Abstract
Saplings of one half-sib family of birch, Betula pendula Roth, were exposed to three ozone concentrations (non-filtered air (NF); non-filtered air + 10-20 nmol O(3) mol(-1) (NF+); non-filtered air + 40-60 nmol O(3) mol(-1) (NF++)) in open-top chambers during two growing seasons from 1997 to 1998. Shed leaves were collected regularly during both growing seasons and, in 1998, the dry mass (DM) and nitrogen (N) concentrations ([N]) of the shed leaves were measured to quantify the total amount of N lost through litter fall. Dry mass and [N] were also determined in mid-August for attached, mature and non-senescent leaves, in order to estimate autumnal leaf N resorption efficiency and proportional leaf DM decrease. Net photosynthetic capacity was measured during August and September 1998, in a population of leaves that emerged in mid-July. Photosynthesis declined with increasing leaf age in the NF++ treatment, whereas it remained high throughout the measurement period in the NF and NF+ treatments. In both years, leaves abscised prematurely in the NF++ treatment, whereas this effect was only significant in 1998 in the NF+ treatment. There was a strong linear relationship between proportional leaf shedding and daylight ozone exposure above a threshold of 40 nmol mol(-1) (daylight AOT40) during the growing season. The resorption of N was significantly impaired by ozone, and the smaller autumnal decrease in leaf DM in elevated ozone concentrations suggested that the bulk resorption of leaf DM was also inhibited. Nitrogen resorption efficiencies were 81, 73 and 63% and leaf mass decreases were 45, 36 and 30% in the NF, NF+ and NF++ treatments, respectively. Compared with the NF treatment, total N loss through litter fall was increased by 16 and 122% in the NF+ and NF++ treatments, respectively. We conclude that ozone impaired N resorption from birch leaves before abscission, causing a substantial increase in whole-tree N loss through litter fall.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 15
Claim · model-written summary
Birch photosynthesis declined with leaf age under NF++ ozone.
- Taxon
- birch (Betula pendula)
Betula pendulat0 - Organ / stage
- leafe0
- Treatment
- NF++ treatmente0
- Outcome
- Photosynthesise0
- Direction
- declinede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Photosynthesis declined with increasing leaf age in the NF++ treatment, whereas it remained high throughout the measurement period in the NF and NF+ treatments”
t0“birch (Betula pendula)”
Claim · model-written summary
Birch photosynthesis remained high during measurement under NF and NF+ ozone.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- NF and NF+ treatmentse0
- Outcome
- Photosynthesise0
- Direction
- remained highe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Photosynthesis declined with increasing leaf age in the NF++ treatment, whereas it remained high throughout the measurement period in the NF and NF+ treatments”
t0“birch (Betula pendula)”
Claim · model-written summary
Birch leaves abscised prematurely under NF++ ozone in both years.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- NF++ treatmente0
- Outcome
- leaves abscised prematurelye0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In both years, leaves abscised prematurely in the NF++ treatment, whereas this effect was only significant in 1998 in the NF+ treatment”
t0“birch (Betula pendula)”
Claim · model-written summary
Birch leaf premature abscission under NF+ ozone was significant only in 1998.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- NF+ treatmente0
- Outcome
- leaves abscised prematurelye0
- Qualifier
- only significant in 1998e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In both years, leaves abscised prematurely in the NF++ treatment, whereas this effect was only significant in 1998 in the NF+ treatment”
t0“birch (Betula pendula)”
Claim · model-written summary
Proportional birch leaf shedding had a strong linear relationship with daylight ozone exposure above the stated threshold.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- daylight ozone exposuree0
- Outcome
- proportional leaf sheddinge0
- Qualifier
- above a threshold of 40 nmol mol(-1) (daylight AOT40)e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was a strong linear relationship between proportional leaf shedding and daylight ozone exposure above a threshold of 40 nmol mol(-1) (daylight AOT40) during the growing season”
t0“birch (Betula pendula)”
Claim · model-written summary
Ozone significantly impaired birch leaf nitrogen resorption.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- ozonee0
- Outcome
- resorption of Ne0
- Direction
- impairede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The resorption of N was significantly impaired by ozone, and the smaller autumnal decrease in leaf DM in elevated ozone concentrations suggested that the bulk resorption of leaf DM was also inhibited”
t0“birch (Betula pendula)”
Claim · model-written summary
The smaller autumnal leaf dry mass decrease under elevated ozone suggests inhibited bulk leaf dry mass resorption.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- elevated ozone concentrationse0
- Outcome
- bulk resorption of leaf DMe0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The resorption of N was significantly impaired by ozone, and the smaller autumnal decrease in leaf DM in elevated ozone concentrations suggested that the bulk resorption of leaf DM was also inhibited”
t0“birch (Betula pendula)”
Claim · model-written summary
Birch nitrogen resorption efficiency under NF was 81.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- NFe0
- Outcome
- Nitrogen resorption efficienciese0
- Value
- 81e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen resorption efficiencies were 81, 73 and 63% and leaf mass decreases were 45, 36 and 30% in the NF, NF+ and NF++ treatments, respectively”
t0“birch (Betula pendula)”
Claim · model-written summary
Birch nitrogen resorption efficiency under NF+ was 73.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- NF+e0
- Outcome
- Nitrogen resorption efficienciese0
- Value
- 73e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen resorption efficiencies were 81, 73 and 63% and leaf mass decreases were 45, 36 and 30% in the NF, NF+ and NF++ treatments, respectively”
t0“birch (Betula pendula)”
Claim · model-written summary
Birch nitrogen resorption efficiency under NF++ was 63%.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- NF++e0
- Outcome
- Nitrogen resorption efficienciese0
- Value
- 63%e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen resorption efficiencies were 81, 73 and 63% and leaf mass decreases were 45, 36 and 30% in the NF, NF+ and NF++ treatments, respectively”
t0“birch (Betula pendula)”
Claim · model-written summary
Birch leaf mass decrease under NF was 45.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- NFe0
- Outcome
- leaf mass decreasese0
- Direction
- decreasese0
- Value
- 45e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen resorption efficiencies were 81, 73 and 63% and leaf mass decreases were 45, 36 and 30% in the NF, NF+ and NF++ treatments, respectively”
t0“birch (Betula pendula)”
Claim · model-written summary
Birch leaf mass decrease under NF+ was 36.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- NF+e0
- Outcome
- leaf mass decreasese0
- Direction
- decreasese0
- Value
- 36e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen resorption efficiencies were 81, 73 and 63% and leaf mass decreases were 45, 36 and 30% in the NF, NF+ and NF++ treatments, respectively”
t0“birch (Betula pendula)”
Claim · model-written summary
Birch leaf mass decrease under NF++ was 30%.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- NF++e0
- Outcome
- leaf mass decreasese0
- Direction
- decreasese0
- Value
- 30%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen resorption efficiencies were 81, 73 and 63% and leaf mass decreases were 45, 36 and 30% in the NF, NF+ and NF++ treatments, respectively”
t0“birch (Betula pendula)”
Claim · model-written summary
Birch nitrogen loss through litter fall increased by 16 under NF+ compared with NF.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- NF+e0
- Outcome
- total N loss through litter falle0
- Direction
- increasede0
- Value
- 16e0
- Comparator
- NF treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with the NF treatment, total N loss through litter fall was increased by 16 and 122% in the NF+ and NF++ treatments, respectively”
t0“birch (Betula pendula)”
Claim · model-written summary
Birch nitrogen loss through litter fall increased by 122% under NF++ compared with NF.
- Taxon
- birch (Betula pendula)Betula pendulat0
- Treatment
- NF++e0
- Outcome
- total N loss through litter falle0
- Direction
- increasede0
- Value
- 122%e0
- Comparator
- NF treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with the NF treatment, total N loss through litter fall was increased by 16 and 122% in the NF+ and NF++ treatments, respectively”
t0“birch (Betula pendula)”
The same questions in other papers
ozone · growth · Betula pendula (white birch)Results agree
8 papers in the same direction as this paper
- negative
- negative
- negative
5 papers more in this group
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.