What kind of light mj 'likes ' ? Decoded from it's reflectance ....
- Thread starter stardustsailor
- Start date
stardustsailor
Well-Known Member
And continuing with some more interesting things :
[h=1]Cannabinoid Profile and Elemental Uptake of Cannabis sativa L. as Influenced by Soil Characteristics[/h]
[h=3]Abstract[/h] The consumption of Cannabis products (marihuana) derived from domestic and foreign sources persists in the United States despite its illegality and health hazards. The objectives of this investigation were: 1) to evaluate relationships between soil and plant elements, cannabinoids, and growth of Cannabis sativa L., and 2) to evaluate the practicality of using chemical analysis of Cannabis products to determine their geographic origin. Knowledge of geographic origin is useful to governmental agencies investigating illicit narcotic traffic.
Cannabis sativa L. was grown on 11 different soils for 45 days in the greenhouse.
Soils differed significantly in 15 measured elements and pH.
Plants were grown from seed of Afghan origin.
The following cannabinoids were extracted and measured from leaf tissue: cannabicyclol (CCC), cannabidiol (CBD), Δ[SUP]9[/SUP]-Tetrahydrocannabinol (Δ[SUP]9[/SUP]THC), and cannabinol (CBN).
Fifteen elements measured in leaf tissue and correlated with soil and cannabinoid measurements.
-Soil pH was negatively correlated with leaf concentrations of Mn, Fe, Zn, and S.
-Extractable soil Mg was negatively correlated with N, Δ[SUP]9[/SUP]THC and CBD concentrations in leaf tissue (p < 0.05).
-Plant height was negatively correlated with Δ[SUP]9[/SUP]THC concentration, suggesting enhancement of the narcotic principle of marihuana when grown under stress.
-Extractable soil P[SUB]2[/SUB]O[SUB]5[/SUB] was negatively correlated with CBD concentration while extractable soil Zn was positively correlated with CCC concentration.
Several correlations between soil and plant characteristics having potential value for determination of geographic origin of marihuana were elucidated. However, environmental, harvesting, and analytical procedures used by different workers which do not conform to one another could result in changes in the soil-plant correlations reported herein. Thus, additional studies are required before determination of the geographic origin of Cannabis products by foliar analysis becomes feasible.
https://www.crops.org/publications/aj/abstracts/67/4/AJ0670040491
[h=1]Cannabinoid Profile and Elemental Uptake of Cannabis sativa L. as Influenced by Soil Characteristics[/h]
[h=3]Abstract[/h] The consumption of Cannabis products (marihuana) derived from domestic and foreign sources persists in the United States despite its illegality and health hazards. The objectives of this investigation were: 1) to evaluate relationships between soil and plant elements, cannabinoids, and growth of Cannabis sativa L., and 2) to evaluate the practicality of using chemical analysis of Cannabis products to determine their geographic origin. Knowledge of geographic origin is useful to governmental agencies investigating illicit narcotic traffic.
Cannabis sativa L. was grown on 11 different soils for 45 days in the greenhouse.
Soils differed significantly in 15 measured elements and pH.
Plants were grown from seed of Afghan origin.
The following cannabinoids were extracted and measured from leaf tissue: cannabicyclol (CCC), cannabidiol (CBD), Δ[SUP]9[/SUP]-Tetrahydrocannabinol (Δ[SUP]9[/SUP]THC), and cannabinol (CBN).
Fifteen elements measured in leaf tissue and correlated with soil and cannabinoid measurements.
-Soil pH was negatively correlated with leaf concentrations of Mn, Fe, Zn, and S.
-Extractable soil Mg was negatively correlated with N, Δ[SUP]9[/SUP]THC and CBD concentrations in leaf tissue (p < 0.05).
-Plant height was negatively correlated with Δ[SUP]9[/SUP]THC concentration, suggesting enhancement of the narcotic principle of marihuana when grown under stress.
-Extractable soil P[SUB]2[/SUB]O[SUB]5[/SUB] was negatively correlated with CBD concentration while extractable soil Zn was positively correlated with CCC concentration.
Several correlations between soil and plant characteristics having potential value for determination of geographic origin of marihuana were elucidated. However, environmental, harvesting, and analytical procedures used by different workers which do not conform to one another could result in changes in the soil-plant correlations reported herein. Thus, additional studies are required before determination of the geographic origin of Cannabis products by foliar analysis becomes feasible.
https://www.crops.org/publications/aj/abstracts/67/4/AJ0670040491
stardustsailor
Well-Known Member
[h=1]Photoinhibition of photosynthesis in intact bean leaves: role of light and temperature, and requirement for chloroplast-protein synthesis during recovery[/h]
[h=2]Abstract[/h] Photoinhibition of photosynthesis was induced in intact leaves of Phaseolus vulgaris L. grown at a photon flux density (PFD; photon fluence rate) of 300 μmol·m[SUP]-2[/SUP]·s[SUP]-1[/SUP], by exposure to a PFD of 1400 μmol·m[SUP]-2[/SUP]·s[SUP]-1[/SUP]. Subsequent recovery from photoinhibition was followed at temperatures ranging from 5 to 35°C and at a PFD of either 20 or 140 μmol·m[SUP]-2[/SUP]·s[SUP]-1[/SUP] or in complete darkness. Photoinhibition and recovery were monitored mainly by chlorophyll fluorescence emission at 77K but also by photosynthetic O[SUB]2[/SUB] evolution. The effects of the protein-synthesis inhibitors, cycloheximide and chloramphenicol, on photoinhibition and recovery were also determined. The results demonstrate that recovery was temperature-dependent with rates slow below 15°C and optimal at 30°C. Light was required for maximum recovery but the process was light-saturated at a PFD of 20 μmol·m[SUP]-2[/SUP]·s[SUP]-1[/SUP]. Chloramphenicol, but not cycloheximide, inactivated the repair process, indicating that recovery involved the synthesis of one or more chloroplast-encoded proteins. With chloramphenicol, it was shown that photoinhibition and recovery occurred concomitantly. The temperature-dependency of the photoinhibition process was, therefore, in part determined by the effect of temperature on the recovery process. Consequently, photoinhibition is the net difference between the rate of damage and the rate of repair. The susceptibility of chilling-sensitive plant species to photoinhibition at low temperatures is proposed to result from the low rates of recovery in this temperature range.
http://link.springer.com/article/10.1007/BF00402971
[h=2]Abstract[/h] Photoinhibition of photosynthesis was induced in intact leaves of Phaseolus vulgaris L. grown at a photon flux density (PFD; photon fluence rate) of 300 μmol·m[SUP]-2[/SUP]·s[SUP]-1[/SUP], by exposure to a PFD of 1400 μmol·m[SUP]-2[/SUP]·s[SUP]-1[/SUP]. Subsequent recovery from photoinhibition was followed at temperatures ranging from 5 to 35°C and at a PFD of either 20 or 140 μmol·m[SUP]-2[/SUP]·s[SUP]-1[/SUP] or in complete darkness. Photoinhibition and recovery were monitored mainly by chlorophyll fluorescence emission at 77K but also by photosynthetic O[SUB]2[/SUB] evolution. The effects of the protein-synthesis inhibitors, cycloheximide and chloramphenicol, on photoinhibition and recovery were also determined. The results demonstrate that recovery was temperature-dependent with rates slow below 15°C and optimal at 30°C. Light was required for maximum recovery but the process was light-saturated at a PFD of 20 μmol·m[SUP]-2[/SUP]·s[SUP]-1[/SUP]. Chloramphenicol, but not cycloheximide, inactivated the repair process, indicating that recovery involved the synthesis of one or more chloroplast-encoded proteins. With chloramphenicol, it was shown that photoinhibition and recovery occurred concomitantly. The temperature-dependency of the photoinhibition process was, therefore, in part determined by the effect of temperature on the recovery process. Consequently, photoinhibition is the net difference between the rate of damage and the rate of repair. The susceptibility of chilling-sensitive plant species to photoinhibition at low temperatures is proposed to result from the low rates of recovery in this temperature range.
http://link.springer.com/article/10.1007/BF00402971
stardustsailor
Well-Known Member
[h=1]On the inhibition of photosynthesis by intense light[/h][h=2]Abstract[/h]In strong light destruction of the photosynthetic appartus occurs. This destruction is counteracted by restorative dark reactions. The time course of photoinhibition of both the quantum yield and the photosynthetic saturation rate has first-order character and is only slightly influenced by temperature. It was shown that a photochemical inactivation of the pigment complex is involved.
http://www.sciencedirect.com/science/article/pii/0006300256900038?np=y
Damage from light is directly dependent in light intensity .
Recovery from photoinhibition , is directly dependent on temperature .
http://www.sciencedirect.com/science/article/pii/0006300256900038?np=y
Damage from light is directly dependent in light intensity .
Recovery from photoinhibition , is directly dependent on temperature .
stardustsailor
Well-Known Member
Photoinhibition of Chloroplast Reactions. I. Kinetics and Action Spectra
Abstract
A study was made of photoinhibition of spinach chloroplast reactions. The kinetics and spectral characteristics of the photoinhibition over a range between 230 and 700 mμ have been examined. The decline of activity due to preillumination was independent of wavelength, and dependent upon the number of quanta applied, not upon the rate of application. The effectiveness spectra of photoinhibition indicate that active ultraviolet light is absorbed by a pigment which is not a normal light absorber for photosynthesis and acts with a high quantum efficiency (> 0.1) for photoinhibition.
Active visible light is absorbed by the pigments which sensitize photosynthesis (chlorophyll, carotenoids). A very low quantum efficiency (about 10[SUP]−4[/SUP]) was observed for the photoinhibition with visible light.
The action spectrum of the photoinhibition of dye reduction by chloroplasts and lyophylized Anacystis cells indicated that the damage caused by visible light is due to quanta absorbed by photosystem II. However, since system I might not be involved in dye reduction, the spectra may reflect only damage to photosystem II.
http://www.plantphysiol.org/content/41/6/1037.short
http://www.plantphysiol.org/content/41/6/1037.full.pdf+html
Abstract
A study was made of photoinhibition of spinach chloroplast reactions. The kinetics and spectral characteristics of the photoinhibition over a range between 230 and 700 mμ have been examined. The decline of activity due to preillumination was independent of wavelength, and dependent upon the number of quanta applied, not upon the rate of application. The effectiveness spectra of photoinhibition indicate that active ultraviolet light is absorbed by a pigment which is not a normal light absorber for photosynthesis and acts with a high quantum efficiency (> 0.1) for photoinhibition.
Active visible light is absorbed by the pigments which sensitize photosynthesis (chlorophyll, carotenoids). A very low quantum efficiency (about 10[SUP]−4[/SUP]) was observed for the photoinhibition with visible light.
The action spectrum of the photoinhibition of dye reduction by chloroplasts and lyophylized Anacystis cells indicated that the damage caused by visible light is due to quanta absorbed by photosystem II. However, since system I might not be involved in dye reduction, the spectra may reflect only damage to photosystem II.
http://www.plantphysiol.org/content/41/6/1037.short
http://www.plantphysiol.org/content/41/6/1037.full.pdf+html
stardustsailor
Well-Known Member
[h=1]Photoinhibitory damage is modulated by the rate of photosynthesis and by the photosystem II light-harvesting chlorophyll antenna size[/h]
[h=2]Abstract.[/h] We investigated the effect of photosynthetic electron transport and of the photosystem II (PSII) chlorophyll (Chl) antenna size on the rate of PSII photoinhibitory damage. To modulate the rate of photosynthesis and the light-harvesting capacity in the unicellular chlorophyte Dunaliella salina Teod., we varied the amount of inorganic carbon in the culture medium. Cells were grown under high irradiance either with a limiting supply of inorganic carbon, provided by an initial concentration of 25 mM NaHCO[SUB]3[/SUB], or with supplemental CO[SUB]2[/SUB] bubbled in the form of 3% CO[SUB]2[/SUB] in air. The NaHCO[SUB]3[/SUB]-grown cells displayed slow rates of photosynthesis and had a small PSII light-harvesting Chl antenna size (60 Chl molecules). The half-time of PSII photodamage was 40 min. When switched to supplemental CO[SUB]2[/SUB] conditions, the rate of photodamage was retarded to a t[SUB]1/2[/SUB] = 70 min. Conversely, CO[SUB]2[/SUB]-supplemented cells displayed faster rates of photosynthesis and a larger PSII light-harvesting Chl antenna size (500 Chl molecules). They also showed a rate of photodamage with t[SUB]1/2[/SUB] = 40 min. When depleted of CO[SUB]2[/SUB], the rate of photodamage was accelerated (t[SUB]1/2 [/SUB]  = 20 min). These results indicate that the in-vivo susceptibility to photodamage is modulated by the rate of forward electron transport through PSII. Moreover, a large Chl antenna size enhances the rate of light absorption and photodamage and, therefore, counters the mitigating effect of forward electron transport. We propose that under steady-state photosynthesis, the rate of light absorption (determined by incident light intensity and PS Chl antenna size) and the rate of forward electron transport (determined by CO[SUB]2[/SUB] availability) modulate the oxidation/reduction state of the primary PSII acceptor Q[SUB]A[/SUB], which in turn defines the low/high probability for photodamage in the PSII reaction center.
http://link.springer.com/article/10.1007/s004250050323
[h=2]Abstract.[/h] We investigated the effect of photosynthetic electron transport and of the photosystem II (PSII) chlorophyll (Chl) antenna size on the rate of PSII photoinhibitory damage. To modulate the rate of photosynthesis and the light-harvesting capacity in the unicellular chlorophyte Dunaliella salina Teod., we varied the amount of inorganic carbon in the culture medium. Cells were grown under high irradiance either with a limiting supply of inorganic carbon, provided by an initial concentration of 25 mM NaHCO[SUB]3[/SUB], or with supplemental CO[SUB]2[/SUB] bubbled in the form of 3% CO[SUB]2[/SUB] in air. The NaHCO[SUB]3[/SUB]-grown cells displayed slow rates of photosynthesis and had a small PSII light-harvesting Chl antenna size (60 Chl molecules). The half-time of PSII photodamage was 40 min. When switched to supplemental CO[SUB]2[/SUB] conditions, the rate of photodamage was retarded to a t[SUB]1/2[/SUB] = 70 min. Conversely, CO[SUB]2[/SUB]-supplemented cells displayed faster rates of photosynthesis and a larger PSII light-harvesting Chl antenna size (500 Chl molecules). They also showed a rate of photodamage with t[SUB]1/2[/SUB] = 40 min. When depleted of CO[SUB]2[/SUB], the rate of photodamage was accelerated (t[SUB]1/2 [/SUB]  = 20 min). These results indicate that the in-vivo susceptibility to photodamage is modulated by the rate of forward electron transport through PSII. Moreover, a large Chl antenna size enhances the rate of light absorption and photodamage and, therefore, counters the mitigating effect of forward electron transport. We propose that under steady-state photosynthesis, the rate of light absorption (determined by incident light intensity and PS Chl antenna size) and the rate of forward electron transport (determined by CO[SUB]2[/SUB] availability) modulate the oxidation/reduction state of the primary PSII acceptor Q[SUB]A[/SUB], which in turn defines the low/high probability for photodamage in the PSII reaction center.
http://link.springer.com/article/10.1007/s004250050323
stardustsailor
Well-Known Member
Changes of photosynthesis-related parameters and productivity of
Cannabis sativa under different nitrogen supply
http://eeb.lu.lv/EEB/201108/EEB_9_Malceva.pdf
Cannabis sativa under different nitrogen supply
http://eeb.lu.lv/EEB/201108/EEB_9_Malceva.pdf
RainerRocks
Active Member
I noticed the same thing where cyan takes a nose dive in the white spectrum of led's more so than other WLS so I added cyan to bring it up to par .
stardustsailor
Well-Known Member
Cyan led .. Like a Luxeon cyan ?
RainerRocks
Active Member
Cyan =505 nm
Yes...LXML-PE01-0080
http://www.philipslumileds.com/products/luxeon-rebel/luxeon-rebel-color#deep-red
| Part | Min Lumens | Typ Lumens | Min Wavelength | Max Wavelength |
| LXML-PE01-0060 | 60 @ 350 mA | 110 @ 700 mA | 490 nm | 520 nm |
| LXML-PE01-0070 | 70 @ 350 mA | 122 @ 700 mA | 490 nm | 520 nm |
| LXML-PE01-0080 | 80 @ 350 mA | 133 @ 700 mA | 490 nm | 520 nm |
stardustsailor
Well-Known Member
Another option to pure monochromatic cyan led is the Osram Oslon LUW CR7P EQW .
(pc cyan enhanced -white used along with reds 625 nm in PrevaLed Core Engine ,to produce high CRI white light .
http://www.led1.de/shop/lng/en/osram-prevaled-core-lep-3000-930-hd-c-warm-white.html )
http://catalog.osram-os.com/catalogue/catalogue.do?favOid=0000000d0002937900700023&act=showBookmark
(pc cyan enhanced -white used along with reds 625 nm in PrevaLed Core Engine ,to produce high CRI white light .
http://www.led1.de/shop/lng/en/osram-prevaled-core-lep-3000-930-hd-c-warm-white.html )
http://catalog.osram-os.com/catalogue/catalogue.do?favOid=0000000d0002937900700023&act=showBookmark
stardustsailor
Well-Known Member
ganja 2
Active Member
if marijuana smoke will not die ..
stardustsailor
Well-Known Member
New babies ....
Powerful babies ....
Cree XP-E2 series ...
For 'our' use :
..
http://www.cree.com/led-components-and-modules/products/xlamp/discrete-directional/xlamp-xpe2
Powerful babies ....
Cree XP-E2 series ...
For 'our' use :
..http://www.cree.com/led-components-and-modules/products/xlamp/discrete-directional/xlamp-xpe2
stardustsailor
Well-Known Member
COLUMBIA, S.C. – Sensor Electronic Technology, Inc. (SETi) has launched a new line of UVTOP® products in surface mount packages at the 2013 SPIE Photonics West show. Initial devices added to this product line will operate with peak operating wavelengths at 275nm and 310nm respectively. Additional wavelength specifications will be added to the product line in the near future.
This SMD based line of UVTOP® LEDs has been developed to address high volume markets that demand lower device and assembly costs.
The ceramic package dimensions are 3.5mm x 3.5mm and are available with UV stable encapsulation, a flat glass window, or a hemispherical glass window. Windowless devices are also available.
The entire range of UVTOP® LEDs will remain available in TO packages for lower volume requirements, customized specifications and for customers who prefer a through-hole package.
In 2012, SETi opened its high volume manufacturing facility for UV LEDs, driving the cost of manufacture down and now by employing new high volume packaging techniques and with the use of this cost effective ceramic package, SETi is bringing the world leading UVTOP® LEDs to new mass-volume markets where the TO package is not the most effective solution.
http://news.thomasnet.com/fullstory/UVC-and-UVB-LEDs-are-available-in-SMD-format-20003442
http://www.s-et.com/uvtop.html
This SMD based line of UVTOP® LEDs has been developed to address high volume markets that demand lower device and assembly costs.
The ceramic package dimensions are 3.5mm x 3.5mm and are available with UV stable encapsulation, a flat glass window, or a hemispherical glass window. Windowless devices are also available.
The entire range of UVTOP® LEDs will remain available in TO packages for lower volume requirements, customized specifications and for customers who prefer a through-hole package.
In 2012, SETi opened its high volume manufacturing facility for UV LEDs, driving the cost of manufacture down and now by employing new high volume packaging techniques and with the use of this cost effective ceramic package, SETi is bringing the world leading UVTOP® LEDs to new mass-volume markets where the TO package is not the most effective solution.
http://news.thomasnet.com/fullstory/UVC-and-UVB-LEDs-are-available-in-SMD-format-20003442
http://www.s-et.com/uvtop.html
stardustsailor
Well-Known Member
Impact of LED emission on biological organisms is well known. State of the art literature indicated a reaction of cellular metabolism on different emission spectra, in particular on infra-red, combination of red and blue, blue and green, as well as other spectra of LED emission. There are developed technical recommendations for plants, there are considered influence not only of different spectra but also of different materials in physiotherapy. Investigation has been performed on impact of LED light on animal tissues, in particular rats. LED emission is also considered for treatment of acne, or psoriasis. Several works reported also about influence of LED on cognitive capabilities of computer users. An important issue for LED light in horticulture concerns their economic viability. With advancing technology developments, LEDs are poised to become the light source with the highest electrical energy conversion ratio. LEDs might be used in greenhouses for lighting with selected wavelengths or for night breaks in off-season production of long-day crops. The use of red LED light to power photosynthesis has been widely accepted for two primary reasons. First, it is indicated that red wavelengths (600 to 700 nm) are efficiently absorbed by plant pigments; second, early LEDs were red with the most efficient emitting at 660 nm, close to an absorption peak of chlorophyll. They also saturated phytochrome, creating a high-Pfr photostationary state in the absence of FR or dark reversion.
http://cybertronica.co/?q=node/16
http://cybertronica.co/?q=node/16
stardustsailor
Well-Known Member
[h=1]Impact of LED light on germination, development and persistence of different plants[/h]
Sensitivity of plants to light is well-known. An important issue for LED light in horticulture concerns their economic viability. With advancing technology developments, LEDs are poised to become the light source with the highest electrical energy conversion ratio. LEDs might be used in greenhouses for lighting with selected wavelengths or for night breaks in off-season production of long-day crops [1]. The use of red LED light to power photosynthesis has been widely accepted for two primary reasons [2]. First, it is indicated that red wavelengths (600 to 700 nm) are efficiently absorbed by plant pigments; second, early LEDs were red with the most efficient emitting at 660 nm, close to an absorption peak of chlorophyll. They also saturated phytochrome, creating a high-Pfr photostationary state in the absence of FR or dark reversion.
The other main wavelength included in early studies has been in the blue region (400 to 500 nm) of the visible spectrum. The source [1] describes on effects of infrared (IR) LEDs of 880 nm and 935 nm on etiolated oat seedlings.
Spectroradiometric analysis of those long-wavelength sources showed that actual peak emission wavelengths averaged 916 nm and 958 nm, respectively. Compared with dark-grown controls, seedlings grown with 880 (916)-nm LEDs had shorter overall length but more advanced leaf emergence than either dark- or 935 (95
-nm-grown seedlings.
Also, the proportion of mesocotyl tissue was significantly higher for seedlings grown with either IR source or dark grown, whereas the proportion of coleoptile tissue was significantly lower. An ancillary observation was that the IR LED radiation made seedlings significantly straighter and trained them to the gravity vector. The authors proposed the activation of a “gravitropism photon-sensing system” with potential involvement of phytochrome [3].
Red and blue light best drive photosynthetic metabolism, so it is no surprise that these light qualities are particularly efficient in advancing the developmental characteristics associated with autotrophic growth habits. Photosynthetically inefficient light qualities also impart important environmental information to a developing plant. For example, far-red light reverses the effect of phytochromes, leading to changes in gene expression, plant architecture, and reproductive responses.
Recent evidence shows that green light also has discrete effects on plant biology, and the mechanisms that sense this light quality are now being elucidated.
Green light has been shown to affect plant processes via cryptochrome-dependent and cryptochrome-independent means. Generally, the effects of green light oppose those directed by red and blue wavebands [4]. Similar effects investigated by NASA Biological Sciences research group at Kennedy Space Center, which performed several experiments with lettuce, one of the Advanced Life Support candidate crops, to evaluate the effects of green light in a controlled environment. Lettuce showed similar growth and photosynthetic rates with the addition of 5 % supplemental green light compared to the red and blue LEDs only grown plants. The addition of green light provided an aesthetic appeal of a green appearance. However, light sources with a higher fraction of green photons (> 50 % of total PPF) resulted in the reduced plant growth [5].
It is also demonstrated that under influence of dedicated combination of LED spectra, there is a development of a larger biomass of plans, e.g. [6]. The effect of LED light of different wavelengths was studied not only by using plants but also with mushroom. For instance [7] reports on the mycelial biomass production of medicinal Ling Zhi or Reishi mushroom Ganoderma lucidum. Optimum production was obtained at wavelengths between 425 and 475 nm, which correspond to the blue light, followed in order by white light, darkness, red light, and yellow light.
[h=4]References[/h]
[1] Gioia D. Massa, Hyeon-Hye Kim, Raymond M. Wheeler, and Cary A. Mitchell, Plant Productivity in Response to LED Lighting, HortScience December, 43:1951-1956, 2008
[2] Mirela Maria Matioc-Precup, Dorina Cachiţă-Cosma, The Germination And Growth Of Brassica Oleracea L. Var. Capitata F. Rubra Plantlets Under The Influence Of Colored Light Of Different Provenance”, Studia Universitatis “Vasile Goldiş”, Seria Ştiinţele Vieţii Vol. 22, issue 2, 2012, pp. 193-202, Vasile Goldis University Press, 2012
[3] Johnson, C.F., Brown, C.S.,Wheeler, R.M., Sager, J.C.,Chapman, D.K.,Deitzer, G.F. Infrared light-emitting diode radiation causes gravitropic and morphological effects in dark-grown oat seedlings. Photochem. Photobiol. 63:238–242, (1996)
[4] Kevin M. Folta1, Stefanie A. Maruhnich, Green light: a signal to slow down or stop, Journal of Experimental Botany, Vol. 58, No. 12, pp. 3099–3111, doi:10.1093/jxb/erm130, 2007
[5] Kim, H.H., Wheeler, R.M., Sager, J.C., Gains, G.D. and Naikane, J.H. 2006. Evaluation Of Lettuce Growth Using Supplemental Green Light With Red And Blue Light-Emitting Diodes In A Controlled Environment - A Review Of Research At Kennedy Space Center. Acta Hort. (ISHS) 711:111-120
[6] Duong Tan Nhut1, T. Takamura1, H. Watanabe2, K. Okamoto3 & M. Tanaka, Responses of strawberry plantlets cultured in vitro under superbright red and blue light-emitting diodes (LEDs), Plant Cell, Tissue and Organ Culture 73: 43–52, 2003
[7] Zapata, Paola A, Rojas, Diego F., Ramirez, David A., Fernandez, Carlos, Atehortua, Lucia, Effect of Different Light-Emitting Diodes on Mycelial Biomass Production of Ling Zhi or Reishi Medicinal Mushroom Ganoderma lucidum (W. Curt.: Fr.) P. Karst. (Aphyllophoromycetideae), Begell House, V.11, N 1, P 93-99, 10.1615/IntJMedMushr.v11.i1.110, 2009
Sensitivity of plants to light is well-known. An important issue for LED light in horticulture concerns their economic viability. With advancing technology developments, LEDs are poised to become the light source with the highest electrical energy conversion ratio. LEDs might be used in greenhouses for lighting with selected wavelengths or for night breaks in off-season production of long-day crops [1]. The use of red LED light to power photosynthesis has been widely accepted for two primary reasons [2]. First, it is indicated that red wavelengths (600 to 700 nm) are efficiently absorbed by plant pigments; second, early LEDs were red with the most efficient emitting at 660 nm, close to an absorption peak of chlorophyll. They also saturated phytochrome, creating a high-Pfr photostationary state in the absence of FR or dark reversion.
The other main wavelength included in early studies has been in the blue region (400 to 500 nm) of the visible spectrum. The source [1] describes on effects of infrared (IR) LEDs of 880 nm and 935 nm on etiolated oat seedlings.
Spectroradiometric analysis of those long-wavelength sources showed that actual peak emission wavelengths averaged 916 nm and 958 nm, respectively. Compared with dark-grown controls, seedlings grown with 880 (916)-nm LEDs had shorter overall length but more advanced leaf emergence than either dark- or 935 (95
-nm-grown seedlings. Also, the proportion of mesocotyl tissue was significantly higher for seedlings grown with either IR source or dark grown, whereas the proportion of coleoptile tissue was significantly lower. An ancillary observation was that the IR LED radiation made seedlings significantly straighter and trained them to the gravity vector. The authors proposed the activation of a “gravitropism photon-sensing system” with potential involvement of phytochrome [3].
Red and blue light best drive photosynthetic metabolism, so it is no surprise that these light qualities are particularly efficient in advancing the developmental characteristics associated with autotrophic growth habits. Photosynthetically inefficient light qualities also impart important environmental information to a developing plant. For example, far-red light reverses the effect of phytochromes, leading to changes in gene expression, plant architecture, and reproductive responses.
Recent evidence shows that green light also has discrete effects on plant biology, and the mechanisms that sense this light quality are now being elucidated.
Green light has been shown to affect plant processes via cryptochrome-dependent and cryptochrome-independent means. Generally, the effects of green light oppose those directed by red and blue wavebands [4]. Similar effects investigated by NASA Biological Sciences research group at Kennedy Space Center, which performed several experiments with lettuce, one of the Advanced Life Support candidate crops, to evaluate the effects of green light in a controlled environment. Lettuce showed similar growth and photosynthetic rates with the addition of 5 % supplemental green light compared to the red and blue LEDs only grown plants. The addition of green light provided an aesthetic appeal of a green appearance. However, light sources with a higher fraction of green photons (> 50 % of total PPF) resulted in the reduced plant growth [5].
It is also demonstrated that under influence of dedicated combination of LED spectra, there is a development of a larger biomass of plans, e.g. [6]. The effect of LED light of different wavelengths was studied not only by using plants but also with mushroom. For instance [7] reports on the mycelial biomass production of medicinal Ling Zhi or Reishi mushroom Ganoderma lucidum. Optimum production was obtained at wavelengths between 425 and 475 nm, which correspond to the blue light, followed in order by white light, darkness, red light, and yellow light.
[h=4]References[/h]
[1] Gioia D. Massa, Hyeon-Hye Kim, Raymond M. Wheeler, and Cary A. Mitchell, Plant Productivity in Response to LED Lighting, HortScience December, 43:1951-1956, 2008
[2] Mirela Maria Matioc-Precup, Dorina Cachiţă-Cosma, The Germination And Growth Of Brassica Oleracea L. Var. Capitata F. Rubra Plantlets Under The Influence Of Colored Light Of Different Provenance”, Studia Universitatis “Vasile Goldiş”, Seria Ştiinţele Vieţii Vol. 22, issue 2, 2012, pp. 193-202, Vasile Goldis University Press, 2012
[3] Johnson, C.F., Brown, C.S.,Wheeler, R.M., Sager, J.C.,Chapman, D.K.,Deitzer, G.F. Infrared light-emitting diode radiation causes gravitropic and morphological effects in dark-grown oat seedlings. Photochem. Photobiol. 63:238–242, (1996)
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