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Thread: Photosynthesis pigments

  1. #1 Photosynthesis pigments 
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    Ok, I understand that leaves are green because of chlorophyll a, which is naturally green in pigment, but if viewed with red lightm what colour would appear from a chlorophyll extract?


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    Forum Isotope Zelos's Avatar
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    if there were only red light and we assume it only reflects green the leave would probably look black since it absorbs the red light


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  4. #3  
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    Thanks... I figured that, but that was merely speculations as i have not been able to find any sources to confirm. Thanks.

    You wouldn't happen to know if photorespiration occurs primarily because an increase in oxygenase activity relative to caboxylase activity as temperature increases.

    Also, am I correct to assume that air temperature, amount to water in sorl, brigtness of ambient light, turgor pressure of the gurad cells, and humidity will affect the opening and closing of the stomata? I know the last 3 are. The amount of water will create the turgor pressure or relieving of the pressure so I'd like to think it does too.

    Thanks...I'm doing my exam review and finding the above difficult.
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  5. #4  
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    Have a look at the grass under sodium light, you'll see it appears as grey only.
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  6. #5  
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    probably cause they reflect little of all colors but my statement were based on the assumption it didnt
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  7. #6  
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    so you have me confused...does the red light produce a black pigment when viewing the chlorophyll?
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  8. #7  
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    if it doesnt reflect anything but green yes
    if it reflects a little bit of all colors wich is the most likly case it will seem greyish
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  9. #8  
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    The leaves are not 'pure' green, they are mostly a lighter green which indicates the presence of red and blue, they therefore reflect some light which you see as grey because in low light levels you lose color perception.
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  10. #9  
    Forum Isotope Zelos's Avatar
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    Correct
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  11. #10  
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    Ok...I understand that the red and blue lights are mostly absorbed whereas the green light is poorly, resulting the dominance of green light. So, you are suggesting that red light is a low level light, which would result in a chlorophyll extract to appear grey because we lose colour perception.
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  12. #11  
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    I am saying there are a lot of factors involved - light wavelength, spectral bandwidth, intensity, the characteristics of the human eye, the composition of the leaves. It's a hell of a science within itself, and, here one can only geive a few generalisations.

    A 'blue' object is anything other than blue, it just reflects blue light.

    No object is truly a single color and will therefore always reflect some light at other wavelengths. If you have a real interest in this I'd recommend googling it to get an idea.
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