A fast method to prepare microslides of wood in advanced stages of decay

摘要

Biologically degraded wood in advanced stages of decay has a very soft and brittle structure that causes many problems during sectioning. Embedding wood specimens in different kinds of media ensures preparation of good quality microsections, but the preparation time is very long. The proposed method does not only have a reduced preparation time but also minimizes costs and consumption of chemicals while improving stabilization of the specimen and en hancing the quality of sections. The crux of the method is application of a reinforcing layer of transparent nail polish gel on a dry specimen that has been only stabilized (not embedded) with PEG 1500 medium. The gel is applied on a specimen in two layers just before sectioning. The first layer infiltrates the specimen sufficiently deep to fill the lumens and cell walls and allows preparation of thin sections from decayed wood. The second layer reinforces the section and allows better handling. Subsequently, the reinforcing and embedding layers are removed using pure acetone. This innovative method has so far been successfully tested on specimens that were degraded by the fungus Pleurotus ostreatus (mass loss 55% and 83%) and the fungus Phaeolus schweinitzii (mass loss 45%), taken from Fagus sylvatica and Pinus sylvestris species, a hardwood and softwood respectively with contrasting wide vessels and narrow tracheids.