scholarly journals Accuracy of Quantum Sensors Measuring Yield Photon Flux and Photosynthetic Photon Flux

HortScience ◽  
1993 ◽  
Vol 28 (12) ◽  
pp. 1197-1200 ◽  
Author(s):  
Charles Barnes ◽  
Theodore Tibbitts ◽  
John Sager ◽  
Gerald Deitzer ◽  
David Bubenheim ◽  
...  
Keyword(s):  
Photosynthetically Active Radiation ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Broad Band ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Light Emitting ◽  
Active Radiation ◽  
Radiation Sources ◽  
Two Measures

Photosynthesis is fundamentally driven by photon flux rather than energy flux, but not all absorbed photons yield equal amounts of photosynthesis. Thus, two measures of photosynthetically active radiation have emerged: photosynthetic photon flux (PPF), which values all photons from 400 to 700 nm equally, and yield photon flux (YPF), which weights photons in the range from 360 to 760 nm according to plant photosynthetic response. We selected seven common radiation sources and measured YPF and PPF from each source with a spectroradiometer. We then compared these measurements with measurements from three quantum sensors designed to measure YPF, and from six quantum sensors designed to measure PPF. There were few differences among sensors within a group (usually <5%), but YPF values from sensors were consistently lower (3 % to 20 %) than YPF values calculated from spectroradiometric measurements. Quantum sensor measurements of PPF also were consistently lower than PPF values calculated from spectroradiometric measurements, but the differences were <7% for all sources, except red-light-emitting diodes. The sensors were most accurate for broad-band sources and least accurate for narrow-band sources. According to spectroradiometric measurement, YPF sensors were significantly less accurate (>9% difference) than PPF sensors under metal halide, high-pressure sodium, and low-pressure sodium lamps. Both sensor types were inaccurate (>18% error) under red-light-emitting diodes. Because both YPF and PPF sensors are imperfect integrators, and because spectroradiometers can measure photosynthetically active radiation much more accurately, researchers should consider developing calibration factors from spectroradiometric data for some specific radiation sources to improve the accuracy of integrating sensors.

scholarly journals Growth Responses of Ornamental Annual Seedlings Under Different Wavelengths of Red Light Provided by Light-emitting Diodes

HortScience ◽  
2013 ◽  
Vol 48 (12) ◽  
pp. 1478-1483 ◽  
Author(s):  
Heidi Marie Wollaeger ◽  
Erik S. Runkle
Keyword(s):  
Light Intensity ◽  
Light Emitting Diodes ◽  
Chlorophyll Concentration ◽  
Red Light ◽  
Plant Production ◽  
Photon Flux ◽  
Growth Responses ◽  
Fresh Weight ◽  
Light Emitting ◽  
Shoot Fresh Weight

Light-emitting diodes (LEDs) are of increasing interest in controlled environment plant production because of their increasing energy efficiency, long lifetime, and colors can be combined to elicit desirable plant responses. Red light (600–700 nm) is considered the most efficient wavelength for photosynthesis, but little research has compared growth responses under different wavelengths of red. We grew seedlings of impatiens (Impatiens walleriana), petunia (Petunia ×hybrida), tomato (Solanum lycopersicum), and marigold (Tagetes patula) or salvia (Salvia splendens) at 20 °C under six sole-source LED lighting treatments. In the first experiment, a photosynthetic photon flux (PPF) of 160 μmol·m−2·s–1 was provided for 18 h·d−1 by 10% blue (B; peak = 446 nm) and 10% green (G; peak = 516 nm) lights, with the remaining percentages consisting of orange (O; peak = 596 nm)–red (R; peak = 634 nm)–hyper red (HR; peak = 664 nm) of 20–30–30, 0–80–0, 0–60–20, 0–40–40, 0–20–60, and 0–0–80, respectively. There were no consistent effects of lighting treatment across species on any of the growth characteristics measured including leaf area, plant height, or shoot fresh weight. In a second experiment, seedlings were grown under two light intensities (low, 125 μmol·m−2·s–1 and high, 250 μmol·m−2·s–1) consisting of 10% B and 10% G light and the following percentages of R–HR: 0–80, 40–40, 80–0. Shoot fresh weight was similar in all light treatments, whereas shoot dry weight was often greater under the higher light intensity, especially under the 40–40 treatments. Leaf chlorophyll concentration under 40–40low, 80–0low, or both was often greater than that in plants under the high light treatments, indicating that plants acclimated to the lower light intensity to better use photons available for photosynthesis. We conclude that O, R, and HR light have generally similar effects on plant growth at the intensities tested when background G and B lights are provided and thus, selection of red LEDs for horticultural applications could be based on other factors such as economics and durability.

Overview of the Grow Lights Used in Greenhouses and Plant Factories

2021 ◽  
Vol 1 (42) ◽  
pp. 105-113
Author(s):  
Dmitriy Burynin ◽  
◽  
Aleksandr Smirnov
Keyword(s):  
Photosynthetically Active Radiation ◽  
Crop Production ◽  
Light Emitting Diodes ◽  
Research Purpose ◽  
Vegetable Crops ◽  
Cold Climates ◽  
Light Emitting ◽  
Led Lighting ◽  
Active Radiation ◽  
Advantages And Disadvantages

Phyto-emitters for plants are used to grow vegetables in cold climates all year round and to increase the yield in places with insufficient solar radiation. In recent years, the crop lighting industry has been undergoing innovative changes. Thanks to light-emitting diodes, the market for plant lighting is growing rapidly. (Research purpose) The research purpose is in studying the market of lighting for crop production, analyzing the advantages and disadvantages of various phyto-emitters for growing plants in closed agroecosystems. (Materials and methods) The article presents a review on the state of the vegetable growing sector in the closed ground in Russia, as well as works on phyto-emitters for growing plants. The collected materials on phyto-emitters were classified and analyzed, and the prospects for their implementation were proposed. Authors used the methods of a systematic approach. (Results and discussion) The possibilities of light-emitting diodes and arc sodium tube lamps were studied. The device of phyto-emitters on top of the canopy of high vegetable crops leads to an uneven distribution of light, LED irradiators in the aisle leads to an increase in the amount of harvest. It was found that LED lamps are more effective for shelving plant cultivation. In cold climates, plant factories can be more rational than greenhouses with additional illumination under LED lighting. LED irradiators for crop production were classified according to the type of lamp. The article lists the most popular types of phyto-emitters based on LEDs. LED lighting systems designed to provide a sufficient level of photosynthetically active radiation are ideal for growing plants. (Conclusions) The selection of the spectrum of photosynthetically active radiation for plants can accelerate their growth and development, improve the quality of plants and fruits. Despite the impressive characteristics of LED irradiators, arc sodium tube lamps continue to be competitive when used as the main lighting in greenhouses.

scholarly journals The Efficiency of LED Irradiation for Cultivating High-Quality Tomato Seedlings

2021 ◽  
Vol 13 (16) ◽  
pp. 9426
Author(s):  
Kulyash Meiramkulova ◽  
Zhanar Tanybayeva ◽  
Assel Kydyrbekova ◽  
Arysgul Turbekova ◽  
Serik Aytkhozhin ◽  
...  
Keyword(s):  
High Pressure ◽  
Photosynthetic Pigments ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Control Treatment ◽  
Photon Flux ◽  
Nanoparticle Coating ◽  
Light Emitting ◽  
Tomato Seedlings ◽  
Significant Difference

Light qualities are considered to affect many plant physiological processes during growth and development. To investigate how light qualities make an influence on tomato seedlings under greenhouse conditions, the growth and morphological parameters of tomato seedlings (Fortizia F1RC hybrid) were studied under three supplemental light irradiations such as light-emitting diodes with nanoparticle coating (LED 1—Red light-emitting diodes); Blue, Green, Yellow, Red light-emitting diodes (LED 2), and traditional high-pressure sodium (HPS) lamps with different photosynthetic photon flux density and the same irradiation time for 33 days. Morphological appearances of three groups of tomato seedlings were different between light treatments, that is, the plants under LED-1 and LED-2 were shorter than those under HPS, while stem diameter, leaf area, dry and fresh weights, and health indices of tomato seedlings grown under alternative light sources were higher than of those cultivated under traditional HPS lights. However, the higher plant height was in plants containing traditional high-pressure sodium lamps treatment. Photosynthetic pigments were shown to have a significant difference under respective light irradiations of LEDs. The levels of photosynthetic pigments were higher in the leaves of seedlings under LED 1 and LED 2, and lower in those that underwent HPS control treatment. Based on the data of morphological and statistical analysis, LEDs with nanoparticle coating proved to be beneficial factors for the growth of tomato seedlings under greenhouse conditions.

scholarly journals Improving Spinach, Radish, and Lettuce Growth under Red Light-emitting Diodes (LEDs) with Blue Light Supplementation

HortScience ◽  
2001 ◽  
Vol 36 (2) ◽  
pp. 380-383 ◽  
Author(s):  
Neil C. Yorio ◽  
Gregory D. Goins ◽  
Hollie R. Kagie ◽  
Raymond M. Wheeler ◽  
John C. Sager
Keyword(s):  
Blue Light ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Dry Weight ◽  
Photon Flux ◽  
Light Emitting ◽  
Fluorescent Lamps ◽  
Spinacea Oleracea ◽  
Total Dry Weight ◽  
Red Leds

Radish (Raphanus sativus L. cv. Cherriette), lettuce (Lactuca sativa L. cv. Waldmann's Green), and spinach (Spinacea oleracea L. cv. Nordic IV) plants were grown under 660-nm red light-emitting diodes (LEDs) and were compared at equal photosynthetic photon flux (PPF) with either plants grown under cool-white fluorescent lamps (CWF) or red LEDs supplemented with 10% (30 μmol·m-2·s-1) blue light (400-500 nm) from blue fluorescent (BF) lamps. At 21 days after planting (DAP), leaf photosynthetic rates and stomatal conductance were greater for plants grown under CWF light than for those grown under red LEDs, with or without supplemental blue light. At harvest (21 DAP), total dry-weight accumulation was significantly lower for all species tested when grown under red LEDs alone than when grown under CWF light or red LEDs + 10% BF light. Moreover, total dry weight for radish and spinach was significantly lower under red LEDs + 10% BF than under CWF light, suggesting that addition of blue light to the red LEDs was still insufficient for achieving maximal growth for these crops.

scholarly journals Day-long Alterations of the Photomorphogenic Light Environment Affect Young Watermelon Plant Growth: Implications for Use with Rowcovers

1997 ◽  
Vol 7 (3) ◽  
pp. 261-264 ◽  
Author(s):  
Dennis R. Decoteau ◽  
Heather A. Hatt Graham
Keyword(s):  
Plant Growth ◽  
Blue Light ◽  
Light Quality ◽  
Citrullus Lanatus ◽  
Red Light ◽  
Broad Band ◽  
Metal Halide ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Metal Halide Lamps

The sensitivity of watermelon [Citrullus lanatus (Thumb.) Matsum & Naki `Sugar Baby'] plant growth to day-long alterations in light quality was determined by exposing plants to light transmitted through broad band wavelength selective filters. Of the three acetate filters analyzed (nos. 19, 27, and 74), filter no. 74 transmitted the least amount of photosynthetic photon flux (PPF) (400 to 700 nm), the smallest red light: far-red light ratio (R:FR) (645:735 nm), and the greatest amount of blue light (400 to 500 nm) radiation from metal halide lamps. Plants grown under filter no. 74 were taller, had elongated petioles, and had a greater amount of petiole and stem biomass than plants grown under the other filters. Spectral transmission properties of commercially available rowcover materials were evaluated for variation of PPF, R:FR, and blue light. Clear polyethylene rowcovers were completely permeable to all measured (330 to 850 nm) wavelengths of radiation from metal halide lamps. White polyethylene rowcovers were the least permeable of the rowcover materials to wavelengths of radiation with decreases in the PPF, R:FR, and blue light. Spunbonded polyester materials slightly reduced PPF, R:FR, and blue light. Plants grown under white polyethylene and spunbonded materials grew taller (longer stems) than plants grown under the clear polyethylene rowcover. Petiole lengths were generally longer for plants grown under white polyethylene. Our results suggests that alterations in the R:FR and blue light due to selected wavelength transmission through commercially available rowcover material alter early watermelon growth.

scholarly journals Understanding the luminescent nature of organic radicals for efficient doublet emitters and pure-red light-emitting diodes

2020 ◽  
Vol 19 (11) ◽  
pp. 1224-1229 ◽  
Author(s):  
Alim Abdurahman ◽  
Timothy J. H. Hele ◽  
Qinying Gu ◽  
Jiangbin Zhang ◽  
Qiming Peng ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Red Light ◽  
Organic Radicals ◽  
Light Emitting

Synthesis and Characterization of Thieno[3,4-b]pyrazine Materials for Solution-processible Organic Red Light-emitting Diodes

2011 ◽  
Vol 40 (4) ◽  
pp. 417-419 ◽  
Author(s):  
Qing Li ◽  
Jiuyan Li ◽  
Lijun Deng ◽  
Qian Wang ◽  
Zhanxian Gao ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Red Light ◽  
Synthesis And Characterization ◽  
Light Emitting

(K0.5Na0.5)NbO3:Eu3+/Bi3+: a novel, highly efficient, red light-emitting material with superior water resistance behavior

RSC Advances ◽  
2015 ◽  
Vol 5 (6) ◽  
pp. 4707-4715 ◽  
Author(s):  
Qiwei Zhang ◽  
Haiqin Sun ◽  
Tao Kuang ◽  
Ruiguang Xing ◽  
Xihong Hao
Keyword(s):  
Blue Light ◽  
White Light ◽  
High Performance ◽  
Water Resistance ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Light Emitting ◽  
Highly Efficient ◽  
White Light Emitting Diodes

Materials emitting red light (∼611 nm) under excitation with blue light (440–470 nm) are highly desired for fabricating high-performance white light-emitting diodes (LEDs).

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