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Color and Light?

BruceF

BruceF

Member
Joined
19 Feb 2014
Messages
144
Location
Colorado
I think a lot of attention is paid to what exactly makes red plants red and such and it seems to me the real answer to that discussion is all about light. I hear people talk about limiting nutrients or raising nutrients but I find those things to really be secondary to light. So I am wondering what that means exactly. Is it simply intensity? Or is it spectrum or what?
 
I guess intensity is the key.Under intense lightning near to the surface ordinary Bacopa.

IMG_3227.JPG
 
Wattage? It seems to me like horsepower for cars.It does not tell exactly how fast it will be,it can be disastrous to drive,but unless it is high enough you cant go fast...
 
We use par though most of us can't actually measure that at home.


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I guess red spectrum is needed too. Red plants may dislike red spectrum,
so they produce red pigments to reflect it off. And if there is no or little red in the light,
they probably won't turn red because there is no need to do that.
 
xim said:
I guess red spectrum is needed too. Red plants may dislike red spectrum,
so they produce red pigments to reflect it off. And if there is no or little red in the light,
they probably won't turn red because there is no need to do that.
Click to expand...

There is a 137 pages of discussion about what is the best spectrum/colour combination in a Turkish Aquarium forum. There is a nice example of distribution of the LEDs and their numbers on the following page.
So I do agree spectrum is very important too.But I know there are some people out there can get nice red with only white LEDs

https://www.akvaryum.com/Forum/bitkili_tankda_led_kullanimi_k772480_sn126.asp
 
Hi all,
xim said:
I guess red spectrum is needed too. Red plants may dislike red spectrum,
so they produce red pigments to reflect it off.
Click to expand...
I think it is the other way around. Anthocyanin production is meant to be stimulated by blue and UV light, and the anthocyanins block these wavelengths (red wavelengths of light are reflected).

Amongst other benefits, the red pigments act as a "sunscreen" to protect the photosynthetic systems (principally photosystem II) from photoinhibition.

I don't know about any research in aquatic plants, <"but in "Lollo Rosso" lettuce"> anthocyanin production is almost entirely dependent on exposure to UV light (wavelengths shorter than 370 nm).

From Tsormpatsidis, E., et al. "UV irradiance as a major influence on growth, development and secondary products of commercial importance in Lollo Rosso lettuce ‘Revolution’grown under polyethylene films." Environmental and Experimental Botany 63 (2008): 232-239.
Plants under a complete UV blocking film (UV400) produced up to 2.2 times more total above ground dry weight than plants under the UV transparent film. In contrast, anthocyanin content in plants under the UV blocking film was approximately eight times lower than in plants under a UV transparent film. Furthermore, there was a curvilinear relationship between the anthocyanin content and UV wavelength cutoff such that above 370 nm there was no further reduction in anthocyanin content.
Click to expand...
cheers Darrel
 
Member jur4ik is a proffesinal aquascaper featuring as guest host at the scapfu podcasts about aquascaping. The one about light he stated, if i'm not mistaken the best over all collor to grow aquarium plants is in the range of 8000K. I guess this also goes for red plants.

Seems also very spieces depended how a plant playes with it's colors, not all plants with red tendencies react the same to same conditions.

I'm growing Rotala Mexicana Goia in my tank.. Which is a rather low staying Rotala which has the tendency to turn red under favorable conditions. I managed to get it's tips kinda pinkish with my lights and regular fert regime and inch above the substrate. But for some reason i see it fluctuate with this color. At the time it's just green again without me changing things significantly, might be fert related. Also growing Rotala Colorata, which is much larger and only turns pinky very close the the surface. This colorata i did also put in the garden pond last summer and it turned burgundy red within days even it's leave shape changed. The pond is not extra fertilized and left to its own devices. So i do not know what's in the pond when it comes to ferts but surely less than the tank. I guess for this Colorata it certainly was the sun light doing that.

I've seen my Echinodorus shoot out a new young red leaf, which turned greener the closer it got to the surface, now this same leaf is growing emersed above the tank shining bright green an inch away from the lights. :)
 
Last edited by a moderator:
Hi all,
zozo said:
So i do not know what's in the pond when it comes to ferts but surely less than the tank. I guess for this Colorata it certainly was the sun light doing that.
Click to expand...
If the plant isn't instantly fried you will often get that. Probably because summer sunlight would have <"much more energy"> than all but the brightest lights.

cheers Darrel
 
dw1305 said:
Hi all, If the plant isn't instantly fried you will often get that. Probably because summer sunlight would have <"much more energy"> than all but the brightest lights.

cheers Darrel
Click to expand...

What i found most remarkable is the change in appearance of this plant in different conditions. Actualy i'm growing it under 3 different conditions.. Very low light, low tech tugged away in a shaded corner. And it grows very slow, stays very short with also rather compact internodes and less elongated light green leaves. High Tech under higher light, where it grows longer internodes and more elongated bright green leaves. And under (very high) natural light in low tech conditions it completely changed, very compact with more round leaves in dark red color.

I remember you indeed stated before about a year ago in a topic, that there is not yet artificial light invented comming close to real daylight, not even on a cloudy day. even if we perceive the artificial light as brighter it never isn't brighter than daylight. :) Growing tropical plants outside in the pond makes this realy obvious and intresting, to see what difference it makes.. :)
 
Kadir Mumyakmaz said:
...
So I do agree spectrum is very important too.But I know there are some people out there can get nice red with only white LEDs
...
Click to expand...

White light also contains red spectrum unless it would look cyan.
But after reading Darrel's post, I'm rethinking about the need of red spectrum now. :)
 
dw1305 said:
Hi all, I think it is the other way around. Anthocyanin production is meant to be stimulated by blue and UV light, and the anthocyanins block these wavelengths (red wavelengths of light are reflected).

Amongst other benefits, the red pigments act as a "sunscreen" to protect the photosynthetic systems (principally photosystem II) from photoinhibition.

I don't know about any research in aquatic plants, <"but in "Lollo Rosso" lettuce"> anthocyanin production is almost entirely dependent on exposure to UV light (wavelengths shorter than 370 nm).

From Tsormpatsidis, E., et al. "UV irradiance as a major influence on growth, development and secondary products of commercial importance in Lollo Rosso lettuce ‘Revolution’grown under polyethylene films." Environmental and Experimental Botany 63 (2008): 232-239.cheers Darrel
Click to expand...

So the reason plants look red is probably not because they want to reject red spectrum by reflecting it off.
But it is probably from the process of blocking UV and blue spectrum, i.e., they use red pigments to
absorb/detain blue and UV.

Perhaps kind of like us, we don't protect ourselves by reflecting light off like a mirror.
But we use melanin to dissipate it. Hmmm...


dw1305 said:
Hi all,A low colour temperature light will definitely highlight any red pigments, the plants wouldn't actually be pinker, but they would look it.
...
Click to expand...

Yes, I've acknowledged about this. :thumbup:
 
Part of the reason I ask has to do with this light. It is a philips led floodlight . You can see the reflection. I started using it last week and already the plants are taking on a more vibrant color.

IMG_0111 (1024x768).jpg
 
xim said:
White light also contains red spectrum unless it would look cyan.
But after reading Darrel's post, I'm rethinking about the need of red spectrum now. :)
Click to expand...
Well there is no white light,it is a combination of other colours,so yes there will be some red spectrum.
 
LEDs these days seem to cover the whole daylight spectrum better than any other light source available.. :)
Daylight White emitting leds have the broadest spectrum and are today actualy blue led coated with yellow sulfur which makes it emitting a white broad spectrum light. Here you can see spectral charts of several tested light sources. The first is normal daylight 5500k, and you'll see the whole spectrum is rather lineair covered without much peaks. The lights source coming closest to it down the list is the source over filtered sulfur, which is comparable with todays leds since they are build on sulfer.
figure5a-r.gif

figure5h.gif


Intresting website btw, they have a lot of (honest) info on light and it's sources..

Beware when you buy lights..
The term full-spectrum is not a technical term, but rather a marketing term
Click to expand...
 
I heard a talk last year about how most led light is blue and the rest is mostly chemical coatings. Interestingly there are no white leds so I have no idea how we get white light out of that. I have recently bought a bunch of led lights and quite honestly I find this floodlight to be the most impressive though it does take two of them to light a 29g tank. The light penetrates well and I like the way it seems to create a mottled light and dark in the depth and shadows. I guess the next test for me is to push the ludwiga down and see what happens at a deeper place in the water. Like am I going to get the same wavelength at 10 inches deep or something.
 
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