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)”
Title
Warwick B. Silvester; Lawrence J. Winship PLANT PHYSIOLOGY 1990. doi:10.1104/pp.92.2.480
Other claims from this paper (8)
- Intervention effect Acetylene exposure caused a small decline (5-15%) in nitrogenase activity of Gymnostoma papuanum nodules, with little or no recovery over 15 minutes.
- Intervention effect Acetylene exposure caused a small decline (5-15%) in nitrogenase activity of Casuarina equisetifolia nodules, with little or no recovery over 15 minutes.
- Intervention effect Acetylene exposure caused a sharp decline in nitrogenase activity of Myrica gale nodules, followed by a rapid return to peak activity.
- Intervention effect 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.
- Intervention effect Rapid increases in oxygen tension caused dramatic transient decreases in nitrogenase activity in all actinorhizal species tested.
- Observation 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.
- Mechanism The oxygen-induced effects seen in nodules are a response by the bacterium, not a nodule effect per se.
- Mechanism Oxygen-induced nitrogenase transients in actinorhizal nodules do not appear to result from changes in nodule diffusion resistance.