photosynthesis

[Chucky]

What part of that article I posted did no one understand? The pigments we see in certain plants mean nothing are far as the plant's ability to photosynthize. They still have the same relative amounts of green chlorophyll as other plants. The green chlorophyll pigments are just masked to the human eye by other pigments. It doesn't mean they're any less capable of photosynthesizing.

Mike Maas mentioned that certain variegated plants may be less thrifty than their green relatives. I think that's probably more due to their being clones that aren't able to adapt to certain adversely constraining soil and climatic conditions that the species, which being sexually propagated, can adapt to.

TreeCo mentioned certain tropical plants' ability to more efficiently capture photons. That's because they've evolved the C4 method of photosynthesis instead of the C3 method of photosynthesis that the more temperate species have evolved . It's the same as cool-season grasses versus warm-season grasses. But the added pigments in plants that have been selected for in certain colorful plant cultivars have nothing to do with the efficiency with which they photosynthesize.

 

[glens]

Like with the green laser, leaves are green so the sun can see them better in daylight.

 

[JeffE]

Originally posted by Mike Maas
Why do you suppose when you fly around in an airplane and look down, all you see is green?

I think that Mike is mostly right here, although it's a different issue from the variegated-leaf trees. Those species actually have less chlorophyll per unit of leaf area. The purple-leaf varieties have at least as much chlorophyll as standard trees, just more of other pigments.

Anthocyanins are believed to exist in part to protect leaf tissues from damage due to excess light exposure - it is thought that they provide "light attenuation" (shade) within the leaf when the light exposure threatens to cause oxidation damage, etc. I don't think that the effect on the efficiency of these unusual red cultivars of normally green species has been well-studied, and the Oregon link doesn't address these... umm.. freaks.

It's worth noting that a couple of the more robust purple-leafed varieties I can think of - "Crimson King" Norway maple and European beech ("Atropunicea") are shade-tolerant species... probably when planted in full light, they're normally able to make use of only a small amount of the radiation they receive, thus the extra "shade" from the red pigment is no big deal.

However, even if the purple-leaf varieties are photosynthesizing just as much, producing all that red pigment requires spending resources that could be used elsewhere. Whether this expenditure is enough to have a significant effect on vigor is anyone's guess.

 

[Matt Follett]

Yeah What Jeff E said!

Pardon the following prenuncyatstation, grama, and Spleelling, it's Latte

The anthocyanin thing is a bit of a debate amongst biologists right now... As leaves turn in the fall, do they produce more anthocyanins, and carotinoides, or is it merely these chemicals becoming more pronounced as the chlorophyll disipates...

Anway the question still remains do trees which produce more of these chemicals, which in turn cause them to be "darker" photosynthesize "less well" then those whcih are true green?

As stated, many of the darker leaved plants tend to be somewhat more shade tolerant, or at least tend exhibit less variation when planted full sun, full shade....

It is a thought amongst the botanist types that the anthocyanins are a sun blocker, and are used to help regulate light levels during "stressfull" times, spring and fall, however it is not fully understood whether they slow or reduce the process...

From personal observation, with no imperical data to support it... It would seem that those plants which are less green... grow slower then their true green siblings... and as such one could make the link that this could be attributed to the "shading effect" caused by these "extra" pigments.....

So I don't think 'we' have an solid answer to your question as of yet... But think that when these trees "revert" the reversion often out grows the coloured counterpart, and perhaps this again suggests less vigor ( I think I can use vigor here.. right?, genetic predisposition to growth rate, as opposed to health!) ....

Aw just stirring the pot, and not really bringing anything to the table...

 

[Nickrosis]

Sorry Steven, I can't do much better! I learned about all the topics, but like it's been mentioned, it's not entirely clear for biologists, much less the common man.

I had a professor melt down when asked if a drought will cause better or worse fall color.

 

[SteveBullman]

thanks for all your input

 

[TreemanFJR]

Originally posted by Nickrosis
Sorry Steven, I can't do much better! I learned about all the topics, but like it's been mentioned, it's not entirely clear for biologists, much less the common man.

I had a professor melt down when asked if a drought will cause better or worse fall color.

Down here in Jackson county we had the driest August ever recorded. We aslo had very bad fall color...

Didnt realize it since you mentioned it Nick. Im not really sure if it goes hand in hand.

 

[Big A]

Here in Eastern UK we had wet summer and beautiful Fall colours.

 

[Nickrosis]

Ah, but this is all anecdotal to date.

 

[SteveBullman]

so anyway, i was talking today with big A about this thread at work......could copper beach be more prone to diseases as they dont photosynthesize as well and common beech.
also purple plum has very dense foliage, could this be to compensate for having less clorophyll
anyone have any examples of red leaved trees that carry dense foliage?

 

[ROLLACOSTA]

Originally posted by Big A
Here in Eastern UK we had wet summer and beautiful Fall colours.

nowhere near as good as last years. to be honest i don't think the autum colors this year where very good at all..

 

[Nickrosis]

Originally posted by stephenbullman
so anyway, i was talking today with big A about this thread at work......could copper beach be more prone to diseases as they dont photosynthesize as well and common beech.

Trees are opportunistic, though.

In the forest, the green leaves have absorbed all but the green spectrum which is reflected back. So the "copper" leaves are absorbing that green and spewing out the darker spectrums they can't capitalize (or photosynthesize) on.

So don't feel badly for them! They're taking advantage of the situation.