Abstract
To achieve clean and high-quality spinach production, the effects of daily light integral (DLI) and light spectrum on growth, nutritional quality, and energy yield of hydroponic spinach (Spinacia oleracea L.) were investigated in a closed plant factory under light-emitting diode (LED) lighting. The hydroponic spinach plants were grown under 16 combinations of four levels of DLI (11.5, 14.4, 17.3, and 20.2 mol m−2 day−1) with four light spectra: LED lamps with ratio of red light to blue light (R:B ratio) of 0.9, 1.2, and 2.2 and fluorescent lamps with R:B ratio of 1.8 as control. The results show that total fresh and dry weights, energy yield, and light energy use efficiency (LUE) of harvested spinach were higher under D17.3-L1.2 treatment compared to other treatments. The higher net photosynthetic rates were shown at DLI of 17.3 mol m−2 day−1 regardless of light quality. Higher vitamin C contents of spinach in all LED treatments were obtained compared with the control. L1.2 treatments with higher fraction of blue light led to more vitamin C content, lower nitrate content, and higher LUE independent of DLI. L2.2 treatment with more fraction of red light was beneficial to reduce oxalate accumulation. Power consumption based on increased total fresh weight under LED lamps with R:B ratio of 1.2 in different DLIs was over 38% lower than that under the fluorescent lamps and 1.73 kWh per 100 g FW at DLI of 17.3 mol m−2 day−1. In conclusion, lighting environment in DLI of 17.3 mol m−2 day−1 using LED lamps with R:B ratio of 1.2 is suggested for the design of a LED plant factory for hydroponic spinach production.
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Claims 10
Claim · model-written summary
D17.3-L1.2 produced higher spinach fresh and dry weight, energy yield and light-use efficiency than other treatments.
- Taxon
- spinach
Spinacia oleraceae0 - Treatment
- D17.3-L1.2 treatmente0
- Outcome
- total fresh and dry weights, energy yield, and light energy use efficiency (LUE)e0
- Direction
- highere0
- Comparator
- other treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total fresh and dry weights, energy yield, and light energy use efficiency (LUE) of harvested spinach were higher under D17.3-L1.2 treatment compared to other treatments”
Claim · model-written summary
Net photosynthetic rate was higher at DLI 17.3 regardless of spectrum.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- DLI of 17.3 mol m−2 day−1e0
- Outcome
- net photosynthetic ratese0
- Direction
- highere0
- Qualifier
- regardless of light qualitye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The higher net photosynthetic rates were shown at DLI of 17.3 mol m−2 day−1 regardless of light quality.”
t0“Spinach”
Claim · model-written summary
All LED treatments produced higher spinach vitamin C than fluorescent control.
- Taxon
- spinachSpinacia oleraceae0
- Treatment
- all LED treatmentse0
- Outcome
- vitamin C contentse0
- Direction
- Highere0
- Comparator
- controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Higher vitamin C contents of spinach in all LED treatments were obtained compared with the control.”
Claim · model-written summary
L1.2 increased vitamin C content independent of DLI.
- Taxon
- SpinachSpinacia oleraceat0
- Treatment
- L1.2 treatmentse0
- Outcome
- vitamin C contente0
- Direction
- moree0
- Qualifier
- independent of DLIe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“L1.2 treatments with higher fraction of blue light led to more vitamin C content, lower nitrate content, and higher LUE independent of DLI.”
t0“Spinach”
Claim · model-written summary
L1.2 reduced nitrate content independent of DLI.
- Taxon
- SpinachSpinacia oleraceat0
- Treatment
- L1.2 treatmentse0
- Outcome
- nitrate contente0
- Direction
- lowere0
- Qualifier
- independent of DLIe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“L1.2 treatments with higher fraction of blue light led to more vitamin C content, lower nitrate content, and higher LUE independent of DLI.”
t0“Spinach”
Claim · model-written summary
L1.2 raised light-use efficiency independent of DLI.
- Taxon
- SpinachSpinacia oleraceat0
- Treatment
- L1.2 treatmentse0
- Outcome
- LUEe0
- Direction
- highere0
- Qualifier
- independent of DLIe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“L1.2 treatments with higher fraction of blue light led to more vitamin C content, lower nitrate content, and higher LUE independent of DLI.”
t0“Spinach”
Claim · model-written summary
L2.2 red-rich lighting reduced oxalate accumulation.
- Taxon
- SpinachSpinacia oleraceat0
- Treatment
- L2.2 treatmente0
- Outcome
- oxalate accumulatione0
- Direction
- reducee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“L2.2 treatment with more fraction of red light was beneficial to reduce oxalate accumulation.”
t0“Spinach”
Claim · model-written summary
LED lamps at R:B 1.2 used over 38% less power per fresh-weight gain than fluorescent lamps.
- Taxon
- SpinachSpinacia oleraceat0
- Treatment
- LED lamps with R:B ratio of 1.2e0
- Outcome
- Power consumption based on increased total fresh weighte0
- Direction
- lowere0
- Value
- 38%e0
- Comparator
- fluorescent lampse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Power consumption based on increased total fresh weight under LED lamps with R:B ratio of 1.2 in different DLIs was over 38% lower than that under the fluorescent lamps”
t0“Spinach”
Claim · model-written summary
At DLI 17.3, LED R:B 1.2 consumed 1.73 kWh per 100 g fresh weight.
- Taxon
- SpinachSpinacia oleraceat0
- Treatment
- DLI of 17.3 mol m−2 day−1e0
- Outcome
- 1.73 kWh per 100 g FWe0
- Value
- 1.73 kWh per 100 g FWe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“1.73 kWh per 100 g FW at DLI of 17.3 mol m−2 day−1”
t0“Spinach”
Claim · model-written summary
The authors recommend DLI 17.3 with LED R:B 1.2 for hydroponic spinach factories.
- Taxon
- spinachSpinacia oleraceae0
- Outcome
- DLI of 17.3 mol m−2 day−1 using LED lamps with R:B ratio of 1.2 is suggested for the design of a LED plant factorye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lighting environment in DLI of 17.3 mol m−2 day−1 using LED lamps with R:B ratio of 1.2 is suggested for the design of a LED plant factory for hydroponic spinach production”
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See all 28 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.