And so the threadjacking begins. It is certainly true that we see many sad yellow green etiolated Heliamphora in cultivation. It is also true that cfl's have disadvantages, including inefficiency. I have never tried to illuminate large areas with cfl's, but they are handy for illuminating tall and narrow individuals that can't play well with a lighting solution that is supposed to illuminate a bunch of smaller plants and one or two tall ones. I think Butch is saying as much when he says cfls are good for specimens. FWIW, this is what tatei Cerro Duida looks like after years of growing under cfls:
https://farm4.staticflickr.com/3912/14450907472_d31cc692fd_o.jpg
In any case, I think all growers should interpret this claim with great care:
While many can grow them, few get the color that they should.
My purpose here is to discuss the evidence we have, not to start a fight. Spreading our increasing knowledge of photoprotection has been kind of a hobby horse for me, I think it's really important that artificial light growers understand the newer research on anthocyanins, coloration, and photoprotection.
What color should Heliamphora have? Clearly, yellow green etiolated plants are unattractive and are not displaying their true leaf form. Increasing the light will restore leaf form, but this can occur without reaching full blood red coloration. In this photo I think both plants exhibit their true leaf form, but neither is blood red. FWIW the pulchella was growing under a 27 watt cfl for convenience, while the sarracenioides was growing under t12's. (The latter too, I readily agree, are inefficient light sources.)
https://www.flickr.com/photos/51764444@N03/10595479653/
If we add even more light, or drop the temp, we can keep the leaf form but also attain full blood red coloration. I agree that full blood red or purple coloration is attractive to the eye. And if the grower's goal is to achieve that coloration, so be it. Add more light and/or drop the temperature, they'll turn really red. There's no mystery to it, it's easily done.
However, my (perhaps false) perception is that many growers go a step further, and believe that full blood red coloration is not just a horticultural goal, it's a sign that the plant has reached its optimal state. In other words, full blood red is not just pleasing to the eye, full blood red is *evidence* that the plant is maximally happy. This view, which I am not attributing to Butch or anyone else for that matter, is at best questionable, and at worst, simply false. It is also the case that if efficiency is a key criterion, *no* artificial light gardener should ever apply enough light to turn a Heliamphora blood red.
Why? Older literature (some is referenced in eg Juniper et al) focused on interpreting coloration in terms of prey attraction. However, evidence continues to mount that anthocyanins serve an essential photoprotective function. Here is an easily available older paper on photoprotection, but you can find much more on the subject:
http://onlinelibrary.wiley.com/doi/10.1046/j.1469-8137.2002.00482.x/pdf
Things we know for sure:
1) In simple terms, blue and red light are the photosynthetically useful wavelengths.
2) The enzymes involved in photosynthesis use these wavelengths to make sugar, they are essential for plant life.
3) The rate at which these enzymes can process photons is temperature dependent. At lower temps, the rate drops.
4) When photons are supplied in excess of the rate at which the enzymes can process them, bad things happen. One bad thing is reactive oxygen species will form; in simple terms, these are undesirable substances that can damage the plant.
Given claim (1) and (2), it's sort of mysterious why a Heliamphora or any other plant would turn full blood red. Red light makes food! So why on earth would a plant turn red and *reflect* that light away? The answer used to be adaptation to attract prey, but it is increasingly clear that the correct answer is that the plant is protecting itself from more photons than it can process at that temperature. In other words, the plant is turning red specifically in order to reject excess photons that would otherwise create ROS and cause damage. This interpretation is consistent with my own experience, Favian's, and I daresay all growers: drop the temp and or increase the light, and the plant turns red. In habitat in Oregon, I'll never forget seeing green Darlingtonia along the edge of a frigid snowmelt stream. They had runners extending into the water, and young plantlets on those runners were completely submerged, and full blood red. The same clones exposed to the same sun, yet the underwater plants were blood red. It's because the water was so cold, the plantlets could not take that much light, so they were reflecting it back. Rejecting it is maybe a better description.
Full blood red coloration on a Heliamphora simply is not evidence that the plant has reached *its* optimal state. It is evidence that the plant is getting more light than it can profitably use, so the plant is reflecting that energy away, in order to protect itself. It is at best unclear whether a blood red Heliamphora is successfully managing overexposure to light, or whether it is suffering from ROS related damage despite its efforts to reflect away red light (or in the extreme purple cases, red *and* blue light.). Even if one wants to question the photoprotective interpretation of anthocyanin production, it is indisputable that a blood red plant is returning the supplied red wavelengths to sender. This is why I say, if efficiency is really a key criterion for an artificial light grower, it is undeniable that light is being wasted on a blood red plant--the plant is definitely reflecting it rather than absorbing it, the evidence supports the view that it is reflecting it so as not to be damaged by the excess of photons, it is certain that excess photons can cause damage, and it is unknown whether a blood red Heliamphora is experiencing damage from excess photons.
I think the research on photoprotection is fascinating, and like I said, I think it is very relevant for artificial light growers as they evaluate the growth of their plants and the performance and scale of their light systems. All light systems have advantages and disadvantages, this is indisputable. And like I said, full blood red is attractive to the eye; if that's the grower's goal, that's their business imo. But I do think we have very good reasons to question the view that full blood red coloration is evidence that the plant is maximally happy. (And as I said, maybe that view is a straw man, I've never seen anyone make that claim. But I suspect that some believe it.) We also have good reason to reject full blood red coloration if efficiency is a key goal, because such plants are indisputably reflecting away PAR that has been supplied at great cost, effort, and in many cases, by burning coal. It would definitely be more efficient to supply less light, and possibly (though this is unclear), the plants would be healthier, even if less attractive to the eye.
