scholarly journals Developments in application of light and scanning electron microscopy techniques for cell wall degradation studies

1996 ◽  
Vol 44 (4) ◽  
pp. 357-373
Author(s):  
F.M. Engels

The results of recent technological developments in light and scanning electron microscopy closely used for research on forage cell wall degradation in ruminants, are reviewed. The indigestibility of forages by rumen microorganisms used to be ascribed mainly to an overall presence of lignin in the plant material. However, early light microscopic observations without application of histochemical staining revealed that some leaf and stem tissues were degraded completely. The early use of lignin detecting dyes, such as acid phloroglucinol or safranin, in light microscopy made it possible to discriminate between lignified undegradable and unlignified degradable plant tissues. The introduction of the scanning electron microscope enabled a further discrimination between degradable and undegradable cell wall and cell wall layers in plant tissues. As a result of continuous improvement of the techniques used in microscopy, e.g. section to slide, mirror sectioning, microspectrophotometry and cryo-ultramilling, forage indigestibility can now be attributed to the specific deposition and location of cutin/suberin or lignin layers inside the plant cell wall. These structural layers form barriers hindering access of rumen microorganisms to degradable parts of the cell wall.

2001 ◽  
Vol 9 (3) ◽  
pp. 14-15 ◽  
Author(s):  
B. A. Richardson ◽  
C. W. Mims

Several years ago Honegger (1985) described a simple technique for removing plant cell protoplasm in order to reveal details of interfaces between plant cells and fungal structures. This technique involves the use of Ariel a commercially available washing powder (Proctor and Gamble) containing a Bacillus substilis derived protease. We since have used this technique with excellent results to examine not only the morphology of fungal haustoria inside leaf cells of various host plants but also features of the inner surface of the host cell wall with scanning electron microscopy (SEM). Here we describe the procedure we have used to prepare samples for study and provide examples of the types of images we have obtained from our samples.


2013 ◽  
Vol 47 ◽  
pp. 13-20
Author(s):  
O. V. Anissimova

Algae samples were collected during different seasons from 1997 to 2011 in two swamps located at Zvenigorod Biological Station in Moscow Region. There were found 25 Cosmarium species and varieties, 9 taxa of them being new to the region. Descriptions of the taxa were specified by observation of cell wall ornamentation with light and scanning electron microscopy. Original descriptions, photos and drawings of algae are presented.


2014 ◽  
Vol 84 (18) ◽  
pp. 1939-1947 ◽  
Author(s):  
Geoffrey RS Naylor ◽  
Margaret Pate ◽  
Graham J Higgerson

Previous researchers established a set of reference cottons with known fiber maturity and linear density (fineness) values based on the analysis of a large number of individual transverse fiber cross-sections viewed under the optical microscope. Part 1 identified that the limited optical resolution of the captured images may be the source of a significant systematic error in the assigned values of cell wall area and hence fiber maturity and linear density values. In this paper the optical microscopy technique was implemented. Individual cross-sections were measured using this approach and also higher resolution and higher magnification images were obtained using scanning electron microscopy. It was found that the data obtained from optical microscopy were similar to the SEM data, with the perimeter being 2% smaller, the cell wall area being 6% larger and the maturity ratio values being 8% higher. It was concluded that the combined approach of utilizing SEM in conjunction with optical imaging is a useful approach for verifying and perhaps correcting the data obtained from optical imaging. Further the SEM images highlighted that the current experimental protocol does not adequately address the challenge of ensuring that the fibers are mounted normal to the plane of cutting the transverse cross-section. Modeling demonstrated that while maturity ratio values are relatively insensitive to this misalignment, measured cell wall area values and hence fiber linear density values will be overestimated. This may be the major source of error associated with the technique and warrants further attention in future studies.


2017 ◽  
pp. 66
Author(s):  
Aída Carrillo-Ocampo ◽  
E.M. Engleman

With methods of light microscopy, histochemical staining and scanning electron microscopy, it was found that the ovule in the seed of Tigridia pavonia (Iridaceae) is anatropous, bitegmic, and crassinucellate. During development, the exotegmen is crushed and the endotegmen persists with tannins in the lumens and in the walls, which also react positively for lignin. The exotesta contains tannins and its outer walls are convex, thickened, and cuticularized. The mesotesta has multiple layers, accumulates abundant lipids, and forms a bulge in the chalaza. The cell walls of the endotesta collapse and accumulate tannins. In the chalaza, a hypostasal cushion contains tannins in the lumens and in the walls, which also react positively for lignin. At the micropylar end of the seed there is an operculum which consists of: a) a slightly crushed exotegmen, b) an endotegmen with cuticular thickenings that are concentric with respect to the micropyle, c) hemispherical deposists of cutin on the anticlinal walls of the endotegmen, and c) a thin layer of endosperm that covers the radicle. During its cellular stage of development, the endosperm has conspicuous transfer walls at the chalazal end next to the nucella. The embryo is small and has a conical cotyledon.


2021 ◽  
Vol 12 ◽  
Author(s):  
Sergey Mursalimov ◽  
Nobuhiko Ohno ◽  
Mami Matsumoto ◽  
Sergey Bayborodin ◽  
Elena Deineko

Serial block-face scanning electron microscopy (SBF-SEM) was used here to study tobacco male meiosis. Three-dimensional ultrastructural analyses revealed that intercellular nuclear migration (INM) occurs in 90–100% of tobacco meiocytes. At the very beginning of meiosis, every meiocyte connected with neighboring cells by more than 100 channels was capable of INM. At leptotene and zygotene, the nucleus in most tobacco meiocytes approached the cell wall and formed nuclear protuberances (NPs) that crossed the cell wall through the channels and extended into the cytoplasm of a neighboring cell. The separation of NPs from the migrating nuclei and micronuclei formation were not observed. In some cases, the NPs and nuclei of neighboring cells appeared apposed to each other, and the gap between their nuclear membranes became invisible. At pachytene, NPs retracted into their own cells. After that, the INM stopped. We consider INM a normal part of tobacco meiosis, but the reason for such behavior of nuclei is unclear. The results obtained by SBF-SEM suggest that there are still many unexplored features of plant meiosis hidden by limitations of common types of microscopy and that SBF-SEM can turn over a new leaf in plant meiosis research.


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