteria for the evaluation of low-temperature Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100145820 ◽

1986 ◽

Vol 44 ◽

pp. 902-903

Author(s):

Alan Beckett

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Low Temperature ◽

Conformational Changes ◽

Chemical Vapour ◽

List Type ◽

Dimensional Changes ◽

Critical Point Drying ◽

Temperature Scanning ◽

Scanning Electron

Low temperature scanning electron microscopy (LTSEM) has been evaluated with special reference to its application to the study of morphology and development in microorganisms. A number of criteria have been considered and have proved valuable in assessing the standard of results achieved. To further aid our understanding of these results, it has been necessary to compare those obtained by LTSEM with those from more conventional preparatory procedures such as 1) chemical fixation, dehydration and critical point-drying; 2) freeze-drying with or without chemical vapour fixation before hand.The criteria used for assessing LTSEM for the above purposes are as follows: 1)Specimen immobilization and stabilization2)General preservation of external morphology3)General preservation of internal morphology4)Exposure to solvents5)Overall dimensional changes6)Cell surface texture7)Differential conformational changes8)Etching frozen-hydrated material9)Beam damage10)Specimen resolution11)Specimen life

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