scholarly journals End-Of-Day LED Lightings Influence the Leaf Color, Growth and Phytochemicals in Two Cultivars of Lettuce

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1475 ◽  
Author(s):  
Yamin Li ◽  
Rui Shi ◽  
Haozhao Jiang ◽  
Linyuan Wu ◽  
Yiting Zhang ◽  
...  
Keyword(s):  
Lactuca Sativa ◽  
White Light ◽  
Growth Stage ◽  
Dark Period ◽  
Red Light ◽  
Shoot Biomass ◽  
Artificial Light ◽  
Ultraviolet A ◽  
Leaf Color ◽  
Plant Factory

Four light treatments (W: white light; EOD-B: end-of-day enhanced blue light; EOD-FR: end-of-day supplementary far-red light; EOD-UV: end-of-day supplementary ultraviolet-A light) were designed to explore the effects of end-of-day (EOD) lightings (30 min before dark period) on leaf color, biomass and phytochemicals accumulation in two lettuce cultivars (Lactuca sativa cv. ‘Red butter’ and ‘Green butter’) in artificial light plant factory. EOD-FR stimulated the plant and shoot biomass of two cultivars, and EOD-B suppressed the growth of ‘Red butter’ but induced higher biomass in ‘Green butter’. EOD lightings generated brighter, greener and yellower leaf in ‘Red butter’ at harvest, but the highest lightness and the deepest redness of ‘Green butter’ leaf were observed in the middle growth stage. ‘Red butter’ had prominent higher contents of chlorophylls and carotenoids, while these pigments showed less sensitivity to the interaction of cultivars and EOD lightings. EOD lightings impeded the accumulation of anthocyanin in two cultivars, except EOD-UV slightly increased the anthocyanin contents in ‘Green butter’. EOD-UV strengthened the antioxidant capability of ‘Green butter’, but EOD lightings had different effects on the antioxidant and nutritional compound contents in two lettuce cultivars.

scholarly journals Specific Light-Emitting Diodes Can Suppress Sporulation of Podosphaera pannosa on Greenhouse Roses

Plant Disease ◽  
2010 ◽  
Vol 94 (9) ◽  
pp. 1105-1110 ◽  
Author(s):  
A. Suthaparan ◽  
S. Torre ◽  
A. Stensvand ◽  
M. L. Herrero ◽  
R. I. Pettersen ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
White Light ◽  
Light Emitting Diodes ◽  
Dark Period ◽  
Red Light ◽  
Suppressive Effect ◽  
Continuous Illumination ◽  
Light Emitting ◽  
Dark Interval ◽  
Red Leds

When rose plants bearing colonies of Podosphaera pannosa were placed in a wind tunnel, the number of conidia trapped was directly proportional to intensity of daylight-balanced (white) light from 5 to 150 μmol m–2 s–1. Illumination of samples using blue (420 to 520 nm) light-emitting diodes (LEDs) increased the number of conidia trapped by a factor of approximately 2.7 over white light but germination of conidia under blue light was reduced by approximately 16.5% compared with conidia germination under white light. The number of conidia trapped under far-red (>685 nm) LEDs was approximately 4.7 times higher than in white light, and 13.3 times higher than under red (575 to 675 nm) LEDs, and germination was not induced compared with white light. When mildewed plants were exposed to cycles of 18 h of white light followed by 6 h of blue, red, far-red light, or darkness, light from the red LEDs reduced the number of conidia trapped by approximately 88% compared with darkness or far-red light. Interrupting the above dark period with 1 h of light from red LEDs also reduced the number of conidia trapped, while a 1-h period of light from far-red following the 1 h of light from red LEDs nullified the suppressive effect of red light. Our results indicate that brief exposure to red light during the dark interval may be as effective as continuous illumination in suppressing powdery mildew in greenhouse rose plant (Rosa × hybrida).

The effects of blue and red light on Acetabularia mediterranea after a long dark period: recovery of the endogenous rhythms of transcellular electrical potential and chloroplast velocity

1986 ◽  
Vol 64 (6) ◽  
pp. 1134-1137 ◽  
Author(s):  
Hélène Borghi ◽  
Simone Puiseux-Dao ◽  
Anne-Catherine Dazy
Keyword(s):  
Blue Light ◽  
White Light ◽  
Cytoplasmic Streaming ◽  
Dark Period ◽  
Red Light ◽  
Electrical Potential ◽  
Strong Increase ◽  
Endogenous Rhythms ◽  
Period 2 ◽  
Acetabularia Mediterranea

After a long dark period (2 – 8 weeks), the transcellular electrical potential along the cell of Acetabularia mediterranea has almost disappeared and cytoplasmic streaming is at a stop. Irradiation with continuous blue light (450 nm) induces the transcellular electrical potential to increase and oscillate. After two shorter oscillations, the rhythm becomes firmly established with a period around 23 h. This behaviour is similar to that observed in white light, where the final period is around 26 h. White light and blue light induce the appearance of endogenous diurnal oscillations in the velocity of the cytoplasmic streaming which resumes following a periodicity pattern similar to that of the transcellular electrical potential. Irradiation with continuous red light (650 nm) causes a strong increase of transcellular electrical potential and recovery of cytoplasmic streaming but seldom induces these two processes to resume with the typical oscillations. However, after irradiation with blue light, the rhythm of transcellular electrical potential persists for some time in red light but disappears progressively. When blue light is given after red light, the transcellular electrical potential rhythm resumes immediately. Blue light may be considered as a "Zeitgeber."

scholarly journals Effect of Daily Light Integral on Cucumber Plug Seedlings in Artificial Light Plant Factory

Horticulturae ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 139
Author(s):  
Jiawei Cui ◽  
Shiwei Song ◽  
Jizhu Yu ◽  
Houcheng Liu
Keyword(s):  
Dry Matter ◽  
Plant Biomass ◽  
Photochemical Efficiency ◽  
Early Spring ◽  
Production Costs ◽  
Shoot Biomass ◽  
Artificial Light ◽  
Cucumber Seedlings ◽  
Plant Factory ◽  
Speed Up

In a controlled environment, in an artificial light plant factory during early spring or midsummer, vegetable seedlings can be uniform, compact, and high quality. Appropriate light parameters can speed up the growth of seedlings and save on production costs. Two experiments were carried out in this study: (1) cucumber seedling growth under different daily light integrals (DLIs) (5.41–11.26 mol·m−2·d−1) and optimum DLI for seedling production were explored (experiment 1: Exp. 1); (2) under the same DLI selected by Exp. 1, the effects of different light intensities and photoperiods on cucumber seedlings were investigated (experiment 2: Exp. 2). The root biomass, root-to-shoot ratio, seedling index, and shoot dry matter rate increased as the DLI increased from 5.41 to 11.26 mol·m−2·d−1, while the shoot biomass and leaf area decreased in Exp. 1. The cucumber seedlings became more compact as DLI increased, but more flowers developed after transplanting when the DLI was 6.35 mol·m−2·d−1. Under the optimal DLI (6.35 mol·m−2·d−1), the optimal intensity was 110–125 μmol·m−2·s−1, and the optimal photoperiod was 14–16 h, in which plant biomass, shoot dry matter rate, seedling index, and photochemical efficiency were higher.

scholarly journals Participation of labile and stabile phytochrome in the control of chlorophyll accumulation during the deetiolation of oat seedlings

2014 ◽  
Vol 57 (1) ◽  
pp. 137-147
Author(s):  
Mariusz Cymerski ◽  
Jan Kopcewicz
Keyword(s):  
Chlorophyll A ◽  
White Light ◽  
Dark Period ◽  
Accumulation Rate ◽  
Red Light ◽  
Phytochrome A ◽  
Etiolated Seedlings ◽  
Chlorophyll Accumulation ◽  
Phytochrome System ◽  
Chlorophyll A And B

The effect of the phytochrome system on the accumulation rate of chlorophyll-a and b in 96-hour-old oat seedlings during the first 3 hours of white light action was investigated. It was established that initial irradiation with red light stimulated the accumulation rate of both forms of chlorophyll. This effect depended on the level of the P<sub>FR</sub> form of phytochrome obtained during the initial irradiation and it reached the treshold value in the case of about 20% of P<sub>FR</sub> in relation to P<sub>R</sub> in etiolated seedlings. Far red light stimulated only the accumulation of chlorophyll-a. The effect of red light was reversible if far red light was applied directly after red light. The reversibility diminished gradually together with the extension of the dark period between red and far red light, disappearing completely after 6 hours. The results suggest the participation of two pools of phytochrome - a labile and a stabile one - in the reaction stimulating chlorophyll accumulation. A model of labile phytochrome action through the destruction products of phytochrome is proposed.

scholarly journals Growth and Nutrient Element Content of Hydroponic Lettuce are Modified by LED Continuous Lighting of Different Intensities and Spectral Qualities

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1678
Author(s):  
Wenke Liu ◽  
Lingyan Zha ◽  
Yubin Zhang
Keyword(s):  
Continuous Light ◽  
Element Content ◽  
Shoot Biomass ◽  
Artificial Light ◽  
Limited Information ◽  
Nutrient Element ◽  
Plant Factory ◽  
Fe And Mn ◽  
Normal Light ◽  
Cu And Zn

LED red (R) and blue (B) continuous light (CL) is a potential efficient way to increase plant productivity of plant factory with artificial light (PFAL), but limited information was explored about their effects on plant mineral nutrition. In an environmentally controlled plant factory with artificial light (PFAL), the effects of CL of different intensities and spectral qualities, emitted by R and B LEDs on growth and nutrient element content and accumulation of lettuce (Lactuca sativa L.), were conducted in three hydroponic experiments. Two treatments, normal light (12 h/12 h) and CL (24 h/0 h) in experiment 1, three CL intensities (100, 200 and 300 μmol·m−2·s−1) in experiment 2, and three CL light qualities (1R:3B, 1R:1B and 3R:1B) in experiment 3 were designed. The results showed that CL significantly increased the fresh and dry lettuce shoot biomass compared with normal light, and shoot fresh and dry biomass increased with the intensity increment of CL. In experiment 3, shoot fresh biomass was great under high R light proportion CL treatment, while dry shoot biomass remained unchanged. Both CL and CL with increased intensities promoted shoot C content and accumulation in lettuce. CL reduced N, P, K, Ca, Mg, Cu and Zn contents in lettuce shoot, while Fe and Mn contents did not change compared to NL. Moreover, CL increased Ca, Fe and Mn accumulation. 100–200 μmol·m−2·s−1 CL facilitated N, P, Ca, Mg, Fe, Mn, Cu and Zn contents in shoot, but K content was not influenced compared with 300 μmol·m−2·s−1. The data showed that high B light ratio (75%) facilitated C content comparison with low B ratios (50% and 25%). However, lettuce grown under 3R1B treatment had the higher C accumulation. Shoot N, P, K, Ca, Mg, Fe, Mn and Zn contents were higher under 1R1B treatment, and Cu content did not affected by light quality. Moreover, accumulation of N, P, K, Ca, Mg, Fe, Mn, Zn and Cu in shoot was higher under 1R1B treatment, while P, Ca, Mg, Mn accumulation under 3R1B treatment was the lowest. In conclusion, CL tends to reduce shoot mineral element contents due to dilution effect as shoot dry weight increases compared to NL. However, long-term (12 days) CL composed of 1R1B, 100–200 μmol·m−2·s−1 tends to obtain relative higher K, Ca, Fe and Zn contents in the greater dry lettuce shoot.

An influence of water regime on the light response in germination of lettuce (Lactuca sativa var. Grand Rapids) seed

1971 ◽  
Vol 49 (8) ◽  
pp. 1359-1362 ◽  
Author(s):  
A. I-hsiung Hsiao ◽  
G. M. Simpson
Keyword(s):  
Lactuca Sativa ◽  
White Light ◽  
Water Regime ◽  
Red Light ◽  
Light Response ◽  
Lactuca Sativa L ◽  
Grand Rapids ◽  
Influence Of Water ◽  
Low Levels ◽  
Petri Plate

The germination response of Lactuca sativa L. var. Grand Rapids to different light qualities (red, blue, far-red, white) compared with darkness, is modified by the level of water in the petri plate used for germinating the seeds. Far-red light and blue light inhibit germination for 24 h in all levels of water studied whereas red inhibits in low levels and promotes in high levels. White light inhibits germination in low levels of water but not in high levels. At least part of the inhibiting effects of light on germination in low levels of water may be associated with induced lowering of water potential in the seeds.

scholarly journals Production of Potato (Solanum tuberosum L.) Seed Tuber under Artificial LED Light Irradiation in Plant Factory

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 297
Author(s):  
Md Hafizur Rahman ◽  
Md Obyedul Kalam Azad ◽  
Md Jahirul Islam ◽  
Md Soyel Rana ◽  
Kui-hua Li ◽  
...  
Keyword(s):  
White Light ◽  
Seed Tuber ◽  
Red Light ◽  
Photosynthetic Pigment ◽  
Plant Production ◽  
Photon Flux ◽  
Node Number ◽  
Potato Varieties ◽  
Led Light ◽  
Plant Factory

Plant production in a plant factory is an innovative and smart idea to grow food anytime, anywhere, regardless of the outer environment. However, potato pre-basic seed tuber (PBST) production in a plant factory is a comparatively new initiative. Therefore, the aim of this study was to optimize the artificial LED light spectrum to produce PBST in a plant factory. Two potato varieties such as Golden king (V48) and Chungang (V41) were grown in soil substrate under different combination of artificial LED light combinations (such as red+blue+far-red, red+blue+white, blue+far-red, blue+white, red+far-red, and red+white) maintaining photosynthetic photon flux density (PPFD) of 100 mol m−2s−1, temperature 23/15 °C (day/night), and relative humidity 70%. The study revealed that, overall, potato plant growth (viz.; plant height, node number, leaf number, leaf length and width, fresh and dry weight) was enhanced by the red+far red light for both potato varieties. The total seed tuber number per plant was higher in red+blue+white light for V48, and red+far-red for V41. The fresh tuber weight was the highest in the red+blue+far-red light for V48 and red+blue+white for V41. The highest accumulated photosynthetic pigment (total Chlorophyll, Chlorophyll a, b and Carotenoid) was observed in red+blue+white light for both varieties. The total carbohydrate content and total sucrose content were higher in red+blue+far red and red +far red light treatment for V48 and V41, respectively. Finally, considering all factors, it is concluded that the red+blue+white light combination is deemed to be appropriate for the potato PBST production in plant factory conditions.

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