Supplementary material
Instructional video: https://doi.org/10.6084/m9.figshare.4781254.v1
PDF and CAD plans of the support plate: https://doi.org/10.6084/m9.figshare.4785490.v1I describe the production and the application of a low-tech, easy-to-handle sectioning aid, which might be helpful for everyone who struggles with cross sectioning bryophytes. Technical plans and an instructional video are provided as supplementary material

Hepenstrick, Daniel

Lindbergia

ZHAW digitalcollection

BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions,research libraries, and research funders in the common goal of maximizing access to critical research.A simple, magnet-assisted bryophyte cross sectioning tool for beginners and forteaching in bryologyAuthor(s): Daniel HepenstrickSource: Lindbergia, 41(1)Published By: Dutch Bryological and Lichenological Society and Nordic Bryological Societyhttps://doi.org/10.25227/linbg.01099URL: http://www.bioone.org/doi/full/10.25227/linbg.01099BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological,and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and bookspublished by nonprofit societies, associations, museums, institutions, and presses.Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance ofBioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use.Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercialinquiries or rights and permissions requests should be directed to the individual publisher as copyright holder.1A simple, magnet-assisted bryophyte cross sectioning tool for beginners and for teaching in bryologyDaniel HepenstrickD. Hepenstrick (daniel.hepenstrick@zhaw.ch), Inst. of Natural Resource Science, ZHAW Zurich Univ. of Applied Sciences, Grüental, CH-8820 Wädenswil, Switzerland, and: WSL Swiss Federal Research Inst., Birmensdorf, Switzerland, and: Dept of Environmental Systems Science, ETH, Zürich, Switzerland.I describe the production and the application of a low-tech, easy-to-handle sectioning aid, which might be helpful  for everyone who struggles with cross sectioning bryophytes. Technical plans and an instructional video are provided as supplementary material.High-quality cross sections of bryophyte leaves, stems or thalli are important for the identification of species and the study of bryophyte morphology (Fig. 1). While expe-rienced bryologists section bryophytes easily, fast and rou-tinely, those new to the field often struggle with this task, which involves, simultaneously, fixing a tiny object under the dissection microscope with one hand while precisely cut-ting it with the other (Nishimura 1997, Pilkington 2013). Moreover, newcomers to bryology are frequently also begin-ners in microscopy. Thus, failure in appropriate sectioning (e.g. too thick sections) of bryophytes is common and often leads to frustration. Worst of all, it could dampen students’ enthusiasm of working with bryophytes, leading them to give up the discipline. In order to enhance beginners’ sectioning success, I developed a low-tech, easy-to-handle sectioning aid, whose production and application is described in the present article.Among the large variety of sectioning methods applied by bryologists, technical sectioning aids such as micro-tomes, pith and wax embedding (O’Brien and McCully 1981) are rarely used due to their time consuming applica-tion (Glime and Wagner 2013). Hence, also the present method is kept simple and fast: it basically is an exten-sion of the widely applied “double slide sectioning tech-nique” (Glime and Wagner 2013) with a magnetic support plate. This allows a specimen to be fixed on a slide aided by a second slide which is placed at 90 degrees to the first slide and which is pressed down by means of magnets attached to it (Fig. 2). This set-up fixes the specimen into position without the involvement of the hands and there-fore allows the cutting of sections with a razor blade that is guided by both hands. The latter substantially facilitates sectioning.Production of the two involved components, a metallic support plate and a magnetic slide, is straightforward. The support plate is made of a 120  96  1 mm ferromagnetic rust-proof steel sheet type EN 1.4016 (AISI 430) tailored by an industrial laser cutter. This type of steel is widely used for domestic appliances, and many companies that sell steel sheet have this in stock and are able to cut it using a laser. By sending the technical plans from the supplementary mate-rial (PDF plan and corresponding CAD file) to the respec-tive company, a set of 20 support plates can be produced for less than €10 per piece (mainly processing costs). The tem-plate is set up for standard 76  26 mm microscope slides (DIN ISO 8037-1), whereas for slides with other dimen-sions, this has to be modified as specified in the PDF plan. After production, the eight laser-cut tongues are manually bent upwards (e.g. with the help of a slotted screwdriver), so that their underneath edges just reach the surface of the plate. The two lateral tongues are used to tightly align a non-magnetic (e.g. aluminium, wood or plastic) rectangular strip of ca. 120  10  4 mm, which is glued into its position, ideally with a two-part adhesive glue. The magnetic slide is a standard microscope slide with cut, not bevelled, edges. On each narrow side, a neodymium magnet (ferritic mag-nets are generally too weak) is aligned to the edges and glued to the slide. Commercially available self-adhesive 20  10  1 mm neodymium magnets ( €0.50 per piece;  www.supermagnete.com ) have proven suitable for this application, but other neodymium magnets can also be used (e.g. fixed with double-sided tape). Lindbergia 41: linbg.01099, 2018doi: 10.25227/linbg.01099© 2018 The Author. This is an Open Access articleSubject Editor and Editor-in-Chief: Nils Cronberg. Accepted 3 November 2017This work is licensed under the terms of a Creative Commons Attribution 4.0 International License (CC-BY)  http://creativecommons.org/licenses/by/4.0/ . The license permits use, distribution and reproduction in any medium, provided the original work is properly cited.2Application of the method is demonstrated in an instructional video in the supplementary material, which may help to harness the magnetic aid for teaching and personal use. Sectioning starts with the positioning of a standard microscope slide on the support plate in the area between the six central tongues. This prevents the slide from gliding away during sectioning and correctly aligns it with the lateral non-magnetic strip. On this lower slide, a specimen is placed and then fixed with the magnetic slide. Fixation starts by directly aligning one narrow side of the magnetic slide against the inner edge of the non-magnetic strip (magnets orientated upwards). Then, the magnetic slide is gently laid down on the specimen so that it is partly covered. Slight pressure on the middle of the magnetic slide will tilt it to a horizontal position. Now, the magnetic slide fixes the specimen by means of the lateral magnets, which symmetrically apply pressure on the orthogonally and centrally orientated lower slide. The support plate with the fixed specimen can now be placed under the dissecting microscope (in case the above steps have not already been conducted there). The part of the specimen that protrudes from the magnetic slide is set on focus and cut into sec-tions, as thinly as possible, with a razor blade that is con-trolled with both hands. After cutting, the magnetic slide is removed and sections that remain stuck on the blade and/or the lower slide are pushed into a drop of water placed on the lower slide. Then, a cover slip is laid on the sections and the slide is grasped through semicircle slots for examination under the light microscope.This method can be varied depending on the type of specimen involved and on personal preferences. Some of the possible variations are also shown in the instructional video. For extra stability or in case of thick specimens, the magnetic slide can be placed with downwards ori-entated magnets, which will prevent it from tilting. For this option, the magnets have to be equal in height to the slides being used. In order to increase the force by which the specimen is pressed down, additional magnets can be placed on the magnets attached to the magnetic slide. This also enhances the stability of the system and might be useful for fine specimens that need to be pressed down more powerfully for proper fixation. Notably, if the applied magnets are too strong, the magnetic slide will bend and therefore loose pressure. Further, reorientation of the specimen might be achieved by actively tilting and shifting the magnetic slide or by pushing it slightly back-wards while sectioning, which will gradually expose the specimen. Also, orientation of the support plate, guidance and type of the razor blade, amount of specimen mate-rial and of water involved etc. can be varied according to individual preferences. I encourage users to find their own best setting, which will most probably vary for different types of specimen.The method has been informally assessed in the Bachelor course ‘Biology of Bryophytes and Ferns’ 2016, which is taught at Swiss Federal Institute of Technology in Zurich (ETH Zurich). After several practical days, in which stu-dents sectioned bryophytes in a traditional way (i.e. fixing of specimen with forceps), they were introduced to the present method. The students readily applied the magnetic aid and in the subsequent oral evaluation they (n = 19) concordantly agreed that it substantially enhanced their success in prepar-ing cross-sections of bryophyte leaves and stems. Hence, in future courses the magnetic aid will be incorporated from the beginning.Everyone who struggles with cross sectioning bryophytes, especially people new to bryology and microscopy, might profit from the presented method. Low priced production makes the aid an affordable method for use during teaching Figure 1. A leaf cross section showing the leaf anatomy of Polyt-richaceae with lamellae and the forked terminal cells, which are diagnostic for Polytrichum commune. This section is the best result out of three trials with the magnetic sectioning aid by someone who had never sectioned a bryophyte before. In all three trials, sections with clearly recognisable diagnostic features were present.Figure 2. The magnetic sectioning aid with fixed Polytrichum leaves ready for sectioning. The support plate (A) consists of a magnetic, rust-free steel sheet with laser cut tongues (B) which are slightly bent upwards, and a non-magnetic strip (C) which helps to align the magnetic slide (D) with its attached neodymium magnets (E) centrally on the lower slide (F) in order to fix the specimen for sectioning. Sections are cut under a dissecting microscope with a razor blade that is guided with both hands. The semicircle slots (G) help to place and grasp the lower slide.3in class, and it might well be applied for sectioning materials other than bryophytes.Acknowledgements – The technical plans were provided by courtesy of Diethelm AG (Hermetschwil, Switzerland). I would like to thank Ariel Bergamini for evaluating the method in his course, Nicolas Phan-huy for Fig. 1, Aron Marty for help with the instructional video and Rolf Holderegger and Caroline Hyde-Simon for valuable feedback on the manuscript.Caution note – The method involves sharp, fragile and magnetic objects. Their handling might cause injury from which the author declines any liability.ReferencesGlime, J. M. and Wagner, D. H. 2013. Laboratory techniques: slide preparation and stains. – In: Glime, J. M. (ed.), Bryophyte ecology. Vol. 3, Methods, Chapter 2.2. (11 September 2013), pp. 3–27 (accessed 12 December 2016). Available at  www.bryoecol.mtu.edu .Pilkington, S. 2013. Hand lenses and microscopes part 2: choosing a microscope. – Field Bryol. 107: 32–35.Nishimura, N. 1997. Easy ways to make transverse sections under the dissecting microscope. – Bryol. Res. 7: 30–31.O’Brien, T. P. and McCully M. E. 1981. The study of plant structure principles and selected methods. – Backwell.Supplementary material:Instructional video:  https://doi.org/10.6084/m9.figshare.4781254.v1 PDF and CAD plans of the support plate:  https://doi.org/10.6084/m9.figshare.4785490.v1 

A simple, magnet-assisted bryophyte cross sectioning tool for beginners and for teaching in bryology

ZHAW Zürcher Hochschule für Angewandte Wissenschaften

Daniel Hepenstrick

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A simple, magnet-assisted bryophyte cross sectioning tool for beginners and for teaching in bryology

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ZHAW Zürcher Hochschule für Angewandte Wissenschaften

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