# [Wet Thumb Forum]-Plants and the spectrum



## MarcinB (Apr 16, 2004)

Yes I know, plants adapt well to different light spectrum and the colour tmperature of the bulbs doesn't really matter. But don't you think that sometimes it may influence the overall shape of the plant? Some folks noticed that under 10000K bulbs (Philips Aquarelle) some plants don't grow upright, but lay down on the substrate. Another example is from my own experience. I used to have one 30W 4000K fluorescent bulb over a 30G tank. Under that light the Cabomba sp. grew quite well. One day I replaced the old bulb with a new 10000K one. After that the mentioned plant just stoped. After a few weeks i switched back to the old 4000K bulb and Cambomba started to grow immediately.

Ps. I'm doing my best, but just in case: Sorry for my English


----------



## MarcinB (Apr 16, 2004)

Yes I know, plants adapt well to different light spectrum and the colour tmperature of the bulbs doesn't really matter. But don't you think that sometimes it may influence the overall shape of the plant? Some folks noticed that under 10000K bulbs (Philips Aquarelle) some plants don't grow upright, but lay down on the substrate. Another example is from my own experience. I used to have one 30W 4000K fluorescent bulb over a 30G tank. Under that light the Cabomba sp. grew quite well. One day I replaced the old bulb with a new 10000K one. After that the mentioned plant just stoped. After a few weeks i switched back to the old 4000K bulb and Cambomba started to grow immediately.

Ps. I'm doing my best, but just in case: Sorry for my English


----------



## imported_aspen (Feb 20, 2003)

your english is fine.









spectrum does matter. i had a tank with the back open to a south window. the plants grew great, except they didn't grow up. the sun came in through the water and some light was too harshly refracted to reach the plants. you need red AND blue, to get bushy AND tall plants.

rick


----------



## Kurt Reinhart (Mar 4, 2003)

Hi, I'm a total newbie to growing plants in tanks. However, I'm a terrestrial plant ecologist & thought that some of my understanding of terrestrial plant ecology might relate to aquatic plant ecology.

Plant growth is strongly regulated by the ratio of red:far-red light. Plants detect changes in R:Fr with the phytochrome complex. This complex is considered a single input multiple output system because the plant detects one thing, R:Fr and responds in multiple ways listed below. Plant foliage or canopy coverage not only reduce the light quantity below the foliage but also reduces the R:Fr. Chloroplast pigment reduce the Red in light and decreases the R:Fr. Shade intolerant species often alter their morphology with <R:Fr light. They increase their height and the distance between leaf nodes [the plants appear stretched). They also alter a number of other things [e.g. seed germination, bud dormancy, chloroplast expansion, flowering, plant architecture, etc.). Shade tolerant species appear to not respond as much to shade and changes in R:Fr.

Since water attenuates light of different spectral quality differently then changes in light quantity may also alter light quality (R:Fr). Thus, neutral filtration of light does not alter R:Fr but water is probably attenuating high frequency light (red more than blue and far-red more the red [I'm speculating on the later part]) more than low frequency light.

Example: green foliage or green filters (plastic film) do the following: <R:Fr and <PAR.
neutral filters (paper, cheese cloth, etc.) do the following: =R:Fr and <PAR.

http://www.aquabotanic.com/glossostigmaarticle.htm
This link shows the response of Glossostigma to different light quantities. But the change in growth response of Gloss. is a classic R:Fr response and not a response to just changes in photosynthetically active radiation (PAR).

Wolfgang Amri (the author of the info. on the site) was able to get small Gloss growth when he changed the lights instead of tall Gloss. I suspect that he increased the R:Fr ratio of light...

I propose that water does the following to light.
light characteristics above water
R:Fr of light= 1/1
but low quantity/low PAR

water attenuates more Fr than red
R:Fr in tank= 0.75/0.5=1.5

add new bulbs
light characteristics above water
R:Fr of light= 1/1
but higher quantity/higher PAR

water attenuates more Fr than red
R:Fr in tank= 0.85/0.55=1.55 (both R and Fr increase but R more than Fr since Fr is attenuated more by the water; alternative hypothesis new bulbs emit different R:Fr ratios thus the intial amount 1/1 may have varied with bulbs).

Am I missing some underwater logic. Have scientists related R:Fr to aquatic plant growth? I can do a post on an ecology list server to see what ecologist think

Can turtles and plants coexist in a tank?


----------



## MarcinB (Apr 16, 2004)

Interesting, I thought that phytochrome affects only the blooming process. I didn't know that it also influences plant morphology. What about other pigments like cryptochrome?


----------



## Roger Miller (Jun 19, 2004)

I'm not sure how much weight I could apply to red:far red ratios. Most of us use fluorescent lights that may not produce any far red at all. The spectrum that *is* produced varies from light to light depending on its phosphors and age.

I looked into spectral effects a little several years ago when I had some strange problems. At the time I was using Philips Ultralume and Advantage X tubes. Both types of tubes have the same phosphors and so both have the same output spectrum. The "red" spike in their spectrum was actually on the orange side of red. According to their published spectrum there was very little true red and I don't recall that there was anything at longer wavelengths.

That and other wierdness is possible for any triphosphor bulb. The red spike in their spectrum may not be a true red and far red may be lacking. It's hard to guess what significance there may be to the red:far red effects in that case.

The problem I had was that some of my plants -- especially H. corymbosa -- dropped older leaves while they were still pretty healthy looking. After I took the Philips lights off the tank the plants started holding their leaves. Some time later my replacement tubes failed to light, so I put the Ultralume and Advantage X tubes back on. I think that my plants dropped more leaves in one day following the change back to the Philips lights than they had in the previous month without them. The lack of a true red in their spectrum was the only thing I ever saw that seemed odd enough to explain the effect.


Roger Miller


----------



## Kurt Reinhart (Mar 4, 2003)

Both cryptochrome (perception of blue light) and phytochrome (perception of far-red light relative to red light) affect stem elongation [i just looked this up to make sure in Plant Physiological Ecology-Lambers, Chapin, & Pons].

I just downloaded a couple of pdf files. The titles are listed below and relate to r:fr. If you're interested in reading either of these articles send me an e-mail.

"Proximity signal and shade avoidance differences between early and late successional trees" by Gilbert, Jarvis, and Smith in Nature

Smith 2000. Phytochromes and light signal perception by plants an emerging synthesis. Nature. 407(6804):585-591.

After I submitted my previous e-mail, I began to reflect on the topic and realized that artificial light sources probably produce very little far-red light (or light beyond the visible spectrum) as mentioned in a previous post. It does seem that in the case I mentioned above with Gloss. that the plant is altering its morphology because of light quality aspect that it is sensing and not simply responding to changes in PAR. However, it may be blue, red, or far-red light that is being added or removed. The red:far-red system is like an on/off switch. One type of light turns the phytochrome on and the other light form turns it off. In some cases, relatively minor changes in the ratio between the two lead to activation of one or more processes by having the system turned on just a bit more than it is turned off.

Food for thought.
Cheers, Kurt ; ; ; ;

Can turtles and plants coexist in a tank?


----------



## MarcinB (Apr 16, 2004)

So it looks like the light spectrum sometimes could be an useful tool for an aquatic gardener. It could be used to induce the desirable changes in the morfology of some species of aquarium plants.


----------



## jpmtotoro (Feb 13, 2003)

hey kurt are you asking if turtles can live in a planted tank or is that just your signature? sorry i can't partake in your discussion here, i'm just smiling and nodding









JP


----------



## Guest (Mar 7, 2003)

The Lambers book is a good one. Do a number of pre dawn water potentials or CAM work, and you'll never sleep right again. 

I think you'll find some interesting stuff about the pigments filtering their higher energy down to p680* and p700*. All light used in PS ends up there.

If I put 50 watts of 400nm light and 50 watts of 675nm red light, which plant will get more photons?

Some energy is lost as it travels down hill from 400nm to 680nm or slightly less than 680 to 700nm where the charge separations takes place. 

Plants/algae can adapt and alter their chloroplast, pigments. This can take in the order of a week to several weeks.

Enough time to get a leg up on the competition.
But in a stable community, this effect tends to be supressed. 

You can see this in stable spring ecosystems filled with plants for hundreds of years.
But go north to some dimitic lakes that freeze each year, and plants only grow some of the year,algae part of the year and not much when there's ice.

Light is filtered out in pure water, but if there's a lot of suspended material, that filters all light, not just red.

Also red light is filtered, but at only 24 inches or less of light, is much going on? Is that significant?

I don't think the filtering of light is significant at the depths here.
I think the main portion of light at the red /far red color is good, but do not forget about the blue light effect, although is doesn't take much, it will cause stomata to open wider with red light. So it can help plants and it also balances the color out to our own eyes. But most of the light energy should ideally be in the red region.

You can talk theory till your blue, but I think overall there is very little difference in light color temps in practical aquatic plant culture.

An easy way to see this is to use a 55 gallon tank and on 2 ft, use one light type and the other another and use one plants or several etc.

I did this and found some leaf color changes etc but nothing as far as significant issues or problems with algae and all the other claims many had said back then.

I've grown plants from 3000-10000K, no issues really except for weird looks to my eyes.

Plants do fine, so does the algae also BTW.

FWIW, 
Regards, 
Tom Barr


----------



## Kurt Reinhart (Mar 4, 2003)

JP,
I really couldn't think of a signature since the only plants that I currently have are hornwort in a tank intended to cultivate snails and guppies for turtle treats. So I wrote the general reason for me becoming interested in trying to understand how to grow plants in aquariums. It seems that most turtle keepers have not serviously decided to try and keep both turtles and plants. I've learned from net resources that keeping plants can be as hard if not harder than keeping turtles. So I suspect that most failures in keeping turtles and plants in the same aquarium relate to three things: 1, most tanks are too small and allow the turtle to mechanically destroy the plants, 2, keeping a turtle that is predominantly a herbivore/omnivore, and 3, not having enough expertise to successfully grow plants even without a turtle. For example, I haven't heard anyone who keeps turtles and plants mention CO2 additions. This is probably critical to allow the plants to cope with the impact of the turtle.

Also, once I saw some of the planted aquariums on the net I was completely amazed in their beauty. I will not start constucting this large turtle tank for several years but have already learned a ton of great things about tank piping (input, output, drains), designing fake stone ledges, and the vast amount of information on plant selection, co2 addition, lighting, soil treatments, and fertilization.

Can turtles and plants coexist in a tank?


----------



## jpmtotoro (Feb 13, 2003)

ok. my dumb girlfriend bought me a baby red earred slider (aquatic turtle) and so i dumped it in my tank until i could find out what to do with it... i awoke the next day to find that some of my plants were completely eaten! he just left the stalks. i moved him to a different planted tank and so far he hasn't eatten any of those plants. i think there were just 2 plants in my tank he wanted to eat, the rest he left alone. same in the other tank, so if you ever put turtles in there, try out different plants first and see what the turtle will eat. i still need to get rid of my turtle though, he's a baby now, but will grow to the size of a half melon. i don't need a melon swimming around in my tank, not gonna work well









JP


----------



## Kurt Reinhart (Mar 4, 2003)

JP,
It sounds like you're lucky your RES only ate one or two plant species. The RES diet (along with many other sliders, cooters, and painted turtles) is known to consist heavily in aquatic vegetation. Thus, keepers of this species usually view aquatic plants as food for their RES and not permenant residents/fixtures. My turtles are diamond back terrapins which naturally exist in brackish water and predominately eat snails, crabs, and fish (probably fish scavengers). My terrapins are captive breed and live in freshwater which is typical, while wild caught specimens must be kept in brackish water. My terrapins are very energetic and constantly seem hungry but they ignore plants as a food source and instead appear to enjoy resting in them

Can turtles and plants coexist in a tank?


----------



## MarcinB (Apr 16, 2004)

I've found an interesting paper on how light quality affects plant morphology. It's about terrestial plants but IMO it's worth reading. Here it is: Clevering and Hundscheid (1999)Scientia Horticulturae 79: 195-205. Let me know if you are interesting in reading this article, I can send you a pdf file. It looks like except the R:FR ratio also the red:blue ratio may be important. I took a look at the light spectrum of some bulbs. As Tom previously mentioned the content of far red light (700-800nm) was marginal. But the R:FR and red:blue ratio varied significantly between the bulbs with different light temperatures. Don't get me wrong, I'm not trying to convince you that you should pay special atention to the light spectrum, color temperature etc. I just think that the light quality can affect aquatic plants morphology, for example: plant height, size and colour of the leaves, internodes length, number of axillary shoots. Obviously some plants are more sensitive to changes in light quality than the others.


----------



## Roger Miller (Jun 19, 2004)

I'd like to see the article. You should be able to get my email address from my user profile.

Roger Miller


----------



## Kurt Reinhart (Mar 4, 2003)

I've been uncovering additional papers that I'll eventually try to summarize and cite (have not had time yet & they aren't pdfs sorry) relating to light quality. I remember reading the brochures that came with some halide systems and they even mentioned that metal vs. sodium halides will encourage fruiting/flowing vs vegetative growth (I don't remember which does which). These generalizations suggest that light bulbs are doing different things even though PAR may be equal. Working in aquariums probably throws all of our generalizations relating to terrestrial plants out the window since water depth and quality are not neccessarily having neutral effects and may instead have more dramatic effects on certain portions of the visible (Blue (425-490) and red) and invisible (far-red; 655 to 665nm [or 640-700] : 725 to 735nm [700-740] respectily) spectrum. Too bad I don't have a spectroradiometer sitting around and more time to fool with this...

I think that we have several issues.
1.) do aquatic plants function similar to terrestrials with regard to blue, red:blue, and red:far-red. This will help us recognize what species are probably changing their morphology in response to light quality.
2.) we can check the specs on our bulbs to identify all these quantities and ratios but we need to know how water alters what the lights produce (i.e. the lights produce X but the plants perceive Y). This understanding may allow us to develop speciality lighting (or the use of already available bulbs) for aquatic species that are light or shade adapted. From the reference to Glossostigma elatinoides that I made previously, this species seems to be a classic example of a light adapted plant that is extremely sensitive to subtle changes in light quality and may make a great lab rat for future comparisons. I'm not sure if aquariums planted with many different species will benefit much from this info. but people growing mostly light demanding species may be able to pull off better growth or morphology with by optimizing their light quality instead of maximizing their light quantity (PAR).

Can turtles and plants coexist in a tank?


----------



## plantbrains (Mar 11, 2003)

Initially the light can do some of what they say.
But over time the plants adapt pretty good.

The old 5000-6500K range is still about the best mix with most of the light being in the red and some blue.

This is common stuff that's been done 101 times in a many horticultural test.
Stick with the above K ranges and that's about all folks need to worry about here in practical terms.

Beyond 700nm, nothing is going to work. Energy does not flow back uphill, doesn't matter what type of pigment you have. Some bacteriochlophyll's go down to 865nm but no algae or higher plants use this pigment.

You can search the "blue light effect" on the web for more info. Or pick up any recent plant physiology book.

Theory is fine and terrestrial studies as well, but simple practical "does it work in the tank" test can tell you quite a bit.

Regards, 
Tom Barr


----------



## MarcinB (Apr 16, 2004)

> quote:
> 
> You should be able to get my email address from my user profile.


Sorry Roger, but the email provided in your profile does not work. Actually it doesn't look like an email address to me


----------



## Roger Miller (Jun 19, 2004)

It's the right email address, but you must replace the "-at-" with a "@".

Roger Miller


----------



## wetmanNY (Feb 1, 2003)

If you've been searching "blue light effect" and you aren't getting results, try "aquatic+plant photomorphogenesis" at www.google.com

Food for thought.


----------



## defdac (May 10, 2004)

Here is an interesting paper on how light signals affects growth patterns of terrestrial plants:
http://cc.joensuu.fi/photobio/pdf/notes1.pdf

[email protected]_, www.akvarie.net [email protected]_,


----------



## George Willms (Jul 28, 2004)

I was just wondering if anybody has tried using 50/50 bulbs or not and why? If the red-blue ratio is important, would this be a good solution?


George


----------



## George Willms (Jul 28, 2004)

Van Grow...are you still here? I was hoping you might be able to shed some light on my previous question! Thanks.

George


----------



## gpodio (Feb 4, 2004)

I bought a smart light not so long ago and it came with a 50/50 tube. The light was very dim but it did not stay on long enough to see the effects on the plants. Look wise it would make a great moon light, otherwise the colors were completely washed out by the blue, I'd look into something with a better CRI.

Giancarlo Podio


----------



## George Willms (Jul 28, 2004)

I actually like the colors that come from using some 50/50's, when I had JBJ, things looked too washed out, so I had one 50/50, and one full-spectrum. My new fixture (coralife) came with 2 50/50's and it actually looks fine to me. I'm more concerned about whether or not anyone knows if they are good for plants, indifferent or bad.

George


----------

