scholarly journals Supplemental LED lighting increases pansy growth

2015 ◽  
Vol 33 (4) ◽  
pp. 428-433
Author(s):  
Nezihe Koksal ◽  
Meral Incesu ◽  
Ahmet Teke

ABSTRACT: Pansy (Viola cornuta) is a facultative long-day plant that flowers from October until March in Turkey. During the winter months, low light levels can limit plant growth and development. Light emitting diodes (LEDs) can provide supplemental lighting in greenhouses which produce same light intensity with less energy than conventional incandescent lighting. Light emitting diode technologies have enabled affordable and efficient light systems to be installed in greenhouses and plastic tunnels in the field. In this experiment we evaluated the effects of supplemental red-orange LED lightening on the growth and development of pansy cv. Blue Blotch grown in plastic tunnels. The energy, which LEDs are to consume, was provided through a solar panel system with the aim of drawing attention to the cleanliness of solar energy source. Five hours of supplement LED lighting was applied after dusk starting from November to February. Pansy growth and development parameters were compared with non-light supplied control plants. Supplemental LED lighting significantly increased plant biomass weight, flower number and leaves number at the rate of 52%, 72%, and 47%, respectively. Moreover, LED lighting increased plant growth rate (0.109 and 0.306 g of fresh weight), compared with the no light control. LED lighting, however, had no effect on length of stems, number of branches and the diameter of flowers. Thus, this study indicated that pansies are light limited during the winter months and supplemental LED lighting can significantly increase pansy growth and development.

Author(s):  
John D. Bullough ◽  
Yi-wei Liu

Airfield lighting for runways and taxiways is currently undergoing a transition from filament-based incandescent sources to light emitting diodes (LEDs). Although models to assess the relative brightness, discomfort glare, and peripheral detectability of signal lights such as those used for aviation exist, their applicability to white LED airfield lighting has not been verified independently. A series of three experiments was conducted to compare white LED sources, having correlated color temperatures of 2,700 K and 5,900 K, in terms of their relative brightness, discomfort glare, and peripheral detectability. The perceived brightness and discomfort glare from the light sources closely matched predictions from the published models, demonstrating the usefulness of these models at characterizing these responses in airfield lighting. In the case of peripheral detectability, there was little to no difference in how quickly the two LEDs were perceived at low light levels, suggesting that there is no need to consider spectral differences between light source spectra for this response when the intensities are similar to those used in the present study.


HortScience ◽  
2019 ◽  
Vol 54 (10) ◽  
pp. 1656-1661 ◽  
Author(s):  
Liang Zheng ◽  
Huaming He ◽  
Weitang Song

Plant growth and development relies on light and is influenced by light. Light-emitting diode (LED) technology is nowadays providing the possibility for regulating plant growth and development by modifying light spectral composition. Many researches have been carried out to figure out the effects of light quality on various aspects of plant behaviors, including plant morphology, physiology, and biochemistry. In this review, we summarized those research outputs, in order to give suggestion of light quality application for both research and production purposes, in the field of productional yield, productional quality for horticultural plants including vegetables or ornamentals in difference with cultivation goals.


Plants ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 176
Author(s):  
Tatjana G. Shibaeva ◽  
Elena G. Sherudilo ◽  
Alexandra A. Rubaeva ◽  
Alexander F. Titov

The effect of continuous lighting (CL, 24 h) and light spectrum on growth and nutritional quality of arugula (Eruca sativa), broccoli (Brassica oleracea var. italic), mizuna (Brassica rapa. var. nipposinica), and radish (Raphanus sativus var. radicula) were investigated in growth chambers under light-emitting diode (LED) and fluorescent lighting. Microgreens were grown under four combinations of two photoperiods (16 h and 24 h) providing daily light integral (DLI) of 15.6 and 23.3 mol m−2 day−1, correspondingly) with two light spectra: LED lamps and fluorescent lamps (FLU). The results show that fresh and dry weights as well as leaf mass per area and robust index of harvested arugula, broccoli, mizuna, and radish seedlings were significantly higher under CL compared to 16 h photoperiod regardless of light quality. There were no visible signs of leaf photodamage. In all CL-treated plants higher chlorophyll a/b and carotenoid-to-chlorophyll ratios were observed in all plants except mizuna. CL treatment was beneficial for anthocyanin, flavonoid, and proline accumulation. Higher activities of antioxidant enzymes (catalase, superoxide dismutase, ascorbate peroxidase, and guaiacol peroxidase) were also observed in CL-treated plants. In most cases, the effects were more pronounced under LED lighting. These results indicate that plants under mild oxidative stress induced by CL accumulated more non-enzymatic antioxidants and increased the activities of antioxidant enzymes. This added nutritional value to microgreens that are used as functional foods providing health benefits. We suggest that for arugula, broccoli, mizuna, and radish, an LED CL production strategy is possible and can have economic and nutritional benefits.


2019 ◽  
Vol 805 ◽  
pp. 141-145
Author(s):  
Nguyen Phuc Thien

The aim of these studies was mainly to investigate the effects of monochromatic LEDs applied singly on the in vitro plant growth and morphogenesis. Various morphological and physiological parameters are considered that influence the growth and development of plants in vitro under red LED light as compared to those under normal light. Upon exposure to LED, in vitro-raised plants have shown significant improvements in growth and morphogenesis. In particular, red and blue lights, either alone or in combination, have a significant influence on plant growth. The present study gives an overview of the fundamentals of LEDs and describes their effects on in vitro plant growth and morphogenesis and their future potentials. The main objective of this study was to carry out line and combing ability of plant growth on tomato.


2020 ◽  
Vol 10 (4) ◽  
pp. 1330
Author(s):  
Vincent K. S. Hsiao ◽  
Teng-Yun Cheng ◽  
Chih-Feng Chen ◽  
Hao Shiu ◽  
Yong-Jin Yu ◽  
...  

We investigated a light emitting diode (LED) lighting system applied to a water bamboo field during winter season at night, and the results indicated that this lighting system can prevent the stunting of water bamboo leaves and further assist its growth. Compared with previous LED systems, in which the LED bulbs were placed directly above water bamboo leaves, our LED lighting system presents the benefit of easy handling during harvest. To prevent the inhomogeneous coverage of LED light patterns, a new design of LED lenses was also incorporated.


Weed Science ◽  
2011 ◽  
Vol 59 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Marisa Alcorta ◽  
Matthew W. Fidelibus ◽  
Kerri L. Steenwerth ◽  
Anil Shrestha

Horseweed has become increasingly common and difficult to control in San Joaquin Valley vineyards, due in part, to the evolution of glyphosate resistance. The development of weed-suppressive vineyard designs in which the trellis design, spacing, and row orientation combine to cast dense shade on the weed canopy zone (WCZ) may reduce weed growth. The relevance of such a system to horseweed, which can grow to be as tall, or taller, than a typical grapevine trellis, is uncertain. Also unknown is whether a glyphosate-resistant (GR) biotype and glyphosate-susceptible (GS) biotype would perform similarly under such conditions. Therefore, we compared the growth and development of two potted horseweed biotypes (GR and GS) in vinerows oriented east–west (EW) and north–south (NS). Rows oriented EW allowed less light penetration to the WCZ than NS rows throughout the study, and horseweed biotypes responded to low light levels by producing leaves with larger specific leaf area and leaf area ratios than those in the NS rows. Also, the leaf, stem, and root dry weight of the horseweed plants in the EW rows was reduced by 30% compared to the horseweed plants in NS rows. Leaf number was also reduced in the horseweed plants in the EW rows, but only for the GS biotype. Row orientation did not affect phenological development or the number of seeds produced by the GR or GS biotypes, but the GR biotype budded, flowered, and set seed approximately 1 wk earlier than the GS biotype. Thus, shade associated with the EW vinerows reduced horseweed growth, but not fecundity, and the GR biotype reached reproductive maturity earlier than the GS biotype.


2020 ◽  
Vol 15 (6) ◽  
pp. 734-742
Author(s):  
Hailiang Liu ◽  
Jiade Cheng ◽  
Asnidar Hanim Yusuf

Light Emitting Diode (LED) is widely used in garden landscape decoration because of its small size, low power, concentrated light, and the capability of showing more vivid colors. While designing the LED lighting system, considering that a single Advanced RISC Machine (ARM)-based control system cannot achieve large-scale LED display, and a single Field Programmable Gate Array (FPGA)-based control system cannot control the lighting system well, an LED system with the combination of ARM processor-FPGA is proposed. In this system, the ARM processor is used as the major control component. The Linux system realizes remote monitoring and intelligent management of image data. In addition, FPGA is used for LED data output. The lighting system consists of a major control node and a lighting node. The nodes are connected in parallel through a chain network. The major control node uses an ARM Cortex processor and is equipped with a Linux operating system. The lighting node uses ARM + FPGA hardware architecture. During the experiments, the LED lighting system is tested first. The results show that the reading and writing speed is fast. The LED display screen meets the lighting requirements. This LED lighting system is used for night lighting of garden landscapes. During the brightness test, the brightness of lighting objects and the background is used as research objects. Experiments have proved that the ratio of the lighting object brightness to the background brightness between (Yu, M. and Li, X., 2012. A little current k-factor method for measuring junction temperature of aviation lighting power led. Guangxue Jishu/Optical Technique, 38(3), pp.371–375; Monas, A., Verma, A., Gawari, A. and Paswan, R. S., 2016. Portable network monitor using arm processor. Procedia Computer Science, 92, pp.493–497.) is suitable for night lighting of garden landscape decoration, which will not bring discomfort to people who enjoy night scenery.


HortScience ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 268-271 ◽  
Author(s):  
Miguel Urrestarazu ◽  
Cinthia Nájera ◽  
María del Mar Gea

Light-emitting diode (LED) lamps signify one of the most important advances in artificial lighting for horticulture over the last few decades. The objective of this study was to compare the cultivation of four horticultural plants using a conventional white LED tube (T0) light against one with a good spectral fit to the maximum photosynthetic response (T1) at two intensities. The experiment was carried out with two types of young lettuce, tomato, and bell pepper plants. In a controlled environment chamber, six and four lamps per square meter were used to achieve high (H) and low (L) intensity, respectively. We measured the lighting parameters illuminance (lux) and photosynthetic photon flux (PPF) intensity (µmol·m−2·s−1). The dry and fresh weight, leaf area (LA), and specific index were measured to gauge plant growth. The photosynthetic activity and energy efficiency (EE) were recorded for each species over 60 days of cultivation. The results clearly demonstrate that, compared with conventional LED lamps, the specific horticultural LED lamps with an improved light spectrum increased the EE of the evaluated vegetables by 26%. At both the studied light intensities, plant growth was clearly more closely linked to the spectral fit of the light to the maximum photosynthetic response recorded by McCree (1972) than to PPF or illuminance (lux). We therefore suggest that a specific, detailed spectral distribution study be conducted to predict the effect of the specific quantity and quality of light used in this study on a single parameter of plant growth.


HortScience ◽  
2021 ◽  
pp. 1-7
Author(s):  
Namiko Yamori ◽  
Yoriko Matsushima ◽  
Wataru Yamori

In indoor environments such as hotels, the light intensity is generally insufficient for managing plants, and flower buds often fail to open. Lamps placed above (downward lighting) take up space. We assessed the applicability of lighting from underneath (upward lighting) for the indoor management of roses. We grew plants indoors in dim light for 2 weeks under three conditions: 1) without supplemental lighting, 2) with downward light-emitting diode (LED) lighting, and 3) with LED lighting. We quantified photosynthetic components (chlorophyll and rubisco) and the maximum quantum yield of photosystem II (Fv/Fm, an indicator of plant health) to determine the effects of each treatment on the quality and photosynthetic abilities of the leaves. We determined the ratios of dead and opened flower buds to elucidate the effects of supplemental lighting on flower bud maturation. Management without supplemental lighting decreased the number of flowers and resulted in lower-leaf senescence. Downward LED lighting promoted blooming but also resulted in lower-leaf senescence. However, upward LED lighting promoted blooming and maintained the photosynthetic abilities of the leaves, including the lower leaves. This study shows a strong case for using upward LED lighting in appropriate settings for indoor plant management and LED-based horticulture.


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