Promotion of lettuce growth under an increasing daily light integral depends on the combination of the photosynthetic photon flux density and photoperiod

Kelly, Nathan; Choe, Daegeun; Meng, Qingxiang; Runkle, Erik S.

doi:10.1016/j.scienta.2020.109565

Cited by 91 publications

(95 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This decrease can be explained by the saturation-type photosynthesis-light response curve. This also explains why Kelly et al (2020) did not find a decrease in LUE DW as their PPFD levels were much lower (120 to 270 μmol m –2 s –1 at 16 h daylength) than in our experiment. Here the highest LUE was achieved at 200 μmol m –2 s –1 , 24°C air temperature and 28°C root temperature: 44 g FW and 1.23 g DW per mol incident light.…”

Section: Discussioncontrasting

confidence: 64%

Plant Factories Are Heating Up: Hunting for the Best Combination of Light Intensity, Air Temperature and Root-Zone Temperature in Lettuce Production

et al. 2021

View full text Add to dashboard Cite

This study analyzed interactions among photon flux density (PPFD), air temperature, root-zone temperature for growth of lettuce with non-limiting water, nutrient, and CO2 concentration. We measured growth parameters in 48 combinations of a PPFD of 200, 400, and 750 μmol m–2 s–1 (16 h daylength), with air and root-zone temperatures of 20, 24, 28, and 32°C. Lettuce (Lactuca sativa cv. Batavia Othilie) was grown for four cycles (29 days after transplanting). Eight combinations with low root-zone (20 and 24°C), high air temperature (28 and 32°C) and high PPFD (400 and 750 μmol m–2 s–1) resulted in an excessive incidence of tip-burn and were not included in further analysis. Dry mass increased with increasing photon flux to a PPFD of 750 μmol m–2 s–1. The photon conversion efficiency (both dry and fresh weight) decreased with increasing photon flux: 29, 27, and 21 g FW shoot and 1.01, 0.87, and 0.76 g DW shoot per mol incident light at 200, 400, and 750 μmol m–2 s–1, respectively, averaged over all temperature combinations, following a concurrent decrease in specific leaf area (SLA). The highest efficiency was achieved at 200 μmol m–2 s–1, 24°C air temperature and 28°C root-zone temperature: 44 g FW and 1.23 g DW per mol incident light. The effect of air temperature on fresh yield was linked to all leaf expansion processes. SLA, shoot mass allocation and water content of leaves showed the same trend for air temperature with a maximum around 24°C. The effect of root temperature was less prominent with an optimum around 28°C in nearly all conditions. With this combination of temperatures, market size (fresh weight shoot = 250 g) was achieved in 26, 20, and 18 days, at 200, 400, and 750 μmol m–2 s–1, respectively, with a corresponding shoot dry matter content of 2.6, 3.8, and 4.2%. In conclusion, three factors determine the “optimal” PPFD: capital and operational costs of light intensity vs the value of reducing cropping time, and the market value of higher dry matter contents.

show abstract

Section: Discussioncontrasting

confidence: 64%

Plant Factories Are Heating Up: Hunting for the Best Combination of Light Intensity, Air Temperature and Root-Zone Temperature in Lettuce Production

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The photosynthetic efficiency of the plants was improved because of the different light quality from the QD films, under which more biomass was produced per mol of photons than under the Control film. For vegetative growth in lightlimiting environments, when DLI is reduced, the biomass accumulation is linearly reduced for most crops [33][34][35][36][37][38] .…”

Section: Resultsmentioning

confidence: 99%

Optimizing spectral quality with quantum dots to enhance crop yield in controlled environments

et al. 2021

View full text Add to dashboard Cite

Bioregenerative life-support systems (BLSS) involving plants will be required to realize self-sustaining human settlements beyond Earth. To improve plant productivity in BLSS, the quality of the solar spectrum can be modified by lightweight, luminescent films. CuInS2/ZnS quantum dot (QD) films were used to down-convert ultraviolet/blue photons to red emissions centered at 600 and 660 nm, resulting in increased biomass accumulation in red romaine lettuce. All plant growth parameters, except for spectral quality, were uniform across three production environments. Lettuce grown under the 600 and 660 nm-emitting QD films respectively increased edible dry mass (13 and 9%), edible fresh mass (11% each), and total leaf area (8 and 13%) compared with under a control film containing no QDs. Spectral modifications by the luminescent QD films improved photosynthetic efficiency in lettuce and could enhance productivity in greenhouses on Earth, or in space where, further conversion is expected from greater availability of ultraviolet photons.

show abstract

“…Thus, in the next test, the 2-h B treatment was adjusted to deliver an equivalent DLI to the most effective 4 days treatment (∼21.3 mol m −2 d −1 , Table 4) and broadspectrum PAR LEDs were supplemented with the resulting 2h B at different times in the diel cycle. Increasing daily light integral (DLI), or the total sum of radiation in a 24-h period, allows higher radiation sums with lower PPFD, thus avoiding negative effects of saturating light levels and increasing lettuce fresh and dry mass (Kelly et al, 2020). Supplemental B at midday resulted in the highest NPQ which could be associated with midday depression of photosynthesis, stomatal closure, and reduced ability to dissipate light energy photochemically (Koyama and Takemoto, 2014).…”

Section: Discussionmentioning

confidence: 99%

“…Increasing the photon flux density (PFD) results in a linear increase in photosynthetic rate (Kelly et al, 2020) until light exceeds photosynthetic capacity and photosynthesis becomes limited by other factors such as CO 2 (Herron and Mauzerall, 1972;Robinson, 2001). Light use efficiency may also be limited by photoprotective strategies that reduce the risk of photo-oxidative damage by limiting the light interception and absorption and by enhancing dissipative routes (Adams and Demmig-Adams, 1992;Takahashi and Badger, 2011).…”

Section: Introductionmentioning

confidence: 99%

Producing Enhanced Yield and Nutritional Pigmentation in Lollo Rosso Through Manipulating the Irradiance, Duration, and Periodicity of LEDs in the Visible Region of Light

2020

View full text Add to dashboard Cite

Pigmented food are an important part of the human diet, and anthocyanins have demonstrable protection against tumor production in mouse models and beneficial effects on human liver chemistry. As such, producing pigmented crops is important for a nutritionally diverse diet. Lollo rosso lettuce is a fast-growing pigmented plant, is rich in phenolic compounds, and represents a suitable system to test optimization strategies for yield and anthocyanin production. High-energy UV wavebands are often used to stimulate increased pigmentation; however, we hypothesized that optimizing visible wavebands would deliver both yield and quality improvements. Growing Lollo rosso under irradiances between 5 and 180 W m–2 using visible waveband LEDs produced 0.4 g fresh weight per W m–2 in the linear portion of the curve between 5 and 40 W m–2 and achieved an approximate asymptote of 20 g fresh weight at around 100–120 W m–2 for yield. Anthocyanin content increased linearly with irradiance. We attempted to optimize the visible wavebands by supplementing half the asymptotic energy for 15 days with supplemental red (R) or blue (B) wavebands in the peaks of photosynthetic activity (430–460 and 630–660 nm). R and B affected rosette morphology with no significant impact on yield, but B significantly increased anthocyanin content by 94% compared to R. We therefore focused on further optimizing B by shortening the daily duration of supplemental B. The minimum B treatment that lacked significant pigment induction was 1 h. We hypothesized that short durations would be more active at different times in the diurnal cycle. Supplemental B was applied for 2 h at four different times. A night-break with B produced the highest yield and anthocyanin content. Our research demonstrates new ways to efficiently use readily available LEDs within the PAR wavebands to increase both yield and crop quality in controlled environment agriculture.

show abstract

Promotion of lettuce growth under an increasing daily light integral depends on the combination of the photosynthetic photon flux density and photoperiod

Cited by 91 publications

References 32 publications

Plant Factories Are Heating Up: Hunting for the Best Combination of Light Intensity, Air Temperature and Root-Zone Temperature in Lettuce Production

Plant Factories Are Heating Up: Hunting for the Best Combination of Light Intensity, Air Temperature and Root-Zone Temperature in Lettuce Production

Optimizing spectral quality with quantum dots to enhance crop yield in controlled environments

Producing Enhanced Yield and Nutritional Pigmentation in Lollo Rosso Through Manipulating the Irradiance, Duration, and Periodicity of LEDs in the Visible Region of Light

Contact Info

Product

Resources

About