Abstract
Under natural short days, growers can use photoperiodic lighting to promote flowering of long-day plants and inhibit flowering of short-day plants. Unlike traditional lamps used for photoperiodic lighting, low-intensity light-emitting diode (LED) lamps allow for a wide array of adjustable spectral distributions relevant to regulation of flowering, including red (R) and white (W) radiation with or without far-red (FR) radiation. Our objective was to quantify how day-extension (DE) photoperiodic lighting from two commercially available low-intensity LED lamps emitting R + W or R + W + FR radiation interacted with daily light integral (DLI) to influence stem elongation and flowering of several ornamental species. Long-day plants [petunia ( Petunia × hybrida Vilm.-Andr. ‘Dreams Midnight’) and snapdragon ( Antirrhinum majus L. ‘Oh Snap Pink’)], short-day plants [african marigold ( Tagetes erecta L. ‘Moonsong Deep Orange’) and potted sunflower ( Helianthus annuus L. ‘Pacino Gold’)], and day-neutral plants [pansy ( Viola × wittrockiana Gams. ‘Matrix Yellow’) and zinnia ( Zinnia elegans Jacq. ‘Magellan Cherry’)] were grown at 20/18 °C day/night air temperatures and under low (6–9 mol·m −2 ·d −1 ) or high (16–19 mol·m −2 ·d −1 ) seasonal photosynthetic DLIs from ambient solar radiation combined with supplemental high-pressure sodium lighting and DE LED lighting. Photoperiods consisted of a truncated 9-hour day (0800–1700 hr ) with additional 1-hour (1700–1800 hr , 10 hours total), 4-hour (1700–2100 hr , 13 hours total), or 7-hour (1700–2400 hr , 16 hours total) R + W or R + W + FR LED lighting at 2 μmol·m −2 ·s −1 . Days to visible bud, plant height at first open flower, and time to first open flower (TTF) of each species were influenced by DLI, lamp type, and photoperiod though to different magnitudes. For example, plant height of african marigold and potted sunflower at first open flower was greatest under R + W + FR lamps, high DLIs, and 16-hour photoperiods. Petunia grown under R + W lamps, high DLI, and 10- and 13-hour photoperiods were the most compact. For all species, TTF was generally reduced under high DLIs. For example, regardless of the lamp type, flowering of african marigold occurred fastest under a high DLI and 10-hour photoperiod. Flowering of petunia and snapdragon occurred fastest under a high DLI, R + W + FR lamps, and a 16-hour photoperiod. However, only under high DLIs, R + W or R + W + FR lamps were equally effective at promoting flowering when used to provide DE lighting. Our data suggest that under low DLIs, flowering of long-day plants (petunia and snapdragon) occurs more rapidly under lamps providing R + W + FR, whereas under high DLIs, flowering is promoted similarly under either R + W or R + W + FR lamps.
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Claims 10
Claim · model-written summary
Days to visible bud, plant height at first open flower and time to first open flower were influenced by DLI, lamp type and photoperiod.
- Taxon
- ornamental speciese0
- Treatment
- DLI, lamp type, and photoperiode1
- Outcome
- Days to visible bud, plant height at first open flower, and time to first open flower (TTF)e1
Not reportedComparatorDirection
Verbatim
e0“to influence stem elongation and flowering of several ornamental species”
e1“Days to visible bud, plant height at first open flower, and time to first open flower (TTF) of each species were influenced by DLI, lamp type, and photoperiod though to different magnitudes”
Claim · model-written summary
Plant height of african marigold at first open flower was greatest under R + W + FR lamps, high DLIs and 16-hour photoperiods.
- Taxon
- african marigold
Tagetes erectae1 - Treatment
- R + W + FR lamps, high DLIs, and 16-hour photoperiodse1
- Outcome
- plant heighte1
- Direction
- greateste1
- Qualifier
- at first open flowere1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“plant height of african marigold and potted sunflower at first open flower was greatest under R + W + FR lamps, high DLIs, and 16-hour photoperiods”
Claim · model-written summary
Plant height of potted sunflower at first open flower was greatest under R + W + FR lamps, high DLIs and 16-hour photoperiods.
- Taxon
- potted sunflowere1
- Treatment
- R + W + FR lamps, high DLIs, and 16-hour photoperiodse1
- Outcome
- plant heighte1
- Direction
- greateste1
- Qualifier
- at first open flowere1
Not reportedComparator
Verbatim
e1“plant height of african marigold and potted sunflower at first open flower was greatest under R + W + FR lamps, high DLIs, and 16-hour photoperiods”
Claim · model-written summary
Petunia grown under R + W lamps, high DLI and 10- and 13-hour photoperiods was the most compact.
_flowers_in_Westgate_Gardens%2C_Canterbury.jpg?width=60){kind=small}
PetuniaNot reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_flowers_in_Westgate_Gardens%2C_Canterbury.jpg?width=500)
Verbatim
e1“Petunia grown under R + W lamps, high DLI, and 10- and 13-hour photoperiods were the most compact”
Claim · model-written summary
Time to first open flower of ornamental species was generally reduced under high DLIs.
Not reportedComparator
Verbatim
e0“to influence stem elongation and flowering of several ornamental species”
e1“For all species, TTF was generally reduced under high DLIs”
Claim · model-written summary
Flowering of african marigold occurred fastest under a high DLI and 10-hour photoperiod, regardless of lamp type.
- Taxon
- african marigoldTagetes erectae1
- Treatment
- high DLI and 10-hour photoperiode1
- Outcome
- floweringe1
- Direction
- fasteste1
- Qualifier
- regardless of the lamp typee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“regardless of the lamp type, flowering of african marigold occurred fastest under a high DLI and 10-hour photoperiod”
Claim · model-written summary
Flowering of petunia occurred fastest under a high DLI, R + W + FR lamps and a 16-hour photoperiod.
- Treatment
- high DLI, R + W + FR lamps, and a 16-hour photoperiode1
- Outcome
- Floweringe1
- Direction
- fasteste1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Flowering of petunia and snapdragon occurred fastest under a high DLI, R + W + FR lamps, and a 16-hour photoperiod”
Claim · model-written summary
Flowering of snapdragon occurred fastest under a high DLI, R + W + FR lamps and a 16-hour photoperiod.
- Taxon
- snapdragon
Antirrhinum majuse1 - Treatment
- high DLI, R + W + FR lamps, and a 16-hour photoperiode1
- Outcome
- Floweringe1
- Direction
- fasteste1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Flowering of petunia and snapdragon occurred fastest under a high DLI, R + W + FR lamps, and a 16-hour photoperiod”
Claim · model-written summary
Under high DLIs, R + W or R + W + FR lamps were equally effective at promoting flowering of ornamental species when used as day-extension lighting.
- Taxon
- ornamental speciese0
- Treatment
- R + W or R + W + FR lampse1
- Outcome
- promoting floweringe1
- Direction
- equally effectivee1
- Qualifier
- only under high DLIse1
Not reportedComparator
Verbatim
e0“to influence stem elongation and flowering of several ornamental species”
e1“However, only under high DLIs, R + W or R + W + FR lamps were equally effective at promoting flowering when used to provide DE lighting”
Claim · model-written summary
Under low DLIs, long-day plants flowered more rapidly under lamps providing R + W + FR radiation.
- Taxon
- long-day plantse1
- Treatment
- lamps providing R + W + FRe1
- Outcome
- floweringe1
- Direction
- more rapidlye1
- Qualifier
- under low DLIse1
Not reportedComparator
Verbatim
e1“Our data suggest that under low DLIs, flowering of long-day plants (petunia and snapdragon) occurs more rapidly under lamps providing R + W + FR”
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See all 5 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.