Abstract
Abstract The long‐term interactive effects of ozone and light on whole‐tree carbon balance of sugar maple ( Acer saccharum Marsh.) seedlings were examined, with an emphasis on carbon acquisition, foliar partitioning into starch and soluble sugars, and allocation to growth. Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively). Three years of ozone fumigation reduced the total biomass of seedlings in the low‐ and high‐light treatments by 64 and 41%, respectively, but had no effect on whole‐plant biomass allocation. Ozone had no effect on net photosynthesis until late in the growing season, with low‐light seedlings generally exhibiting more pronounced reductions in photosynthesis. The late‐season reduction in photosynthesis was not due to impaired stomatal function, but was associated more with accelerated senescence or senescence‐like injury. In contrast, the 3·0 × ambient ozone treatment immediately reduced diurnal starch accumulation in leaves by over 50% and increased partitioning of total non‐structural carbohydrates into soluble sugars, suggesting that injury repair processes may be maintaining photosynthesis in late spring and early summer at the expense of storage carbon. The results in the present study indicate that changes in leaf‐level photosynthesis may not accurately predict the growth response of sugar maple to ozone in different light environments. The larger reduction in seedling growth under low‐light conditions suggests that seedlings in gap or closed‐canopy environments are more susceptible to ozone than those in a clearing. Similarly, understanding the effects of tropospheric ozone on net carbon gain of a mature tree will require scaling of leaf‐level responses to heterogeneous light environments, where some leaves may be more susceptible than others.
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Claims 12
Claim · model-written summary
Three years of ozone fumigation reduced total seedling biomass by 64% in the low-light treatment.
- Taxon
- Sugar maple
Acer saccharume1 - Treatment
- ozone fumigatione2
- Outcome
- total biomasse2
- Direction
- reducede2
- Value
- 64e2
- Qualifier
- low‐ and high‐light treatmentse2
- Comparator
- ambiente1
- Setting
- open‐top chamberse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively)”
e2“Three years of ozone fumigation reduced the total biomass of seedlings in the low‐ and high‐light treatments by 64 and 41%, respectively”
Claim · model-written summary
Three years of ozone fumigation reduced total seedling biomass by 41% in the high-light treatment.
- Taxon
- Sugar mapleAcer saccharume1
- Treatment
- ozone fumigatione2
- Outcome
- total biomasse2
- Direction
- reducede2
- Value
- 41%e2
- Qualifier
- low‐ and high‐light treatmentse2
- Comparator
- ambiente1
- Setting
- open‐top chamberse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively)”
e2“Three years of ozone fumigation reduced the total biomass of seedlings in the low‐ and high‐light treatments by 64 and 41%, respectively”
Claim · model-written summary
Ozone had no effect on whole-plant biomass allocation.
- Taxon
- Sugar mapleAcer saccharume1
- Treatment
- ozonee1
- Outcome
- whole‐plant biomass allocatione3
- Direction
- no effecte3
- Comparator
- ambiente1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively)”
e3“but had no effect on whole‐plant biomass allocation”
Claim · model-written summary
Ozone had no effect on net photosynthesis until late in the growing season.
- Taxon
- Sugar mapleAcer saccharume1
- Treatment
- Ozonee4
- Outcome
- net photosynthesise4
- Direction
- no effecte4
- Qualifier
- until late in the growing seasone4
- Comparator
- ambiente1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively)”
e4“Ozone had no effect on net photosynthesis until late in the growing season”
Claim · model-written summary
Late-season reductions in photosynthesis were more pronounced in low-light seedlings.
- Taxon
- Sugar mapleAcer saccharume1
- Treatment
- low‐light seedlingse5
- Outcome
- reductions in photosynthesise5
- Direction
- more pronounced reductionse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively)”
e5“with low‐light seedlings generally exhibiting more pronounced reductions in photosynthesis”
Claim · model-written summary
The late-season reduction in photosynthesis was not due to impaired stomatal function.
- Taxon
- Sugar mapleAcer saccharume1
- Outcome
- late‐season reduction in photosynthesise6
- Qualifier
- not due to impaired stomatal functione6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively)”
e6“The late‐season reduction in photosynthesis was not due to impaired stomatal function, but was associated more with accelerated senescence or senescence‐like injury”
Claim · model-written summary
The late-season reduction in photosynthesis was associated with accelerated senescence or senescence-like injury.
- Taxon
- Sugar mapleAcer saccharume1
- Outcome
- late‐season reduction in photosynthesise6
- Qualifier
- accelerated senescence or senescence‐like injurye6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively)”
e6“The late‐season reduction in photosynthesis was not due to impaired stomatal function, but was associated more with accelerated senescence or senescence‐like injury”
Claim · model-written summary
The 3·0 × ambient ozone treatment immediately reduced diurnal starch accumulation in leaves by over 50%.
- Taxon
- Sugar mapleAcer saccharume1
- Organ / stage
- leavese7
- Treatment
- 3·0 × ambient ozone treatmente7
- Outcome
- diurnal starch accumulation in leavese7
- Direction
- reducede7
- Value
- over 50%e7
- Comparator
- ambiente7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively)”
e7“the 3·0 × ambient ozone treatment immediately reduced diurnal starch accumulation in leaves by over 50% and increased partitioning of total non‐structural carbohydrates into soluble sugars”
Claim · model-written summary
The 3·0 × ambient ozone treatment increased partitioning of total non-structural carbohydrates into soluble sugars.
- Taxon
- Sugar mapleAcer saccharume1
- Treatment
- 3·0 × ambient ozone treatmente7
- Outcome
- partitioning of total non‐structural carbohydrates into soluble sugarse7
- Direction
- increasede7
- Comparator
- ambiente7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively)”
e7“the 3·0 × ambient ozone treatment immediately reduced diurnal starch accumulation in leaves by over 50% and increased partitioning of total non‐structural carbohydrates into soluble sugars”
Claim · model-written summary
Injury repair processes may maintain photosynthesis in late spring and early summer at the expense of storage carbon.
- Taxon
- Sugar mapleAcer saccharume1
- Outcome
- maintaining photosynthesise0
- Qualifier
- injury repair processese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively)”
e0“suggesting that injury repair processes may be maintaining photosynthesis in late spring and early summer at the expense of storage carbon”
Claim · model-written summary
Changes in leaf-level photosynthesis may not accurately predict the growth response of sugar maple to ozone.
- Taxon
- sugar mapleAcer saccharume0
- Outcome
- growth responsee0
- Qualifier
- may not accurately predicte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively)”
e0“The results in the present study indicate that changes in leaf‐level photosynthesis may not accurately predict the growth response of sugar maple to ozone in different light environments”
Claim · model-written summary
The larger reduction in seedling growth under low light suggests that seedlings in gaps or closed canopies are more susceptible to ozone.
- Taxon
- Sugar mapleAcer saccharume1
- Treatment
- low‐light conditionse0
- Outcome
- seedling growthe0
- Direction
- larger reductione0
- Qualifier
- gap or closed‐canopy environmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively)”
e0“The larger reduction in seedling growth under low‐light conditions suggests that seedlings in gap or closed‐canopy environments are more susceptible to ozone than those in a clearing”
The same questions in other papers
ozone · physiology: photosynthesis · Acer saccharum (sugar maple)Results differ
6 papers in the same direction as this paper · 1 in the opposite direction
- negative
- positive
- negative
4 papers more in this group
See all 8 papers →ozone · growth · Acer saccharum (sugar maple)Results differ
8 papers in the same direction as this paper
- negative
- negative
- no effect
5 papers more in this group
See all 9 papers →ozone · quality: sugar starch · Acer saccharum (sugar maple)Results agree
1 paper in the same direction as this paper
- negative
solarization · growth · Acer saccharum (sugar maple)Results agree
2 papers in the same direction as this paper
- negative
- no effect
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.