Abstract
Ethylene production during germination of lettuce seeds (Lactuca sativa L., cv. Premier Great Lakes) occurred at two distinctly different rates. A very low rate of ethylene release was observed prior to the 12th hour of incubation at 22°C. The rate of ethylene production, however, increased 100 fold between the 12th and 16th hour of incubation. This high rate of ethylene production only occurred in the presence of seeds which exhibited a visible protrusion of the radicle. The duration of exposure to a supraoptimal temperature (32°C) was inversely proportional to the percent germination at 32°C. Ethylene production and growth were not blocked by incubating visibly germinated seeds at 32°C. Exogenous ethylene partially restored germination at 32°C, but only in the light. Gibberellic acid partially substituted for the induced light requirement but not for ethylene. It was concluded that the supraoptimal temperature raised the threshold concentration of ethylene required for germination. This threshold requirement was satisfied in the presence of exogenous ethylene. Germination at 32°C was abo dependent upon the presence of GA. With exogenous ethylene present, the GA-mediated system was presumably reinstated or bypassed by exposing the seeds to either light or GA. The initial low rate of ethylene production apparently regulates subsequent germination but only when present at a minimum threshold concentration. Those events initiating germination have obviously occurred prior to the time of radicle emergence. Post-germination ethylene production, therefore, did not break thermodormancy, but occurred simultaneously with radicle emergence.
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Claims 15
Claim · model-written summary
Ethylene release was very low before 12 hours of incubation at 22°C.
- Taxon
- Lactuca sativa L.
Lactuca sativat0 - Outcome
- rate of ethylene releasee0
- Direction
- very lowe0
- Qualifier
- prior to the 12th hour of incubation at 22°Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A very low rate of ethylene release was observed prior to the 12th hour of incubation at 22°C.”
t0“Lactuca sativa L.”
Claim · model-written summary
Ethylene production rose 100-fold between 12 and 16 hours of incubation.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Outcome
- rate of ethylene productione0
- Direction
- increasede0
- Value
- 100 folde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The rate of ethylene production, however, increased 100 fold between the 12th and 16th hour of incubation.”
t0“Lactuca sativa L.”
Claim · model-written summary
High ethylene production occurred only in seeds with visible radicle protrusion.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Organ / stage
- visible protrusion of the radiclee0
- Outcome
- high rate of ethylene productione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This high rate of ethylene production only occurred in the presence of seeds which exhibited a visible protrusion of the radicle.”
t0“Lactuca sativa L.”
Claim · model-written summary
Longer exposure to 32°C corresponded to lower germination at 32°C.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- supraoptimal temperature (32°C)e0
- Outcome
- percent germinatione0
- Direction
- inversely proportionale0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The duration of exposure to a supraoptimal temperature (32°C) was inversely proportional to the percent germination at 32°C.”
t0“Lactuca sativa L.”
Claim · model-written summary
At 32°C, visibly germinated seeds continued ethylene production and growth.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- incubating visibly germinated seeds at 32°Ce0
- Outcome
- Ethylene production and growthe0
- Direction
- not blockede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ethylene production and growth were not blocked by incubating visibly germinated seeds at 32°C.”
t0“Lactuca sativa L.”
Claim · model-written summary
Exogenous ethylene partly restored germination at 32°C in light.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- Exogenous ethylenee0
- Outcome
- germinatione0
- Direction
- partially restorede0
- Qualifier
- only in the lighte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenous ethylene partially restored germination at 32°C, but only in the light.”
t0“Lactuca sativa L.”
Claim · model-written summary
Gibberellic acid partially substituted for the induced light requirement.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- Gibberellic acide0
- Outcome
- induced light requiremente0
- Direction
- partially substitutede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Gibberellic acid partially substituted for the induced light requirement but not for ethylene.”
t0“Lactuca sativa L.”
Claim · model-written summary
Gibberellic acid did not substitute for ethylene.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- Gibberellic acide0
- Outcome
- ethylenee0
- Direction
- not fore0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Gibberellic acid partially substituted for the induced light requirement but not for ethylene.”
t0“Lactuca sativa L.”
Claim · model-written summary
The authors infer that supraoptimal temperature raises the ethylene threshold needed for germination.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- supraoptimal temperaturee0
- Outcome
- germinatione0
- Qualifier
- threshold concentration of ethylenee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It was concluded that the supraoptimal temperature raised the threshold concentration of ethylene required for germination.”
t0“Lactuca sativa L.”
Claim · model-written summary
Exogenous ethylene satisfied the threshold requirement.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- exogenous ethylenee0
- Outcome
- threshold requiremente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This threshold requirement was satisfied in the presence of exogenous ethylene.”
t0“Lactuca sativa L.”
Claim · model-written summary
Germination at 32°C depended on GA presence.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- GAe0
- Outcome
- Germination at 32°Ce0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Germination at 32°C was abo dependent upon the presence of GA.”
t0“Lactuca sativa L.”
Claim · model-written summary
With exogenous ethylene, light or GA presumably reinstated or bypassed the GA-mediated system.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- either light or GAe0
- Outcome
- GA-mediated systeme0
- Qualifier
- exogenous ethylene presente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“With exogenous ethylene present, the GA-mediated system was presumably reinstated or bypassed by exposing the seeds to either light or GA.”
t0“Lactuca sativa L.”
Claim · model-written summary
A minimum threshold of initial low ethylene production apparently regulates later germination.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Outcome
- subsequent germinatione0
- Qualifier
- minimum threshold concentratione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The initial low rate of ethylene production apparently regulates subsequent germination but only when present at a minimum threshold concentration.”
t0“Lactuca sativa L.”
Claim · model-written summary
Initiation of germination occurred before radicle emergence.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Organ / stage
- radicle emergencee0
- Outcome
- events initiating germinatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Those events initiating germination have obviously occurred prior to the time of radicle emergence.”
t0“Lactuca sativa L.”
Claim · model-written summary
Postgermination ethylene production occurred with radicle emergence and did not break thermodormancy.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Organ / stage
- radicle emergencee0
- Outcome
- Post-germination ethylene productione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Post-germination ethylene production, therefore, did not break thermodormancy, but occurred simultaneously with radicle emergence.”
t0“Lactuca sativa L.”
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See all 14 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.