scholarly journals Effects of Irradiation Time and Light Intensity for Night-break Using Compact Self-ballasted Fluorescent Lamps of Red Light on the Flowering and Spray Formation of Spray-type Chrysanthemums

2013 ◽  
Vol 12 (2) ◽  
pp. 187-194 ◽  
Author(s):  
Atsushi Sasaki ◽  
Tadahisa Yoshimura ◽  
Seiichi Suzuki ◽  
Takayoshi Moriyama ◽  
Koki Kanahama
Keyword(s):  
Light Intensity ◽  
Irradiation Time ◽  
Red Light ◽  
Spray Formation ◽  
Fluorescent Lamps

scholarly journals Effect of light intensity and irradiation time on the polymerization process of a dental composite resin

2004 ◽  
Vol 7 (2) ◽  
pp. 313-318 ◽  
Author(s):  
José Augusto César Discacciati ◽  
Alisson Discacciati Neves ◽  
Rodrigo Lambert Oréfice ◽  
Flávio Juliano Garcia Santos Pimenta ◽  
Herbert Haueisen Sander
Keyword(s):  
Light Intensity ◽  
Composite Resin ◽  
Irradiation Time ◽  
Dental Composite ◽  
Polymerization Process ◽  
Dental Composite Resin ◽  
Effect Of Light

scholarly journals The Effects of Day Length and Light Intensity on Tile Growth of Barley

1969 ◽  
Vol 22 (1) ◽  
pp. 53 ◽  
Author(s):  
D Aspinall
Keyword(s):  
Light Intensity ◽  
Linear Relationship ◽  
Light Source ◽  
Blue Light ◽  
Floral Development ◽  
Red Light ◽  
Day Length

The acceleration of flowering in barley due to the inclusion of incandescent illumination in the light source has been shown to be due to the far�red content of the light. A linear relationship between floral development and intensity of far�red light in a 16�hr photoperiod has been established with the cultivar CI5611. Barley appears to be relatively unresponsive to blue light, however.

scholarly journals Effects of Daily Light Integral and LED Spectrum on Growth and Nutritional Quality of Hydroponic Spinach

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1082 ◽  
Author(s):  
Wei Gao ◽  
Dongxian He ◽  
Fang Ji ◽  
Sen Zhang ◽  
Jianfeng Zheng
Keyword(s):  
Vitamin C ◽  
Blue Light ◽  
Nutritional Quality ◽  
Red Light ◽  
Nitrate Content ◽  
Energy Yield ◽  
Daily Light Integral ◽  
Fluorescent Lamps ◽  
Plant Factory ◽  
Light Integral

To achieve clean and high-quality spinach production, the effects of daily light integral (DLI) and light spectrum on growth, nutritional quality, and energy yield of hydroponic spinach (Spinacia oleracea L.) were investigated in a closed plant factory under light-emitting diode (LED) lighting. The hydroponic spinach plants were grown under 16 combinations of four levels of DLI (11.5, 14.4, 17.3, and 20.2 mol m−2 day−1) with four light spectra: LED lamps with ratio of red light to blue light (R:B ratio) of 0.9, 1.2, and 2.2 and fluorescent lamps with R:B ratio of 1.8 as control. The results show that total fresh and dry weights, energy yield, and light energy use efficiency (LUE) of harvested spinach were higher under D17.3-L1.2 treatment compared to other treatments. The higher net photosynthetic rates were shown at DLI of 17.3 mol m−2 day−1 regardless of light quality. Higher vitamin C contents of spinach in all LED treatments were obtained compared with the control. L1.2 treatments with higher fraction of blue light led to more vitamin C content, lower nitrate content, and higher LUE independent of DLI. L2.2 treatment with more fraction of red light was beneficial to reduce oxalate accumulation. Power consumption based on increased total fresh weight under LED lamps with R:B ratio of 1.2 in different DLIs was over 38% lower than that under the fluorescent lamps and 1.73 kWh per 100 g FW at DLI of 17.3 mol m−2 day−1. In conclusion, lighting environment in DLI of 17.3 mol m−2 day−1 using LED lamps with R:B ratio of 1.2 is suggested for the design of a LED plant factory for hydroponic spinach production.

LIGHT-STIMULATED LEAF GROWTH ON INTACT AND EXCISED BEAN PLANTS (PHASEOLUS VULGARIS L.) III. EFFECT OF LIGHT INTENSITY

1999 ◽  
Vol 47 (4) ◽  
pp. 231-236
Author(s):  
Shimon Lavee ◽  
Elizabeth Van Volkenburgh ◽  
Robert Cleland E.
Keyword(s):  
Light Intensity ◽  
Leaf Growth ◽  
Energy Requirement ◽  
Red Light ◽  
Continuous Light ◽  
Leaf Expansion ◽  
Minimal Amount ◽  
Light Intensities ◽  
Bean Plants ◽  
Effect Of Light

The effect of light intensity on primary bean leaf unfolding and elongation was studied with intact and excised 10-day-old plants grown under red light. Continuous light of 40 μmol; m−2S−1 was enough to induce maximal leaf expansion both on intact and excised bean plants. Lower light intensities had a partial effect. The growth rate during the first 24 h in light was linearly related to light intensity up to 130 μmol; m−2S−1, although this light intensity was already supra-optimal for final leaf size. The minimal amount of light energy needed for full leaf expansion was about 15 mol photons m−2. The mode of light application, level of intensity, and irradiance duration were not critical when the total energy requirement was fulfilled. Under insufficient light applications for full leaf expansion, interrupted irradiance and longer low light intensity application induced leaf elongation more efficiently. Generally, the effect of different white light intensities on primary bean leaf expansion was the same on both intact and excised red-light-grown plants.

scholarly journals Analysis of the light intensity dependence of the growth ofSynechocystisand of the light distribution in a photobioreactor energized by 635 nm light

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5256 ◽  
Author(s):  
Alessandro Cordara ◽  
Angela Re ◽  
Cristina Pagliano ◽  
Pascal Van Alphen ◽  
Raffaele Pirone ◽  
...  
Keyword(s):  
Light Intensity ◽  
Photosynthetic Activity ◽  
Genetic Manipulation ◽  
Incident Light ◽  
Red Light ◽  
Clear Correlation ◽  
Heterogeneous Distribution ◽  
Cultivation System ◽  
Modelling Studies ◽  
Set Up

Synechocystisgathered momentum in modelling studies and biotechnological applications owing to multiple factors like fast growth, ability to fix carbon dioxide into valuable products, and the relative ease of genetic manipulation.Synechocystisphysiology and metabolism, and consequently, the productivity ofSynechocystis-based photobioreactors (PBRs), are heavily light modulated. Here, we set up a turbidostat-controlled lab-scale cultivation system in order to study the influence of varying orange–red light intensities onSynechocystisgrowth characteristics and photosynthetic activity.Synechocystisgrowth and photosynthetic activity were found to raise as supplied light intensity increased up to 500 μmol photons m−2s−1and to enter the photoinhibition state only at 800 μmol photons m−2s−1. Interestingly, reverting the light to a non-photo-inhibiting intensity unveiledSynechocystisto be able to promptly recover. Furthermore, our characterization displayed a clear correlation between variations in growth rate and cell size, extending a phenomenon previously observed in other cyanobacteria. Further, we applied a modelling approach to simulate the effects produced by varying the incident light intensity on its local distribution within the PBR vessel. Our model simulations suggested that the photosynthetic activity ofSynechocystiscould be enhanced by finely regulating the intensity of the light incident on the PBR in order to prevent cells from experiencing light-induced stress and induce their exploitation of areas of different local light intensity formed in the vessel. In the latter case, the heterogeneous distribution of the local light intensity would allowSynechocystisfor an optimized usage of light.

scholarly journals The influence of nitrogen fertilizations and light intersity on mother plants productivity and the rooting of cuttings of Chrysanthemum (cultivar - Horim Golden)

2013 ◽  
Vol 45 (1-2) ◽  
pp. 61-74
Author(s):  
Lidia Kozłowska
Keyword(s):  
Light Intensity ◽  
Nitrogen Fertilization ◽  
Carbohydrate Content ◽  
Clear Correlation ◽  
Fluorescent Lamps ◽  
Low Carbohydrate ◽  
Mother Plants ◽  
Rooting Of Cuttings ◽  
Nitrogen Ratio ◽  
High Intensity Light

Mother plants of <i>Chrysanthemum</i> cv. "Horim Golden" have been cultivated at three levels of nitrogen fertilization, dosage for a 3 l pot was 100,500,1000 mg N. The plants were growing with fluorescent lamps on (5000 lx or 10000 lx). The rooting of the cuttings obtained under such conditions took place with 5000 lx. The effect of nitrogen on the productivity of mother plants depended on the light intensity. Higher nitrogen doses affected favourably the number of cuttings, the growth and number of roots per cuttings - only when higher light intensity was applied for mother plants. Light of various intensity used in the cultivation of chrysanthemum mother plants had a significantly higher effect on the dynamics of rooting that did nitrogen fertilization. High intensity light, irrespective of the nitrogen dose used, also increased the weight and number of roots per cutting. Moreover, a clear correlation has been found between the carbohydrate content in cuttings and the dynamics of rooting and the number and weight of roots formed. The process of root formation took place later and was slower in cuttings in which a higher carbohydrate content was found; however, the number and weight of roots formed by these cuttings were considerably higher. In cuttings characterised by a low carbohydrate; total nitrogen ratio a decrease in the number and weight of roots has been found.

scholarly journals Perkecambahan Biji Dictyoneura acuminata Blume. pada Cahaya Merah dan Merah Jauh

2016 ◽  
Vol 7 (1) ◽  
pp. 49
Author(s):  
Fitri Fatma Wardani ◽  
Dian Latifah
Keyword(s):  
Light Intensity ◽  
Papua New Guinea ◽  
Red Light ◽  
The Philippines ◽  
Ornamental Plant ◽  
Experimental Unit ◽  
East Kalimantan ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Greenhouse Control

<p>ABSTRACT</p><p><br />Dictyoneura acuminata Blume is one of species from Sapindaceae which is native to Borneo (Sabah, South Kalimantan, East Kalimantan), the Philippines, Sulawesi, Maluku and Papua New Guinea. Economically, D. acuminata is usually used as an ornamental plant because it has attractive leaves and flowers. D. acuminata propagation can be done by using seed but information on seeds and their germination is still limited. The aim of this study was to determine the pattern of<br />germination and the effect of red and far red light on D. acuminata germination. The experimental design was completely randomized design with one factor and 5 levels. The factors was light with red light, far red light, dark, greenhouse control, and laboratory controls as levels. Each level was repeated 4 times with 10 seeds in each experimental unit. Data showed that far red light causes the seeds germinate 10 days faster than seeds germinated in the greenhouse. D. acuminata seedling<br />height was affected by light. The seedling could grow higher when the light intensity decreased, a process called etiolation.</p><p>Keywords: Dictyoneura acuminata Blume, germination, light</p><p>ABSTRAK</p><p><br />Dictyoneura acuminata Blume adalah salah satu spesies dalam famili Sapindaceae yang merupakan tanaman asli Borneo (Sabah, Kalimantan Selatan, Kalimantan Timur), Filipina, Sulawesi, Maluku dan Papua Nugini. Secara ekonomi, D. acuminata biasanya dimanfaatkan sebagai tanaman hias karena memiliki daun dan bunga yang menarik. Perbanyakan D. acuminata dapat dilakukan dengan menggunakan biji tetapi informasi mengenai biji dan perkecambahannya masih terbatas. Tujuan penelitian ini ialah mengetahui pola perkecambahan dan pengaruh cahaya merah dan merah jauh terhadap perkecambahan biji D. acuminata. Rancangan percobaan yang digunakan adalah Rancangan Acak Lengkap (RAL) dengan satu faktor dan 5 taraf. Faktor yang digunakan yaitu cahaya dengan cahaya merah, cahaya merah jauh, gelap, kontrol rumah kaca, dan kontrol laboratorium sebagai tarafnya. Setiap taraf diulang sebanyak 4 kali dengan 10 biji pada setiap satuan percobaan. Hasil pengamatan menunjukkan bahwa cahaya merah jauh menyebabkan biji berkecambah lebih cepat 10 hari dibandingkan dengan biji yang dikecambahkan di rumah kaca. Tinggi kecambah D. acuminata dipengaruhi oleh perlakuan cahaya yaitu semakin sedikit intensitas cahaya semakin panjang tinggi kecambah, suatu proses yang disebut etiolasi.</p><p>Kata kunci: cahaya, Dicyoneura acuminata Blume, perkecambahan</p>

Spectrophotometric Isolation of Kinetically Different Pools of P-700 and Their Correlation to the Reduction of NADP by Isolated Chloroplasts *. I. The Effect of Light Quality and Intensity

1982 ◽  
Vol 37 (1-2) ◽  
pp. 31-39 ◽  
Author(s):  
Hans J. Rurainski ◽  
Richard Gerhardt ◽  
Gerhard Mader
Keyword(s):  
Light Intensity ◽  
Spectral Characteristics ◽  
Red Light ◽  
Relaxation Times ◽  
Relative Magnitude ◽  
Molar Ratio ◽  
Experimental Conditions ◽  
Turn Over ◽  
Isolated Chloroplasts ◽  
Total P

Excitation of isolated chloroplasts in the presence of ferredoxin and NADP by repeated short flashes yields a polyphasic absorption change at 700 nm. Assuming first-order reactions, the signal may be resolved into three distinct components with average relaxation times of approxi­mately 20 μs, 150 μs and 20 ms. Their relative magnitude is dependent on experimental conditions; their spectral characteristics indicate that all three components may be ascribed to P-700. Concurrent measurements of Y-NADPH, the flash yield of NADP reduction with an enzymatic recycling method, allowed Y-NADPH to be compared to the magnitude of each of the three P-700 components and to total P-700. In general, the data show a good correlation of NADP reduction with the sum of the μs-phases but not with the ms-phase or total P-700. Analysis of light intensity curves (blue or far red flashes) with a mathematical model which yields maximum values for all parameters at infinite light intensity shows that in both cases approximately two moles of the microsecond component of P-700 turn over for each mole of NADPH formed. In contrast, the molar ratio of the ms-component to the yield of NADP reduction is approx. 0.2 in blue and approx. 6.3 in far red light. The data suggest that only that portion of the P-700 pool which relaxes in the microsecond range may be involved in the reduction of NADP while the ms-component is funtionally isolated from linear electron transport.

Photodynamic Therapy for Head and Neck Cancer Xenografts in Athymic Mice

1986 ◽  
Vol 95 (5) ◽  
pp. 602-606 ◽  
Author(s):  
James H. Hill ◽  
Randall L. Plant ◽  
David M. Harris ◽  
Randal C. Paniello
Keyword(s):  
Photodynamic Therapy ◽  
Light Intensity ◽  
Head And Neck ◽  
Treatment Time ◽  
Light Exposure ◽  
Red Light ◽  
Human Head ◽  
Athymic Mice ◽  
Squamous Cancer ◽  
Argon Dye Laser

This study examines efficacy and optimal treatment variables of photodynamic therapy (PDT) for human head and neck squamous cancer (HNSC) xenografts in athymic mice. Two and four days after injection of hematoporphyrin derivative (HPD), tumors were illuminated with red light from an argon-dye laser. Sixty-three tumors were treated. With HPD dose and light intensity constant at 7.5 mg/kg and 100 mW/cm2, respectively, the extent of tumor necrosis was strongly dependent on duration of light exposure. There was no substantial difference in results for 30- and 60-minute treatment durations between animals injected with HPD 2 and 4 days before treatment. After 30 minutes treatment time, responses were seen in 8 of 10 mice (2 days post-HPD) and 11 of 12 mice (4 days post-HPD). After 60 minutes treatment time, toxicity was high. We conclude that, in this model, PDT is effective in selective killing of HNSC. For future comparison studies in this model, if the indicated HPD dose and light intensity are used we recommend a 2-day delay after HPD injection and a light exposure duration of 30 minutes

scholarly journals Comparison of Light Condition-Dependent Differences in the Accumulation and Subcellular Localization of Glutathione in Arabidopsis and Wheat

2021 ◽  
Vol 22 (2) ◽  
pp. 607
Author(s):  
Anna Gasperl ◽  
Eszter Balogh ◽  
Ákos Boldizsár ◽  
Nadine Kemeter ◽  
Richard Pirklbauer ◽  
...  
Keyword(s):  
Light Intensity ◽  
Subcellular Distribution ◽  
Redox State ◽  
Red Light ◽  
Light Condition ◽  
Glutathione Metabolism ◽  
Transcriptional Level ◽  
Leaf Extracts ◽  
Spring Variety ◽  
Arabidopsis Mutant

This study aimed to clarify whether the light condition-dependent changes in the redox state and subcellular distribution of glutathione were similar in the dicotyledonous model plant Arabidopsis (wild-type, ascorbate- and glutathione-deficient mutants) and the monocotyledonous crop species wheat (Chinese Spring variety). With increasing light intensity, the amount of its reduced (GSH) and oxidized (GSSG) form and the GSSG/GSH ratio increased in the leaf extracts of both species including all genotypes, while far-red light increased these parameters only in wheat except for GSH in the GSH-deficient Arabidopsis mutant. Based on the expression changes of the glutathione metabolism-related genes, light intensity influences the size and redox state of the glutathione pool at the transcriptional level in wheat but not in Arabidopsis. In line with the results in leaf extracts, a similar inducing effect of both light intensity and far-red light was found on the total glutathione content at the subcellular level in wheat. In contrast to the leaf extracts, the inducing influence of light intensity on glutathione level was only found in the cell compartments of the GSH-deficient Arabidopsis mutant, and far-red light increased it in both mutants. The observed general and genotype-specific, light-dependent changes in the accumulation and subcellular distribution of glutathione participate in adjusting the redox-dependent metabolism to the actual environmental conditions.

Sign in / Sign up

Export Citation Format

Share Document