scholarly journals Effect of alternating red and blue light irradiation generated by light emitting diodes on the growth of leaf lettuce

2014 ◽  
Author(s):  
Akihiro Shimokawa ◽  
Yuki Tonooka ◽  
Misato Matsumoto ◽  
Hironori Ara ◽  
Hiroshi Suzuki ◽  
...  
Keyword(s):  
Plant Growth ◽  
Blue Light ◽  
Global Climate ◽  
Light Condition ◽  
Light Irradiation ◽  
Fluorescent Light ◽  
Promoting Effect ◽  
Light Emitting ◽  
Simultaneous Irradiation ◽  
Leaf Lettuce

Because global climate change has made agricultural supply unstable, plant factories are expected to be a safe and stable means of food production. As the light source of a plant factory or controlled greenhouse, the light emitting diode (LED) is expected to solve cost problems and promote plant growth efficiently. In this study, we examined the light condition created by using monochromatic red and blue LEDs, to provide both simultaneous and alternating irradiation to leaf lettuce. The result was that simultaneous red and blue irradiation promoted plant growth more effectively than monochromatic and fluorescent light irradiation. Moreover, alternating red and blue light accelerated plant growth significantly even when the total light intensity per day was the same as with simultaneous irradiation. The fresh weight in altering irradiation was almost two times higher than with fluorescent light and about 1.6 times higher than with simultaneous irradiation. The growth-promoting effect of alternating irradiation of red and blue light was observed in different cultivars. From the results of experiments, we offer a novel plant growth method named "Shigyo Method", the core concept of which is the alternating irradiation of red and blue light.

Quality and Intensity of Light in the In Vitro Development of Microstumps of Eucalyptus urophylla in a Photoautotrophic System

2020 ◽  
Vol 66 (6) ◽  
pp. 754-760 ◽  
Author(s):  
Natane A Miranda ◽  
Aloisio Xavier ◽  
Wagner C Otoni ◽  
Ricardo Gallo ◽  
Kellen C Gatti ◽  
...  
Keyword(s):  
Plant Growth ◽  
Light Quality ◽  
Stomatal Density ◽  
Carotenoid Content ◽  
Fluorescent Light ◽  
Eucalyptus Urophylla ◽  
Light Emitting ◽  
Fluorescent Lamps ◽  
Number Of Shoots

Abstract The quality and quantity of light are important factors in controlling in vitro plant growth in photoautotrophic systems. The aim of this study was to evaluate the influence of light quality (fluorescent, white, red, blue, red/blue, and distant red) on microstumps of a Eucalyptus urophylla clone in an in vitro photoautotrophic system, as well as the intensity of fluorescent light (60, 85, 100, and 140 μmol m–2 s–1) in the growth and production of microcutting. The number of shoots and microcutting, the size of the largest shoot, the stomatal density, chlorophyll, and carotenoid content were analyzed. Light quality altered plant growth, and fluorescent light intensity did not affect the microstumps’ production during the evaluation period. In white light-emitting diode (LED) light, there was higher production of carotenoids, with a lower initial production of microcuttings. A smaller number of shoots were obtained in blue LED. In general, the different qualities and light intensities tested allowed for the growth of the Eucalyptus urophylla clone grown in vitro, making it possible to obtain microcuttings under photoautotrophic cultivation. Study Implications In vitro propagation is a stressful process for plants and has limitations for commercial-scale Eucalyptus production. Fluorescent lamps, closed containers, and high sucrose concentrations are traditionally used. To reduce costs and improve production, the use of efficient light sources and photoautotrophic cultivation systems become alternatives. This study investigated the influence of light on the in vitro growth of a Eucalyptus clone in a photoautotrophic system. The quality was more important than the intensity of light. Foresters will be able to indicate the use of LEDs (light-emitting diodes) as a replacement for fluorescent lamps. This approach is useful in enhancing micropropagation techniques.

scholarly journals “Less Blue, More Clean”: Cu2O nano-cubic functionalized hydrogel for the energy transformation of light-emitting screens

RSC Advances ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 5468-5472
Author(s):  
Zhuo Xiang ◽  
Miaoxing Liu ◽  
Fanrong Ai ◽  
Xingwei Ding ◽  
Ping Qiu ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Irradiation ◽  
Energy Transformation ◽  
Light Emitting

Through coverage, blue light irradiation could be absorbed and transformed into photocatalysed power to sterilize the surface.

scholarly journals Spectral Effects of Three Types of White Light-emitting Diodes on Plant Growth and Development: Absolute versus Relative Amounts of Blue Light

HortScience ◽  
2013 ◽  
Vol 48 (4) ◽  
pp. 504-509 ◽  
Author(s):  
Kevin R. Cope ◽  
Bruce Bugbee
Keyword(s):  
Plant Growth ◽  
Blue Light ◽  
Plant Development ◽  
Growth And Development ◽  
Stem Elongation ◽  
Leaf Expansion ◽  
Light Sources ◽  
Plant Growth And Development ◽  
Light Emitting ◽  
White Leds

Light-emitting diodes (LEDs) are a rapidly developing technology for plant growth lighting and have become a powerful tool for understanding the spectral effects of light on plants. Several studies have shown that some blue light is necessary for normal growth and development, but the effects of blue light appear to be species-dependent and may interact with other wavelengths of light as well as photosynthetic photon flux (PPF). We report the photobiological effects of three types of white LEDs (warm, neutral, and cool, with 11%, 19%, and 28% blue light, respectively) on the growth and development of radish, soybean, and wheat. All species were grown at two PPFs (200 and 500 μmol·m−2·s−1) under each LED type, which facilitated testing the effect of absolute (μmol photons per m−2·s−1) and relative (percent of total PPF) blue light on plant development. Root and shoot environmental conditions other than light quality were uniformly maintained among six chambers (three lamp types × two PPFs). All LEDs had similar phytochrome photoequilibria and red:far red ratios. Blue light did not affect total dry weight (DW) in any species but significantly altered plant development. Overall, the low blue light from warm white LEDs increased stem elongation and leaf expansion, whereas the high blue light from cool white LEDs resulted in more compact plants. For radish and soybean, absolute blue light was a better predictor of stem elongation than relative blue light, but relative blue light better predicted leaf area. Absolute blue light better predicted the percent leaf DW in radish and soybean and percent tiller DW in wheat. The largest percentage differences among light sources occurred in low light (200 μmol·m−2·s−1). These results confirm and extend the results of other studies indicating that light quantity and quality interact to determine plant morphology. The optimal amount of blue light likely changes with plant age because plant communities balance the need for rapid leaf expansion, which is necessary to maximize radiation capture, with prevention of excessive stem elongation. A thorough understanding of this interaction is essential to the development of light sources for optimal plant growth and development.

scholarly journals Blue Light-emitting Diode Light Irradiation of Seedlings Improves Seedling Quality and Growth after Transplanting in Red Leaf Lettuce

HortScience ◽  
2010 ◽  
Vol 45 (12) ◽  
pp. 1809-1814 ◽  
Author(s):  
Masahumi Johkan ◽  
Kazuhiro Shoji ◽  
Fumiyuki Goto ◽  
Shin-nosuke Hashida ◽  
Toshihiro Yoshihara
Keyword(s):  
Leaf Area ◽  
Blue Light ◽  
Antioxidant Activities ◽  
Light Emitting Diode ◽  
Red Light ◽  
Seedling Quality ◽  
Carotenoid Content ◽  
Light Emitting ◽  
Leaf Lettuce ◽  
Led Lights

In this study, we determined the effects of raising seedlings with different light spectra such as with blue, red, and blue + red light-emitting diode (LED) lights on seedling quality and yield of red leaf lettuce plants. The light treatments we used were applied for a period of 1 week and consisted of 100 μmol·m−2·s−1 of blue light, simultaneous irradiation with 50 μmol·m−2·s−1 of blue light and 50 μmol·m−2·s−1 of red light, and 100 μmol·m−2·s−1 of red light. At the end of the light treatment, that is 17 days after sowing (DAS), the leaf area and shoot fresh weight (FW) of the lettuce seedlings treated with red light increased by 33% and 25%, respectively, and the dry weight of the shoots and roots of the lettuce seedlings treated with blue-containing LED lights increased by greater than 29% and greater than 83% compared with seedlings grown under a white fluorescent lamp (FL). The shoot/root ratio and specific leaf area of plants irradiated with blue-containing LED lights decreased. At 45 DAS, higher leaf areas and FWs were obtained in lettuce plants treated with blue-containing LED lights. The total chlorophyll (Chl) contents in lettuce plants treated with blue-containing and red lights were less than that of lettuce plants treated with FL, but the Chl a/b ratio and carotenoid content increased under blue-containing LED lights. Polyphenol contents and the total antioxidant status (TAS) were greater in lettuce seedlings treated with blue-containing LED lights than in those treated with FL at 17 DAS. The higher polyphenol contents and TAS in lettuce seedlings at 17 DAS decreased in lettuce plants at 45 DAS. In conclusion, our results indicate that raising seedlings treated with blue light promoted the growth of lettuce plants after transplanting. This is likely because of high shoot and root biomasses, a high content of photosynthetic pigments, and high antioxidant activities in the lettuce seedlings before transplanting. The compact morphology of lettuce seedlings treated with blue LED light would be also useful for transplanting.

Directional blue light irradiation triggers epidermal cell elongation of abaxial side resulting in inhibition of leaf epinasty in geranium under red light condition

2008 ◽  
Vol 115 (2) ◽  
pp. 176-182 ◽  
Author(s):  
Naoya Fukuda ◽  
Mitsuko Fujita ◽  
Yoshitaka Ohta ◽  
Sadanori Sase ◽  
Shigeo Nishimura ◽  
...  
Keyword(s):  
Blue Light ◽  
Epidermal Cell ◽  
Cell Elongation ◽  
Red Light ◽  
Light Condition ◽  
Light Irradiation ◽  
Abaxial Side

scholarly journals Continuous Irradiation with Alternating Red and Blue Light Enhances Plant Growth While Keeping Nutritional Quality in Lettuce

HortScience ◽  
2018 ◽  
Vol 53 (12) ◽  
pp. 1804-1809 ◽  
Author(s):  
Noriko Ohtake ◽  
Masaharu Ishikura ◽  
Hiroshi Suzuki ◽  
Wataru Yamori ◽  
Eiji Goto
Keyword(s):  
Plant Growth ◽  
Leaf Area ◽  
Blue Light ◽  
Nutritional Quality ◽  
Continuous Irradiation ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Fluorescent Lamps ◽  
High Concentrations ◽  
Net Assimilation

Plant factories with artificial lighting have been developed to improve food production, functional ingredients, and profitability. Intensive research has been performed to elucidate the effects of light intensity and wavelength on plant growth and nutritional quality with the use of light-emitting diodes (LEDs). In particular, the effects of monochromatic red, blue, or simultaneous red + blue light have been studied because these wavelengths are predominantly used for photosynthesis. We examined the effects of alternating red and blue light provided by LEDs over a period of 24 hours on the growth and nutritional properties of leafy lettuce. The results clearly show that alternating red and blue light accelerated plant growth significantly compared with white fluorescent lamps or red and blue LEDs at the same daily light integral. Plants grown under alternating red/blue light had a greater net assimilation rate and total and projected leaf area (an indicator of the fraction of leaf area that absorbs more light) than other plants. Additionally, alternating red and blue light maintained high concentrations of sugars, ascorbic acid, and anthocyanins in leaves. Taken together, the results indicate that continuous irradiation with alternating red and blue light could enhance growth while maintaining the nutritional quality in lettuce.

Plant Perception of Light: The role of indoleamines in Scutellaria species

2020 ◽  
Vol 3 (2) ◽  
pp. 161-176
Author(s):  
Jillian A Forsyth ◽  
Lauren A Erland ◽  
Paul R Shipley ◽  
Susan J Murch
Keyword(s):  
Plant Growth ◽  
Blue Light ◽  
White Light ◽  
Light Emitting Diode ◽  
Red Light ◽  
Plant Signaling ◽  
Full Spectrum ◽  
Light Emitting ◽  
Light Spectra ◽  
Lighting Systems

Light mediates plant growth through diverse mechanisms and signaling networks including plant growth regulators (PGRs). We hypothesized that a novel class of PGRs, the indoleamines, are plant signaling molecules that perceive changes in light composition and initiate a cascade of metabolic responses. We used three Scutellaria model species (skullcap): S. lateriflora, S. galericulata and S. racemosa that produce high levels of melatonin and serotonin to investigate this hypothesis. Axenic Scutellaria cultures were exposed to red, blue, green or full spectrum white light spectra provided by light emitting diode (LED) lighting systems, or daylight fluorescent bulbs. Melatonin (MEL), serotonin (5HT), abscisic acid (ABA), auxin (IAA), and jasmonic acid (JA), were quantified by liquid chromatography with tandem mass spectrometry. Melatonin was detected consistently in plants grown under blue light in all species of Scutellaria. In S. galericulata, significant quantities of ABA were detected in plants grown under white light but not detected in plants grown under other light spectra.  In timeline studies of S. racemosa plants exposed to limited red or blue light spectra had significantly reduced levels of tryptamine (TRM), 5HT and MEL in the shoots initially but melatonin was detected after 12 hours and quantifiable amounts of 5HT were detected after 7 days. Supplementation of the culture medium with MEL or 5HT did not change the pattern of MEL in blue light grown cultures but did change patterns of 5HT accumulation.  5HT was highest in plants grown under red light immediately after culture and decreased over 7 days.  These data indicate that the relative amounts of MEL and 5HT are responsive to light spectra and redirect metabolic resources to enable plant adaptations to changing environments.   

scholarly journals Green-light Supplementation for Enhanced Lettuce Growth under Red- and Blue-light-emitting Diodes

HortScience ◽  
2004 ◽  
Vol 39 (7) ◽  
pp. 1617-1622 ◽  
Author(s):  
Hyeon-Hye Kim ◽  
Gregory D. Goins ◽  
Raymond M. Wheeler ◽  
John C. Sager
Keyword(s):  
Plant Growth ◽  
Light Source ◽  
Blue Light ◽  
Light Emitting Diodes ◽  
Green Light ◽  
Light Sources ◽  
Natural Setting ◽  
Light Emitting ◽  
Fluorescent Lamps ◽  
Green Fluorescent

Plants will be an important component of future long-term space missions. Lighting systems for growing plants will need to be lightweight, reliable, and durable, and light-emitting diodes (LEDs) have these characteristics. Previous studies demonstrated that the combination of red and blue light was an effective light source for several crops. Yet the appearance of plants under red and blue lighting is purplish gray making visual assessment of any problems difficult. The addition of green light would make the plant leave appear green and normal similar to a natural setting under white light and may also offer a psychological benefit to the crew. Green supplemental lighting could also offer benefits, since green light can better penetrate the plant canopy and potentially increase plant growth by increasing photosynthesis from the leaves in the lower canopy. In this study, four light sources were tested: 1) red and blue LEDs (RB), 2) red and blue LEDs with green fluorescent lamps (RGB), 3) green fluorescent lamps (GF), and 4) cool-white fluorescent lamps (CWF), that provided 0%, 24%, 86%, and 51% of the total PPF in the green region of the spectrum, respectively. The addition of 24% green light (500 to 600 nm) to red and blue LEDs (RGB treatment) enhanced plant growth. The RGB treatment plants produced more biomass than the plants grown under the cool-white fluorescent lamps (CWF treatment), a commonly tested light source used as a broad-spectrum control.

scholarly journals Sprouting Broccoli Accumulate Higher Concentrations of Nutritionally Important Metabolites under Narrow-band Light-emitting Diode Lighting

2014 ◽  
Vol 139 (4) ◽  
pp. 469-477 ◽  
Author(s):  
Dean A. Kopsell ◽  
Carl E. Sams ◽  
T. Casey Barickman ◽  
Robert C. Morrow
Keyword(s):  
Blue Light ◽  
Nutritional Quality ◽  
Narrow Band ◽  
Light Treatment ◽  
Fluorescent Light ◽  
Total Carotenoids ◽  
Light Emitting ◽  
Incandescent Light ◽  
Red Led ◽  
The Impact

Previous research in our group demonstrated that short-duration exposure to narrow-band blue wavelengths of light can improve the nutritional quality of sprouting broccoli (Brassica oleacea var. italica) microgreens. The objective of this study was to measure the impact of different percentages of blue light on the concentrations of nutritional quality parameters of sprouting broccoli microgreens and to compare incandescent/fluorescent light with light-emitting diodes (LEDs). Microgreen seeds were cultured hydroponically on growing pads under light treatments of: 1) fluorescent/incandescent light; 2) 5% blue (442 to 452 nm)/95% red (622 to 632 nm); 3) 5% blue/85% red/10% green (525 to 535 nm); 4) 20% blue/80% red; and 5) 20% blue/70% red/10% green in controlled environments. Microgreens were grown at an air temperature of 24 °C and a 16-hour photoperiod using a light intensity of 250 μmol·m−2·s−1 for all light treatments. On emergence of the first true leaf, a nutrient solution of 42 mg·L−1 nitrogen (N) (20% Hoagland’s #2 solution) was used to submerge the growing pads. Microgreens were harvested after 20 days under the light treatments and shoot tissues were processed and measured for nutritionally important shoot pigments, glucosinolates, and mineral nutrients. Microgreens under the fluorescent/incandescent light treatment had significantly lower shoot fresh mass than plants under the 5% blue/95% red, 5% blue/85% red/10% green, and the 20% blue/80% red LED light treatments. The highest concentrations of shoot tissue chlorophyll, β-carotene, lutein, total carotenoids, calcium (Ca), magnesium (Mg), phosphorus (P), sulfur (S), boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), glucoiberin, glucoraphanin, 4-methoxyglucobrassicin, and neoglucobrassicin were found in microgreens grown under the 20% blue/80% red light treatment. In general, the fluorescent/incandescent light treatment resulted in significantly lower concentrations of most metabolites measured in the sprouting broccoli tissue. Results from the current study clearly support data from many previous reports that describe stimulation of primary and secondary metabolite biosynthesis by exposure to blue light wavelengths from LEDs.

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