Abstract
ABSTRACT In the first experiment, saplings of ozone‐sensitive and a more tolerant clone of Betula pendula Roth were exposed to ambient ozone (control treatment, accumulated exposure over a threshold 40 nmol mol − 1 (AOT40) exposure of 1·0 μmol mol − 1 h) and 1·5 × ambient ozone (elevated‐ozone treatment, AOT40 of 17·3 μmol mol − 1 h) over one growing season, 1996. After over‐wintering, the dormant elevated‐ozone saplings were transferred to the control blocks and assessed for short‐term carry‐over effects during the following growing season. In the second experiment, three sensitive, four intermediate and three tolerant clones were grown under ambient ozone (control treatment, AOT40 of 0·5–0·8 μmol mol − 1 h per growing season) and 1·6–1·7 × ambient ozone (elevated‐ozone treatment, AOT40 of 18·3–18·6 μmol mol − 1 h per growing season) from May 1994 until May 1996, and were assessed for long‐term carry‐over effects during growing season 1997, after a 12–16 months recovery period. Deleterious short‐term carry‐over effects of ozone exposure included reduced contents of Rubisco, chlorophyll, carotenoids, starch and nutrients in leaves, lower stomatal conductance, and decreased new shoot growth and net assimilation rate, followed by a 7·5% (shoot dry weight (DW)), 15·2% (root DW) and 23·2% (foliage area) decreased biomass accumulation and yield over the long term, including a reduced root : shoot ratio. However, a slow recovery of relative growth rates during the following two seasons without elevated ozone was apparent. Several long‐lasting structural, biochemical and stomatal acclimation, stress‐defence and compensation reactions were observed in the ozone‐tolerant clone, whereas in the sensitive clone allocation shifted from growth towards defensive phenolics such as chlorogenic acid. The results provide evidence of persistent deleterious effects of ozone which remain long after the ozone episode.
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Claims 11
Claim · model-written summary
Ozone exposure reduced Rubisco, chlorophyll and carotenoid contents in birch leaves.
- Taxon
- Betula pendula
Betula pendulat0 - Treatment
- ozone exposuree2
- Outcome
- Rubisco, chlorophyll, carotenoidse2
- Direction
- reducede2
- Comparator
- ambient ozonee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“birch (Betula pendula Roth)”
e2“Deleterious short‐term carry‐over effects of ozone exposure included reduced contents of Rubisco, chlorophyll, carotenoids, starch and nutrients in leaves, lower stomatal conductance, and decreased new shoot growth and net assimilation rate”
e3“exposed to ambient ozone (control treatment”
Claim · model-written summary
Ozone exposure reduced starch and nutrient contents in birch leaves.
- Taxon
- Betula pendulaBetula pendulat0
- Treatment
- ozone exposuree2
- Outcome
- starch and nutrientse2
- Direction
- reducede2
- Comparator
- ambient ozonee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“birch (Betula pendula Roth)”
e2“Deleterious short‐term carry‐over effects of ozone exposure included reduced contents of Rubisco, chlorophyll, carotenoids, starch and nutrients in leaves, lower stomatal conductance, and decreased new shoot growth and net assimilation rate”
e3“exposed to ambient ozone (control treatment”
Claim · model-written summary
Ozone exposure lowered stomatal conductance in birch.
- Taxon
- Betula pendulaBetula pendulat0
- Treatment
- ozone exposuree2
- Outcome
- stomatal conductancee2
- Direction
- lowere2
- Comparator
- ambient ozonee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“birch (Betula pendula Roth)”
e2“Deleterious short‐term carry‐over effects of ozone exposure included reduced contents of Rubisco, chlorophyll, carotenoids, starch and nutrients in leaves, lower stomatal conductance, and decreased new shoot growth and net assimilation rate”
e3“exposed to ambient ozone (control treatment”
Claim · model-written summary
Ozone exposure decreased new shoot growth and net assimilation rate in birch.
- Taxon
- Betula pendulaBetula pendulat0
- Treatment
- ozone exposuree2
- Outcome
- new shoot growth and net assimilation ratee2
- Direction
- decreasede2
- Comparator
- ambient ozonee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“birch (Betula pendula Roth)”
e2“Deleterious short‐term carry‐over effects of ozone exposure included reduced contents of Rubisco, chlorophyll, carotenoids, starch and nutrients in leaves, lower stomatal conductance, and decreased new shoot growth and net assimilation rate”
e3“exposed to ambient ozone (control treatment”
Claim · model-written summary
Ozone exposure decreased shoot dry weight by 7·5% over the long term.
- Taxon
- Betula pendulaBetula pendulat0
- Treatment
- ozone exposuree4
- Outcome
- shoot dry weight (DW)e2
- Direction
- decreasede2
- Value
- 7·5%e2
- Comparator
- ambient ozonee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“birch (Betula pendula Roth)”
e2“followed by a 7·5% (shoot dry weight (DW)), 15·2% (root DW) and 23·2% (foliage area) decreased biomass accumulation and yield over the long term, including a reduced root : shoot ratio”
e3“exposed to ambient ozone (control treatment”
e4“Deleterious short‐term carry‐over effects of ozone exposure included reduced contents of Rubisco, chlorophyll, carotenoids, starch and nutrients in leaves, lower stomatal conductance, and decreased new shoot growth and net assimilation rate”
Claim · model-written summary
Ozone exposure decreased root dry weight by 15·2% over the long term.
- Taxon
- Betula pendulaBetula pendulat0
- Treatment
- ozone exposuree4
- Outcome
- root DWe2
- Direction
- decreasede2
- Value
- 15·2%e2
- Comparator
- ambient ozonee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“birch (Betula pendula Roth)”
e2“followed by a 7·5% (shoot dry weight (DW)), 15·2% (root DW) and 23·2% (foliage area) decreased biomass accumulation and yield over the long term, including a reduced root : shoot ratio”
e3“exposed to ambient ozone (control treatment”
e4“Deleterious short‐term carry‐over effects of ozone exposure included reduced contents of Rubisco, chlorophyll, carotenoids, starch and nutrients in leaves, lower stomatal conductance, and decreased new shoot growth and net assimilation rate”
Claim · model-written summary
Ozone exposure decreased foliage area by 23·2% over the long term.
- Taxon
- Betula pendulaBetula pendulat0
- Treatment
- ozone exposuree4
- Outcome
- foliage areae2
- Direction
- decreasede2
- Value
- 23·2%e2
- Comparator
- ambient ozonee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“birch (Betula pendula Roth)”
e2“followed by a 7·5% (shoot dry weight (DW)), 15·2% (root DW) and 23·2% (foliage area) decreased biomass accumulation and yield over the long term, including a reduced root : shoot ratio”
e3“exposed to ambient ozone (control treatment”
e4“Deleterious short‐term carry‐over effects of ozone exposure included reduced contents of Rubisco, chlorophyll, carotenoids, starch and nutrients in leaves, lower stomatal conductance, and decreased new shoot growth and net assimilation rate”
Claim · model-written summary
Ozone exposure reduced the root : shoot ratio in birch over the long term.
- Taxon
- Betula pendulaBetula pendulat0
- Treatment
- ozone exposuree4
- Outcome
- root : shoot ratioe2
- Direction
- reducede2
- Comparator
- ambient ozonee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“birch (Betula pendula Roth)”
e2“followed by a 7·5% (shoot dry weight (DW)), 15·2% (root DW) and 23·2% (foliage area) decreased biomass accumulation and yield over the long term, including a reduced root : shoot ratio”
e3“exposed to ambient ozone (control treatment”
e4“Deleterious short‐term carry‐over effects of ozone exposure included reduced contents of Rubisco, chlorophyll, carotenoids, starch and nutrients in leaves, lower stomatal conductance, and decreased new shoot growth and net assimilation rate”
Claim · model-written summary
Relative growth rates showed a slow recovery in the two seasons after elevated ozone exposure ended.
- Taxon
- Betula pendulaBetula pendulat0
- Outcome
- slow recovery of relative growth ratese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“birch (Betula pendula Roth)”
e2“a slow recovery of relative growth rates during the following two seasons without elevated ozone was apparent”
Claim · model-written summary
Structural, biochemical and stomatal acclimation occurred in the ozone-tolerant clone.
- Taxon
- Betula pendulaBetula pendulat0
- Material
- tolerant clonee2
- Outcome
- structural, biochemical and stomatal acclimatione2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“birch (Betula pendula Roth)”
e2“Several long‐lasting structural, biochemical and stomatal acclimation, stress‐defence and compensation reactions were observed in the ozone‐tolerant clone”
Claim · model-written summary
In the sensitive clone, allocation shifted from growth towards defensive phenolics such as chlorogenic acid.
- Taxon
- Betula pendulaBetula pendulat0
- Material
- sensitive clonee2
- Compound
- chlorogenic acide2
- Outcome
- allocation shifted from growth towards defensive phenolicse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“birch (Betula pendula Roth)”
e2“whereas in the sensitive clone allocation shifted from growth towards defensive phenolics such as chlorogenic acid”
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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.