Studying Mushrooms > Using a Microscope > Creating a Section to Study


Using a Microscope: Creating a Section to Study

by Michael Kuo

To study spores from a spore print, no particularly difficult routines are involved with getting what you want to examine on the slide, ready for viewing. Other microscopic structures, however, require special techniques for creating a "section" you can look at. The difficulty involved results from the fact that you must create a cross-section of the mushroom--a cross-section so thin that you can look at it under your microscope at magnification of 1000 times.

Most of the structures you will want to observe can be seen by creating a cross-section of the mushroom's cap, with the gills included. Thus, "sectioning a pileus" is one of the most essential and basic laboratory routines for mycologists--and the rest of us are forced to learn how to do it if we want to get very far with advanced mushroom identification. To be honest, I'm not particularly good at it--though I can usually manage to get a good enough look at things to be able to take the required measurements and know whether the mushroom has, for example, prominent cystidia. Creating the required cross-section takes lots of practice, so you should prepare for disappointing results for the first, oh, 200 attempts.

I will take you through the actual razor-blade-and-mushroom routine in a moment, but first I want to give you the concept involved with sectioning a mushroom's cap, since most sources frustratingly describe the routine without giving you something to visualize and attempt doing with your razor blade. The graphic below is meant to represent the idea behind sectioning a mushroom cap, but it should not be taken too literally (for example, I have widened the thickness of the section for your visual understanding, but your actual section must be paper-thin).

Sectioning a Cap

The thing in the middle of the graphic represents the section you want to create. On the left is the section in relation to the mushroom and its cap; on the right is a schematized diagram of part of the section, under your microscope. You can see that a nice, Roman-aqueduct-reminiscent section would be a pretty nifty thing, allowing you to look at structures on the gills, the cap surface, and in the flesh of the mushroom--with everything held nicely together so that you can figure out what's what.

The bad news is that it took me much less time to create the graphic than it is likely to take a beginner to actually slice a section like the one depicted. This beginner, anyway, struggled for years and made many "blood mounts" before getting the hang of it.

Use Good Razor Blades

Prepare to budget some money for razor blades, because successful sectioning requires super sharp edges. We're talking three or four uses, and it's time for a new one. You'll have to search around at your drug store to find the old-fashioned, single-edged blades in the little safety boxes. Avoid double-edged blades; they are flimsy and, more importantly, dangerous, since you don't have a nice, safe edge to handle.

Step by Step

The graphic below takes you through the process of creating a section like the one schematized above. You will notice that things don't work out so perfectly for me in the photo series--for example, the Agaricus bisporus specimen I'm using has so much flesh in its cap that creating a paper-thin section all the way from the cap surface to tips of the gills would be impossible (for me, anyway), so I have given up and simply used a small piece of the cap's flesh to hold the gill sections together. Also, the section I have cut is too thick to be ideal--but I wanted something that would show up well in the photos.

Sectioning Step-by-Step

In the illustrations I used a 2% KOH mount, staining it with phloxine (see Chemicals, Reagents, and Stains). Despite being so clumsily sliced and thick, the section above afforded the microscopic views below--and I was even able to find a characteristic two-pronged basidium, the defining feature of Agaricus bisporus.

Agaricus bisporus section under microscope

An alternative method for preparing tissues for study using jeweler's forceps can be found in Archie MacAdam's "Preparing Specimens for Microscopy with Jeweller's Forceps" (2004; Field Mycology 5: 81-82).

Cite this page as:

Kuo, M. (2006, February). Using a microscope: Creating a section to study. Retrieved from the MushroomExpert.Com Web site:

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