Abstract
Seedlings of six provenances of Betula pubescens Ehrh. from different latitudes (59–70°N) were grown under six ozone exposure regimes by combining different concentrations and daily exposure periods. The different treatments at increasing O3 exposure over 40 nmol mol−1 (AOT40 given in parentheses) were: 19 nmol mol−1/24 h day−1 (0.1 μmol mol−1‐h), 42 nmol mol−1/12 h day−1 (2.5 μmol mol−1‐h), 44 nmol mol−1/24 h day−1 (7.1 μmol mol−1‐h), 76 nmol mol−1/6 h day−1 (9.4 μmol mol−1‐h), 75 nmol mol−1/12 h day−1 (17.8 μmol mol−1) and 116 nmol mol−1/6 h day−1 (19.8 μmol mol−1) for 40 days at a 24 h day−1 photoperiod in growth chambers placed in a greenhouse. The effect of increasing the O3 exposure from 19 nmol mol−1/24 h (0.1 μmol mol−1‐h AOT40) to 42 nmol mol−1/12 h (2.5 μmol mol−1‐h AOT40) was a decrease in root but not shoot dry weight. A further increase in the exposure to 44 nmol mol−1/24 h (7.1 μmol mol−1‐h AOT40) also decreased the shoot dry weight. An increase in the O3 concentration to 75 (9.4–17.8 μmol mol−1‐h AOT40) and 116 nmol mol−1 (19.8 μmol mol−1‐h AOT40) further decreased shoot and root dry weights. A moderate O3 exposure (42 nmol mol−1/12 h = 2.5 μmol mol−1‐h AOT40) increased the plant height and leaf size, while a further increase in O3 concentration and exposure time decreased both of these variables. The birch provenances generally had a similar response to the O3 treatments. The accumulated O3 exposure over the 0, 10, 20, 30, 40 and 50 nmol mol−1 concentrations (AOT0, AOT10, AOT20, AOT30, AOT40 and AOT50, respectively) was calculated for all O3 treatments. The shoot and root dry weights were correlated best with AOT40 and AOT30, and were estimated to decrease by 10% at an AOT40 of 7.0 and 5.5 μmol mol−1‐h, respectively. The development of O3 injury (yellow stipples/chlorosis) was most marked when correlated with AOT40.
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Claims 11
Claim · model-written summary
Increasing ozone from 19 to 42 nmol mol−1 reduced root dry weight.
- Taxon
- Betula pubescens Ehrh.
Betula pubescenst0 - Treatment
- 42 nmol mol−1/12 he0
- Outcome
- roote0
- Direction
- decreasee0
- Comparator
- 19 nmol mol−1/24 he0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effect of increasing the O3 exposure from 19 nmol mol−1/24 h (0.1 μmol mol−1‐h AOT40) to 42 nmol mol−1/12 h (2.5 μmol mol−1‐h AOT40) was a decrease in root but not shoot dry weight”
t0“Betula pubescens Ehrh.”
Claim · model-written summary
The 19-to-42 ozone increase did not reduce shoot dry weight.
- Taxon
- Betula pubescens Ehrh.Betula pubescenst0
- Treatment
- 42 nmol mol−1/12 he0
- Outcome
- shoot dry weighte0
- Direction
- no_changeinferrede0
- Comparator
- 19 nmol mol−1/24 he0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effect of increasing the O3 exposure from 19 nmol mol−1/24 h (0.1 μmol mol−1‐h AOT40) to 42 nmol mol−1/12 h (2.5 μmol mol−1‐h AOT40) was a decrease in root but not shoot dry weight”
t0“Betula pubescens Ehrh.”
Claim · model-written summary
Ozone at 44 nmol mol−1 also decreased shoot dry weight.
- Taxon
- Betula pubescens Ehrh.Betula pubescenst0
- Treatment
- 44 nmol mol−1/24 he0
- Outcome
- shoot dry weighte0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A further increase in the exposure to 44 nmol mol−1/24 h (7.1 μmol mol−1‐h AOT40) also decreased the shoot dry weight”
t0“Betula pubescens Ehrh.”
Claim · model-written summary
Higher ozone concentrations further decreased shoot and root dry weights.
- Taxon
- Betula pubescens Ehrh.Betula pubescenst0
- Treatment
- 75 (9.4–17.8 μmol mol−1‐h AOT40)e0
- Outcome
- shoot and root dry weightse0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“An increase in the O3 concentration to 75 (9.4–17.8 μmol mol−1‐h AOT40) and 116 nmol mol−1 (19.8 μmol mol−1‐h AOT40) further decreased shoot and root dry weights”
t0“Betula pubescens Ehrh.”
Claim · model-written summary
Moderate ozone exposure increased plant height and leaf size.
- Taxon
- Betula pubescens Ehrh.Betula pubescenst0
- Treatment
- 42 nmol mol−1/12 he0
- Outcome
- plant height and leaf sizee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A moderate O3 exposure (42 nmol mol−1/12 h = 2.5 μmol mol−1‐h AOT40) increased the plant height and leaf size”
t0“Betula pubescens Ehrh.”
Claim · model-written summary
Further ozone exposure decreased height and leaf size.
- Taxon
- Betula pubescens Ehrh.Betula pubescenst0
- Treatment
- O3 concentration and exposure timee0
- Outcome
- these variablese0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a further increase in O3 concentration and exposure time decreased both of these variables”
t0“Betula pubescens Ehrh.”
Claim · model-written summary
Birch provenances generally responded similarly to ozone.
Verbatim
e0“The birch provenances generally had a similar response to the O3 treatments”
Claim · model-written summary
Shoot and root dry weights correlated best with AOT40 and AOT30.
- Taxon
- Betula pubescens Ehrh.Betula pubescenst0
- Treatment
- AOT40 and AOT30e0
- Outcome
- shoot and root dry weightse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The shoot and root dry weights were correlated best with AOT40 and AOT30”
t0“Betula pubescens Ehrh.”
Claim · model-written summary
Shoot dry weight was estimated to decrease 10% at AOT40 of 7.0 μmol mol−1‐h.
- Taxon
- Betula pubescens Ehrh.Betula pubescenst0
- Treatment
- AOT40e0
- Outcome
- shoote0
- Direction
- decreasee0
- Value
- 10%e0
- Qualifier
- 7.0e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The shoot and root dry weights were correlated best with AOT40 and AOT30, and were estimated to decrease by 10% at an AOT40 of 7.0 and 5.5 μmol mol−1‐h, respectively”
t0“Betula pubescens Ehrh.”
Claim · model-written summary
Root dry weight was estimated to decrease 10% at AOT40 of 5.5 μmol mol−1‐h.
- Taxon
- Betula pubescens Ehrh.Betula pubescenst0
- Treatment
- AOT40e0
- Outcome
- root dry weightse0
- Direction
- decreasee0
- Value
- 10%e0
- Qualifier
- 5.5 μmol mol−1‐he0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The shoot and root dry weights were correlated best with AOT40 and AOT30, and were estimated to decrease by 10% at an AOT40 of 7.0 and 5.5 μmol mol−1‐h, respectively”
t0“Betula pubescens Ehrh.”
Claim · model-written summary
Visible ozone injury correlated most strongly with AOT40.
- Taxon
- Betula pubescens Ehrh.Betula pubescenst0
- Treatment
- AOT40e0
- Outcome
- O3 injury (yellow stipples/chlorosis)e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The development of O3 injury (yellow stipples/chlorosis) was most marked when correlated with AOT40”
t0“Betula pubescens Ehrh.”