Not sure what that means but yeah, the Siri are parallel along the stem.Chris S. wrote:Waldo, thank you for the closeup! I've returned to look at it several times since you posted it. I'll be interested to hear what my botanist friends have to say.
Pteridium aquilinum, huh? That's common in my area, too--but is certainly not green right now (of course, we have snow here). I take it that the sori are along the leaf margins?
Cheers,
--Chris
Fern sorus
Moderators: rjlittlefield, ChrisR, Chris S., Pau
Hi Waldo and Chris.
Waldo, do not know which fern you have, but it is definitely not Pteridium. In Pteridium, the sori are massed together in a line under the inrolled edge of the leaf, whereas yours is isolated and on the leaf surface.
See this page for Pteridium sori:
http://www.wnmu.edu/academic/nspages/gi ... linum.html
In most ferns, the sorus is covered by a cap or flap of sterile tissue - the indusium. Your fern appears to have no indusium (I suppose it could have withered away, but I think it is unlikely). The best known fern genus where there is no indusium is Polypodium, and I see that this is also a featured plant in your wood. It is winter green.
There is an interesting page on Polypodium (which includes photos of the sorus) here:
http://mundani-garden.blogspot.pt/2011/ ... -cold.html
And for stomata (two photos showing the "gap" in chloroplast distribution in the guard cells) here:
http://home.hib.no/ansatte/jeb/Planteanatomi/
Guard cells often contain a very large nucleus and I think that this has created the non-fluorescing area that you can see.
BTW - nice photos! - photo2 my favourite.
Thank you for posting!
regards,
Brian
Waldo, do not know which fern you have, but it is definitely not Pteridium. In Pteridium, the sori are massed together in a line under the inrolled edge of the leaf, whereas yours is isolated and on the leaf surface.
See this page for Pteridium sori:
http://www.wnmu.edu/academic/nspages/gi ... linum.html
In most ferns, the sorus is covered by a cap or flap of sterile tissue - the indusium. Your fern appears to have no indusium (I suppose it could have withered away, but I think it is unlikely). The best known fern genus where there is no indusium is Polypodium, and I see that this is also a featured plant in your wood. It is winter green.
There is an interesting page on Polypodium (which includes photos of the sorus) here:
http://mundani-garden.blogspot.pt/2011/ ... -cold.html
And for stomata (two photos showing the "gap" in chloroplast distribution in the guard cells) here:
http://home.hib.no/ansatte/jeb/Planteanatomi/
Guard cells often contain a very large nucleus and I think that this has created the non-fluorescing area that you can see.
BTW - nice photos! - photo2 my favourite.
Thank you for posting!
regards,
Brian
BJ, thank you for your valuable information. It is very likely I misidentified the fern as I merely took the name based on what was mentioned on that web site - of course there could be multiple species as it is quite a large forest. You are correct, the sori are spaced apart like in the second link. I will try and take a photo of the fern when I can.
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rjlittlefield
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Brian,
Thanks for the explanation of the stomatal dark spots being large nuclei where the chloroplasts are absent. Makes perfect sense.
Since you’ve saved me the trouble of asking plant physiologists to tell me what these spots are, can you take a stab at the next dumb question I would ask: “Why would it be adaptive for stomata to have particularly large nuclei?”
I also did not think this specimen looked like Pteridium, which is why I asked if the sori were located along the leaf margins.
Waldo, thanks for the “old photo”! Definitely looks like a polypody, as Brian said. For comparison, in this old post I showed a sorus from Polypodium virginianum. (I also have the frond that it was removed from on my desk as I type this). While your specimen is very likely* a different species, the family resemblance is pretty strong. (* I at first typed "almost surely," but with the current pace of taxonomic revision, what is split today may be lumped ten years from now.)
Cheers,
--Chris
Thanks for the explanation of the stomatal dark spots being large nuclei where the chloroplasts are absent. Makes perfect sense.
Since you’ve saved me the trouble of asking plant physiologists to tell me what these spots are, can you take a stab at the next dumb question I would ask: “Why would it be adaptive for stomata to have particularly large nuclei?”
I also did not think this specimen looked like Pteridium, which is why I asked if the sori were located along the leaf margins.
Waldo, thanks for the “old photo”! Definitely looks like a polypody, as Brian said. For comparison, in this old post I showed a sorus from Polypodium virginianum. (I also have the frond that it was removed from on my desk as I type this). While your specimen is very likely* a different species, the family resemblance is pretty strong. (* I at first typed "almost surely," but with the current pace of taxonomic revision, what is split today may be lumped ten years from now.)
Cheers,
--Chris
Hi Chris,
answering your question about the size of the nucleus in guard cells is way way above my pay grade....but if I may speculate...
Firstly; it might be an illusion. Gaurd cells are small relative to other cells in the leaf and have a small cell vacuole. So perhaps the absolute size of the nucleus is no bigger, but the size relative to the size of the cell is greater?
Secondly; guard cells are very active relative to other leaf cells, sensing environment conditions and then responding by opening or closing the stoma. When I went to college, opening and shutting was considered a simple osmotic response (or perhaps I didn't pay enough attention !!). Now, it is clearly shown to involve a complex signalling process involving the plant hormone abscicic acid, microtubules and calcium ions before the osmotic process (the movement of potassium ions in/out of the vacuole and subsequent water movements) does the work. So the nucleus in a guard cell is a busy very active nucleus and perhaps needs to be bigger?
Just speculation...perhaps you should talk to your plant physiologist friends !
regards,
Brian
answering your question about the size of the nucleus in guard cells is way way above my pay grade....but if I may speculate...
Firstly; it might be an illusion. Gaurd cells are small relative to other cells in the leaf and have a small cell vacuole. So perhaps the absolute size of the nucleus is no bigger, but the size relative to the size of the cell is greater?
Secondly; guard cells are very active relative to other leaf cells, sensing environment conditions and then responding by opening or closing the stoma. When I went to college, opening and shutting was considered a simple osmotic response (or perhaps I didn't pay enough attention !!). Now, it is clearly shown to involve a complex signalling process involving the plant hormone abscicic acid, microtubules and calcium ions before the osmotic process (the movement of potassium ions in/out of the vacuole and subsequent water movements) does the work. So the nucleus in a guard cell is a busy very active nucleus and perhaps needs to be bigger?
Just speculation...perhaps you should talk to your plant physiologist friends !
regards,
Brian
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