Abstract
Nitrogenase activity in root nodules of four species of actinorhizal plants showed varying declines in response to exposure to acetylene (10% v/v). Gymnostoma papuanum (S. Moore) L. Johnson. and Casuarina equisetifolia L. nodules showed a small decline (5-15%) with little or no recovery over 15 minutes. Myrica gale L. nodules showed a sharp decline followed by a rapid return to peak activity. Alnus incana ssp. rugosa (Du Roi) Clausen. nodules usually showed varying degrees of decline followed by a slower return to peak or near-peak activity. We call these effects acetylene-induced transients. Rapid increases in oxygen tension also caused dramatic transient decreases in nitrogenase activity in all species. The magnitude of the transient decrease was related to the size of the O(2) partial pressure (pO(2)) rise, to the proximity of the starting and ending oxygen tensions to the pO(2) optimum, and to the time for which the plant was exposed to the lower pO(2). Oxygen-induced transients, induced both by step jumps in pO(2) and by O(2) pulses, were also observed in cultures of Frankia. The effects seen in nodules are purely a response by the bacterium and not a nodule effect per se. Oxygen-induced nitrogenase transients in actinorhizal nodules from the plant genera tested here do not appear to be a result of changes in nodule diffusion resistance.
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Claims 9
Claim · model-written summary
Acetylene exposure caused a small decline (5-15%) in nitrogenase activity of Gymnostoma papuanum nodules, with little or no recovery over 15 minutes.
- Taxon
- Gymnostoma papuanum
Gymnostoma papuanume2 - Treatment
- acetylene (10% v/v)e1
- Outcome
- Nitrogenase activitye1
- Direction
- small declinee2
- Value
- 5-15%e2
- Qualifier
- little or no recovery over 15 minutese2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Nitrogenase activity in root nodules of four species of actinorhizal plants showed varying declines in response to exposure to acetylene (10% v/v)”
e2“Gymnostoma papuanum (S. Moore) L. Johnson. and Casuarina equisetifolia L. nodules showed a small decline (5-15%) with little or no recovery over 15 minutes”
Claim · model-written summary
Acetylene exposure caused a small decline (5-15%) in nitrogenase activity of Casuarina equisetifolia nodules, with little or no recovery over 15 minutes.
- Taxon
- Casuarina equisetifolia
Casuarina equisetifoliae2 - Treatment
- acetylene (10% v/v)e1
- Outcome
- Nitrogenase activitye1
- Direction
- small declinee2
- Value
- 5-15%e2
- Qualifier
- little or no recovery over 15 minutese2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Nitrogenase activity in root nodules of four species of actinorhizal plants showed varying declines in response to exposure to acetylene (10% v/v)”
e2“Gymnostoma papuanum (S. Moore) L. Johnson. and Casuarina equisetifolia L. nodules showed a small decline (5-15%) with little or no recovery over 15 minutes”
Claim · model-written summary
Acetylene exposure caused a sharp decline in nitrogenase activity of Myrica gale nodules, followed by a rapid return to peak activity.
- Taxon
- Myrica gale
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Myrica galee2 - Treatment
- acetylene (10% v/v)e1
- Outcome
- Nitrogenase activitye1
- Direction
- sharp declinee2
- Qualifier
- followed by a rapid return to peak activitye2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e1“Nitrogenase activity in root nodules of four species of actinorhizal plants showed varying declines in response to exposure to acetylene (10% v/v)”
e2“Myrica gale L. nodules showed a sharp decline followed by a rapid return to peak activity”
Claim · model-written summary
Acetylene exposure caused varying degrees of decline in nitrogenase activity of Alnus incana ssp. rugosa nodules, followed by a slower return to peak or near-peak activity.
- Taxon
- Alnus incana ssp. rugosa
Alnus incana subsp. rugosae2 - Treatment
- acetylene (10% v/v)e1
- Outcome
- Nitrogenase activitye1
- Direction
- varying degrees of declinee2
- Qualifier
- followed by a slower return to peak or near-peak activitye2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Nitrogenase activity in root nodules of four species of actinorhizal plants showed varying declines in response to exposure to acetylene (10% v/v)”
e2“Alnus incana ssp. rugosa (Du Roi) Clausen. nodules usually showed varying degrees of decline followed by a slower return to peak or near-peak activity”
Claim · model-written summary
Rapid increases in oxygen tension caused dramatic transient decreases in nitrogenase activity in all actinorhizal species tested.
- Taxon
- actinorhizal plantse0
- Treatment
- Rapid increases in oxygen tensione1
- Outcome
- nitrogenase activitye1
- Direction
- transient decreasese1
- Qualifier
- in all speciese1
Not reportedComparator
Verbatim
e0“Nitrogenase activity in root nodules of four species of actinorhizal plants showed varying declines in response to exposure to acetylene (10% v/v)”
e1“Rapid increases in oxygen tension also caused dramatic transient decreases in nitrogenase activity in all species”
Claim · model-written summary
The magnitude of the oxygen-induced transient decrease in nitrogenase activity was related to the size of the pO(2) rise, to the proximity of the starting and ending oxygen tensions to the pO(2) optimum, and to the time at the lower pO(2).
- Taxon
- actinorhizal plantse0
- Treatment
- size of the O(2) partial pressure (pO(2)) risee1
- Outcome
- The magnitude of the transient decreasee1
- Qualifier
- the proximity of the starting and ending oxygen tensions to the pO(2) optimume1
Not reportedDirection
Verbatim
e0“Nitrogenase activity in root nodules of four species of actinorhizal plants showed varying declines in response to exposure to acetylene (10% v/v)”
e1“The magnitude of the transient decrease was related to the size of the O(2) partial pressure (pO(2)) rise, to the proximity of the starting and ending oxygen tensions to the pO(2) optimum, and to the time for which the plant was exposed to the lower pO(2)”
Claim · model-written summary
Oxygen-induced transients in nitrogenase activity were also observed in cultures of Frankia, induced by step jumps in pO(2) and by O(2) pulses.
- Taxon
- actinorhizal plantse0
- Material
- cultures of Frankiae1
- Treatment
- step jumps in pO(2) and by O(2) pulsese1
- Outcome
- Oxygen-induced transientse1
FrankiaOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogenase activity in root nodules of four species of actinorhizal plants showed varying declines in response to exposure to acetylene (10% v/v)”
e1“Oxygen-induced transients, induced both by step jumps in pO(2) and by O(2) pulses, were also observed in cultures of Frankia”
Claim · model-written summary
The oxygen-induced effects seen in nodules are a response by the bacterium, not a nodule effect per se.
Verbatim
e0“Nitrogenase activity in root nodules of four species of actinorhizal plants showed varying declines in response to exposure to acetylene (10% v/v)”
e1“The effects seen in nodules are purely a response by the bacterium and not a nodule effect per se”
Claim · model-written summary
Oxygen-induced nitrogenase transients in actinorhizal nodules do not appear to result from changes in nodule diffusion resistance.
Verbatim
e0“Nitrogenase activity in root nodules of four species of actinorhizal plants showed varying declines in response to exposure to acetylene (10% v/v)”
e1“Oxygen-induced nitrogenase transients in actinorhizal nodules from the plant genera tested here do not appear to be a result of changes in nodule diffusion resistance”
The same questions in other papers
acetylene · physiology: enzyme activity · Alnus incana (gray alder)Results agree
2 papers in the same direction as this paper
- negative
- negative
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.