Abstract
The effects on growth and flowering of two short-day and two long-day plants when grown under different conditions of illumination are described. The plants fully investigated were Kalanchoe blossfeldiana and Xanthium pennsylvanicum and the annual varieties of Hyoscyamus niger and Beta vulgaris. Wintex barley, Iberis umbellata, and tomato were also grown in some selected treatments. The conditions investigated comprised continuous full daylight (24 hours), full daylight for the whole of the daily photoperiod and full daylight for half the photoperiods, the other half consisting of either daylight reduced by shading or light from incandescent lamps or fluorescent tubes (daylight-matching type), all of the same low intensity. Two lengths of photoperiod were used for each species, one nearly optimal for flowering, the other closer to the critical day-length; and the order of the low and high light treatments was varied. These factors were combined factorially. Data were collected (or derived) for the following characteristics, though not always for all the species grown: dry weights, leaf areas, heights, water contents, epidermal cell sizes, net assimilation rates, times to flowering, leaf-number increments until flowering, numbers of inflorescences, stomatal apertures, and leaf postures. Among other effects, the data revealed that in all four species investigated the adverse effects on over-all growth to be expected from reduction of the daily photoperiod or of the intensity of illumination are in fact minimized. This compensation was effected mainly by large increases in leaf areas, even though in all cases half the daily photoperiod consisted of full daylight. There are indications that increased efficiencies (net assimilation rates) may also have been involved. The leaf-area increases appear to have been due to increased cell size rather than cell number and a close positive correlation with water content was found. The most striking among the effects on flowering was the failure of sugar-beet to bolt when half of its photoperiod (totals of 20 and 14 hours) consisted of light from fluorescent lamps. The flowering of barley and Hyoscyamus was also delayed considerably under these conditions. The deficiency of red in the spectrum of the fluorescent light is believed to have been the cause. By contrast, the flowering of Iberis, a crucifer, was not affected.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 10
Claim · model-written summary
Reduced photoperiod or light intensity had minimized adverse effects on overall growth in four species.
- Taxon
- all four species investigatede0
- Treatment
- reduction of the daily photoperiod or of the intensity of illuminatione0
- Outcome
- over-all growthe0
- Direction
- minimizede0
Not reportedComparator
Verbatim
e0“in all four species investigated the adverse effects on over-all growth to be expected from reduction of the daily photoperiod or of the intensity of illumination are in fact minimized”
Claim · model-written summary
Leaf area increased substantially in the four species.
Not reportedTaxon
Verbatim
e0“This compensation was effected mainly by large increases in leaf areas”
Claim · model-written summary
Net assimilation rates may have increased.
Not reportedTaxon
Verbatim
e0“There are indications that increased efficiencies (net assimilation rates) may also have been involved”
Claim · model-written summary
Leaf-area increases appeared to result from increased cell size rather than number.
Not reportedTaxon
Verbatim
e0“The leaf-area increases appear to have been due to increased cell size rather than cell number”
Claim · model-written summary
Leaf area was positively correlated with water content.
Not reportedTaxonOrgan / stage
Verbatim
e0“a close positive correlation with water content was found”
Claim · model-written summary
Sugar-beet failed to bolt with fluorescent light for half of photoperiods of 20 and 14 hours.
- Taxon
- sugar-beet
Beta vulgaris subsp. vulgarise0 - Treatment
- light from fluorescent lampse0
- Outcome
- failure of sugar-beet to bolte0
- Qualifier
- totals of 20 and 14 hourse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“failure of sugar-beet to bolt when half of its photoperiod (totals of 20 and 14 hours) consisted of light from fluorescent lamps”
Claim · model-written summary
Flowering of barley was delayed under fluorescent light.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaree0 - Treatment
- these conditionse0
- Outcome
- flowering of barleye0
- Direction
- delayed considerablye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“The flowering of barley and Hyoscyamus was also delayed considerably under these conditions”
Claim · model-written summary
Flowering of Hyoscyamus was delayed under fluorescent light.
- Taxon
- Hyoscyamus
Hyoscyamuse0 - Treatment
- these conditionse0
- Outcome
- flowering of barley and Hyoscyamuse0
- Direction
- delayed considerablye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The flowering of barley and Hyoscyamus was also delayed considerably under these conditions”
Claim · model-written summary
The authors attributed delayed flowering to deficient red light.
Not reportedTaxon
Verbatim
e0“The deficiency of red in the spectrum of the fluorescent light is believed to have been the cause”
Claim · model-written summary
Iberis flowering was unaffected.
IberisNot reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the flowering of Iberis, a crucifer, was not affected”
The same questions in other papers
light · organism · Beta vulgaris (beet)Positive and negative results
1 in the opposite direction
- positive
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.