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Yolanta Saks, Lilian Sonego, and Ruth Ben-Arie

Mature-green `Anna' apples (Malus domestics Borkh.) reddened after harvest as a result of exposure to continuous cool-white fluorescent light. Color development was most rapid at 20C but most intense at 13C. At 2C, although the induction of red pigmentation was the slowest, a 72-hr exposure rendered color not significantly different from that of red, commercially harvested fruit. The development of color was light-intensity dependent, approaching saturation at 14.5 W·m-2 (at 13 C). No differences in fruit ripening were found between fruit that developed color under artificial light and red fruit from the commercial harvest, in spite of some stimulation of ethylene production during illumination.

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Theoharis Ouzounis, Eva Rosenqvist, and Carl-Otto Ottosen

. 2007 Effect of light wavelength on in vitro organogenesis of a Cattleya hybrid Acta Biol. Cracov. Ser. Bot. 49 113 118 Darko, E. Heydarizadeh, P. Schoefs, B. Sabzalian, M.R. 2014 Photosynthesis under artificial light: The shift in primary and secondary

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Eva María Almansa, Antonio Espín, Rosa María Chica, and María Teresa Lao

In this work, we present the study of the behavior of 15 tomato cultivars under different grow lights to evaluate the quality of seedlings in the production system. The lamps used are: compact fluorescent, high-efficiency fluorescent, fluorescent, and pure blue light-emitting diodes (B-LEDs). The trial was carried out in a culture chamber with the temperature and relative humidity continuously controlled. Spectral radiation was measured at the canopy level. The following were quantified: fresh, dry biomass partitioning organs (leaves, stems, and roots), the total dry weight/total fresh weight relationship, shoot/root ratio, and indole acetic acid. We found high-efficiency fluorescent light treatment has a very interesting spectral quality for all cultivar applications as a result of it having the lowest photosynthetically active radiation (PAR):near infrared (NIR), blue:red (B:R), blue:far red (B:FR), and red:far red (R:FR) ratios; ‘Conquista’, ‘Velasco’, and ‘Lynna’ are cultivars that show sensitivity to special wavebands (ultraviolet, B, R, and FR). ‘Ikram’, ‘Saladar’, and ‘Delizia’ tolerate the lack of minimum energy and spectral quality.

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Yoshiaki Kitaya, Genhua Niu, Toyoki Kozai, and Maki Ohashi

Lettuce (Lactuca sativa L. cv. Summer-green) plug transplants were grown for 3 weeks under 16 combinations of four levels (100, 150, 200, and 300 μmol·m-2·s-1) of photosynthetic photon flux (PPF), two photoperiods (16 and 24 h), and two levels of CO2 (400 and 800 μmol·mol-1) in growth chambers maintained at an air temperature of 20 ±2 °C. As PPF increased, dry mass (DM), percent DM, and leaf number increased, while ratio of shoot to root dry mass (S/R), ratio of leaf length to leaf width (LL/LW), specific leaf area, and hypocotyl length decreased. At the same PPF, DM was increased by 25% to 100% and 10% to 100% with extended photoperiod and elevated CO2 concentration, respectively. Dry mass, percent DM, and leaf number increased linearly with daily light integral (DLI, the product of PPF and photoperiod), while S/R, specific leaf area, LL/LW and hypocotyl length decreased as DLI increased under each CO2 concentration. Hypocotyl length was influenced by PPF and photoperiod, but not by CO2 concentration. Leaf morphology, which can be reflected by LL/LW, was substantially influenced by PPF at 100 to 200 μmol·m-2·s-1, but not at 200 to 300 μmol·m-2·s-1. At the same DLI, the longer photoperiod promoted growth under the low CO2 concentration, but not under the high CO2 concentration. Longer photoperiod and/or higher CO2 concentration compensated for a low PPF.

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Yuki Sago

Tipburn, a leaf marginal apex necrosis, is a serious problem in vegetable production under controlled environments ( Cox et al., 1976 ), such as in closed plant production systems equipped with artificial light ( Son and Takakura, 1989 ). Tipburn is

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Toshio Shibuya, Junki Komuro, Norio Hirai, Yoshiko Sakamoto, Ryosuke Endo, and Yoshiaki Kitaya

High-performance transplant production systems using artificial light have been developed as a way to produce high-quality transplants regardless of the weather ( Kozai, 2007 ; Kozai et al., 2006 ). The plants grown under the fluorescent lamps used

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Humberto Aguirre-Becerra, Juan Fernando García-Trejo, Cristina Vázquez-Hernández, Aurora Mariana Alvarado, Ana Angélica Feregrino-Pérez, Luis Miguel Contreras-Medina, and Ramón G. Guevara-Gonzalez

-saving because lamps were only activated from 4 to 12 h per day instead of all day long; this is a commonly used strategy in places where daylight provides an adequate amount of solar radiation. Results have suggested that adding hours of artificial light to the

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Dominic P. Petrella, James D. Metzger, Joshua J. Blakeslee, Edward J. Nangle, and David S. Gardner

to determine artificial light conditions capable of inducing anthocyanin synthesis in rough bluegrass to evaluate the suitability of this turfgrass as a source of anthocyanin. Using high-intensity white light, rough bluegrass was able to increase

Open access

Lie Li, Yu-xin Tong, Jun-ling Lu, Yang-mei Li, and Qi-chang Yang

artificial light is the sole light source for plant growth. In past decades, traditional artificial light sources, such as fluorescent, high-pressure sodium, and metal halide lamps, have been used in tissue culture, growth chambers, and greenhouses to

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Chase Jones-Baumgardt, David Llewellyn, Qinglu Ying, and Youbin Zheng

light signaling. Historically, the most commonly used artificial light sources for controlled environment crop production have been fluorescent tubes in SS environments ( Kozai, 2013 ) and high-intensity discharge lamps such as high-pressure sodium (HPS