Abstract
Abstract A water relations (hydrotime) model was employed to characterize the responses of lettuce ( Lactuca sativa L.) seed germination to temperature, water potential (ψ), endosperm disruption, and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC). The base water potentials (ψ b ), standard deviations of base water potential and hydrotime constants (θ H ) estimated by the model were used to predict the germination rates at reduced ψ and supraoptimal temperatures in the presence or absence of ACC. The distribution of ψ b values among seeds in the population (ψ b ( g )) increased (became more positive) as the imbibition temperature increased, indicating a greater sensitivity of seeds to reduced ψ at thermoinhibitory temperatures. Slitting the seeds at the cotyledonary end to disrupt the integrity of the endosperm extended the high temperature range for germination and maintained lower ψ b ( g ) distributions compared with intact seeds as temperature increased. ACC (10 m m ) in the imbibition solution raised the upper temperature limit for germination by about 2°C, and also lowered ψ b ( g ) values by 0.1 to 0.2 MPa. The effect of ACC on ψ b ( g ) was more pronounced at higher imbibition temperatures and in slit seeds. ACC (via conversion to ethylene) extends the high temperature limit for lettuce seed germination by acting in the embryo to maintain a lower ψ threshold for the initiation of growth as temperature increases. Evidence from other species as well suggests that this may be a general mechanism for the action of ethylene in promoting seed germination.
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Claims 7
Claim · model-written summary
The distribution of base water potential values among lettuce seeds increased as imbibition temperature increased.
- Taxon
- lettuce
Lactuca sativae0 - Treatment
- imbibition temperaturee1
- Outcome
- distribution of ψ b values among seeds in the populatione1
- Direction
- increasede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“characterize the responses of lettuce ( Lactuca sativa L.) seed germination to temperature”
e1“The distribution of ψ b values among seeds in the population (ψ b ( g )) increased (became more positive) as the imbibition temperature increased”
Claim · model-written summary
Slitting the seeds at the cotyledonary end extended the high temperature range for lettuce seed germination compared with intact seeds.
- Taxon
- lettuceLactuca sativae0
- Treatment
- Slitting the seeds at the cotyledonary ende2
- Outcome
- high temperature range for germinatione2
- Direction
- extendede2
- Comparator
- intact seedse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“characterize the responses of lettuce ( Lactuca sativa L.) seed germination to temperature”
e2“Slitting the seeds at the cotyledonary end to disrupt the integrity of the endosperm extended the high temperature range for germination and maintained lower ψ b ( g ) distributions compared with intact seeds as temperature increased”
Claim · model-written summary
Slitting the seeds maintained lower base water potential distributions than intact seeds as temperature increased.
- Taxon
- lettuceLactuca sativae0
- Treatment
- Slitting the seeds at the cotyledonary ende2
- Outcome
- ψ b ( g ) distributionse2
- Direction
- lowere2
- Comparator
- intact seedse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“characterize the responses of lettuce ( Lactuca sativa L.) seed germination to temperature”
e2“Slitting the seeds at the cotyledonary end to disrupt the integrity of the endosperm extended the high temperature range for germination and maintained lower ψ b ( g ) distributions compared with intact seeds as temperature increased”
Claim · model-written summary
ACC in the imbibition solution raised the upper temperature limit for lettuce seed germination by about 2°C.
- Taxon
- lettuceLactuca sativae0
- Treatment
- ACC (10 m m ) in the imbibition solutione3
- Outcome
- upper temperature limit for germinatione3
- Direction
- raisede3
- Value
- by about 2°Ce3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“characterize the responses of lettuce ( Lactuca sativa L.) seed germination to temperature”
e3“ACC (10 m m ) in the imbibition solution raised the upper temperature limit for germination by about 2°C, and also lowered ψ b ( g ) values by 0.1 to 0.2 MPa”
Claim · model-written summary
ACC in the imbibition solution lowered base water potential values of lettuce seeds by 0.1 to 0.2 MPa.
- Taxon
- lettuceLactuca sativae0
- Treatment
- ACC (10 m m ) in the imbibition solutione3
- Outcome
- ψ b ( g ) valuese3
- Direction
- lowerede3
- Value
- by 0.1 to 0.2 MPae3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“characterize the responses of lettuce ( Lactuca sativa L.) seed germination to temperature”
e3“ACC (10 m m ) in the imbibition solution raised the upper temperature limit for germination by about 2°C, and also lowered ψ b ( g ) values by 0.1 to 0.2 MPa”
Claim · model-written summary
The effect of ACC on base water potential was more pronounced at higher imbibition temperatures and in slit seeds.
- Taxon
- lettuceLactuca sativae0
- Treatment
- ACCe4
- Outcome
- effect of ACC on ψ b ( g )e4
- Direction
- more pronouncede4
- Qualifier
- at higher imbibition temperatures and in slit seedse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“characterize the responses of lettuce ( Lactuca sativa L.) seed germination to temperature”
e4“The effect of ACC on ψ b ( g ) was more pronounced at higher imbibition temperatures and in slit seeds”
Claim · model-written summary
ACC, via conversion to ethylene, is proposed to extend the high temperature limit of lettuce seed germination by acting in the embryo to maintain a lower water potential threshold for growth.
- Taxon
- lettuceLactuca sativae5
- Organ / stage
- embryoe5
- Compound
- ethylenee5
- Outcome
- high temperature limit for lettuce seed germinatione5
- Qualifier
- maintain a lower ψ threshold for the initiation of growthe5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“characterize the responses of lettuce ( Lactuca sativa L.) seed germination to temperature”
e5“ACC (via conversion to ethylene) extends the high temperature limit for lettuce seed germination by acting in the embryo to maintain a lower ψ threshold for the initiation of growth as temperature increases”
The same questions in other papers
1-aminocyclopropanecarboxylic acid · growth · Lactuca sativa (garden lettuce)Results differ
6 papers in the same direction as this paper · 3 in the opposite direction
- positive
- positive
- positive
6 papers more in this group
See all 10 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.