Abstract
Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons. In the 2001 growing season, both groups of plants were exposed to ambient (control) and 1.6x ambient (elevated) O3 concentration under similar microclimatic conditions in a free air O3 exposure facility. Growth, net photosynthesis, stomatal conductance, stomatal density, visible foliar injury, starch and nutrient concentrations, bud formation and differences in O3 responses between lower, middle and upper sections of the canopy were determined. The potted saplings were unaffected by elevated O3 concentration, whereas the open-soil-grown trees showed a 3-38% reduction in shoot growth, a 22% reduction in number of overwintering buds, a 26-65% decrease in autumnal net photosynthesis, 30% and 20-23% reductions in starch and nitrogen concentrations of senescing leaves, respectively, and disturbances in stomatal conductance. The greater O3 sensitivity of open-soil-grown trees compared with potted saplings was a result of senescence-related physiological factors. First, a lower net photosynthesis to stomatal conductance ratio in open-soil-grown trees at the end of the season promoted O3 uptake and decreased photosynthetic gain, leading to the onset of visible foliar injuries. Second, decreased carbohydrate reserves may have resulted in deleterious carry-over effects arising from the reduced formation of over-wintering buds. Finally, the leaf-level O3 load was higher for open-soil-grown trees than for potted saplings because of slower leaf senescence in the trees. Thus, O3 sensitivity in European white birch increases with increasing exposure time and tree size.
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Claims 12
Claim · model-written summary
Potted saplings were unaffected by elevated O3 concentration.
- Taxon
- Betula pendula
Betula pendulae1 - Material
- O3-tolerant clonee1
- Treatment
- elevated O3 concentratione2
- Outcome
- Physiological responsese1
- Direction
- unaffectede2
- Comparator
- ambient (control)e3
- Setting
- free air O3 exposure facilitye3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons”
e2“The potted saplings were unaffected by elevated O3 concentration”
e3“both groups of plants were exposed to ambient (control) and 1.6x ambient (elevated) O3 concentration under similar microclimatic conditions in a free air O3 exposure facility”
Claim · model-written summary
Open-soil-grown birch trees showed a 3-38% reduction in shoot growth under elevated O3.
- Taxon
- Betula pendulaBetula pendulae1
- Organ / stage
- shoote4
- Treatment
- 1.6x ambient (elevated) O3 concentratione3
- Outcome
- shoot growthe4
- Direction
- reductione4
- Value
- 3-38%e4
- Comparator
- ambient (control)e3
- Setting
- free air O3 exposure facilitye3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons”
e3“both groups of plants were exposed to ambient (control) and 1.6x ambient (elevated) O3 concentration under similar microclimatic conditions in a free air O3 exposure facility”
e4“the open-soil-grown trees showed a 3-38% reduction in shoot growth”
Claim · model-written summary
Open-soil-grown birch trees had 22% fewer overwintering buds under elevated O3.
- Taxon
- Betula pendulaBetula pendulae1
- Treatment
- 1.6x ambient (elevated) O3 concentratione3
- Outcome
- number of overwintering budse5
- Direction
- reductione5
- Value
- 22%e5
- Comparator
- ambient (control)e3
- Setting
- free air O3 exposure facilitye3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons”
e3“both groups of plants were exposed to ambient (control) and 1.6x ambient (elevated) O3 concentration under similar microclimatic conditions in a free air O3 exposure facility”
e5“a 22% reduction in number of overwintering buds”
Claim · model-written summary
Open-soil-grown birch trees had a 26-65% decrease in autumnal net photosynthesis under elevated O3.
- Taxon
- Betula pendulaBetula pendulae1
- Treatment
- 1.6x ambient (elevated) O3 concentratione3
- Outcome
- autumnal net photosynthesise6
- Direction
- decreasee6
- Value
- 26-65%e6
- Comparator
- ambient (control)e3
- Setting
- free air O3 exposure facilitye3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons”
e3“both groups of plants were exposed to ambient (control) and 1.6x ambient (elevated) O3 concentration under similar microclimatic conditions in a free air O3 exposure facility”
e6“a 26-65% decrease in autumnal net photosynthesis”
Claim · model-written summary
Senescing leaves of open-soil-grown birch trees had 30% lower starch concentration under elevated O3.
- Taxon
- Betula pendulaBetula pendulae1
- Organ / stage
- senescing leavese7
- Treatment
- 1.6x ambient (elevated) O3 concentratione3
- Outcome
- starche7
- Direction
- reductionse7
- Value
- 30%e7
- Comparator
- ambient (control)e3
- Setting
- free air O3 exposure facilitye3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons”
e3“both groups of plants were exposed to ambient (control) and 1.6x ambient (elevated) O3 concentration under similar microclimatic conditions in a free air O3 exposure facility”
e7“30% and 20-23% reductions in starch and nitrogen concentrations of senescing leaves, respectively”
Claim · model-written summary
Senescing leaves of open-soil-grown birch trees had 20-23% lower nitrogen concentration under elevated O3.
- Taxon
- Betula pendulaBetula pendulae1
- Organ / stage
- senescing leavese7
- Treatment
- 1.6x ambient (elevated) O3 concentratione3
- Outcome
- nitrogen concentrationse7
- Direction
- reductionse7
- Value
- 20-23%e7
- Comparator
- ambient (control)e3
- Setting
- free air O3 exposure facilitye3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons”
e3“both groups of plants were exposed to ambient (control) and 1.6x ambient (elevated) O3 concentration under similar microclimatic conditions in a free air O3 exposure facility”
e7“30% and 20-23% reductions in starch and nitrogen concentrations of senescing leaves, respectively”
Claim · model-written summary
Elevated O3 caused disturbances in stomatal conductance of open-soil-grown birch trees.
- Taxon
- Betula pendulaBetula pendulae1
- Treatment
- 1.6x ambient (elevated) O3 concentratione3
- Outcome
- stomatal conductancee4
- Comparator
- ambient (control)e3
- Setting
- free air O3 exposure facilitye3
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons”
e3“both groups of plants were exposed to ambient (control) and 1.6x ambient (elevated) O3 concentration under similar microclimatic conditions in a free air O3 exposure facility”
e4“disturbances in stomatal conductance”
Claim · model-written summary
The greater O3 sensitivity of open-soil-grown birch trees was a result of senescence-related physiological factors.
- Taxon
- Betula pendulaBetula pendulae1
- Outcome
- O3 sensitivitye2
- Qualifier
- senescence-related physiological factorse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons”
e2“The greater O3 sensitivity of open-soil-grown trees compared with potted saplings was a result of senescence-related physiological factors”
Claim · model-written summary
A lower net photosynthesis to stomatal conductance ratio in open-soil-grown trees promoted O3 uptake and led to visible foliar injuries.
- Taxon
- Betula pendulaBetula pendulae1
- Outcome
- onset of visible foliar injuriese2
- Qualifier
- a lower net photosynthesis to stomatal conductance ratioe2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons”
e2“a lower net photosynthesis to stomatal conductance ratio in open-soil-grown trees at the end of the season promoted O3 uptake and decreased photosynthetic gain, leading to the onset of visible foliar injuries”
Claim · model-written summary
Decreased carbohydrate reserves may have caused deleterious carry-over effects through reduced over-wintering bud formation.
- Taxon
- Betula pendulaBetula pendulae1
- Outcome
- deleterious carry-over effectse2
- Qualifier
- decreased carbohydrate reservese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons”
e2“decreased carbohydrate reserves may have resulted in deleterious carry-over effects arising from the reduced formation of over-wintering buds”
Claim · model-written summary
Leaf-level O3 load was higher in open-soil-grown trees than in potted saplings because of slower leaf senescence in the trees.
- Taxon
- Betula pendulaBetula pendulae1
- Outcome
- leaf-level O3 loade2
- Qualifier
- slower leaf senescencee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons”
e2“the leaf-level O3 load was higher for open-soil-grown trees than for potted saplings because of slower leaf senescence in the trees”
Claim · model-written summary
O3 sensitivity in European white birch increases with longer exposure time and larger tree size.
- Taxon
- European white birchBetula pendulae0
- Treatment
- increasing exposure timee0
- Outcome
- O3 sensitivitye0
- Direction
- increasese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O3 sensitivity in European white birch increases with increasing exposure time and tree size”
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See all 9 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.