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Broccoli (Brassica oleracea L. Botrytis group `Green Duke') seeds were cultured in vitro photoautotrophically (without sugar in the medium) or photomixotrophically (with sugar in the medium) for 3 weeks at 23 °C and 150 μmol·m-2·s-1 photosynthetic photon flux (PPF). Vessels were then stored at 5 °C under 1.6, 4.1, or 8.6 μmol·m-2·s-1 of white (400-800 nm), red (600-700 nm), or blue (400-500 nm) light. Concentrations of CO2 inside the vessels were monitored until equilibrium was reached. Light compensation point was reached at 3.5 μmol·m-2·s-1 for photoautotrophic seedlings and at 6.5 μmol·m-2·s-1 for photomixotrophic seedlings. Therefore, in the long-term storage experiment, seedlings were stored for 4, 8, or 12 weeks at 5 °C in darkness or under 5 μmol·m-2·s-1 (average light compensation point) of white, red, or blue light. Illumination during storage was necessary to maintain dry mass, leaf area, and regrowth potentials of in vitro seedlings. All seedlings stored in darkness were of poor quality and died when transferred to the greenhouse. Red light during storage increased seedling dry mass and chlorophyll content and improved overall appearance, whereas blue light decreased chlorophyll content and increased stem elongation. The addition of 2% sucrose to media increased dry mass and leaf area and maintained overall seedling quality during illuminated storage. However, plantlets stored for more than 4 weeks did not survive poststorage greenhouse conditions, regardless of light treatment.

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Broccoli (Brassica oleracea L. Botrytis group `Green Duke') seeds were cultured photoautotrophically (without sugar) or photomixotrophically (with sugar) in vitro for 3 weeks at 23 °C and150 μmol·m-2·s-1 photosynthetic photon flux (PPF). In vitro seedlings were stored for 0, 4, 8, or 12 weeks at 5 °C in darkness or under 5 μmol·m-2·s-1 of white (400–800 nm), blue (400–500 nm), or red (600–700 nm) light. Photosynthetic ability and soluble sugar contents were determined after removal from storage. Photomixotrophic seedlings contained approximately five times more soluble sugars than did photoautotrophic seedlings. Dark storage reduced soluble sugars in both photoautotrophic and photomixotrophic plants, but photosynthetic ability was maintained for up to 8 weeks in the latter whereas it decreased in the former. Illumination in storage increased leaf soluble sgars in both photoautotrophic and photomixotrophic seedlings. Soluble sugars in stems decreased during storage regardless of illumination, but remained higher in illuminated seedlings. Red light was more effective in increasing or maintaining leaf and stem soluble sugars than was white or blue light. Regardless of media composition or illumination, storage for more tan 8 weeks resulted in dramatic losses in quality and recovery, as well as photosynthetic ability. Seedlings stored for 12 weeks comletely lost their photosynthetic ability regardless of media composition or illumination. The results suggest that carbohydrate, supplied in the media or through illumination, is essential for maintenance of photosynthetic ability during low-temperature storage for up to 4 or 8 weeks.

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excitation energy through alternate pathways; e.g., the xanthophyll cycle. Adams and Demmig-Adams (1992) compared the changes in xanthophyll cycle activity in response to diurnal changes in light intensity between slow-growing species with low

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standard production practices to determine responses to three environmental stressors to which postproduction poinsettia plants are commonly exposed: low light levels, low temperatures, and low substrate moisture. Materials and methods Three experiments

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the responses of the seedlings grown under metal-halide lamps that provided a spectrum similar to that of natural light and under a fluorescent lamp with low R:FR light. Materials and Methods Expt. 1: Comparison of high red

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affects plant growth and development. The variation in light intensity, photoperiod, and spectra can induce numerous physiological responses that shape plant morphogenesis ( Hasan et al. 2017 ; Park and Runkle 2018 ; Son et al. 2016 ). For example

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expression increased about two to fourfold in response to higher light conditions. Table 4. The relative fold expression of flavonoid structural genes in mature Capsicum annuum ‘G02C27’ leaves under high light versus low light (16 h of 435 μmol·s −1

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acclimation responses to low light. One acclimation response to low light intensity is an increase in leaf area, such as that observed in strawberry ( Jurik et al., 1979 ). In Expt. 2, leaf area at a PPF of 125 μmol·m −2 ·s –1 was similar to or greater than

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to cultivate many vegetables (especially, sun-type plant species), including tomato, paprika, and cucumber, under such low light intensities in a PFAL because they require higher light intensities for growth. The light–response curve of the

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costs of plasticity in response to low light in Sinapis arvensis J. Evol. Biol. 16 313 323 Terashima, I. Fujita, T. Inoue, T. Chow, W.S. Oguchi, R. 2009 Green light drives leaf photosynthesis more efficiently than red light in strong white light

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