[PDF] A new sledge microtome to combine wood AnAtomy And tree-ring

View - Download A new sledge microtome to combine wood AnAtomy And tree-ring

Previous PDF

Next PDF

IAWA Journal 36 (4), 2015IAWA Journal 36 (4), 2015: 452-459 © International Association of Wood Anatomists, 2015 DOI 10.1163/22941932-20150114

Published by Koninklijke Brill NV, Leiden

A new sledge microtome to combine wood ANATOMY

AND TREE-RING ECOLOGY

1, *, s. Lucchinetti 2 , and F.H. Schweingruber 1 1 Swiss Federal Research Institute WSL, Landscape Dynamics/Dendroecology, Zürcherstrasse 111,

8903 Birmensdorf, Switzerland

2 Schenkung Dapples, Mechanische Werkstatt, Flühgasse 80, 8008 Zürich, Switzerland *Corresponding author; e-mail: holger.gaertner@wsl.ch

ABSTRACT

Based on the Reichert Om E microtome a more sophisticated, nevertheless solely mechanically operated microtome was developed enabling to section specimens of various forms and sizes. The materials used and the special construction of the microtome resulted in a higher stability of the moving parts whilst simultaneously reducing weight. As a result of the high stability of the sledge guidance, bigger

sections can be cut enabling more detailed analyses of anatomical structures within plant stems, roots or branches as well as their variation back in time.

Consequently, wood anatomical parameters can be integrated more easily in time-series analyses supporting the aims of a quantitative wood ecology. Keywords: Dendroecology, sectioning, time-series analyses. [In the online version of this paper Figures 1OE5 are reproduced in colour.]

INTRODUCTION

For detailed wood anatomical studies within the scope of a changing climate, the prep- aration of sections is essential to strengthen the understanding of the form and func- tional evolution of the xylem in different climatic regions. Nevertheless, details about micro-technique, especially the application of microtomes have hardly been discussed

6FKZHLQJUXEHU°*lUWQHUet al. 2014, 2015).

Most wood anatomical analyses are done on small specimens, mostly blocks of about

1 cubic cm to cut transverse, radial and tangential sections. To analyse age-dependent

or environmentally induced anatomical variations, e.g., along a cross section of a tree stem, the ability to section bigger specimens would be of importance, but most current microtomes are not capable to cut big sections. The inability of cutting bigger sections of more or less dense woody material is as-

FP°WKLFNQHVV

th

1852-1888). The technical base for preparing sections of that size does no longer exist

reconstruction of environmental conditions of the past, large sections are required to

YLDIUHHDFFHVV

reduce the amount of sample preparation needed to an affordable minimum. Big sec- tions will allow to expand wood anatomical research to a highly resolved, time related, ecologically based wood anatomy. With this, the ability of analyzing new parameters and developing new methodologies to understand the short- and long-term effects of environmental factors on woody plant bodies is given.

1LHYHUJHOWIRUFXWWLQJPLFURVHFWLRQVRIHQWLUHLQFUHPHQWFRUHV*lUWQHUet al.

2015; Ivanova et al.et al. 2014). As a

further step towards combining wood anatomy and dendroecology, we present a new sledge microtome enabling to cut big specimens of all forms for the detailed analyses of structural variations within the respective plant part to be analyzed back in time.

Reichert OmE

WSL-Lab-Microtome

microtome body (cast iron) sliding surfaces sled (block) microtome body (aluminum)

YLDIUHHDFFHVV

IAWA Journal 36 (4), 2015

the Lab-microtome

Basic principles

A basic requirement for cutting sections of wood, no matter if using rotation or sledge microtomes, is the stability of the device. This is the main reason why old pure weight of the device guarantees stability during the sectioning procedure. One of to be applicable for small specimens ranging from low to high density. The bigger the Figure 2. Construction of the knife-holder platform. OE a: Stabilizing pole in position; b and c: knife holder stabilized by the pole for cutting sections of high density woods. knife-holder block opening for stabilizing pole knife-holder platform stopper for the platform angled stop for automated sample uplift linear guide 1 linear guide 2 stopper for the platform

sled 1 sled 2

a b c

YLDIUHHDFFHVV

sample and/or the higher the density, the higher the forces occurring while cutting. When a certain threshold is exceeded, the knife is lifted up and cutting sections is no longer possible. We cannot specify this threshold, because it varies depending on the respective combination of sample size and density. For instance, we realized that it Larix deciduae.g., boiling), if severe compression wood occurs within the sample.

Construction

We aimed at developing a more sophisticated, nevertheless manually operated mi- crotome while increasing stability and nevertheless reducing weight. Consequently, the body of the microtome was constructed as a frame consisting of four aluminum plates forming the base for all components of the microtome. The knife holder is placed in the centre of an aluminum platform, which is mounted tome frame. The ball-bearing guided sleds only allow a two-dimensional movement m) providing maximum stability of the knife holder in all directions other than along the guides while cutting. Figure 3. A: Side view of the mounted knife holder of the Lab-Microtome; 1: Knife-holder block; position of the knife-holder block on the platform. The position can be changed by opening and placed in the sample holder of the microtome.

YLDIUHHDFFHVV

IAWA Journal 36 (4), 2015

blade holder) is horizontally and vertically adjustable to adapt its position depending on the size and density of the sample. When sectioning samples of high density, the position, the pole stabilizes the knife holder and prevents it from being turned sideward 7KHVDPSOHKROGHULVSODFHGZLWKLQDIUDPHWKDWDOORZVDÀQHFRUUHFWLRQRIWKHRUL- of transverse, tangential or radial sections. The frame is set on a pole which is placed parallel linear guides. The precise upward movement of the platform and with this of the sample is realized by a micrometer screw connecting the platform and a hand wheel allowing for upward movements of the sample in steps of 1 m. The semi-automatic uplift system is constructed in the same way as it was done for the Reichert OM E.

Sectioning procedure

The basic sectioning procedure is comparable for all samples. After adjusting the e.g., perpendicular to the longitudinal sectioning. Depending on the size and density of the material, the vertical angle of the A). The more dense the material is, the steeper the angle of the knife needs to be. The exact position has to be adapted for each specimen, A) is applicable for most softwoods. Although it is common practice to place the entire sample in water for several minutes before sectioning to soften the material, at least for bigger samples only the part to be m- a stable microtome blade.

YLDIUHHDFFHVV

m); A1 and A4: Fagus sylvatica; A2 and A3: Larix decidua. - B: Examples for the range of pos- related micro photos); B1: Acer campestreFagus sylvatica,

Pinus sylvestris

B4: Piper nigrumCycas circinalis, leaf, enrolled, sample

YLDIUHHDFFHVV

IAWA Journal 36 (4), 2015

sectioned should be water-saturated. The problem is the fact that the entire sample gets softened when it is completely water-saturated and, as a result, bigger samples tend to high forces always occurring while the knife cuts off a section. In extreme cases, the sample is lifted up in the central part to such an amount, that the knife gets stuck in the sample. the surface of the sample with water by using a brush, wait for a moment until it is soaked in the upper part of the sample and start cutting. Make sure, that the part to be always depends on the specimen. The construction allows disks of branches, roots or Special clamps were developed to allow cutting 5-mm and 10-mm increment cores up to a length of 6 cm, but also micro cores taken using, e.g. et alB cores enables preparing cores for isotopic analysis. The surface can be prepared to analyze the common ring structure and micro sections can be taken to further analyze the anatomical structure without contaminating the remaining sample. Furthermore, when stabilizing the blade with the pole, 800 m sections can be cut from the core e.g.et al. 2014). This procedure also re- the core to a certain amount and then soak the surface until roughly a 1-mm layer is soaked before the micro sections can be cut.

CONCLUSION

A big drawback in sectioning woods until nowadays was the fact that samples were restricted to a relatively small size. The enhanced stability of the Lab-microtome helps resolving this problem and enables cutting a wide range of specimens, from petioles

REFERENCES

development of tissue preparation. Heinemann, London.

Dendrochronologia 34: 19-23.

YLDIUHHDFFHVV

cores and time series analysis of varying cell parameters. Dendrochronologia 28: 85-92. lysis. Verlag Dr. Kessel, Remagen.

WUHHVWHPV,$:$-ˆ˛²ˆ

13 18

O studies. New Phytol. 201: 1045OE1055.

Accepted: 10 August 2015

YLDIUHHDFFHVV

quotesdbs_dbs21.pdfusesText_27

[PDF] slow poisoning symptoms

[PDF] slp vocabulary goals

[PDF] smart device policy

[PDF] smiley drapeau france

[PDF] smileys food truck paris tx

[PDF] sncf manage booking

[PDF] sncf paris nice train de nuit

[PDF] sncf refund

[PDF] sncf tgv angers paris horaires

[PDF] sncf tgv nantes paris horaires et prix

[PDF] sncf tgv paris dijon horaires

[PDF] sncf tgv paris geneve horaires

[PDF] sncf train paris nice horaire

[PDF] soa exam ifm study note

[PDF] soa exam ifm syllabus