Abstract
1. The effect on germination of brief conditioning at various temperatures of the grains or seeds of several species of plants was studied, and the effects of such conditioning on light-sensitivity, enzyme activity, and, in two instances, on subsequent growth were observed. Grains of crabgrass and Sporobolus airoides and seeds of flax and radish were conditioned at temperatures ranging from 10⚬ to 65⚬ or 75⚬ C. for 1 hour while possessing various moisture contents from air-dry (9-10%) to fully imbibed (40-44%). Air-dry grains of corn and wheat, seeds of radish and flax, and seeds of other species were conditioned at temperatures of 100⚬ C. for 20, 40, or 60 minutes, or exposed to higher temperatures. 2. Crabgrass and, to a lesser extent, Sporobolus exhibited what is termed a threefold response to light. After conditioning at 10⚬ C., germination percentage was higher in darkness than in light; after conditioning at higher temperatures (50⚬ C. or more), germination became relatively greater in light-in one case, light-obligate. Responses to light varied with differences in water content as well as with temperature of pretreatment. 3. After treatments which resulted in the suppression of germination, the activity of enzymes and the degree of autolysis were diminished. Loss of viability through heat treatments is not in all cases correlated with the loss of oxidase activity. 4. Treatments preventing germination of Sporobolus could be overcome in some proportion of the grains by the addition of glucose, sucrose, or hydroquinone; light, glucose, or light and glucose were similarly effective on crabgrass grains. 5. Grains of Sporobolus conditioned at 60⚬ C. for 1 hour and then planted in soil produced stunted plants; stunting was observed at the third and twelfth weeks after planting. 6. Many instances were observed in which temperature conditioning acting alone or with light promoted more germination than in the control groups. This is discussed in terms of increased chemical activity, the possible effects of light on enzyme activity, and the generally observed stimulatory effect of sudden changes in temperature. The possible relation of the latter point to changes in protoplasmic viscosity is mentioned. 7. In all cases a combination of high water content and high conditioning temperature was deleterious to germination. The upper limit of heat tolerance for seeds of a number of species heated dry is less than 135⚬ C. for 15 minutes. The most resistant species studied were wheat, flax, and radish; of these, wheat is most tolerant to high temperatures and is little affected by as much as 60 minutes' exposure to 100⚬ C. 8. The relative insensitivity of flax and radish seed over a wide range of conditions was found to be of interest. This may be related to the high oil content of these seeds. They are more resistant to treatment at 100⚬ C. than bean and corn, which are both low in oil. The responses of flax and radish to increasing time of exposure to this temperature are similar. Light is clearly inhibitory to these two species after the heat treatment, while it makes little or no difference in the germination of corn and bean. 9. Flax seeds heated 110⚬ C. for 65 minutes exhibit the following characteristics: (a) poor germination in Petri dishes with water, (b) much improved germination in soil or soil extract, (c) improved germination with ascorbic acid, (d) certain abnormalities in the roots of young seedlings, and (e) a stunting of plants grown in soil from seeds so treated. It is suggested that the efficacy of certain agents in overcoming partially the injurious effects of heat is related to their oxidation-reduction activity. 10. The heat resistance of flax and radish is discussed briefly in terms of a protective action of the oils present, possibly an antioxidant function of the unsaturated fatty acids. 11. The data here presented are of limited value in a strictly quantitative sense but demonstrate that brief heat and cold treatments can have numerous effects on the physiological system of the seed. Some of the factors limiting the reproducibility of results are mentioned, and the difficulty of interpretation of the results, owing to the complex and heterogeneous nature of the seed, is pointed out.
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Claims 20
Claim · model-written summary
Cold conditioning increased crabgrass germination in darkness relative to light.
Verbatim
e0“After conditioning at 10⚬ C., germination percentage was higher in darkness than in light”
e1“Grains of crabgrass and Sporobolus airoides”
Claim · model-written summary
High temperature conditioning made crabgrass germination greater in light.
Verbatim
e0“Crabgrass and, to a lesser extent, Sporobolus exhibited what is termed a threefold response to light. After conditioning at 10⚬ C., germination percentage was higher in darkness than in light; after conditioning at higher temperatures (50⚬ C. or more), germination became relatively greater in light-in one case, light-obligate”
Claim · model-written summary
High temperature conditioning also made Sporobolus germination relatively greater in light, to a lesser extent than crabgrass.
- Taxon
- Sporobolus
Sporoboluse0 - Treatment
- higher temperatures (50⚬ C. or more)e0
- Outcome
- germinatione0
- Direction
- greatere0
- Comparator
- darknesse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Crabgrass and, to a lesser extent, Sporobolus exhibited what is termed a threefold response to light. After conditioning at 10⚬ C., germination percentage was higher in darkness than in light; after conditioning at higher temperatures (50⚬ C. or more), germination became relatively greater in light-in one case, light-obligate”
Claim · model-written summary
Seed water content changed the light response to temperature pretreatment.
- Treatment
- temperature of pretreatmente0
- Outcome
- Responses to lighte0
- Direction
- variede0
- Qualifier
- water contente0
Not reportedTaxon
Verbatim
e0“Responses to light varied with differences in water content as well as with temperature of pretreatment”
Claim · model-written summary
Treatments suppressing germination diminished enzyme activity and autolysis.
- Treatment
- treatments which resulted in the suppression of germinatione0
- Outcome
- activity of enzymes and the degree of autolysise0
- Direction
- diminishede0
Not reportedTaxonComparator
Verbatim
e0“After treatments which resulted in the suppression of germination, the activity of enzymes and the degree of autolysis were diminished”
Claim · model-written summary
Heat induced viability loss was not always correlated with oxidase activity loss.
Not reportedTaxon
Verbatim
e0“Loss of viability through heat treatments is not in all cases correlated with the loss of oxidase activity”
Claim · model-written summary
Glucose restored germination in a fraction of heat-treated Sporobolus grains.
- Taxon
- SporobolusSporoboluse0
- Treatment
- glucosee0
- Outcome
- germinatione0
- Direction
- overcomee0
- Qualifier
- some proportion of the grainse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatments preventing germination of Sporobolus could be overcome in some proportion of the grains by the addition of glucose, sucrose, or hydroquinone”
Claim · model-written summary
Sucrose restored germination in a fraction of heat-treated Sporobolus grains.
- Taxon
- SporobolusSporoboluse0
- Treatment
- sucrosee0
- Outcome
- germinatione0
- Direction
- overcomee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatments preventing germination of Sporobolus could be overcome in some proportion of the grains by the addition of glucose, sucrose, or hydroquinone”
Claim · model-written summary
Hydroquinone restored germination in a fraction of heat-treated Sporobolus grains.
- Taxon
- SporobolusSporoboluse0
- Treatment
- hydroquinonee0
- Outcome
- germinatione0
- Direction
- overcomee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatments preventing germination of Sporobolus could be overcome in some proportion of the grains by the addition of glucose, sucrose, or hydroquinone”
Claim · model-written summary
Light or glucose restored germination in crabgrass grains.
- Taxon
- crabgrasse0
- Treatment
- light, glucose, or light and glucosee0
- Outcome
- effectivee0
- Direction
- effectivee0
Not reportedComparator
Verbatim
e0“light, glucose, or light and glucose were similarly effective on crabgrass grains”
Claim · model-written summary
Heating Sporobolus grains at 60°C for one hour stunted plants after planting.
- Taxon
- SporobolusSporoboluse0
- Treatment
- 60⚬ C. for 1 houre0
- Outcome
- stunted plantse0
- Direction
- stuntede0
- Qualifier
- third and twelfth weeks after plantinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Grains of Sporobolus conditioned at 60⚬ C. for 1 hour and then planted in soil produced stunted plants; stunting was observed at the third and twelfth weeks after planting”
Claim · model-written summary
Temperature conditioning sometimes promoted germination compared with controls.
- Treatment
- temperature conditioning acting alone or with lighte0
- Outcome
- germinatione0
- Direction
- moree0
- Comparator
- control groupse0
Not reportedTaxon
Verbatim
e0“temperature conditioning acting alone or with light promoted more germination than in the control groups”
Claim · model-written summary
Combining high seed water content and high conditioning temperature harmed germination.
- Treatment
- high water content and high conditioning temperaturee0
- Outcome
- germinatione0
- Direction
- deleteriouse0
Not reportedTaxonComparator
Verbatim
e0“In all cases a combination of high water content and high conditioning temperature was deleterious to germination”
Claim · model-written summary
Wheat seeds were most heat tolerant and little affected by 60 minutes at 100°C.
- Taxon
- wheat
Triticum aestivume0 - Treatment
- 60 minutes' exposure to 100⚬ Ce0
- Outcome
- tolerant to high temperaturese0
- Direction
- most tolerante0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“wheat is most tolerant to high temperatures and is little affected by as much as 60 minutes' exposure to 100⚬ C”
Claim · model-written summary
Flax and radish seeds resisted 100°C treatment better than bean and corn seeds.
Not reportedTaxon
Verbatim
e0“They are more resistant to treatment at 100⚬ C. than bean and corn”
Claim · model-written summary
Light inhibited flax germination after heat treatment.
- Taxon
- flax
Linum usitatissimume1 - Treatment
- Lighte0
- Outcome
- germinatione2
- Direction
- inhibitorye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Light is clearly inhibitory to these two species after the heat treatment”
e1“flax and radish seed”
e2“germination of corn and bean”
Claim · model-written summary
Light inhibited radish germination after heat treatment.
- Taxon
- radish
Raphanus sativuse1 - Treatment
- Lighte0
- Outcome
- germinatione2
- Direction
- inhibitorye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Light is clearly inhibitory to these two species after the heat treatment”
e1“flax and radish seed”
e2“germination of corn and bean”
Claim · model-written summary
Soil or soil extract improved germination of flax seeds heated at 110°C for 65 minutes.
- Taxon
- FlaxLinum usitatissimume0
- Treatment
- soil or soil extracte0
- Outcome
- germinatione0
- Direction
- improvede0
- Comparator
- Petri dishes with watere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Flax seeds heated 110⚬ C. for 65 minutes exhibit the following characteristics: (a) poor germination in Petri dishes with water, (b) much improved germination in soil or soil extract”
Claim · model-written summary
Ascorbic acid improved germination of flax seeds heated at 110°C for 65 minutes.
- Taxon
- FlaxLinum usitatissimume0
- Treatment
- ascorbic acide0
- Outcome
- germinatione0
- Direction
- improvede0
- Comparator
- Petri dishes with watere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Flax seeds heated 110⚬ C. for 65 minutes exhibit the following characteristics: (a) poor germination in Petri dishes with water, (b) much improved germination in soil or soil extract, (c) improved germination with ascorbic acid”
Claim · model-written summary
Flax plants from seeds heated at 110°C for 65 minutes had abnormal roots and stunted growth.
- Taxon
- FlaxLinum usitatissimume0
- Outcome
- abnormalities in the roots of young seedlingse0
- Qualifier
- stunting of plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Flax seeds heated 110⚬ C. for 65 minutes exhibit the following characteristics: (a) poor germination in Petri dishes with water, (b) much improved germination in soil or soil extract, (c) improved germination with ascorbic acid, (d) certain abnormalities in the roots of young seedlings, and (e) a stunting of plants grown in soil from seeds so treated”
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ascorbic acid · growth · Linum usitatissimum (flax)Results agree
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light · growth · Linum usitatissimum (flax)Results differ
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See all 30 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.