For my first post here I would like to share with you this grayscale picture of Russula spores. In a few words, russulas are common mushrooms you can find in almost every ecosystem. This genus, together with Lactarius (those ones exude a milky substance), belongs to the family Russulaceae, which contains a large number of species which can hardly be identified without a microscope. However, the genus itself is easily recognizable due to striking characteristics such as friable, chalk-like stalks and waxy gills.
Microscopy
From the microscopic point of view, russulas are also very interesting (at least much more than Lactarius species). Most of them have small globulous spores with a more or less developed ornementation, from low warts to dense reticulum. This ornementation is hyaline and thus cannot be directly observed in brightfield microscopy. Fortunately, it is amyloid and turn to black with Melzer's reagent (recipe : 5 g potassium iodide, 2 g iodine and 100 g chloral hydrate in 100 mL distilled water. Be careful, chloral hydrate is highly toxic).
How to proceed?
Just put a russula gills on a microscope slide and immerge it into Melzer's reagent. Wait for 2-3 minutes and rinse with distilled water. Then cut into pieces and mount in chloral lactophenol (caution: never ever sniff the microscope slide and work in a ventilated area, the mounting medium contains chloral hydrate and phenol which are highly toxic). Add the coverslip and dissociate the tissues by applying gentle pressures with something like a rubber. Then, you are ready to observe it through the microscope!
Let's observe!
As a rule of thumb, a decent x60 objective with NA 0.8 is enough (but you might need a better lens for taking photos). I usually take 3 to 5 photos from the top to the middle of the spores. These snaps are then aligned and stacked (Zerene Stacker, Helicon Focus... I suppose you know that better than me) to get the final picture. Here it is :
This image was shot with a Canon EOS 500D on top of an Olympus BH2 BHT equiped with Olympus SPlanApo 60/1.4 and filter Nikon ND2.
Some of you may also notice the amyloid supra-apicular region on some spores.
Caveats
Specialists could argue that this method led to the photography of young immature spores, and they would be right. But, for some physical (brownian movement, flows in sample due to the increased temperature) and observational reasons (immersion oil viscosity), spores in suspension are much more difficult, if not impossible, to immobilize, even in albuminated water (well, I should try
)
