Colourful Exploration of Lichen Structure
Posted: Fri Feb 12, 2021 10:13 pm
Hi all, well, finally got a few slides made of a foliose lichen!
These are they (or some of them) as on a twig from an apple tree in my garden)
Having made a very quick test-slide the other day (see the story from the beginning in this earlier post for more detail on the process..) I had a little play-about today with a variety of stains, to see what I can bring out of the first slides, cut at a rather thick 10µ. I'll be sectioning to about 5µ probably over this weekend in an attempt to bring out more detail, but the nature of lichen isn't a regular structure of neat cells as found in true plants. Rather they have essentially a 'sandwich' structure of fungal-filaments and algal cells, sometimes in clumps, singly, chains etc depending on the variety of alga 'partnered' with the fungus of the 'whole' as it were - i.e. the lichen proper.
Also I know virtually nothing about lichen - so please add any detail of interpretation of these images to this thread if you have the knowledge. I've tried to label the parts as best I can at this time, but am highly likely to be in error in areas, except maybe for the identification of the algae and the fungal-hyphae - maybe - please bear with any errors seen here with my labelling - I'm a very new lichen-botherer!
Some colour and hopefully structure,
Here's a portion of the thallus of the lichen, sectioned then stained with a common combination of safranin and alcian-blue stains, both of which will be virtually permanent when mounted as slides - hopefully...
It's pretty clear here that there's no regularity of structure, as mentioned above, within this tangle of fungal hyphae at the center or 'medulla' of this lichen!
Fungal hyphae in medulla, closer-in.
Interesting to see how the thallus edge is structured also...
In an attempt to increase contrast of staining in some structures I then switched to the application of 'orange-g' stain, together (this is not a simultaneous stain protocol, the stains are applied, differentiated and assessed individually and serially) with 'rhodamine-B' (red) and a tiny touch of 'lacto-phenol cotton-blue' (which is barely seen). Overall the contrast is high however and colourful, which is always a nice feature I think.
The fungal elements have I think been stained green by the combination of LPCB and OG stains, both of which may have bonded with the algae to give green, an effect often seen with the use of a yellow and a blue stain in the same tissue - not always do they mix, but they often do. I think this is what the green is due to - the tissue was certainly not still green when sectioned and mounted!
Some of the algae also seems to have been stained red by the rhodamine-B rather than green as aforementioned.... Also it seems that algal filaments can be seen to wrap around some of the algae that are red-stained.... Seemingly a paradox but maybe the algae are different or in different states in each apparent staining result? I personally have no idea as I know nothing about lichen or indeed algae staining, this is my first attempt with this fascinating 'stuff'...
Easier to see closer-in.
It occurs to me, having had a look around the net, that these red-staining algae (if that's indeed what they are) which seem 'packaged' almost, by fungal hyphae thread, may be a reproductive structure called 'soredia' (sing soredium). If they are, I wonder why they stain red and seemingly other algae in the same staining protocol seem to stain green? Of course my assumptions for this question may themselves be totally wrong - if anyone has any knowledge of this please feel free to add to the thread as I for one would be very interested to know more!
Labelled as best I can - please correct errors - I'm learning about lichen as I go...
I also noticed that, in the upper and lower cortyex there seem to be areas that haven't taken stain, and they are not random - perhaps crystals or birefringent structures/particles lie within? So, a quick look through crossed polarisers may help..
It seems to be the case as they seem to be glowing appropriately....
Application of a full-wave retarder plate in addition to the crossed-polarisers should give diferrent colour-shifts in structures with a regular orientation such as strands or crystals may possess (or at least this is my very basic understanding of retardation-plates - please add info if you can) according to their orientation to the 'axis' of the retardation plate (I think...).
This effect does seem to be shown also, although I don't really have an interpretation for exactly what it shows I'm afraid, I'm virtally in the dark with lichens I'm afraid. A nice coloured image at least.
I'm afraid that's all I have time for this evening, but even from these early slides it seems clear that these lichen thingies have a lot of hidden details worth exploring. I have 22 more tissue wax-blocks from which to make sections (see earlier post referenced in link above) and some include the reproductive 'cup-like' structures that lichens have, which I believe are called 'apothecia' (sing apothecium) - which may be very interesting to see sectioned and stained - looking forward to finding some in sectioning!
These are they (or some of them) as on a twig from an apple tree in my garden)
Having made a very quick test-slide the other day (see the story from the beginning in this earlier post for more detail on the process..) I had a little play-about today with a variety of stains, to see what I can bring out of the first slides, cut at a rather thick 10µ. I'll be sectioning to about 5µ probably over this weekend in an attempt to bring out more detail, but the nature of lichen isn't a regular structure of neat cells as found in true plants. Rather they have essentially a 'sandwich' structure of fungal-filaments and algal cells, sometimes in clumps, singly, chains etc depending on the variety of alga 'partnered' with the fungus of the 'whole' as it were - i.e. the lichen proper.
Also I know virtually nothing about lichen - so please add any detail of interpretation of these images to this thread if you have the knowledge. I've tried to label the parts as best I can at this time, but am highly likely to be in error in areas, except maybe for the identification of the algae and the fungal-hyphae - maybe - please bear with any errors seen here with my labelling - I'm a very new lichen-botherer!
Some colour and hopefully structure,
Here's a portion of the thallus of the lichen, sectioned then stained with a common combination of safranin and alcian-blue stains, both of which will be virtually permanent when mounted as slides - hopefully...
It's pretty clear here that there's no regularity of structure, as mentioned above, within this tangle of fungal hyphae at the center or 'medulla' of this lichen!
Fungal hyphae in medulla, closer-in.
Interesting to see how the thallus edge is structured also...
In an attempt to increase contrast of staining in some structures I then switched to the application of 'orange-g' stain, together (this is not a simultaneous stain protocol, the stains are applied, differentiated and assessed individually and serially) with 'rhodamine-B' (red) and a tiny touch of 'lacto-phenol cotton-blue' (which is barely seen). Overall the contrast is high however and colourful, which is always a nice feature I think.
The fungal elements have I think been stained green by the combination of LPCB and OG stains, both of which may have bonded with the algae to give green, an effect often seen with the use of a yellow and a blue stain in the same tissue - not always do they mix, but they often do. I think this is what the green is due to - the tissue was certainly not still green when sectioned and mounted!
Some of the algae also seems to have been stained red by the rhodamine-B rather than green as aforementioned.... Also it seems that algal filaments can be seen to wrap around some of the algae that are red-stained.... Seemingly a paradox but maybe the algae are different or in different states in each apparent staining result? I personally have no idea as I know nothing about lichen or indeed algae staining, this is my first attempt with this fascinating 'stuff'...
Easier to see closer-in.
It occurs to me, having had a look around the net, that these red-staining algae (if that's indeed what they are) which seem 'packaged' almost, by fungal hyphae thread, may be a reproductive structure called 'soredia' (sing soredium). If they are, I wonder why they stain red and seemingly other algae in the same staining protocol seem to stain green? Of course my assumptions for this question may themselves be totally wrong - if anyone has any knowledge of this please feel free to add to the thread as I for one would be very interested to know more!
Labelled as best I can - please correct errors - I'm learning about lichen as I go...
I also noticed that, in the upper and lower cortyex there seem to be areas that haven't taken stain, and they are not random - perhaps crystals or birefringent structures/particles lie within? So, a quick look through crossed polarisers may help..
It seems to be the case as they seem to be glowing appropriately....
Application of a full-wave retarder plate in addition to the crossed-polarisers should give diferrent colour-shifts in structures with a regular orientation such as strands or crystals may possess (or at least this is my very basic understanding of retardation-plates - please add info if you can) according to their orientation to the 'axis' of the retardation plate (I think...).
This effect does seem to be shown also, although I don't really have an interpretation for exactly what it shows I'm afraid, I'm virtally in the dark with lichens I'm afraid. A nice coloured image at least.
I'm afraid that's all I have time for this evening, but even from these early slides it seems clear that these lichen thingies have a lot of hidden details worth exploring. I have 22 more tissue wax-blocks from which to make sections (see earlier post referenced in link above) and some include the reproductive 'cup-like' structures that lichens have, which I believe are called 'apothecia' (sing apothecium) - which may be very interesting to see sectioned and stained - looking forward to finding some in sectioning!