DrPhoton
New member
I was worried about the interpretation of the results. Because of less overall light, they could stretch more. Which people can interpret as more growth. But a closer look at the dry mass would show the complete opposite.
There are also other variables which can indirectly affect the potential for growth. For example as you know from my articles, light quantity is more important than light quality in multispectrum light. However monochromatic light has poor efficacy to plants. Even at the same flux levels compared to multispectrum light. This has nothing to do with photosynthetic efficiency and this is key to interpretation of light quality and plants. Plants photosynthetic response to different wavelengths of light is practicaly the same and the differences are insignificant. However plants do thrive better with multispectrum light sources. This has to do with radiation capture. Multispectrum light facilitates healthy morphology that increases radiation capture by factors such as stem and petiole elongation and leaf area index. The photosynthetic efficiency is unchanged, however the plants ability to capture light because of favoured mophology is improved. This is basically a result from blue light and the shade avoidance response.
This is where this light cycle program could have worked. However less overall light means the overall DLI of blue is changed and depending on the light source, can be a negative or positive response. But the same result can still be obtained with standard light cycles with ideal DLI of blue. But with the advantage of more potential for growth with the increased DLI of light.
Let me really confuse the heck out of you. Ignore the following if you wish, im just rambling now. Theres actually much further complexities in the process of understanding what makes an efficient light source. It becomes easier to understand when you get to learn the biochemical reactions of photosynthesis in plants and light physics.
So lets break it down.
Electrical efficiency: Describes how much output energy is produced from input energy. Excess energy not produced for the wanted effect is a byproduct of inefficient conversion.
Photon efficiency: How efficiently a photon of light is emitted per unit of energy (usually joules or watts)
Energy efficiency: How efficiently energy is used to provide work or purpose.
Lets talk about LED for a second. Blue diodes are more electrically efficient than Red diodes. But Red diodes have a higher energy efficiency so it can be better to use more Red than Blue. You might be wondering how the heck does that work ?. Well as you might know, as the wavelength of light gets shorter, energy density gets higher. This is why ionizing radiation is bad, because it contains enough energy to knock an electron off an atom.
Because shorter wavelengths contain higher density of energy, it goes without saying that more energy is required to generate photons of shorter wavelength. Even though a light source could have equal electrical efficiency at all wavelengths.
Shorter wavelengths will produce fewer photons than longer wavelengths because they require more energy. For example with a LED light source, which for this example is 100% electrically efficient, a source producing light at 350nm at 100 watts produces 380umol of light. But a source at 650nm produces 550umol. Even though they are both 100% electrically efficient, they produce differing amounts of photons. This is because as previously said, shorter wavelengths require more energy to produce an equivalent photon of longer wavelengths
So you would be correct to assume, well why is blue still not better?, it has a higher energy desnity. The reason is from something called the stokes shift. So a 450nm photon of light contains about 2.7ev of energy compared to a 650nm photon of light of around 1.9ev. Plants can only absorb energy at a specific density. If you look at photosystems they have a special pair of chlorophyll at the center, where all light energy is concentrated to. P680 and p700. Which average to about 1.78ev of energy it can absorb. So when a Red photon of light at 650nm reaches this center, it looses 0.12ev of energy as heat through photochemical quenching. But when a blue photon at 450nm reaches the center it looses 0.92ev of energy. And as we have worked out, plants do not utilize this excess energy and goes to waste.
So although blue at 450nm can have identicle electrical efficiency, red at 650nm can be more energy efficient as it can produce more photons for the same amount of energy. So red at 650nm has a higher photon efficiency than blue at 450nm. Electrical effciency, Photon efficiency and energy efficiency.
Now you may remember in my articles that light quantitiy is more important than light quality. This is still the case when referring to light efficacy for plants. Again more complexities in the interpretation of the meanings of light efficacy. Light quality with respect to photosynthetic efficiency has been shown to have very little difference in plant growth. Indicating that the differences of the photosynthetic efficiency with different wavelengths of light is insignificant and more focus should be placed on light quantity rather than light quality. However. Plant morphology to light, changes the radiation capture efficiency, which earlier studies neglected when assesing plant photosynthetic efficiency. Plant morphology that increases radiation caputure by increasing aspects such as leaf area index, has increased photosynthetic capacity with the same photosynthetic efficiency. However the extent of this is again, insignificant with typical light sources.
So sorry for clogging your thread KingKush, im just verbally thinking haha. You say the word and il remove it if its too unrelated.
There are also other variables which can indirectly affect the potential for growth. For example as you know from my articles, light quantity is more important than light quality in multispectrum light. However monochromatic light has poor efficacy to plants. Even at the same flux levels compared to multispectrum light. This has nothing to do with photosynthetic efficiency and this is key to interpretation of light quality and plants. Plants photosynthetic response to different wavelengths of light is practicaly the same and the differences are insignificant. However plants do thrive better with multispectrum light sources. This has to do with radiation capture. Multispectrum light facilitates healthy morphology that increases radiation capture by factors such as stem and petiole elongation and leaf area index. The photosynthetic efficiency is unchanged, however the plants ability to capture light because of favoured mophology is improved. This is basically a result from blue light and the shade avoidance response.
This is where this light cycle program could have worked. However less overall light means the overall DLI of blue is changed and depending on the light source, can be a negative or positive response. But the same result can still be obtained with standard light cycles with ideal DLI of blue. But with the advantage of more potential for growth with the increased DLI of light.
Let me really confuse the heck out of you. Ignore the following if you wish, im just rambling now. Theres actually much further complexities in the process of understanding what makes an efficient light source. It becomes easier to understand when you get to learn the biochemical reactions of photosynthesis in plants and light physics.
So lets break it down.
Electrical efficiency: Describes how much output energy is produced from input energy. Excess energy not produced for the wanted effect is a byproduct of inefficient conversion.
Photon efficiency: How efficiently a photon of light is emitted per unit of energy (usually joules or watts)
Energy efficiency: How efficiently energy is used to provide work or purpose.
Lets talk about LED for a second. Blue diodes are more electrically efficient than Red diodes. But Red diodes have a higher energy efficiency so it can be better to use more Red than Blue. You might be wondering how the heck does that work ?. Well as you might know, as the wavelength of light gets shorter, energy density gets higher. This is why ionizing radiation is bad, because it contains enough energy to knock an electron off an atom.
Because shorter wavelengths contain higher density of energy, it goes without saying that more energy is required to generate photons of shorter wavelength. Even though a light source could have equal electrical efficiency at all wavelengths.
Shorter wavelengths will produce fewer photons than longer wavelengths because they require more energy. For example with a LED light source, which for this example is 100% electrically efficient, a source producing light at 350nm at 100 watts produces 380umol of light. But a source at 650nm produces 550umol. Even though they are both 100% electrically efficient, they produce differing amounts of photons. This is because as previously said, shorter wavelengths require more energy to produce an equivalent photon of longer wavelengths
So you would be correct to assume, well why is blue still not better?, it has a higher energy desnity. The reason is from something called the stokes shift. So a 450nm photon of light contains about 2.7ev of energy compared to a 650nm photon of light of around 1.9ev. Plants can only absorb energy at a specific density. If you look at photosystems they have a special pair of chlorophyll at the center, where all light energy is concentrated to. P680 and p700. Which average to about 1.78ev of energy it can absorb. So when a Red photon of light at 650nm reaches this center, it looses 0.12ev of energy as heat through photochemical quenching. But when a blue photon at 450nm reaches the center it looses 0.92ev of energy. And as we have worked out, plants do not utilize this excess energy and goes to waste.
So although blue at 450nm can have identicle electrical efficiency, red at 650nm can be more energy efficient as it can produce more photons for the same amount of energy. So red at 650nm has a higher photon efficiency than blue at 450nm. Electrical effciency, Photon efficiency and energy efficiency.
Now you may remember in my articles that light quantitiy is more important than light quality. This is still the case when referring to light efficacy for plants. Again more complexities in the interpretation of the meanings of light efficacy. Light quality with respect to photosynthetic efficiency has been shown to have very little difference in plant growth. Indicating that the differences of the photosynthetic efficiency with different wavelengths of light is insignificant and more focus should be placed on light quantity rather than light quality. However. Plant morphology to light, changes the radiation capture efficiency, which earlier studies neglected when assesing plant photosynthetic efficiency. Plant morphology that increases radiation caputure by increasing aspects such as leaf area index, has increased photosynthetic capacity with the same photosynthetic efficiency. However the extent of this is again, insignificant with typical light sources.
So sorry for clogging your thread KingKush, im just verbally thinking haha. You say the word and il remove it if its too unrelated.
