Abstract
Carbon dioxide exchange rates (CER) were measured as a function of photosynthetic photon flux densities (PPFDs) on seedlings of two loblolly pine (Pinus taeda L.) families following 6- or 12-week exposures to variable levels of ozone (filtered or ambient air + 160 nl L/sup -1/) and acid precipitation (pH 3.5, 4.3, and 5.0). Exposures were made in open-top field chambers. CERs of whole shoots were measured in an open infrared gas analysis system at 6 levels of PPFD (0, 33, 60, 410, 800, and 1660 ..mu..mol m/sup -2/ s/sup -1/). Compared with control plants, ozone-treated seedlings exhibited statistically significant reduction in light-saturated CER of 36 and 28% for plants measured at 6- and 12-weeks, respectively. At 12 weeks, pH 3.5 and 4.3 precipitation treatments enhanced light-saturated CER by an average of 37% over that observed for seedlings exposed to the pH 5.0 treatment. No differences in dark respiration (CER at 0 PPFD) were detected between treatments. Enhancements of CER resulting from acid precipitation treatments were of the same magnitude as CER reductions due to ozone exposures.
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Claims 5
Claim · model-written summary
Ozone reduced light-saturated shoot CER by 36% after six weeks versus controls.
- Taxon
- Pinus taeda L.
Pinus taedat0 - Treatment
- ozone-treated seedlingse0
- Outcome
- light-saturated CERe0
- Direction
- reductione0
- Value
- 36e0
- Qualifier
- 6- and 12-weekse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ozone-treated seedlings exhibited statistically significant reduction in light-saturated CER of 36 and 28% for plants measured at 6- and 12-weeks, respectively”
t0“Pinus taeda L.”
Claim · model-written summary
Ozone reduced light-saturated shoot CER by 28% after twelve weeks versus controls.
- Taxon
- Pinus taeda L.Pinus taedat0
- Treatment
- ozone-treated seedlingse0
- Outcome
- light-saturated CERe0
- Direction
- reductione0
- Value
- 28%e0
- Qualifier
- 6- and 12-weekse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ozone-treated seedlings exhibited statistically significant reduction in light-saturated CER of 36 and 28% for plants measured at 6- and 12-weeks, respectively”
t0“Pinus taeda L.”
Claim · model-written summary
At 12 weeks pH 3.5 precipitation enhanced light-saturated CER by an average 37% relative to pH 5.0 precipitation.
- Taxon
- Pinus taeda L.Pinus taedat0
- Treatment
- pH 3.5e0
- Outcome
- light-saturated CERe0
- Direction
- enhancede0
- Value
- 37%e0
- Qualifier
- At 12 weekse0
- Comparator
- pH 5.0 treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At 12 weeks, pH 3.5 and 4.3 precipitation treatments enhanced light-saturated CER by an average of 37% over that observed for seedlings exposed to the pH 5.0 treatment.”
t0“Pinus taeda L.”
Claim · model-written summary
At 12 weeks pH 4.3 precipitation enhanced light-saturated CER by an average 37% relative to pH 5.0 precipitation.
- Taxon
- Pinus taeda L.Pinus taedat0
- Treatment
- 4.3 precipitation treatmentse0
- Outcome
- light-saturated CERe0
- Direction
- enhancede0
- Value
- 37%e0
- Qualifier
- At 12 weekse0
- Comparator
- pH 5.0 treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At 12 weeks, pH 3.5 and 4.3 precipitation treatments enhanced light-saturated CER by an average of 37% over that observed for seedlings exposed to the pH 5.0 treatment.”
t0“Pinus taeda L.”
Claim · model-written summary
Dark respiration did not differ between treatments.
- Taxon
- Pinus taeda L.Pinus taedat0
- Treatment
- treatmentse0
- Outcome
- dark respiratione0
- Direction
- No differencese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No differences in dark respiration (CER at 0 PPFD) were detected between treatments.”
t0“Pinus taeda L.”
The same questions in other papers
rainfall · molecular: metabolites · Pinus taeda (loblolly pine)Positive and negative results
1 in the opposite direction
- negative
ph · molecular: metabolites · Pinus taeda (loblolly pine)Positive and negative results
1 in the opposite direction
- negative
ozone · molecular: metabolites · Pinus taeda (loblolly pine)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.