Ceps need sunlight?

[cowshill]

Well, we all know that fungi don't have chlorophyll and don't use sunlight to produce their food. But I just came to the conclusion (though this may be old news to you) that they do respond to sunlight in process of producing their fruit bodies. At least in the case of this cep.



It was growing among the roots of a tree. The left side was caught under a small root and had not been able to push through the moss to daylight. You can see the crease in the cap where the root had held it down. You can also see that this side is much lighter in colour than the right side, which had been exposed to more direct sunlight. This caused me to remember the time that, while harvesting one cep, I had discovered another, well formed but still completely underground, and its cap had been pure white.

But what is really interesting is the pores on the underside.



Here you can see that the pores on the shaded left side are completely undeveloped, while on the sunny side they are mature and, presumably ready to shed spores. So my surmise is that, while the cep does not use sunlight for energy, it appears to use the light to judge when it is above ground and in position to finish developing to be able to sow its spores. Is this correct?

- Jim

[Chris Yeates]

hi Jim

an interesting one - I would suggest that temperature may be more of a factor here, rather than light

Chris

[SheffieldLass]

Originally Posted by Chris Yeates

hi Jim

an interesting one - I would suggest that temperature may be more of a factor here, rather than light

Chris

Where they push up through a thick layer of conifer needles I've been seeing the same thing - often the whole cap is above the ground, but with a raised carpet of needles still over part of the cap, and that bit is whitish. They also do seem to be paler when under dense conifers than those in a lighter location such as by the edge of a path.

Melanie

[alge]

Originally Posted by SheffieldLass

Where they push up through a thick layer of conifer needles I've been seeing the same thing - often the whole cap is above the ground, but with a raised carpet of needles still over part of the cap, and that bit is whitish. They also do seem to be paler when under dense conifers than those in a lighter location such as by the edge of a path.

Melanie

hi Jim

an interesting one - I would suggest that temperature may be more of a factor here, rather than light

Chris

Jim,

Last year we had a cold snap for a few nights mid September the caps were much darker for a few days after, it then warmed up a bit and the new fruit bodies reverted to the lighter buff colour cap for a few weeks until it cooled off in late October and as before the caps darkened. This only happened in the more open Chestnut coppice and among the mature well spaced Pines. The three other patches of troops i was visiting during that period were under dense Beech and Chestnut that were only coppiced three years previous. One of the things on my agenda this year is to see if the cap colour change happens again if we have an air temperature drop then a warming. I'm inclined to suspect Chris is right. Maybe we could get a few people to take a note of night time temperature and see if correlates to changes in cap colour in exposed ceps?

Alex

[cowshill]

I'm resurrecting this post from August to add my conclusions from ceps I have seen through the season. My observations indicate that the more sunlight a cep has seen the darker the cap colour. I occasionally have found a cep that is still completely underground (when it is right next to an exposed one that I am digging out of the turf), and these are always pure white - not a trace of colour. Ceps that are just emerging will be light tan where the center has pushed through, but still white at the edges of the cap that have not yet seen daylight. And of course those that have fully emerged and spent time in the light will be the distinctive cep dark brown.

I still find the most interesting aspect of this to be the idea, as indicated in my original post and pictures, that the tubes also appear to respond to daylight to proceed with their final development. Also the simple idea that an organism that does not use sunlight for photosynthesis still relies on it to provide the timing mechanism for part of its development. Perhaps this is a common attribute of many fungi, but just not so evident in most. Would an amanita or an agaricus break the egg if it never saw daylight - or would it develop its gills and shed spores?

- Jim

P.S. I have not noticed anything obviously related to temperature. And since our "warm" here in the north is the equivalent to "cold" in the south, if temperature were a major factor then our northern ceps would always be very light coloured, which is definitely not the case.