Abstract
Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP) in a greenhouse compartment in midwinter at latitude 59° north. The study included 10 different treatments and six rose cultivars, altogether 900 plants. The 16 and 20 h LP were applied with or without a dark period of 8 and 4 h·day-1, respectively, by timing the LP in relation to daylight that lasted for 7 - 8 h. Number of days until flowering decreased with an increase in PFD and in LP up to 24 day-1 and was unaffected by the timing of the 16 and 20 h·day-1 LP. Number of flowers and plant dry weight increased 20% to 30% by increasing the PFD. Plant dry weight increased by increasing the LP from 16 to 20 h·day-1 (about 25%), but no effect was found with a further increase to 24 h·day-1. Mean growth rate until flowering increased 30% to 40% by increasing the PFD or by increasing the LP from 16 to 20 h day-1, while little effect was found by a further increase to 24 h·day-1. Increasing the photosynthetic active radiation (PAR) by increasing the LP from 16 to 20 h·day-1 increased the growth rate more than increasing the PFD did. Three of the cultivars were tested for water loss after the detachment of some leaves. Leaves that had developed without a dark period showed a considerably higher water loss than the treatments that included a dark period of 4 or 8 h·day-1. The keeping quality at indoor conditions, however, was unaffected by the treatment due to sufficient watering. Powdery mildew developed significantly more on plants grown with a dark period of 8 h as compared with the other treatments. It was concluded that 20 h·day-1 LP including a dark period of 4 h·day-1 and a PFD of at least 150 μmol·m-2·s-1 should be applied to miniature roses during the winter months in order to effectively produce miniature pot roses with a high quality.
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Claims 12
Claim · model-written summary
Days to flowering of miniature roses decreased as photon flux density and lighting period increased.
RosaNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP)”
e1“Number of days until flowering decreased with an increase in PFD and in LP up to 24 day-1 and was unaffected by the timing of the 16 and 20 h·day-1 LP”
Claim · model-written summary
Days to flowering were unaffected by the timing of the 16 and 20 h/day lighting periods.
- Treatment
- timing of the 16 and 20 h·day-1 LPe1
- Outcome
- Number of days until floweringe1
- Direction
- unaffectede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP)”
e1“Number of days until flowering decreased with an increase in PFD and in LP up to 24 day-1 and was unaffected by the timing of the 16 and 20 h·day-1 LP”
Claim · model-written summary
Increasing PFD raised flower number and plant dry weight by 20% to 30%.
- Treatment
- increasing the PFDe2
- Outcome
- Number of flowers and plant dry weighte2
- Direction
- increasede2
- Value
- 20% to 30%e2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP)”
e2“Number of flowers and plant dry weight increased 20% to 30% by increasing the PFD”
Claim · model-written summary
Increasing LP from 16 to 20 h/day raised plant dry weight by about 25%.
- Treatment
- increasing the LP from 16 to 20 h·day-1e3
- Outcome
- Plant dry weighte3
- Direction
- increasede3
- Value
- about 25%e3
- Comparator
- from 16e3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP)”
e3“Plant dry weight increased by increasing the LP from 16 to 20 h·day-1 (about 25%), but no effect was found with a further increase to 24 h·day-1”
Claim · model-written summary
Increasing LP further to 24 h/day had no effect on plant dry weight.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP)”
e3“Plant dry weight increased by increasing the LP from 16 to 20 h·day-1 (about 25%), but no effect was found with a further increase to 24 h·day-1”
Claim · model-written summary
Increasing PFD or LP from 16 to 20 h/day raised mean growth rate until flowering by 30% to 40%.
- Treatment
- by increasing the PFD or by increasing the LP from 16 to 20 h day-1e4
- Outcome
- Mean growth rate until floweringe4
- Direction
- increasede4
- Value
- 30% to 40%e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP)”
e4“Mean growth rate until flowering increased 30% to 40% by increasing the PFD or by increasing the LP from 16 to 20 h day-1, while little effect was found by a further increase to 24 h·day-1”
Claim · model-written summary
Increasing LP to 24 h/day had little effect on mean growth rate until flowering.
- Treatment
- a further increase to 24 h·day-1e4
- Outcome
- Mean growth rate until floweringe4
- Direction
- no_changeinferrede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP)”
e4“Mean growth rate until flowering increased 30% to 40% by increasing the PFD or by increasing the LP from 16 to 20 h day-1, while little effect was found by a further increase to 24 h·day-1”
Claim · model-written summary
Raising PAR through a longer LP increased growth rate more than raising PFD did.
- Treatment
- by increasing the LP from 16 to 20 h·day-1e5
- Outcome
- growth ratee5
- Direction
- increasede5
- Qualifier
- more than increasing the PFD dide5
- Comparator
- increasing the PFDe5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP)”
e5“Increasing the photosynthetic active radiation (PAR) by increasing the LP from 16 to 20 h·day-1 increased the growth rate more than increasing the PFD did”
Claim · model-written summary
Leaves grown without a dark period lost considerably more water after detachment.
- Treatment
- Leaves that had developed without a dark periode6
- Outcome
- water losse6
- Direction
- highere6
- Comparator
- a dark period of 4 or 8 h·day-1e6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP)”
e6“Leaves that had developed without a dark period showed a considerably higher water loss than the treatments that included a dark period of 4 or 8 h·day-1”
Claim · model-written summary
Keeping quality of cut miniature roses was unaffected by the treatment.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP)”
e7“The keeping quality at indoor conditions, however, was unaffected by the treatment due to sufficient watering”
Claim · model-written summary
Powdery mildew developed significantly more on plants with an 8 h dark period than on other treatments.
- Treatment
- a dark period of 8 he1
- Interactor
- Powdery mildewe1pathogen
- Outcome
- developede1
- Direction
- significantly moree1
- Comparator
- the other treatmentse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP)”
e1“Powdery mildew developed significantly more on plants grown with a dark period of 8 h as compared with the other treatments”
Claim · model-written summary
Growing miniature roses under 20 h/day lighting with a 4 h dark period and at least 150 μmol·m-2·s-1 PFD is recommended for high-quality pot roses in winter.
Verbatim
e1“It was concluded that 20 h·day-1 LP including a dark period of 4 h·day-1 and a PFD of at least 150 μmol·m-2·s-1 should be applied to miniature roses during the winter months in order to effectively produce miniature pot roses with a high quality”
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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.