Abstract
The action of prolonged far-red on seed germination was studied in Lactuca sativa L. var. Grand Rapids. Exposure of imbibed seeds to 6 hours far-red before the application of gibberellic acid (GA(3)) and thiourea completely prevented germination. Using GA(3), this far-red was effective after the sixth hour of imbibition. At 6, 12, and 18 hours of imbibition equal durations of far-red had equal effects. The kinetics of far-red action was investigated: it was found that although far-red for several hours, irrespective of the energy level, was needed for maximum inhibition, shorter durations (15 and 30 mins) were also appreciably effective provided they were followed by several hours darkness before the supply of GA(3). This is taken to indicate the existence of labile product(s) of the action of a far-red sensitive pigment. Evidence is provided for the existence of promotive dark processes controlled by this pigment, which are essential for germination whether triggered by GA(3), thiourea or red-light. A model for the operation of the pigment system is proposed and its role in the germination mechanism of this seed is discussed.
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Claims 6
Claim · model-written summary
Six hours of far-red before gibberellic acid and thiourea prevented germination.
- Taxon
- Lettuce
Lactuca sativat0 - Treatment
- 6 hours far-rede0
- Outcome
- germinatione0
- Direction
- preventede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exposure of imbibed seeds to 6 hours far-red before the application of gibberellic acid (GA(3)) and thiourea completely prevented germination.”
t0“Lettuce Seed”
Claim · model-written summary
Far-red was effective after the sixth hour of imbibition with GA(3).
- Taxon
- LettuceLactuca sativat0
- Outcome
- far-red was effectivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Using GA(3), this far-red was effective after the sixth hour of imbibition.”
t0“Lettuce Seed”
Claim · model-written summary
Equal far-red durations had equal effects at 6, 12 and 18 hours of imbibition.
- Taxon
- LettuceLactuca sativat0
- Outcome
- equal effectse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At 6, 12, and 18 hours of imbibition equal durations of far-red had equal effects.”
t0“Lettuce Seed”
Claim · model-written summary
Several hours of far-red were needed for maximum inhibition.
- Taxon
- LettuceLactuca sativat0
- Outcome
- maximum inhibitione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“far-red for several hours, irrespective of the energy level, was needed for maximum inhibition”
t0“Lettuce Seed”
Claim · model-written summary
Short far-red exposures were effective when followed by darkness before GA(3).
- Taxon
- LettuceLactuca sativat0
- Outcome
- appreciably effectivee0
- Value
- 15 and 30 minse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shorter durations (15 and 30 mins) were also appreciably effective provided they were followed by several hours darkness before the supply of GA(3).”
t0“Lettuce Seed”
Claim · model-written summary
Promotive dark processes controlled by a far-red sensitive pigment were inferred to be essential for germination.
- Taxon
- LettuceLactuca sativat0
- Outcome
- germinatione0
- Qualifier
- promotive dark processese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Evidence is provided for the existence of promotive dark processes controlled by this pigment, which are essential for germination whether triggered by GA(3), thiourea or red-light.”
t0“Lettuce Seed”
The same questions in other papers
light · growth · Lactuca sativa (garden lettuce)Positive and negative results
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- positive
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See all 300 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.