Abstract
The flow of sap in Populus tremuloides was studied by the thermoelectric method immediately prior to and at several periods of time after radical girdling. Similarly, the flow of sap in Betula papyrifera was studied before and after girdling or injection with metabolic inhibitors or a filtrate of a culture of Ceratocystis ulmi.None of the treatments caused any significant change in the speed at which the sap flowed. However, the rate at which the temperature rose at the upper (downstream) thermocouple decreased significantly in girdled trees and in most trees treated with metabolic inhibitors. That decrease was first noticed 4 days after poisoning with 0.1 m mercuric chloride, and 1 day after poisoning with either 0.01 m picric acid or a culture filtrate of Ceratocystis ulmi. A 0.05 m trichloroacetic acid solution caused a decrease in the rate of temperature rise about 2 hours after the tree was injected. The rate of temperature rise returned to normal the next day after the injection with trichloroacetic but again showed a decrease after 42 days.Increases in the rate of heat rise were noted the day after the birch trees were girdled, and all girdled trees showed a significant decrease in the rate of heat rise sometime after they were girdled. Many of the girdled trees showed no sap flow or even an apparent downward flow of xylem sap sometime after girdling.Laboratory experiments indicated that the blocking of the vessels by air emboli would result in a significant change in the rate of temperature rise, not accompanied by a significant change in the speed at which the sap flowed. Since air emboli caused similar results to those actually experienced in the field, the data are interpreted as the result of blocked or nonfunctional vessels.All of the data agree with that of earlier workers. Cessation of upward flow occurs only in girdled trees after rather long periods of time. It is suggested that cessation could be caused by tyloses and air emboli. All of the data are also in agreement with the passive theories of sap ascent. However, the trichloroacetic acid experiments suggest the existence of a repair mechanism or a second means of sap movement.
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Claims 14
Claim · model-written summary
Treatments did not significantly change xylem sap-flow speed.
- Treatment
- Metabolic Inhibitors and Girdlingt0
- Outcome
- speed at which the sap flowede0
- Direction
- None of the treatments caused any significant changee0
Not reportedTaxonComparator
Verbatim
e0“None of the treatments caused any significant change in the speed at which the sap flowed”
t0“Xylem Sap Flow as Affected by Metabolic Inhibitors and Girdling”
Claim · model-written summary
Girdling significantly decreased downstream thermocouple heat-rise rate.
- Treatment
- girdlede0
- Outcome
- rate at which the temperature rose at the upper (downstream) thermocouplee0
- Direction
- decreasede0
Not reportedTaxonComparator
Verbatim
e0“the rate at which the temperature rose at the upper (downstream) thermocouple decreased significantly in girdled trees”
Claim · model-written summary
Most metabolic inhibitor treatments significantly decreased downstream thermocouple heat-rise rate.
- Treatment
- metabolic inhibitorse0
- Outcome
- rate at which the temperature rose at the upper (downstream) thermocouplee0
- Direction
- decreasede0
Not reportedTaxonComparator
Verbatim
e0“the rate at which the temperature rose at the upper (downstream) thermocouple decreased significantly in girdled trees and in most trees treated with metabolic inhibitors”
Claim · model-written summary
Mercuric chloride reduced heat-rise rate beginning four days after treatment.
- Treatment
- 0.1 m mercuric chloridee0
- Outcome
- decreasee0
- Direction
- decreasee0
- Qualifier
- 4 days after poisoninge0
Not reportedTaxonComparator
Verbatim
e0“That decrease was first noticed 4 days after poisoning with 0.1 m mercuric chloride”
Claim · model-written summary
Picric acid reduced heat-rise rate beginning one day after treatment.
Not reportedTaxonComparatorOutcomeDirection
Verbatim
e0“1 day after poisoning with either 0.01 m picric acid or a culture filtrate of Ceratocystis ulmi”
Claim · model-written summary
Ceratocystis ulmi culture filtrate reduced heat-rise rate beginning one day after treatment.
Not reportedTaxonComparatorOutcomeDirection
Verbatim
e0“1 day after poisoning with either 0.01 m picric acid or a culture filtrate of Ceratocystis ulmi”
Claim · model-written summary
Trichloroacetic acid decreased heat-rise rate after two hours, returned to normal the next day, and decreased again after 42 days.
- Treatment
- 0.05 m trichloroacetic acid solutione0
- Outcome
- rate of temperature risee0
- Direction
- decreasee0
- Qualifier
- about 2 hours after the tree was injectede0
Not reportedTaxonComparator
Verbatim
e0“A 0.05 m trichloroacetic acid solution caused a decrease in the rate of temperature rise about 2 hours after the tree was injected. The rate of temperature rise returned to normal the next day after the injection with trichloroacetic but again showed a decrease after 42 days”
Claim · model-written summary
Birch heat-rise rate increased the day after girdling.
Not reportedComparator
Verbatim
e0“Increases in the rate of heat rise were noted the day after the birch trees were girdled”
Claim · model-written summary
All girdled trees later showed a significant decrease in heat-rise rate.
Not reportedComparator
Verbatim
e0“all girdled trees showed a significant decrease in the rate of heat rise sometime after they were girdled”
Claim · model-written summary
Many girdled trees later showed absent or apparently downward xylem sap flow.
- Taxon
- treese0
- Treatment
- girdlinge0
- Outcome
- sap flowe0
- Direction
- no sap flow or even an apparent downward flowe0
Not reportedComparator
Verbatim
e0“Many of the girdled trees showed no sap flow or even an apparent downward flow of xylem sap sometime after girdling”
Claim · model-written summary
Air emboli in laboratory vessels changed heat-rise rate significantly without significantly changing sap-flow speed.
Not reportedTaxonComparator
Verbatim
e0“blocking of the vessels by air emboli would result in a significant change in the rate of temperature rise, not accompanied by a significant change in the speed at which the sap flowed”
Claim · model-written summary
The authors interpret the field measurements as arising from blocked or nonfunctional vessels.
Not reportedTaxon
Verbatim
e0“the data are interpreted as the result of blocked or nonfunctional vessels”
Claim · model-written summary
The authors suggest tyloses and air emboli may cause eventual cessation of upward flow in girdled trees.
Verbatim
e0“Cessation of upward flow occurs only in girdled trees after rather long periods of time. It is suggested that cessation could be caused by tyloses and air emboli”
Claim · model-written summary
Trichloroacetic acid results suggest a repair mechanism or second sap-movement route.
Not reportedTaxon
Verbatim
e0“the trichloroacetic acid experiments suggest the existence of a repair mechanism or a second means of sap movement”