Abstract
summary One‐year‐old half‐sib loblolly pine (Pinus taeda L.) seedlings were planted in a sandy loam soil having approximately 15 or 35 mg kg −1 of exchangeable Mg and were exposed to subambient, ambient, or twice ambient (0.02, 0.05, or 0.09 μl O 3 1 −1 , respectively) concentrations of O 3 in open‐top chambers from April to October 1988. The cold hardiness of seedlings was tested on October 24, January 24, and March 21 by subjecting needle samples from the first and last growth flush to temperatures of ‐5, ‐10, ‐15, and ‐ 20 °C and determining relative electrical conductivity of the diffusate. Seedlings exposed to twice ambient O 3 levels during the growing season were less hardened in early autumn and spring than seedlings exposed to ambient or subambient levels of O 3 , suggesting that O 3 affects the plant's hardening and dehardening processes. Ozone and soil Mg treatments had no significant effects on visible injury of shoots following freezing treatments, nor were any visible symptoms of injury due to O 3 evident during the study. Water potential components of excised shoots were estimated using pressure‐volume analysis. Osmotic potentials became more negative over the dormant period, suggesting that solutes had accumulated in the cells as seedlings hardened. Seedlings grown in high Mg soil had less negative osmotic potentials in January and March than those grown in low Mg soil, suggesting that seedlings in high Mg soil were more susceptible to cold temperatures, probably due to greater physiological activity.
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Claims 5
Claim · model-written summary
Twice-ambient ozone left seedlings less hardened in early autumn and spring than ambient or subambient ozone.
- Taxon
- Pinus taeda L.
Pinus taedat0 - Treatment
- twice ambient O 3 levelse0
- Outcome
- hardenede0
- Direction
- less hardenede0
- Qualifier
- early autumn and springe0
- Comparator
- ambient or subambient levels of O 3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seedlings exposed to twice ambient O 3 levels during the growing season were less hardened in early autumn and spring than seedlings exposed to ambient or subambient levels of O 3”
t0“Pinus taeda L.”
Claim · model-written summary
Ozone and magnesium treatments had no significant effect on visible freeze injury.
- Taxon
- Pinus taeda L.Pinus taedat0
- Treatment
- Ozone and soil Mg treatmentse0
- Outcome
- visible injury of shootse0
- Direction
- no significant effectse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ozone and soil Mg treatments had no significant effects on visible injury of shoots following freezing treatments”
t0“Pinus taeda L.”
Claim · model-written summary
No visible ozone injury occurred during the study.
- Taxon
- Pinus taeda L.Pinus taedat0
- Outcome
- visible symptoms of injury due to O 3e0
- Direction
- nor were anye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nor were any visible symptoms of injury due to O 3 evident during the study.”
t0“Pinus taeda L.”
Claim · model-written summary
Shoot osmotic potentials became more negative during dormancy.
- Taxon
- Pinus taeda L.Pinus taedat0
- Outcome
- Osmotic potentialse0
- Direction
- more negativee0
- Qualifier
- over the dormant periode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Osmotic potentials became more negative over the dormant period”
t0“Pinus taeda L.”
Claim · model-written summary
High-soil-magnesium seedlings had less negative osmotic potentials in January and March than low-magnesium seedlings.
- Taxon
- Pinus taeda L.Pinus taedat0
- Treatment
- high Mg soile0
- Outcome
- osmotic potentialse0
- Direction
- less negativee0
- Qualifier
- January and Marche0
- Comparator
- low Mg soile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seedlings grown in high Mg soil had less negative osmotic potentials in January and March than those grown in low Mg soil”
t0“Pinus taeda L.”
The same questions in other papers
ozone · crop injury · Pinus taeda (loblolly pine)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- 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.