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Plants do use green light, mostly in some cases

Discussion in 'General Plant Topics' started by Tom Barr, Feb 25, 2009.

  1. Tom Barr

    Tom Barr Founder
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  2. JDowns

    JDowns Lifetime Charter Member
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    Well I think the past also confirms this. For years people used nothing more than household flourescent bulbs which are predominatly green in the spectrum, and grew plants just fine. I think people need to settle on a spectrum that looks good to the human eye rather than speculating which bulb grows plants better. Doesn't ADA even sell a hqi bulb that is very rich in the green spectrum?
     
  3. Tom Barr

    Tom Barr Founder
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    Well, I've had more than few run ins over this topic about the middle bans being used by plants and that the Red/blue spikes are appealing to some fol's eyes, but they do not significantly make the light bulb more efficient and have a higher PUR etc.
    They use other pigments to grab this light as it filters through the tissue and the epidermis.

    Amano/ ADA suggested filtering from the forest around the aquatic plants, but few, hardly any aquatic plants lie in such dark locations in forest, they live mostly in open marshes...........

    They could have stated this citation, or said what these authors said, rather than that bull manure.

    It still shows the light works well in those color ranges/nm etc.
    Just their reasons for it working are simply put, wrong.

    Now some plants, like Egeria and myriophyllums etc are only 2-3 cells thick on their leaves, so the filtering of the light is not great, but the filtering of red light is in water...........and Green algae are around, so that also absorbs some like the forets/trees etc like ADa claimed, again, missing the other things that are present in nature.

    I really kind of hate ADA's "nature" poem crap, it's really not very nature oriented Science wise. If you hold such respect for nature, then you learn why, how it works, what things cause it to be the way that it is, not some poem about what you'd like it to be.

    Big difference.




    Regards,
    Tom Barr
     
  4. paludarium

    paludarium Guest

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    Hi Tom,

    thanks for the link. I found an interesting article down there:
    Green light: a signal to slow down or stop

    Fig. 2 showed the inhibitory effect of green light on plants growth. Unfortunately the research was done more than 50 years ago, and tested for only 6 days. Like to hear your opinion.

    Regards,
    Erich
     
  5. Tom Barr

    Tom Barr Founder
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    That's a good review, the issue that the other paper I cited suggest, it is different from external light issues like the review paper cited here by you.

    Intenral celluluar canopies play a role and where the actual light energy being converted is a much more precise location and where the photosynthetic environment actualy is.

    We can add Blue, Green, Red light etc, but if the light is green where the action is taking place................what does that say about green light?

    Interesting concept.

    External green light might play another role or **changes** to that light.
    Which we as aquarist rarely expose plants to unlike the daily sun/seasonal etc.

    Regards,
    Tom Barr
     
  6. paludarium

    paludarium Guest

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    If the result is replicable and green light does have inhibitory effects on plants growth, I suppose that both PAR and PUR have to be recounted. But I don't know so far any article that is supportive to the result done 50 years ago. Or maybe tomato is an exception.

    Regards,
    Erich
     
  7. Tom Barr

    Tom Barr Founder
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    There are few sudies done on red, blue and green light in aquatic species.
    Bowes and few others did one. There was significant difference, but not much at all, just barely.

    http://www.apms.org/japm/vol15/v15p29.pdf


    Regards,
    Tom Barr
     
  8. paludarium

    paludarium Guest

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  9. defdac

    defdac Lifetime Members
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    Cool stuff. Does this mean that the photosynthetic action spectrum is of no use (measuring O2 output from plants relative the the frequency they are exposed to)?

    Or is that important also?
     
  10. Tom Barr

    Tom Barr Founder
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    I honestly do not know.
    One thing I learned many years ago, and was in my first light article in the newsletter as well, all in all, folks really do not know that much about light and plants.

    Internals light environments vs external light sources?
    This changes and maybe very different plant to plant.
    Spinach(hundreds of cells thick) vs say Hydrilla (2 cells thick only).
    Water, angle, turbidity of the water/color etc, and lower light make the environmental factors much different for aquatic plants than those of terrestrial plants. Then there are 400 species to pick and choose from.

    Will Riccia's response be different than that of Anubias? Should we compare just fast growing stems or rossette swords? How do we compare?

    To answer such questions, we need to be very clever, or do a lot of work, or likely, both.

    From a horticultural standpoint, all they use is sunlight, it's "free". So fake light is of little/less use. Tropica uses fake light but they live pretty far north in latitude, so they need supplemental light (longer photoperoid).

    Singapore, Florida, etc........not at all.

    Given the wide range of habits I've found plats in natural systems, and the wide range we see in aquariums, I'm very hesitant to ascribe cause or blame to observations due to light.

    I know they can adapt and must ....to survive.
    Which is better for plants?
    Sort of hard to say really.

    Folks have a loit of trouble getting nutrients/CO2 right so light is troublesome also. I just make an assumption for PAR, like many botantist, and live with it:eek:

    Maybe later, some folks will do more there.

    Regards,
    Tom Barr
     
  11. defdac

    defdac Lifetime Members
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    This article shows there are quite big discrepancies between different research about yellow and green light:
    An Error Occurred Setting Your User Cookie
    They also talk about yellow-green light actually supress growth.

    This article discuss how the measurments of carbon fixation deep with the leaf is very tricky - but it's still a bit over my head to see if it refutes or agrees with the main article discussed here:
    http://www.publish.csiro.au/?act=view_file&file_id=SA0403568.pdf

    Please fill in the gaps, because this was a bit like opening a pandoras box =)
     
  12. Tom Barr

    Tom Barr Founder
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    Well, unless it's an aquatic speciesadapted to submersed life vs an emergent grow nursery plant, I'm hesitant to say much.

    It is a pandora's box.

    And that's the problem, with no simple way out I can see for hobbyists to measure and answer. You could use electron transport chain stuff ro measure this.

    I did this for a lab where we used Red, Blue, Green and Yellow filters and spinach chloroplast. We used a blue dye to measure the quantified changes in Cholorplast exposured to the light.

    Mashed up choloplast are not whole plants however...............

    And each species have it's own unique canopy.............

    Regards,
    Tom Barr
     
  13. Philosophos

    Philosophos Lifetime Charter Member
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    So how can this effect PUR, when PUR is already an examination of how plants respond to certain spectrums of light? What's the ratio of energy used for CO2 fixation vs. that which is expended in the upper 20% of the leaf? It'd sort of seem strange that plants would evolve to be green and reflect such an important spectrum involved with their own growth. The other study seems to show that under green light, plants branch less and have less wet/dry weight. Isn't this the sort of thing we're trying to encourage?

    -Philosophos
     
  14. defdac

    defdac Lifetime Members
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    PUR isn't affected much. Photosynthetic actionspectrums contains green and shows that plants respond much more, photosynthetically wise, to blue and red light which still holds.

    In kindergarten we see how fast plants grow under green light and under blue/red etc. Plants grow really slow under green light compared to the other colors =)

    They can use green, and it might even be needed deep inside the plants but is it more efficient than use for example blue only light? Nope.

    This is also rather uninteresting for hobbyists since all type of normal flourecents (fancy or cheap) have a green spike in them. Some more, some less.

    You can grow plants under blue-red LED-light so green light can't be that important..
     
  15. paludarium

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    If green light does stop or supress the plants growth, that means green light affects the plants growth in a negative way, therefore I assume that PUR has to be recounted. However, it seems that plants also grow under pure green light:rolleyes: .

    Regards,
    Erich
     
  16. Philosophos

    Philosophos Lifetime Charter Member
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    Ok, so this re-affirms what I was concerned with. Plants not using green at all always seemed kind of funny to me given the usual discrepancies between PAR vs. PUR. I guess it wasn't much different from what I've seen, and I was expecting a migraine of a concept. Correct me if I'm wrong.

    As for adapting to green, this doesn't seem too exceptional from what I've understood of plants already. UVA/UVB papers are kind of interesting on this one. Immersed vs. emerged, low vs. high light, carotenoid buggery etc. all seem to show the adaptability of plants. If this isn't right, the idea I've got in my head requires more space and time to verify than I have available to test it all.

    -Philosophos
     
  17. Tom Barr

    Tom Barr Founder
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    I think most research does not address man made sources of light, they focus on natural systems, and how they change with respect to light and wavelength.

    Not much is done in horticulture where light is artificial, unless you are growing weed or something. Those people are not the brightest folks:rolleyes:

    There's also an aesthetic component here.
    Most folks want nice fat high yields. Aesthetics is less an issue unless it affects the sales of the crop.

    Give the specifics of the goal and issues with aquariums, I do not think we will find much resolve. But I would exercise caution and not assume much here.


    Regards,
    Tom Barr
     
  18. VaughnH

    VaughnH Lifetime Charter Member
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    It was mentioned that in early grade school education we learn about how green light doesn't give as much growth as red or blue. One reason for that may be that our eyes see green light very intensely, but not so much blue light and not red light at all. So, if we use our eyes to put "equal" amounts of red light, blue light, and green light on 3 pots of plants, we are actually providing ten times as much light to the red lighted plants as to the green lighted plants, and a lesser, but still substantially greater amount to the blue lighted plants. So, of course the green would grow slower. That isn't likely to be the whole story, but it is part of it.
     
  19. Philosophos

    Philosophos Lifetime Charter Member
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    Vaughn, I wouldn't be surprised if you're right to some degree. Most people I've talked to don't know the difference between lumens and millimoles. I wonder what the average grade school text says about it these days, and how it compares to higher education. So often this hobby seems to be using brain floss to get the bad memes out.

    Tom, I'm kind of surprised if what you're saying is true. You'd think the understanding of how plants react to various spectrums of light would be vital for places that grow their vegetables through hydroponics. I'm thinking of assisted lighting in the winter months, mostly.

    And just for laughs, I'm not sure if this says more about the intellect of bureaucrats or pot farmers:
    Health Canada Marijuana (originally published in the Globe and Mail)
    TL;DR version: The government couldn't figure it out, so they let stoners grow it for them now.

    -Philosophos
     
  20. Tom Barr

    Tom Barr Founder
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    Well, they did do a well cited study, using Coolo ,whites vs the fancy schmancy "plant bulbs" Vita light, Gro lux etc................no significant difference between them.
    Most researchers do not even monkey with this stuff.
    They just use the cheaper MH's and the cool whites for growth.

    I've had little issues other than my personal perception of the color.
    Growth wise, no differences I've ever been able to detect when PAR was equal.

    If you filter all the Red/blue out etc, well......I would expect less obviously, but if you have little more here and there of certain peaks, as long as you have some of each............I think it matters much less.

    So having some green spike in there is not bad, as long as there's some Blue, Red, yellow etc.

    Few bulbs are very specific to just one hideous color.
    Filters are most often used for color studies, but not popular these days.

    Hydroponics might be popular etc, but they use green houses and warmer regions where they do not need added light and if they use the added light, it's often yellow MH's.

    Regards,
    Tom Barr
     
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