Abstract
Abstract Little is known about the relative impact of lighting duration and light intensity on lettuce production, as well as whether daily light integrals (DLIs) play a significant role during different plant growth stages. Four DLIs were tested: 8.64, 11.52, 12.96, and 17.28 mol m −2 day −1 as supplemental lighting, which were obtained from a combination of supplemental light intensities at 200 and 300 µmol m −2 day −1 for 12 and 16 h. Sunlight was used as control. A direct correlation was observed between DLIs and yield, total fresh weight, and total dry weight. Under supplemental lighting, relative growth rate (RGR) increased due to an increase in net assimilation rate (NAR) rather than in leaf area ratio (LAR). Plants in the seedling stage were more sensitive to an elevation in DLI than in the head stage. This was confirmed by a greater increase in NAR compared to their corresponding control under the same DLI. Increasing DLI also improved lettuce quality via reducing nitrate and increasing protein content. Higher DLIs (12.96 and 17.28 mol m −2 day −1 ) led to a decrease in maximum quantum yield of photosystem II and an increase in performance index. In conclusion, manipulating RGR through NAR adjustments proved to be more effective than changes in LAR, and adjusting supplemental DLI at each stage was necessary to achieve a larger NAR and, consequently, a larger RGR.
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Claims 9
Claim · model-written summary
DLI correlated directly with yield, total fresh weight and total dry weight.
- Taxon
- lettuce
Lactuca sativat0 - Treatment
- DLIse0
- Outcome
- yield, total fresh weight, and total dry weighte0
- Direction
- direct correlatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A direct correlation was observed between DLIs and yield, total fresh weight, and total dry weight”
t0“lettuce”
Claim · model-written summary
Supplemental light raised relative growth rate through net assimilation rate rather than leaf area ratio.
- Taxon
- lettuceLactuca sativat0
- Treatment
- supplemental lightinge0
- Outcome
- relative growth rate (RGR)e0
- Direction
- increasede0
- Qualifier
- increase in net assimilation rate (NAR) rather than in leaf area ratio (LAR)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under supplemental lighting, relative growth rate (RGR) increased due to an increase in net assimilation rate (NAR) rather than in leaf area ratio (LAR)”
t0“lettuce”
Claim · model-written summary
Seedlings were more sensitive to raised DLI than plants at the head stage.
- Taxon
- lettuceLactuca sativat0
- Organ / stage
- seedling stagee0
- Outcome
- more sensitive to an elevation in DLIe0
- Direction
- more sensitivee0
- Comparator
- head stagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants in the seedling stage were more sensitive to an elevation in DLI than in the head stage”
t0“lettuce”
Claim · model-written summary
Seedlings had a larger NAR increase against their controls at equal DLI.
- Taxon
- lettuceLactuca sativat0
- Treatment
- same DLIe0
- Outcome
- NARe0
- Direction
- greater increasee0
- Comparator
- corresponding controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“greater increase in NAR compared to their corresponding control under the same DLI”
t0“lettuce”
Claim · model-written summary
Increasing DLI reduced nitrate.
- Taxon
- lettuceLactuca sativae0
- Treatment
- Increasing DLIe0
- Outcome
- nitratee0
- Direction
- reducinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing DLI also improved lettuce quality via reducing nitrate and increasing protein content”
Claim · model-written summary
Increasing DLI raised protein content.
- Taxon
- lettuceLactuca sativae0
- Treatment
- Increasing DLIe0
- Outcome
- protein contente0
- Direction
- increasinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing DLI also improved lettuce quality via reducing nitrate and increasing protein content”
Claim · model-written summary
Higher DLIs reduced maximum quantum yield of photosystem II.
- Taxon
- lettuceLactuca sativat0
- Treatment
- Higher DLIs (12.96 and 17.28 mol m −2 day −1 )e0
- Outcome
- maximum quantum yield of photosystem IIe0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Higher DLIs (12.96 and 17.28 mol m −2 day −1 ) led to a decrease in maximum quantum yield of photosystem II and an increase in performance index”
t0“lettuce”
Claim · model-written summary
Higher DLIs increased performance index.
- Taxon
- lettuceLactuca sativat0
- Treatment
- Higher DLIs (12.96 and 17.28 mol m −2 day −1 )e0
- Outcome
- performance indexe0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Higher DLIs (12.96 and 17.28 mol m −2 day −1 ) led to a decrease in maximum quantum yield of photosystem II and an increase in performance index”
t0“lettuce”
Claim · model-written summary
The authors recommend adjusting supplemental DLI at each stage to increase NAR and RGR.
- Taxon
- lettuceLactuca sativat0
- Outcome
- adjusting supplemental DLI at each stagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“adjusting supplemental DLI at each stage was necessary to achieve a larger NAR and, consequently, a larger RGR”
t0“lettuce”
The same questions in other papers
light · physiology: photosynthesis · Lactuca sativa (garden lettuce)Positive and negative results
18 papers in the same direction as this paper · 56 in the opposite direction
- positive
- positive
- positive
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See all 75 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.