Lichen Squash

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mrsonchus
Posts: 4175
Joined: Tue Feb 03, 2015 9:42 pm
Location: Cumbria, UK

Lichen Squash

#1 Post by mrsonchus » Wed Mar 03, 2021 9:56 pm

Hi all, some may remember the recent adventure of the lichens I posted.
This resulted in the production of some pretty nice permanent lichen-section slides (of the species Xanthia.parietina as it transpired). Well, as I was tidying-up in the lab today I placed some lichens into their dry storage jars. I gathered a fine crop of fertile lichens (fertile in the sense that they had mature apothecia including ascospores within) from a fine craggy old tree I spotted on my way to the supermarket about a week ago. These are the lichens I'm storing dry, until some higher mp wax arrives, I have some 60°C mp wax on the way which may give cleaner sections...

Here's the fine crop gathered, containing several lichen species I think...
Image

So, before I stashed these away I sorted out a few of the Xanthia.parietina apothecia and placed them into a few drops of water for a couple of minutes, before dissecting a couple of the apothecia with the thallus removed from around them. A simple matter then to place them onto a slide in a drop of water with the addition of a drop of the easily-obtained fungal-stain lactophenol cotton-blue.
With coverslip applied and the application of light squashing pressure, which also squeezed out excess stain and water, leaving a pretty clear water-mount and some nicely stained spores, I had a water-mount of stained ascospores to observe under my trusty compound 'scope.

The result was better than I expected, with the ascospores seen in images from the aforementioned slides stained quite nicely, in their 'fresh' unsectioned state.

This is a piece of the Xanthia.parietina lichen dry, in a sunny position thia lichen is usually quite bright shades of orange! The cup-like structures seen on the surface of the flatter parts (the thallus) are the apothecia, and it's these that I removed and stained in the following images....
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The squashed and stained pieces didn't look too promising....
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Scanning the slide however soon revealed just what I was hoping for - many nicely stained ascospores!
Here's an image with the bits & pieces removed from the background. This is a good complementary image to those from the permanent slides detailed in earlier posts, showing the overall shape, size and gross structure of the spores very clearly and with the high contrast afforded by the lactophenol cotton-blue stain used.
Image

These spores would I think also be quite easy to mount permanently in resin as with the sectioned slides. Together they would be an interesting addition to my collection.

The sections made and mounted down at between 10µ to 2µ give a very different view, which while quite detailed doesn't give such a clear demonstration of the overall gross structure of the spores specifically. Obviously both 'versions' have their merits, the permanent slides for starters by virtue of that permanence (although I'm pretty sure I can permanently mount the whole-spore examples above without much trouble...) and the inclusion in some detail of the surrounding fungal matrix, apothecia detail, algal cells etc.

The two versions,

The sectioned mounts as permanent slides, lots of detail but very different to the spore whole-mounts...
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Again the spores whole-mounted in water and stained with LP cotton-blue stain....
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It's been literally a very revealing adventure with these lichens that I've had great fun with! When I get around to repeating some sections of apothecia embedded in the harder 60°C wax I'll post any nice images and worthwile details. Thanks for looking all, hope you like these little gems! :D
John B

perrywespa
Posts: 112
Joined: Mon Jun 15, 2020 9:13 pm
Location: Georgia

Re: Lichen Squash

#2 Post by perrywespa » Wed Mar 03, 2021 10:34 pm

John,
As usual, your slides are beautiful and this whole series has been very educational. Thanks for all your hard work and for sharing.
Perry
Insatiably curious.

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