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Re: Red light, green light

On Jul 23,  3:48pm, George Booth wrote:

> "Uh-huh", thought I, "well, well, what about plants with RED leaves?
> I guess they aren't reflecting green light, are they?  They might
> actually be refecting God's Own red light!  They might even THRIVE
> with strong green light!".  You know, plants like Rotala spp..
> Alternanthera spp., Ammania spp., Ludwigia spp., etc.
> So, any comments?  I mean about green wavelengths being useful to
> plants with red leaves, not about my ponderous prose.

That got me curious and I loaded one of Amano's picture into my computer
and examined the RGB values of the red leaves.  The picture I used
was the one with penny wort in the foreground and some Alternanthera spp. in
the background.  Before you flame me, I do not have access to
proper spectral analysis equipment.

Some of the RGB values I got: 249/192/179, 231/166/125, 204/109/67, etc.
(the higher the value, the more light in that colour is reflected).
So typically almost all red light and a lot of green light are reflected
off these red leaves.  In contrast, the RGB values on the penny wort:
89/183/83, 104/174/41, 177/234/133, etc.

Given the high green value reflected.  If these red plants uses green light,
they are using it in a very inefficient way.  My wild guess is the natural
habitat of these plants are brightly lighted but limited in some essential
nutrient (CO2 or N, perhaps?).  The plants simply cannot utilize all the
light available and evolved to only take the blue light.  This hypothesis
seems to agree with the observation that red plants do better under very
strong light in aquarium.

This is of course utterly unscientific.

Louis Lin