Abstract
The approaching legalisation and associated increasing demand for medicinal and recreational Cannabis sativa L. will lead to a growing relevance for lighting systems designed for Cannabis sativa L. The interplay between plant density, light spectrum, light distribution, yield, and secondary metabolite distribution within the plant has not yet been studied. To fill this knowledge gap, a CBD-dominant Cannabis sativa L. strain was grown in a greenhouse experiment with two plant densities (2.66 and 12 plants −1 m−2) under two different light spectra. The chosen light spectra were two LED fixtures, Solray385 (SOL) and AP67, with an R: FR ratio of 12.9 and 3.7, respectively. The results indicated that light-induced effects on individual plants can be transferred to the plant stock. A low R: FR ratio induced a 16% increase in dry flower yield in the last ten days of flowering, while a change in the light spectrum could increase the potential maximum plant density per square metre. The two spectra did not affect (CBD + CBDA) yield, as a lower flower yield compensated for a higher concentration. CBDA concentration was not significantly affected by plant density. In contrast, the higher density led to an increased total cannabidiol concentration (CBD + CBDA) and altered the distribution of terpenes. Here, the light distribution over the plant stock is particularly decisive, as a more homogenous illumination led to an increased terpene concentration of up to 41%. A Photon Conversion Efficacy (PCE) of 0.05 g mol−1 under SOL and 0.06 g mol−1 under AP67 was achieved. Plants in the centre under the highest light intensity of 1200 PAR showed up to 48% reduced efficacy. These results strongly suggest that light intensity needs to be fine-tuned to the cultivation system to prevent a reduction in efficacy, resulting in yield and quality losses.
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Claims 13
Claim · model-written summary
Light effects on individual plants were transferable to the plant stock.
- Taxon
- Cannabis sativa L.
Cannabis sativat0 - Outcome
- light-induced effects on individual plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“light-induced effects on individual plants can be transferred to the plant stock”
t0“Cannabis sativa L.”
Claim · model-written summary
A low R: FR ratio increased dry flower yield by 16% in the last ten days of flowering.
- Taxon
- Cannabis sativa L.Cannabis sativat0
- Treatment
- low R: FR ratioe0
- Outcome
- dry flower yielde0
- Direction
- increasee0
- Value
- 16%e0
- Qualifier
- last ten days of floweringe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A low R: FR ratio induced a 16% increase in dry flower yield in the last ten days of flowering”
t0“Cannabis sativa L.”
Claim · model-written summary
Changing the light spectrum could increase maximum plant density.
- Taxon
- Cannabis sativa L.Cannabis sativat0
- Treatment
- change in the light spectrume0
- Outcome
- potential maximum plant density per square metree0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a change in the light spectrum could increase the potential maximum plant density per square metre”
t0“Cannabis sativa L.”
Claim · model-written summary
The two spectra did not affect CBD plus CBDA yield.
- Taxon
- Cannabis sativa L.Cannabis sativat0
- Treatment
- two spectrae0
- Outcome
- (CBD + CBDA) yielde0
- Direction
- did not affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The two spectra did not affect (CBD + CBDA) yield, as a lower flower yield compensated for a higher concentration”
t0“Cannabis sativa L.”
Claim · model-written summary
Lower flower yield compensated for a higher concentration in CBD plus CBDA yield.
- Taxon
- Cannabis sativa L.Cannabis sativat0
- Outcome
- flower yielde0
- Qualifier
- higher concentratione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a lower flower yield compensated for a higher concentration”
t0“Cannabis sativa L.”
Claim · model-written summary
Plant density did not significantly affect CBDA concentration.
- Taxon
- Cannabis sativa L.Cannabis sativat0
- Treatment
- plant densitye0
- Outcome
- CBDA concentratione0
- Direction
- not significantly affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CBDA concentration was not significantly affected by plant density”
t0“Cannabis sativa L.”
Claim · model-written summary
Higher density increased total cannabidiol concentration.
- Taxon
- Cannabis sativa L.Cannabis sativat0
- Treatment
- higher densitye0
- Outcome
- total cannabidiol concentration (CBD + CBDA)e0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the higher density led to an increased total cannabidiol concentration (CBD + CBDA)”
t0“Cannabis sativa L.”
Claim · model-written summary
Higher density altered terpene distribution.
- Taxon
- Cannabis sativa L.Cannabis sativat0
- Treatment
- higher densitye0
- Outcome
- distribution of terpenese0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the higher density led to an increased total cannabidiol concentration (CBD + CBDA) and altered the distribution of terpenes”
t0“Cannabis sativa L.”
Claim · model-written summary
More homogeneous illumination increased terpene concentration by up to 41%.
- Taxon
- Cannabis sativa L.Cannabis sativat0
- Treatment
- more homogenous illuminatione0
- Outcome
- terpene concentratione0
- Direction
- increasede0
- Value
- up to 41%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a more homogenous illumination led to an increased terpene concentration of up to 41%”
t0“Cannabis sativa L.”
Claim · model-written summary
Photon Conversion Efficacy was 0.05 g mol−1 under SOL.
- Taxon
- Cannabis sativa L.Cannabis sativat0
- Treatment
- SOLe0
- Outcome
- Photon Conversion Efficacy (PCE)e0
- Value
- 0.05 g mol−1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A Photon Conversion Efficacy (PCE) of 0.05 g mol−1 under SOL and 0.06 g mol−1 under AP67 was achieved”
t0“Cannabis sativa L.”
Claim · model-written summary
Photon Conversion Efficacy was 0.06 g mol−1 under AP67.
- Taxon
- Cannabis sativa L.Cannabis sativat0
- Treatment
- AP67e0
- Outcome
- Photon Conversion Efficacy (PCE)e0
- Value
- 0.06 g mol−1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A Photon Conversion Efficacy (PCE) of 0.05 g mol−1 under SOL and 0.06 g mol−1 under AP67 was achieved”
t0“Cannabis sativa L.”
Claim · model-written summary
Plants in the centre at 1200 PAR had up to 48% reduced efficacy.
- Taxon
- Cannabis sativa L.Cannabis sativat0
- Outcome
- efficacye0
- Direction
- reducede0
- Value
- up to 48%e0
- Qualifier
- highest light intensity of 1200 PARe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants in the centre under the highest light intensity of 1200 PAR showed up to 48% reduced efficacy”
t0“Cannabis sativa L.”
Claim · model-written summary
The authors recommend tuning light intensity to the cultivation system to prevent efficacy losses.
- Taxon
- Cannabis sativa L.Cannabis sativat0
- Outcome
- light intensity needs to be fine-tuned to the cultivation systeme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“light intensity needs to be fine-tuned to the cultivation system to prevent a reduction in efficacy, resulting in yield and quality losses”
t0“Cannabis sativa L.”
The same questions in other papers
density · molecular: metabolites · Cannabis sativaPositive and negative results
2 papers in the same direction as this paper · 1 in the opposite direction
- positive
- no effect
- no effect
light · molecular: metabolites · Cannabis sativaPositive and negative results
9 papers in the same direction as this paper · 1 in the opposite direction
- positive
- positive
- no effect
7 papers more in this group
See all 11 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.