Abstract
The effects of ozone exposure on carbon‐fixation‐related processes in Pinus halepensis Mill. needles were assessed over 3 months under controlled conditions. Ozone fumigation (200 ppb) did not induce a modification of either net CO 2 assimilation or stomatal conductance in 1‐year‐old needles, whereas ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1.39) activity was shown to be reduced by a half. Moreover, this ozone‐induced reduction in Rubisco activity was associated with a decrease in the quantity of Rubisco, as determined by the decrease in the large subunit (LSU). On the other hand, 200‐ppb ozone fumigation induced a strong increase in both activity and quantity of another carboxylating enzyme, phospho enol pyruvate carboxylase (PEPC, EC 4.1.1.31), generally considered in C 3 plants to participate in carbon catabolism processes. Ozone induced a significant decrease in the Rubisco/PEPC activity ratio which promotes the role of PEPC in trees under ozone stress. The role of this carboxylase will be discussed.
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Claims 7
Claim · model-written summary
Ozone did not change net CO2 assimilation in one-year-old pine needles.
- Taxon
- Pinus halepensis
Pinus halepensise1 - Organ / stage
- 1‐year‐old needlese0
- Treatment
- Ozone fumigation (200 ppb)e0
- Outcome
- net CO 2 assimilatione0
- Direction
- did not induce a modificatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ozone fumigation (200 ppb) did not induce a modification of either net CO 2 assimilation or stomatal conductance in 1‐year‐old needles”
e1“Pinus halepensis Mill. needles”
Claim · model-written summary
Ozone did not change stomatal conductance in one-year-old pine needles.
- Taxon
- Pinus halepensisPinus halepensise1
- Treatment
- Ozone fumigation (200 ppb)e0
- Outcome
- stomatal conductancee0
- Direction
- did not induce a modificatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ozone fumigation (200 ppb) did not induce a modification of either net CO 2 assimilation or stomatal conductance in 1‐year‐old needles”
e1“Pinus halepensis Mill. needles”
Claim · model-written summary
Ozone halved Rubisco activity.
- Taxon
- Pinus halepensisPinus halepensise2
- Treatment
- Ozone fumigation (200 ppb)e1
- Gene
- Rubiscoe0
- Outcome
- Rubisco, EC 4.1.1.39) activitye0
- Direction
- reducede0
- Value
- a halfe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1.39) activity was shown to be reduced by a half.”
e1“Ozone fumigation (200 ppb)”
e2“Pinus halepensis Mill. needles”
Claim · model-written summary
Ozone reduced Rubisco quantity as indicated by the large subunit.
- Taxon
- Pinus halepensisPinus halepensise1
- Treatment
- ozonee0
- Gene
- Rubiscoe0
- Outcome
- quantity of Rubiscoe0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this ozone‐induced reduction in Rubisco activity was associated with a decrease in the quantity of Rubisco, as determined by the decrease in the large subunit (LSU).”
e1“Pinus halepensis Mill. needles”
Claim · model-written summary
Ozone strongly increased PEPC activity.
- Taxon
- Pinus halepensisPinus halepensise1
- Treatment
- 200‐ppb ozone fumigatione0
- Gene
- PEPCe0
- Outcome
- activitye0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“200‐ppb ozone fumigation induced a strong increase in both activity and quantity of another carboxylating enzyme, phospho enol pyruvate carboxylase (PEPC, EC 4.1.1.31)”
e1“Pinus halepensis Mill. needles”
Claim · model-written summary
Ozone strongly increased PEPC quantity.
- Taxon
- Pinus halepensisPinus halepensise1
- Treatment
- 200‐ppb ozone fumigatione0
- Gene
- PEPCe0
- Outcome
- quantitye0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“200‐ppb ozone fumigation induced a strong increase in both activity and quantity of another carboxylating enzyme, phospho enol pyruvate carboxylase (PEPC, EC 4.1.1.31)”
e1“Pinus halepensis Mill. needles”
Claim · model-written summary
Ozone significantly decreased the Rubisco to PEPC activity ratio.
- Taxon
- Pinus halepensisPinus halepensise1
- Treatment
- Ozonee0
- Outcome
- Rubisco/PEPC activity ratioe0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ozone induced a significant decrease in the Rubisco/PEPC activity ratio”
e1“Pinus halepensis Mill. needles”
The same questions in other papers
ozone · physiology: gas exchange · Pinus halepensis (Aleppo pine)Results agree
1 paper in the same direction as this paper
- negative
ozone · physiology: photosynthesis · Pinus halepensis (Aleppo pine)Results agree
4 papers in the same direction as this paper
- negative
- negative
- negative
1 paper more in this group
See all 5 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.