Abstract
This study aimed to evaluate the effect of dynamic red and blue light parameters on the physiological responses and key metabolites in lettuce and also the subsequent impact of varying light spectra on nutritive value. We explored the metabolic changes in carotenes, xanthophylls, soluble sugars, organic acids, and antioxidants; the response of photosynthetic indices [photosynthetic (Pr) and transpiration (Tr) rates]; and the intracellular to ambient CO 2 concentration ratios ( C i / C a ) in lettuce ( Lactuca sativa L. “Lobjoits Green Cos”). They were cultivated under constant (con) or parabolic (dyn) blue (B, 452 nm) and/or red (R, 662 nm) light-emitting diode (LED) photosynthetic photon flux densities (PPFDs) at 12, 16, and 20 h photoperiods, maintaining consistent daily light integrals (DLIs) for each light component in all treatments, at 2.3 and 9.2 mol m –2 per day for blue and red light, respectively. The obtained results and principal component analysis (PCA) confirmed a significant impact of the light spectrum, photoperiod, and parabolic profiles of PPFD on the physiological response of lettuce. The 16 h photoperiod resulted in significantly higher content of xanthophylls (neoxanthin, violaxanthin, lutein, and zeaxanthin) in lettuce leaves under both constant and parabolic blue light treatments (BconRdyn 16 h and BdynRdyn 16 h, respectively). Lower PPFD levels under a 20 h photoperiod (BdynRdyn 20 h) as well as higher PPFD levels under a 12 h photoperiod (BdynRdyn 12 h) had a pronounced impact on leaf gas exchange indices (Pr, Tr, C i / C a ), xanthophylls, soluble sugar contents, and antioxidant properties of lettuce leaves. The parabolic PPFD lighting profile over a 16 h photoperiod (BdynRdyn 16 h) led to a significant decrease in C i / C a , which resulted in decreased Pr and Tr, compared with constant blue or red light treatments with the same photoperiod (BconRdyn and BdynRcon 16 h). Additionally, constant blue lighting produced higher α + β-carotene and anthocyanin (ARI) content and increased carotenoid to chlorophyll ratio (CRI) but decreased biomass accumulation and antioxidant activity.
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Claims 7
Claim · model-written summary
Light spectrum, photoperiod, and parabolic PPFD profiles significantly affected lettuce physiology.
- Taxon
- lettuce
Lactuca sativae0 - Treatment
- light spectrum, photoperiod, and parabolic profiles of PPFDe0
- Outcome
- physiological response of lettucee0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The obtained results and principal component analysis (PCA) confirmed a significant impact of the light spectrum, photoperiod, and parabolic profiles of PPFD on the physiological response of lettuce.”
Claim · model-written summary
A 16 h photoperiod produced significantly higher leaf xanthophyll content under both specified blue light profiles.
- Taxon
- lettuceLactuca sativae0
- Organ / stage
- leavese0
- Treatment
- 16 h photoperiode0
- Outcome
- content of xanthophyllse0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The 16 h photoperiod resulted in significantly higher content of xanthophylls (neoxanthin, violaxanthin, lutein, and zeaxanthin) in lettuce leaves under both constant and parabolic blue light treatments (BconRdyn 16 h and BdynRdyn 16 h, respectively).”
Claim · model-written summary
The 20 h and 12 h parabolic profiles had a pronounced impact on leaf gas exchange indices, xanthophylls, sugars, and antioxidant properties.
- Taxon
- lettuceLactuca sativae0
- Treatment
- Lower PPFD levels under a 20 h photoperiode0
- Outcome
- leaf gas exchange indicese0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Lower PPFD levels under a 20 h photoperiod (BdynRdyn 20 h) as well as higher PPFD levels under a 12 h photoperiod (BdynRdyn 12 h) had a pronounced impact on leaf gas exchange indices (Pr, Tr, C i / C a ), xanthophylls, soluble sugar contents, and antioxidant properties of lettuce leaves.”
Claim · model-written summary
The 16 h parabolic profile significantly decreased intracellular to ambient CO2 ratio relative to constant blue or red treatments.
- Treatment
- BdynRdyn 16 he0
- Outcome
- C i / C ae0
- Direction
- decreasee0
- Comparator
- constant blue or red light treatmentse0
Not reportedTaxon
Verbatim
e0“The parabolic PPFD lighting profile over a 16 h photoperiod (BdynRdyn 16 h) led to a significant decrease in C i / C a , which resulted in decreased Pr and Tr, compared with constant blue or red light treatments with the same photoperiod (BconRdyn and BdynRcon 16 h).”
Claim · model-written summary
The 16 h parabolic profile decreased photosynthetic and transpiration rates relative to constant blue or red treatments.
- Treatment
- BdynRdyn 16 he0
- Outcome
- Pr and Tre0
- Direction
- decreasede0
- Comparator
- constant blue or red light treatmentse0
Not reportedTaxon
Verbatim
e0“The parabolic PPFD lighting profile over a 16 h photoperiod (BdynRdyn 16 h) led to a significant decrease in C i / C a , which resulted in decreased Pr and Tr, compared with constant blue or red light treatments with the same photoperiod (BconRdyn and BdynRcon 16 h).”
Claim · model-written summary
Constant blue lighting raised carotene and anthocyanin content and the carotenoid to chlorophyll ratio.
- Treatment
- constant blue lightinge0
- Outcome
- α + β-carotene and anthocyanin (ARI) contente0
- Direction
- highere0
Not reportedTaxonComparator
Verbatim
e0“Additionally, constant blue lighting produced higher α + β-carotene and anthocyanin (ARI) content and increased carotenoid to chlorophyll ratio (CRI) but decreased biomass accumulation and antioxidant activity.”
Claim · model-written summary
Constant blue lighting decreased biomass accumulation and antioxidant activity.
- Treatment
- constant blue lightinge0
- Outcome
- biomass accumulation and antioxidant activitye0
- Direction
- decreasede0
Not reportedTaxonComparator
Verbatim
e0“Additionally, constant blue lighting produced higher α + β-carotene and anthocyanin (ARI) content and increased carotenoid to chlorophyll ratio (CRI) but decreased biomass accumulation and antioxidant activity.”
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See all 52 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.