Question for you Chlorophile. Have you personally been able to induce good color from plants under low light by starving them?
I only ask because I have read this several times, but don't know of anyone who has actually done it. And I'm not saying it doesn't happen, I've just never seen it.
I know for me I've never seen plants get better color from starving them under either low or high light. For me, starving plants under either light just results in dead or dying plants (and algae). I get the best color out of well fed happy plants.
So I am wondering is starving plants really a technique that brings out color??
Burr I wonder what your thoughts are on this???
Personally yes, atleast Bacopa Caroliniana it gets very copper at the tips in my tank that is neglected. Far far more than the B. Colorata in my high tech tank. Honestly if I took the two stems out you'd get them backwards.
As far as the botany is concerned, there are two ways to produce red coloration.
Anthocyanin is present all the time, but when the plant can't produce chlorophyll quick enough or transfer it the anthocyanin is all that is present and you get a red coloration
Same thing happens in the fall during before the leafs absence, not so much in plants with quiescence though as they don't drop the leaf, ergo they do not stop the flow of chlorophyll until the leaf is simply dead.
I think in actively growing plants it a little different, but I've seen dennis wong talk about it plenty and demonstrate it as well.
Like we talk about traces being a limiting factor at times, or N, or P..
When nothing is limiting except light I don't think you will induce good coloration.
If somethings are limiting more than light, the plant can't cope as well and the current lighting might produce more stress response and ergo anthocyanins.
This is something unique to red plants, but its definitely something I can prove with pictures I have in my library.
I have pics of rotala rotundifolia looking better than nearly anyones I've ever seen, under a single Current Satelite + pro, during a very lean part of my early tank set up.
And I think it's a large part of why many of the original dutch guys who were running lower light to maintain lower growth rates (and therefor keeping the scape the way they intend for longer) ran very lean dosing.
as far as the gas analogy goes: a car designed to run 87 octane wont benefit from 93.. in plants though I think if you pour good gas on them but the gas pedal isn't pressed all the way you won't see any results.
It shouldn't be a confusing concept, why does higher light produce certain physiology in the first place?
It's pushing a plant to some kind of nutrient limit.
If you limit it in another way, half throttle should push it to a similar limit.
Exceptions abound of course, node length and leaf density are gonna be largely independent of things like coloration.
Nitrogen in turfgrass produces dark green coloration..
Without it you get yellowing.
Nitrogen on trees in the fall will completely negate red coloration even on maple and red oak.
Theres definitely science behind it, but I think when people say they can't reproduce it they are operating a tank with high fish load and couldn't actually provide the low N level necessary even if they tried.