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We know based on Photosynthesis (Chlorophyll A & B) that the plants utilize primarily 439nm, 469nm, 642nm, and 667nm, (4-bands) while most other wavelengths are use a little. Aside from these colors we know that humans must see their plants to monitor their health, which requires the use of white or green light (1-band) in small quantities will work, as these reflect off the plant. Lastly a light should contain 740nm far-red (1-band), which triggers flowering within the plant during a 12/12 light cycle. 740nm also stimulates the Emerson Enhancement effect, which increases photosynthesis rates up to 30%! UV light in the region of 285-315nm also has a benefit for resin-producing plants such as poison ivy or cannabis.
The visible colors of light from shortest to longest wavelength are: violet, blue, green, yellow, orange, and red. Ultraviolet radiation has a shorter wavelength than the visible violet light. Infrared radiation has a longer wavelength than visible red light. White light is a mixture of the colors of the visible spectrum. Here is a summary of wavelengths (nm).
200 – 280 nm UVC ultraviolet range which is generally harmful to plants. LEDs in this spectrum are non-existant or very expensive. You can see on the bar graph below that it borders with X-ray wavelength.
280 – 315 nm Includes harmful UVB ultraviolet light which causes plants colors to fade. This is the part of spectrum reaching Earth around noon.
315 – 380 nm Range of UVA ultraviolet light which is neither harmful nor beneficial to most plants.
380 – 400 nm Start of visible light spectrum. Process of chlorophyll absorption begins. UV protected plastics ideally block out any light below this range.
400 – 520 nm This range includes violet, blue, and green bands. Peak absorption by chlorophyll occurs, and a strong influence on photosynthesis. (promotes vegetative growth)
520 – 610 nm This range includes the green, yellow, and orange bands and has less absorption by pigments.
610 – 720 nm This is the red band. Large amount of absorption by chlorophyll occurs, and most significant influence on photosynthesis. (promotes flowering and budding) The ratio of red (660nm) to far red (730nm) in sunlight is about 1.2:1
**As with exposure to
continuous far-red radiation, blue light also promotes flowering through the mediation of
cryptochromes photoreceptors
720 – 1000 nm There is little absorption by Chlorophyll here, but Phytochrome uses a nice portion. Flowering and germination is influenced. Near and above the higher end of the band is the Infrared spectrum, which can also be heat and could cause elongation or affect water absorption/transpiration.
**The phytochrome photosystem includes the two interconvertable forms of phytochromes, Pr and Pfr, which have their sensitivity peaks in the red at 660 nm and in the far-red at 730 nm, respectively. photosystems: photosynthetic, phytochrome and cryptochrome or blue/UV-A (ultraviolet- A). In the photosynthetic photosystem, the existing pigments are chlorophylls and carotenoids. Chlorophylls are located in the chloroplasts’ thylakoids located in the leaf mesophyll cells of plants. Here, the quantity or the energy of the radiation is the most significant aspect, since the activity of those pigments is closely related to the light harvest. The two most important absorption peaks of chlorophyll are located in the red and blue regions from 625 to 675 nm and from 425 to 475 nm, respectively. Additionally, there are also other localized peaks at near-UV (300 – 400 nm) and in the far-red region (700 – 800 nm). Carotenoids such as xanthophylls and carotenes are located in the chromoplast plastid organelles on plant cells and absorb mainly in the blue region. They are also known as auxiliary photoreceptors of chlorophyll. Photomorphogenetic responses mediated by phytochromes are usually related to the sensing of the light quality through the red (R) to far-red (FR) ratio (R/FR). Phytochromes are probably the most intensively investigated group of photoreceptors . In Arabidopsis there are five identified phytochromes: phyA, phyB,phyC, phyD and phyE . The importance of phytochromes can be evaluated by the different physiological responses where they are involved, such as leaf expansion, neighbour perception, shade avoidance, stem elongation, seed germination and flowering induction. Although shade-avoidance response is usually controlled by phytochromes through the sensing of R/FR ratio, the blue-light and PAR level is also involved in the related adaptive morphological responses. Blue- and UV-A (ultraviolet A)-sensitive photoreceptors are found in the cryptochrome photosystem. Blue light absorbing pigments include both cryptochrome (cry1, cry2) and phototropins (phot1, phot2). They are involved in several different tasks, such as monitoring the quality, quantity, direction and periodicity of the light. The different groups of blue- and UV-A-sensitive photoreceptors mediate important morphological responses such as endogenous rhythms, organ orientation, stem elongation and stomatal opening, germination, leaf expansion, root growth and phototropism. Phototropins
regulate the pigment content and the positioning of photosynthetic organs and organelles in order to optimize the light harvest and photoinhibition. As with exposure to continuous far-red radiation, blue light also promotes flowering through the mediation of cryptochromes photoreceptors. Moreover, blue-light-sensitive photoreceptors (e.g. flavins and carotenoids) are also sensitive to the near-ultraviolet radiation, where a localized sensitivity peak can be found at around 370 nm.
UV LEDS:
Although radiation of wavelengths below 300 nm can be highly harmful to the chemical bonds of molecules and to DNA structure, plants do absorb radiation in this range.
http://www.ledsgrowinggreen.com/why_le1.gif
Vtech
The visible colors of light from shortest to longest wavelength are: violet, blue, green, yellow, orange, and red. Ultraviolet radiation has a shorter wavelength than the visible violet light. Infrared radiation has a longer wavelength than visible red light. White light is a mixture of the colors of the visible spectrum. Here is a summary of wavelengths (nm).
200 – 280 nm UVC ultraviolet range which is generally harmful to plants. LEDs in this spectrum are non-existant or very expensive. You can see on the bar graph below that it borders with X-ray wavelength.
280 – 315 nm Includes harmful UVB ultraviolet light which causes plants colors to fade. This is the part of spectrum reaching Earth around noon.
315 – 380 nm Range of UVA ultraviolet light which is neither harmful nor beneficial to most plants.
380 – 400 nm Start of visible light spectrum. Process of chlorophyll absorption begins. UV protected plastics ideally block out any light below this range.
400 – 520 nm This range includes violet, blue, and green bands. Peak absorption by chlorophyll occurs, and a strong influence on photosynthesis. (promotes vegetative growth)
520 – 610 nm This range includes the green, yellow, and orange bands and has less absorption by pigments.
610 – 720 nm This is the red band. Large amount of absorption by chlorophyll occurs, and most significant influence on photosynthesis. (promotes flowering and budding) The ratio of red (660nm) to far red (730nm) in sunlight is about 1.2:1
**As with exposure to
continuous far-red radiation, blue light also promotes flowering through the mediation of
cryptochromes photoreceptors
720 – 1000 nm There is little absorption by Chlorophyll here, but Phytochrome uses a nice portion. Flowering and germination is influenced. Near and above the higher end of the band is the Infrared spectrum, which can also be heat and could cause elongation or affect water absorption/transpiration.
**The phytochrome photosystem includes the two interconvertable forms of phytochromes, Pr and Pfr, which have their sensitivity peaks in the red at 660 nm and in the far-red at 730 nm, respectively. photosystems: photosynthetic, phytochrome and cryptochrome or blue/UV-A (ultraviolet- A). In the photosynthetic photosystem, the existing pigments are chlorophylls and carotenoids. Chlorophylls are located in the chloroplasts’ thylakoids located in the leaf mesophyll cells of plants. Here, the quantity or the energy of the radiation is the most significant aspect, since the activity of those pigments is closely related to the light harvest. The two most important absorption peaks of chlorophyll are located in the red and blue regions from 625 to 675 nm and from 425 to 475 nm, respectively. Additionally, there are also other localized peaks at near-UV (300 – 400 nm) and in the far-red region (700 – 800 nm). Carotenoids such as xanthophylls and carotenes are located in the chromoplast plastid organelles on plant cells and absorb mainly in the blue region. They are also known as auxiliary photoreceptors of chlorophyll. Photomorphogenetic responses mediated by phytochromes are usually related to the sensing of the light quality through the red (R) to far-red (FR) ratio (R/FR). Phytochromes are probably the most intensively investigated group of photoreceptors . In Arabidopsis there are five identified phytochromes: phyA, phyB,phyC, phyD and phyE . The importance of phytochromes can be evaluated by the different physiological responses where they are involved, such as leaf expansion, neighbour perception, shade avoidance, stem elongation, seed germination and flowering induction. Although shade-avoidance response is usually controlled by phytochromes through the sensing of R/FR ratio, the blue-light and PAR level is also involved in the related adaptive morphological responses. Blue- and UV-A (ultraviolet A)-sensitive photoreceptors are found in the cryptochrome photosystem. Blue light absorbing pigments include both cryptochrome (cry1, cry2) and phototropins (phot1, phot2). They are involved in several different tasks, such as monitoring the quality, quantity, direction and periodicity of the light. The different groups of blue- and UV-A-sensitive photoreceptors mediate important morphological responses such as endogenous rhythms, organ orientation, stem elongation and stomatal opening, germination, leaf expansion, root growth and phototropism. Phototropins
regulate the pigment content and the positioning of photosynthetic organs and organelles in order to optimize the light harvest and photoinhibition. As with exposure to continuous far-red radiation, blue light also promotes flowering through the mediation of cryptochromes photoreceptors. Moreover, blue-light-sensitive photoreceptors (e.g. flavins and carotenoids) are also sensitive to the near-ultraviolet radiation, where a localized sensitivity peak can be found at around 370 nm.
UV LEDS:
Although radiation of wavelengths below 300 nm can be highly harmful to the chemical bonds of molecules and to DNA structure, plants do absorb radiation in this range.
Vtech
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