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William R. Okie and Bryan Blackburn

black or translucent plastic bag covering the front in a chamber with a 12-h diurnal cycle. Light levels were reduced ≈10% by the translucent cover and 98% by the black cover. Temperature was ≈0.5 °C cooler in the dark box. To minimize light effects

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Marc W. van Iersel and David Gianino

cycle, which can be used during the subsequent off cycle of the LED light. Our goal was to develop an automated, adaptive control system for LED grow lights that can prevent the PPF at the canopy level from dropping below a user-defined threshold. We

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D.G. Mortley, C.K. Bonsi, W.A. Hill, and C.E. Morris

`Georgia Red' peanut (Arachis hypogaea L.) was grown hydroponically at 20/16 °C, 24/20 °C, 28/24 °C, and 32/28 °C, day/night air temperatures to evaluate effects on pod and seed yield, flowering, harvest index, and oil content. Ten-day-old peanut seedlings were transplanted into rectangular nutrient film technique troughs (0.15 × 0.15 × 1.2 m) and grown for 110 days. Growth chamber conditions were as follows: photosynthetic photon flux (PPF) mean of 436 μmol·m-2·s-1, 12 h light/12 h dark cycle, and 70% ± 5% relative humidity. The nutrient solution used was a modified half-Hoagland with pH and electrical conductivity maintained between 6.5 to 6.7, and 1000 to 1300 μS·cm-1, respectively, and was replenished weekly. Vegetative growth (foliage, stem growth, total leaf area, and leaf number) was substantially greater at increasingly warmer temperatures. Reproductive growth was significantly influenced by temperature. Flowering was extremely sensitive to temperature as the process was delayed or severely restricted at 20/16 °C. The number of gynophores decreased with temperature and was virtually nonexistent at the lowest temperature. Pod yield increased with temperatures up to 28/24 °C but declined by 15% at the highest temperature (32/28 °C). Seed yield, maturity, and harvest index were highest at 28/24 °C. Oil content (percent crude fat) increased an average of 23% and was highest at the warmest temperature (32/28 °C). These results clearly suggest that vegetative and reproductive growth, as well as oil content of peanut in controlled environments, are best at warmer temperatures of 28/24 °C to 32/28 °C than at cooler temperatures of 20/16 °C to 24/20 °C.

Open access

Zunfu Lv, Simeng Zhang, and Guoquan Lu

content between the light and dark treatment. In general, the light intensity and photon-cycle had little effect on the soluble sugar content of ‘Xuzhou 22’ sweetpotato buds, and the quality of ‘Fushu 7-6’ and ‘Xushu 22’ bud vegetables was lower than that

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Ryoichi Nakajima, Shungo Otagaki, Katsuhiro Shiratake, and Shogo Matsumoto

short day and high temperature conditions (SDHT 30/25; an 8-h light at 30 °C and a 16-h dark at 25 °C, used as a negative control), short day and middle temperature conditions (SDMT 30/20; an 8-h light at 30 °C and a 16-h dark at 20 °C), flower inductive

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Yeh-Jin Ahn and Grace Qianhong Chen

mature seeds were placed on shoot induction media containing 1, 5, or 10 μ m thidiazuron (TDZ). For the first week of culture initiation, cotyledon explants were cultured under the day/night (16/8 h) cycle (light) or in the dark (dark) at constant 26 °C

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Marc W. van Iersel, Geoffrey Weaver, Michael T. Martin, Rhuanito S. Ferrarezi, Erico Mattos, and Mark Haidekker

form antheraxanthin and zeaxanthin, which leads to the dissipation of excess absorbed light energy as heat ( Demmig-Adams et al., 2012 ; Horton, 2012 ; Rochaix, 2014 ). In the dark period following the light cycle, F v /F m was ≈0.815. This high F v

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Shuyang Zhen and Marc W. van Iersel

-adapted plant Heuchera americana when supplemental light was provided at the same ambient PPF ( van Iersel and Gianino, 2017 ). In addition to adaptation, short-term acclimation to light, typically taking place within minutes to weeks (within the life cycle

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Dean A. Kopsell, Carl E. Sams, T. Casey Barickman, and Robert C. Morrow

hydroponic tray system for microgreen culture. Two tray systems were placed under each lighting treatment in controlled environment chambers (Model E15; Conviron) to germinate seeds at 24 ± 1 °C in darkness. Light treatments were initiated 24 h after seeding

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Samuel Contreras, Mark A. Bennett, James D. Metzger, and David Tay

flowering, plants were transferred into growth chambers representing one of two treatments: a) short day (SD), consisting of 8 h fluorescent light plus 16 h of darkness daily, or b) long day (LD), consisting of 4 h incandescent light, 8 h fluorescent light