Abstract
A method was developed for carrying out gas-exchange and chlorophyll-fluorescence measurements simultaneously during fumigation of spruce twigs with peroxidic photooxidants. It is thus now possible to investigate how a pollutant affects distinct sectors of the photosynthetic apparatus of the plant: whereas fluorescence reveals any changes in the primary light reaction, CO 2 gas-exchange measurements supply information about the biochemical reactions of the Calvin cycle. Results of short-time fumigation with 750 ppb ozone are presented here. Gas-exchange and fluorescence data are affected strongly in early summer, but not in autumn. The assimilation rate decreases significantly: primarily as a result of Rubisco activity and possibly because of direct inhibition of the electron-transport chain as well. Closure of the stomata leads to further reduction in the assimilation rate. Though no damage becomes visible on the needles, the perturbance of the photosynthetic apparatus caused by ozone fumigation is not reversible within 24 h.
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Claims 7
Claim · model-written summary
The developed method enables simultaneous gas exchange and fluorescence measurements during spruce fumigation.
- Outcome
- gas-exchange and chlorophyll-fluorescence measurements simultaneouslye0
PiceaNot reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A method was developed for carrying out gas-exchange and chlorophyll-fluorescence measurements simultaneously during fumigation of spruce twigs with peroxidic photooxidants.”
Claim · model-written summary
Short ozone fumigation strongly affected gas exchange and fluorescence in early summer but not autumn.
- Treatment
- 750 ppb ozonee0
- Outcome
- Gas-exchange and fluorescence datae0
- Direction
- affected stronglye0
- Comparator
- autumne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Results of short-time fumigation with 750 ppb ozone are presented here. Gas-exchange and fluorescence data are affected strongly in early summer, but not in autumn.”
t0“Spruce”
Claim · model-written summary
Ozone significantly decreased spruce assimilation rate.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The assimilation rate decreases significantly”
e1“750 ppb ozone”
t0“Spruce”
Claim · model-written summary
Rubisco activity was identified as the primary reason for decreased assimilation rate.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primarily as a result of Rubisco activity”
e1“The assimilation rate decreases significantly”
t0“Spruce”
Claim · model-written summary
Direct electron transport inhibition was offered as a possible additional reason for lower assimilation.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“possibly because of direct inhibition of the electron-transport chain as well”
e1“The assimilation rate decreases significantly”
t0“Spruce”
Claim · model-written summary
Stomatal closure further reduced assimilation rate.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Closure of the stomata leads to further reduction in the assimilation rate.”
t0“Spruce”
Claim · model-written summary
Ozone-induced disturbance of spruce photosynthesis did not reverse within 24 hours despite no visible needle injury.
- Organ / stage
- needlese0
- Outcome
- perturbance of the photosynthetic apparatuse0
- Direction
- not reversible within 24 he0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Though no damage becomes visible on the needles, the perturbance of the photosynthetic apparatus caused by ozone fumigation is not reversible within 24 h.”
t0“Spruce”
The same questions in other papers
ozone · physiology: gas exchange · PiceaResults 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.