Abstract
1. Seeds obtained from selfing Hemerocallis minor and from intercrossing hybrid Hemerocallis plants of complex origin were used in a series of experiments in 1953, 1954, and 1955 to determine the nature of seed dormancy in this genus. 2. Freshly harvested seeds germinate to a limited extent but only within a narrow temperature range. Minimum, optimum, and maximum temperatures for non-stratified seeds were found to be above 16⚬, 22⚬-25⚬, and below 33⚬ C., respectively. 3. Differential peeling experiments demonstrated that an endosperm membrane one cell thick, which covers the protruding tip of the hypocotyl, was responsible for delayed germination at 22⚬ C., while at 16⚬ C., in addition to the membrane, endosperm storage tissue restricts gaseous diffusion. Complete germination was brought about at 16⚬ C. either by removing a wedge of storage tissue to expose about one-fourth of the embryo axis or by completely excising the embryo, as compared with little or no germination of intact seeds. Sealing of the hypocotyl tip with petroleum jelly or lanolin, following removal of the diminutive endosperm membrane, greatly retarded germination. 4. Results from seeds planted in soil in greenhouse flats and stratified outdoors during the winter for various periods indicated that 1 or 2 months of stratification sufficed for the breaking of dormancy. Stratified seeds germinated over a greater temperature range than did non-treated seeds. 5. Controlled stratification experiments carried out in Petri dishes indicated that 0⚬-10⚬ C. was the general range for after-ripening, with the optimum being near the lower temperatures. Inconsistent results were obtained with stratification temperatures below freezing. As little as a day of stratification at the optimum temperature was sufficient to increase slightly the percentage of germination at 16⚬ C. incubation over that of the controls. Longer periods of stratification were necessary at the higher temperatures of the effective range to bring about corresponding increases of germination. After-ripened seeds germinate over a greater temperature range than do non-stratified seeds. Thus, conditioned seeds germinate readily at 10⚬ C. and even lower. After-ripened seeds likewise are able to germinate at a slightly higher temperature than do non-conditioned seeds, providing the inhibitory effect of the enveloping structures has been removed. 6. After-ripening occurred only at low temperatures and only when the seeds were moist. The optimum degree of moisture saturation seems to be a function of the stratification temperature. Thus, with stratification at 3.5⚬ C., seeds reacted similarly over a wide range of moisture content, but, when stratified at -4⚬ C., the degree of saturation appeared to determine the efficiency of stratification more critically. 7. Oxygen must be available to the seeds if effective after-ripening is to occur during stratification. 8. The after-ripening effect persists for as long as 1 month after stratification if the seeds are maintained in an air-dry condition. 9. Presence of an inhibitor substance could not be demonstrated in non-stratified seeds, nor could any evidence be found of a stimulatory substance in after-ripened seeds. 10. Possible interpretations of the results obtained are discussed in the light of other investigations in the field of seed dormancy.
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Claims 19
Claim · model-written summary
Fresh seeds germinated only to a limited extent over a narrow temperature range.
- Taxon
- Hemerocallis
_v2.jpg?width=60)
Hemerocallist0 - Organ / stage
- Freshly harvested seedse0
- Outcome
- germinatee0
- Qualifier
- narrow temperature rangee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_v2.jpg?width=500)
Verbatim
e0“Freshly harvested seeds germinate to a limited extent but only within a narrow temperature range”
t0“Hemerocallis”
Claim · model-written summary
Non-stratified seed minimum, optimum and maximum temperatures were above 16, 22-25 and below 33 C.
- Taxon
- HemerocallisHemerocallist0
- Outcome
- Minimum, optimum, and maximum temperaturese0
- Value
- above 16⚬, 22⚬-25⚬, and below 33⚬ C.e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Minimum, optimum, and maximum temperatures for non-stratified seeds were found to be above 16⚬, 22⚬-25⚬, and below 33⚬ C., respectively”
t0“Hemerocallis”
Claim · model-written summary
An endosperm membrane delayed germination at 22 C.
- Taxon
- HemerocallisHemerocallist0
- Organ / stage
- endosperm membranee0
- Outcome
- delayed germinatione0
- Qualifier
- at 22⚬ C.e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an endosperm membrane one cell thick, which covers the protruding tip of the hypocotyl, was responsible for delayed germination at 22⚬ C.”
t0“Hemerocallis”
Claim · model-written summary
Endosperm storage tissue restricted gaseous diffusion at 16 C.
- Taxon
- HemerocallisHemerocallist0
- Organ / stage
- endosperm storage tissuee0
- Outcome
- gaseous diffusione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“at 16⚬ C., in addition to the membrane, endosperm storage tissue restricts gaseous diffusion”
t0“Hemerocallis”
Claim · model-written summary
Removing storage tissue enabled complete germination at 16 C.
- Taxon
- HemerocallisHemerocallist0
- Treatment
- removing a wedge of storage tissuee0
- Outcome
- germinatione0
- Direction
- Completee0
- Comparator
- intact seedse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Complete germination was brought about at 16⚬ C. either by removing a wedge of storage tissue to expose about one-fourth of the embryo axis or by completely excising the embryo, as compared with little or no germination of intact seeds”
t0“Hemerocallis”
Claim · model-written summary
Excising the embryo enabled complete germination at 16 C.
- Taxon
- HemerocallisHemerocallist0
- Treatment
- completely excising the embryoe0
- Outcome
- germinatione0
- Direction
- Completee0
- Comparator
- intact seedse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Complete germination was brought about at 16⚬ C. either by removing a wedge of storage tissue to expose about one-fourth of the embryo axis or by completely excising the embryo, as compared with little or no germination of intact seeds”
t0“Hemerocallis”
Claim · model-written summary
Sealing the hypocotyl tip after membrane removal greatly retarded germination.
- Taxon
- HemerocallisHemerocallist0
- Treatment
- petroleum jelly or lanoline0
- Outcome
- germinatione0
- Direction
- greatly retardede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sealing of the hypocotyl tip with petroleum jelly or lanolin, following removal of the diminutive endosperm membrane, greatly retarded germination”
t0“Hemerocallis”
Claim · model-written summary
One or two months of outdoor stratification broke dormancy.
- Taxon
- HemerocallisHemerocallist0
- Treatment
- 1 or 2 months of stratificatione0
- Outcome
- dormancye0
- Direction
- breakinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“1 or 2 months of stratification sufficed for the breaking of dormancy”
t0“Hemerocallis”
Claim · model-written summary
Stratification broadened the germination temperature range.
- Taxon
- HemerocallisHemerocallist0
- Treatment
- Stratifiede0
- Outcome
- temperature rangee0
- Direction
- greatere0
- Comparator
- non-treated seedse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stratified seeds germinated over a greater temperature range than did non-treated seeds”
t0“Hemerocallis”
Claim · model-written summary
After-ripening generally occurred from 0 to 10 C, with lower temperatures optimal.
- Taxon
- HemerocallisHemerocallist0
- Outcome
- after-ripeninge0
- Value
- 0⚬-10⚬ C.e0
- Qualifier
- optimum being near the lower temperaturese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“0⚬-10⚬ C. was the general range for after-ripening, with the optimum being near the lower temperatures”
t0“Hemerocallis”
Claim · model-written summary
One day of optimal stratification slightly increased germination at 16 C over controls.
- Taxon
- HemerocallisHemerocallist0
- Treatment
- a day of stratification at the optimum temperaturee0
- Outcome
- percentage of germinatione0
- Direction
- increase slightlye0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“As little as a day of stratification at the optimum temperature was sufficient to increase slightly the percentage of germination at 16⚬ C. incubation over that of the controls”
t0“Hemerocallis”
Claim · model-written summary
Higher effective stratification temperatures required longer durations to increase germination.
- Taxon
- HemerocallisHemerocallist0
- Outcome
- germinatione0
- Direction
- increasese0
- Qualifier
- higher temperatures of the effective rangee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Longer periods of stratification were necessary at the higher temperatures of the effective range to bring about corresponding increases of germination”
t0“Hemerocallis”
Claim · model-written summary
Conditioned seeds could germinate at 10 C and lower.
- Taxon
- HemerocallisHemerocallist0
- Outcome
- germinatee0
- Value
- 10⚬ C.e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“conditioned seeds germinate readily at 10⚬ C. and even lower”
t0“Hemerocallis”
Claim · model-written summary
After-ripened seeds could germinate at slightly higher temperature after removal of enveloping structures.
- Taxon
- HemerocallisHemerocallist0
- Outcome
- germinatee0
- Direction
- slightly highere0
- Comparator
- non-conditioned seedse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After-ripened seeds likewise are able to germinate at a slightly higher temperature than do non-conditioned seeds, providing the inhibitory effect of the enveloping structures has been removed”
t0“Hemerocallis”
Claim · model-written summary
After-ripening required both low temperature and moist seeds.
- Taxon
- HemerocallisHemerocallist0
- Outcome
- After-ripeninge0
- Qualifier
- low temperatures and only when the seeds were moiste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After-ripening occurred only at low temperatures and only when the seeds were moist”
t0“Hemerocallis”
Claim · model-written summary
Oxygen availability was required for effective after-ripening.
- Taxon
- HemerocallisHemerocallist0
- Outcome
- effective after-ripeninge0
- Qualifier
- Oxygen must be availablee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Oxygen must be available to the seeds if effective after-ripening is to occur during stratification”
t0“Hemerocallis”
Claim · model-written summary
The after-ripening effect persisted one month under air-dry storage.
- Taxon
- HemerocallisHemerocallist0
- Outcome
- after-ripening effecte0
- Value
- 1 monthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The after-ripening effect persists for as long as 1 month after stratification if the seeds are maintained in an air-dry condition”
t0“Hemerocallis”
Claim · model-written summary
No inhibitor was demonstrated in non-stratified seeds.
- Taxon
- HemerocallisHemerocallist0
- Outcome
- Presence of an inhibitor substancee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Presence of an inhibitor substance could not be demonstrated in non-stratified seeds”
t0“Hemerocallis”
Claim · model-written summary
No stimulatory substance was detected in after-ripened seeds.
- Taxon
- HemerocallisHemerocallist0
- Outcome
- stimulatory substancee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nor could any evidence be found of a stimulatory substance in after-ripened seeds”
t0“Hemerocallis”
The same questions in other papers
storage · growth · HemerocallisPositive and negative results
1 in the opposite direction
- negative
seed treatment · growth · HemerocallisPositive and negative results
1 in the opposite direction
- no effect
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.