Abstract
Anthocyanins are a group of human-health-promoting phenolic compounds that influence the pigmentation of red-leaf lettuce ( Lactuca sativa ). Ultraviolet A (UVA; 315–399 nm) and blue (B; 400–499 nm) light can increase the concentrations of phenolic compounds but also suppress cellular expansion, which can limit harvestable biomass accumulation. It is not known whether UVA or B light is more effective at increasing phenolic compound concentrations when they are each applied at the same photon flux density. Our objective was to evaluate the efficacy of UVA and B light when added during the end of production (EOP) at promoting phenolic compound synthesis and red-leaf coloration without limiting biomass accumulation. We grew red-leaf lettuce ‘Rouxai’ in a controlled indoor environment at an air temperature of 22 °C under warm-white and red light-emitting diodes (LEDs). On day 24, 30 or 60 µmol·m −2 ·s −1 from UVA, B, UVA plus B, or red plus green LEDs was added during the last 6 days of the 30-day production period. UVA and B light, alone or combined, similarly increased leaf redness (by up to 72%), total phenolic concentration (by up to 92%), total anthocyanin concentration (by up to 2.7-fold), and relative chlorophyll concentration (by up to 20%) and did not inhibit growth, compared with lettuce grown without EOP supplemental lighting. Considering B light was as effective as UVA light at increasing leaf color and phytonutrient density and that B LEDs are more electrically effective, economical, and durable, an enriched blue-light spectrum at the EOP is a comparatively sustainable method to increase crop quality without suppressing biomass accumulation.
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Claims 6
Claim · model-written summary
UVA and blue light, alone or combined, increased lettuce leaf redness by up to 72% relative to no supplemental lighting.
- Taxon
- lettuce
Lactuca sativae0 - Treatment
- UVA and B light, alone or combinede0
- Outcome
- leaf rednesse0
- Direction
- increasede0
- Value
- 72%e0
- Comparator
- lettuce grown without EOP supplemental lightinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“UVA and B light, alone or combined, similarly increased leaf redness (by up to 72%), total phenolic concentration (by up to 92%), total anthocyanin concentration (by up to 2.7-fold), and relative chlorophyll concentration (by up to 20%) and did not inhibit growth, compared with lettuce grown without EOP supplemental lighting”
Claim · model-written summary
UVA and blue light increased total phenolic concentration by up to 92%.
- Taxon
- lettuceLactuca sativae0
- Treatment
- UVA and B light, alone or combinede0
- Outcome
- total phenolic concentratione0
- Direction
- increasede0
- Value
- 92%e0
- Comparator
- lettuce grown without EOP supplemental lightinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“UVA and B light, alone or combined, similarly increased leaf redness (by up to 72%), total phenolic concentration (by up to 92%), total anthocyanin concentration (by up to 2.7-fold), and relative chlorophyll concentration (by up to 20%) and did not inhibit growth, compared with lettuce grown without EOP supplemental lighting”
Claim · model-written summary
UVA and blue light increased total anthocyanin concentration by up to 2.7-fold.
- Taxon
- lettuceLactuca sativae0
- Treatment
- UVA and B light, alone or combinede0
- Outcome
- total anthocyanin concentratione0
- Direction
- increasede0
- Value
- 2.7-folde0
- Comparator
- lettuce grown without EOP supplemental lightinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“UVA and B light, alone or combined, similarly increased leaf redness (by up to 72%), total phenolic concentration (by up to 92%), total anthocyanin concentration (by up to 2.7-fold), and relative chlorophyll concentration (by up to 20%) and did not inhibit growth, compared with lettuce grown without EOP supplemental lighting”
Claim · model-written summary
UVA and blue light increased relative chlorophyll concentration by up to 20%.
- Taxon
- lettuceLactuca sativae0
- Treatment
- UVA and B light, alone or combinede0
- Outcome
- relative chlorophyll concentratione0
- Direction
- increasede0
- Value
- 20%e0
- Comparator
- lettuce grown without EOP supplemental lightinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“UVA and B light, alone or combined, similarly increased leaf redness (by up to 72%), total phenolic concentration (by up to 92%), total anthocyanin concentration (by up to 2.7-fold), and relative chlorophyll concentration (by up to 20%) and did not inhibit growth, compared with lettuce grown without EOP supplemental lighting”
Claim · model-written summary
UVA and blue light did not inhibit lettuce growth compared with no supplemental lighting.
- Taxon
- lettuceLactuca sativae0
- Treatment
- UVA and B light, alone or combinede0
- Outcome
- growthe0
- Direction
- did not inhibite0
- Comparator
- lettuce grown without EOP supplemental lightinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“UVA and B light, alone or combined, similarly increased leaf redness (by up to 72%), total phenolic concentration (by up to 92%), total anthocyanin concentration (by up to 2.7-fold), and relative chlorophyll concentration (by up to 20%) and did not inhibit growth, compared with lettuce grown without EOP supplemental lighting”
Claim · model-written summary
The authors recommend enriched blue light at end of production as a sustainable way to improve lettuce quality without reducing biomass.
- Treatment
- enriched blue-light spectrum at the EOPe0
- Outcome
- increase crop quality without suppressing biomass accumulatione0
Not reportedTaxon
Verbatim
e0“an enriched blue-light spectrum at the EOP is a comparatively sustainable method to increase crop quality without suppressing biomass accumulation”
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