Manipulating growth, color, and taste attributes of fresh cut lettuce by greenhouse supplemental lighting

Zhang, Mengzi; Whitman, Catherine M.; Runkle, Erik S.

doi:10.1016/j.scienta.2019.03.051

Cited by 39 publications

(25 citation statements)

References 24 publications

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“…Furthermore, the requirement for proper replication of treatments inherently limits the number of LI treatment levels that can be investigated. Sometimes consecutive replication methods are used to increase the number of possible treatment levels and/or replications within the available plots (Gaudreau et al, 1994;Gent, 2014;Hoshi et al, 2011;Sublett et al, 2018;Tani et al, 2014;Zhang et al, 2019). However, because there can be considerable temporal variations in natural lighting (Hoshi et al, 2011;Lopez and Runkle, 2008;Poel and Runkle, 2017;Poorter et al, 2019), concurrent experimental designs are highly preferable for LI research trials in greenhouse environments.…”

Section: Discussionmentioning

confidence: 99%

Different Microgreen Genotypes Have Unique Growth and Yield Responses to Intensity of Supplemental PAR from Light-emitting Diodes during Winter Greenhouse Production in Southern Ontario, Canada

Jones-Baumgardt¹,

Llewellyn²,

Zheng³

2020

horts

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Low natural daily light integrals (DLIs) are a major limiting factor for greenhouse production during darker months (e.g., October to February in Canada). Supplemental lighting (SL) is commonly used to maintain crop productivity and quality during these periods, particularly when the supply chain demands consistent production levels year-round. What remains to be determined are the optimum SL light intensities (LIs) for winter production of a myriad of different commodities. The present study investigated the growth and yield of sunflower (Helianthus annuus L., ‘Black oil’), kale (Brassica napus L., ‘Red Russian’), arugula (Eruca sativa L.), and mustard (Brassica juncea L., ‘Ruby Streaks’), grown as microgreens, in a greenhouse under SL light-emitting diode (LED) photosynthetic photon flux density (PPFD) levels ranging from 17.0 to 304 μmol·m−2·s−1 with a 16-hour photoperiod (i.e., supplemental DLIs from 1.0 to 17.5 mol·m−2·d−1). Crops were sown in a commercial greenhouse near Hamilton, ON, Canada (lat. 43°14′N, long. 80°07′W) on 1 Feb. 2018, and harvested after 8, 11, 12, and 12 days, resulting in average natural DLIs of 6.5, 5.9, 6.2, and 6.2 mol·m−2·d−1 for sunflower, kale, arugula, and mustard, respectively. Corresponding total light integrals (TLIs) ranged from 60 to 188 mol·m−2 for sunflower, 76 to 258 mol·m−2 for kale, 86 to 280 mol·m−2 for arugula, and 86 to 284 mol·m−2 for mustard. Fresh weight (i.e., marketable yield) increased asymptotically with increasing LI and leaf area increased linearly with increasing LI, in all genotypes. Hypocotyl length of mustard decreased and hypocotyl diameter of sunflower, arugula, and mustard increased with increasing LI. Dry weight, robust index, and relative chlorophyll content increased and specific leaf area decreased in kale, arugula, and mustard with increasing LI. Commercial microgreen greenhouse growers can use the light response models described herein to predict relevant production metrics according to the available (natural and supplemental) light levels to select the most appropriate SL LI to achieve the desired production goals as economically as possible.

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Section: Discussionmentioning

confidence: 99%

Different Microgreen Genotypes Have Unique Growth and Yield Responses to Intensity of Supplemental PAR from Light-emitting Diodes during Winter Greenhouse Production in Southern Ontario, Canada

Jones-Baumgardt¹,

Llewellyn²,

Zheng³

2020

horts

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“…Efficiently producing high-quality products has always been a common goal of growers, especially in crop production. The lack of light caused by the geographical location, climate, or outdated facilities will seriously prolong the production time of most crops, which directly results in low yield, high cost and poor quality [11][12][13]. Lately, growers have been paying more attention to 'light fertilization' than to water and nutrition fertilization.…”

Section: Introductionmentioning

confidence: 99%

“…In previous studies, the optimal quality and intensity of supplementary lighting were determined [30][31][32][33][34]. Based on these previous studies, three durations of supplementary light (8,12,16 h/day) at 100 µmol•m −2 •s −1 PPFD using mixed LEDs (W 1 R 2 B 1 ) were tested to investigate the effects of different durations of supplementary lighting on the quality of grafted watermelon plug seedlings grown in a glasshouse after the graft healing period.…”

Section: Introductionmentioning

confidence: 99%

Effect of Supplementary Lighting Duration on Growth and Activity of Antioxidant Enzymes in Grafted Watermelon Seedlings

2020

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Insufficient exposure to light in the winter may result in a longer production periods and lower quality of seedlings in greenhouses for plug growers. Supplementary artificial lighting to plug seedlings may be one solution to this problem. The objective of this study was to assess the effects of the duration of the supplementary light on the growth and development of two watermelon cultivars, ‘Speed’ and ‘Sambok Honey’ grafted onto ‘RS-Dongjanggun’ bottle gourd rootstocks (Lagenaria siceraria Stanld). Seedlings were grown for 10 days in a glasshouse with an average daily natural light intensity of 340 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) and daily supplementary lighting of 8, 12 or 16 h from mixed LEDs (W1R2B1, chip ratio of white:red:blue = 1:2:1) at a light intensity of 100 μmol·m−2·s−1 PPFD, a group without supplementary light was set as the control (CK). The culture environment in a glasshouse had 25/15 °C day/night temperatures, an 85 ± 5% relative humidity, and a natural photoperiod of 8 h. The results showed that all the growth and development parameters of seedlings grown with supplementary light were significantly greater than those without supplementary light (CK). The 12 and 16 h supplementary light resulted in greater growth and development parameters than the 8 h supplementary light did. The same trend was also found with the indexes that reflect the quality of the seedlings, such as the dry weight ratio of the shoot and root, total biomass, dry weight to height ratio of scions, and specific leaf weight. The 12 h and 16 h light supplements resulted in greater Dickson’s quality indexes compared to the 8 h supplementary light, and the 12 h supplementary light showed the greatest use efficiency of the supplementary light. 16 h of daily supplementary light significantly increased the H2O2 content and the antioxidant enzyme activities in seedlings compared to the other treatments. This indicated that 16 h of supplementary light led to certain stresses in watermelon seedlings. In conclusion, considering the energy consumption, 12 h of supplementary light was the most efficient in improving the quality of the two cultivars of grafted watermelon plug seedlings.

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“…The leaves can become thicker and harder. The taste gets more bitter, up to a point where the taste of the produce is not acceptable anymore [20,21]. This means that even when the ESM is lower at higher light intensities, lower intensities are more favorable to produce a tasty lettuce.…”

Section: Discussionmentioning

confidence: 99%

Influence of crop cultivation conditions on space greenhouse equivalent system mass

Zabel

2020

CEAS Space J

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Future crewed space missions will make use of hybrid life support systems to sustain human presence in space and on other planetary bodies. Plants fulfill essential roles in those systems such as carbon dioxide removal, oxygen production, and food production. The systems required to grow plants in space, so-called space greenhouses, are complex and need to be built as efficient as possible. Thereby, the resources mass, volume, energy, and crewtime required to grow a certain amount of food are essential because these parameters define the effectiveness of the space greenhouse. However, the required resources depend on the size of the greenhouse which in turn depends on the productivity of the crops which in turn depend on the cultivation conditions. The output of such a system can be calculated using the Modified Energy Cascade plant production model, which can simulate the food output depending on the cultivation conditions. Traditionally, life support systems are evaluated using the Equivalent System Mass method, which can determine the cost effective life support architecture for a given mission scenario. By combining both, the influence of the cultivation conditions inside the space greenhouse on the effectiveness of the complete system can be investigated. It seems counterintuitive first, but it is more effective to increase the energy per area provided to the plants in the form of light. Although that increases the electrical energy demand per area, the reduction in required cultivation area and, therefore, system size leads to a more efficient system.

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Manipulating growth, color, and taste attributes of fresh cut lettuce by greenhouse supplemental lighting

Cited by 39 publications

References 24 publications

Different Microgreen Genotypes Have Unique Growth and Yield Responses to Intensity of Supplemental PAR from Light-emitting Diodes during Winter Greenhouse Production in Southern Ontario, Canada

Different Microgreen Genotypes Have Unique Growth and Yield Responses to Intensity of Supplemental PAR from Light-emitting Diodes during Winter Greenhouse Production in Southern Ontario, Canada

Effect of Supplementary Lighting Duration on Growth and Activity of Antioxidant Enzymes in Grafted Watermelon Seedlings

Influence of crop cultivation conditions on space greenhouse equivalent system mass

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