Fern spore and stomata in auto-fluorescence

Images made through a microscope. All subject types.

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Didier_Micro
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Fern spore and stomata in auto-fluorescence

Post by Didier_Micro »

Fern spore in auto-fluorescence
Fern spores
Fern spores
and stomata in auto-fluorescence
Stomata
Stomata
Regards

iconoclastica
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Re: Fern spore and stomata in auto-fluorescence

Post by iconoclastica »

Quite nice! Do you know which fern it is?
BTW, it's sporangia, not spores. Sporgangia are capsules that contain the spores.
--- felix filicis ---

Lou Jost
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Re: Fern spore and stomata in auto-fluorescence

Post by Lou Jost »

Ferns are some of the best subjects for fluorescence photography. I've been doing that today too. I notice that the background behind your sporangia is fairly black. Yet fern pinnae almost always fluoresce strongly red, as in your stomata picture, because of the chlorophyll. Cholorophyll fluorescence is unusual because it is part of a photochemical system which has the ability to protect itself and quench some reactions when exposed to strong light. It quickly becomes dull after a few seconds or a few minutes, depending on the strength of the incident light. I suspect this may be happening to you, if you left the UV light on while you set up the picture and set the focus, etc, or if you did a long stack starting from top to bottom. With sporangia it is better to go from bottom to top, so that the pinnae are captured first, and then the sporangia. The sporangia are not part of any quenching system and their colors will last longer, though eventually they too will bleach.

On the other hand maybe you scraped off the sporangia and put them on a black background. If so, disregard my comment.

I have found the sporangia photos of Rogelio Moreno on this forum and elsewhere on the internet to be very inspiring, and they show how beautiful fern sporangia can be. For example:
https://www.nikonsmallworld.com/galleri ... ing-spores
I would love to be able to take such pictures.

Didier_Micro
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Joined: Sat Nov 21, 2020 1:48 pm
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Re: Fern spore and stomata in auto-fluorescence

Post by Didier_Micro »

Thank you for your comments.

You are right Felix, it is sporangia, spores are inside.
I don't know which fern it is. firstly interested by the artistic side, I am not yet a great specialist of nature.

Lou, your comment is very interesting, I will try to do the stacking from bottom to top next time.
I agree about photos of Rogelio Moreno.

Regards
Didier

iconoclastica
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Re: Fern spore and stomata in auto-fluorescence

Post by iconoclastica »

Lou, do you happen to know what substance causes the fluorescense within the annulus cells, and why that changes colour (apparently during maturation)?
--- felix filicis ---

Lou Jost
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Re: Fern spore and stomata in auto-fluorescence

Post by Lou Jost »

Lou, do you happen to know what substance causes the fluorescense within the annulus cells, and why that changes colour (apparently during maturation)?
No, iconoclasta, I don't.
I will try to do the stacking from bottom to top next time.
That will help, but even more important is to minimize the total exposure to UV. Don't use the UV light to set up the stack; use weak normal light. A UV-modified flash can be helpful to prevent exposure to UV during the rail movements and during rail waiting times. An alternative that I am trying tonight is to use in-camera focus bracketing to run the stack by focusing the tube lens. My Panasonic G9 has a buffer of 60 images or so, making it possible to do a 60 image stack in just 2-3 minutes. Even then, I'll use higher ISO than normal to further reduce the stacking time.

Theoretically, the brightest chlorophyll fluorescence happens a second or two after turning on the UV light (Kautsy effect). This might make continuous light better than flash, if the stack can be run quickly enough.

Lou Jost
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Re: Fern spore and stomata in auto-fluorescence

Post by Lou Jost »

My tests were disappointing. The red chlorophyll fluorescence was significantly duller after just 4 seconds, using ASA 400 and 1/2s exposure. By 8 seconds it looked quite dull.

genera
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Re: Fern spore and stomata in auto-fluorescence

Post by genera »

They look like the sporangia from the Pyrrosia lingua ( tongue fern is one common name ), I have in my yard. Are the sporangia grouped in random clusters or organized in lines? The Pyrrosia lingua clusters will be random. The bands on these look like they've just split.
-Gene

iconoclastica
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Re: Fern spore and stomata in auto-fluorescence

Post by iconoclastica »

genera wrote:
Tue May 25, 2021 6:18 pm
They look like the sporangia from the Pyrrosia lingua ( tongue fern is one common name ), I have in my yard. Are the sporangia grouped in random clusters or organized in lines? The Pyrrosia lingua clusters will be random. The bands on these look like they've just split.
Most Leptosporangiate ferns have sporangia like this. There's some variation in the number and width of the indurated cells. Rarely there are extra ornaments.
--- felix filicis ---

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