Abstract
The interactive effects of ozone and light on leaf structure, carbon dioxide uptake and short‐term carbon allocation of sugar maple ( Acer saccharum Marsh.) seedlings were examined using gas exchange measurements and 14 C‐macroautoradiographic techniques. Two‐year‐old sugar maple seedlings were fumigated from budbreak for 5 months with ambient or 3 × ambient ozone in open‐top chambers, receiving either 35% (high light) or 15% (low light) of full sunlight. Ozone accelerated leaf senescence, and reduced net photosynthesis, 14 CO 2 uptake and stomatal conductance, with the effects being most pronounced under low light. The proportion of intercellular space increased in leaves of seedlings grown under elevated ozone and low light, possibly enhancing the susceptibility of mesophyll cells to ozone by increasing the cumulative dose per mesophyll cell. Indeed, damage to spongy mesophyll cells in the elevated ozone × low light treatment was especially frequent. 14 C macroautoradioraphy revealed heterogeneous uptake of 14 CO 2 in well defined areole regions, suggesting patchy stomatal behaviour in all treatments. However, in seedlings grown under elevated ozone and low light, the highest 14 CO 2 uptake occurred along larger veins, while interveinal regions exhibited little or no uptake. Although visible symptoms of ozone injury were not apparent in these seedlings, the cellular damage, reduced photosynthetic rates and reduced whole‐leaf chlorophyll levels corroborate the visual scaling of whole‐plant senescence, suggesting that the ozone × low light treatment accelerated senescence or senescence‐like injury in sugar maple.
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Claims 11
Claim · model-written summary
Ozone accelerated leaf senescence.
- Taxon
- sugar maple
Acer saccharumt0 - Treatment
- Ozonee0
- Outcome
- leaf senescencee0
- Direction
- acceleratede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ozone accelerated leaf senescence”
t0“sugar maple”
Claim · model-written summary
Ozone reduced net photosynthesis.
- Taxon
- sugar mapleAcer saccharumt0
- Treatment
- Ozonee0
- Outcome
- net photosynthesise0
- Direction
- reducede0
- Qualifier
- most pronounced under low lighte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ozone accelerated leaf senescence, and reduced net photosynthesis, 14 CO 2 uptake and stomatal conductance, with the effects being most pronounced under low light”
t0“sugar maple”
Claim · model-written summary
Ozone reduced 14 CO 2 uptake.
- Taxon
- sugar mapleAcer saccharumt0
- Treatment
- Ozonee0
- Outcome
- 14 CO 2 uptakee0
- Direction
- reducede0
- Qualifier
- most pronounced under low lighte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ozone accelerated leaf senescence, and reduced net photosynthesis, 14 CO 2 uptake and stomatal conductance, with the effects being most pronounced under low light”
t0“sugar maple”
Claim · model-written summary
Ozone reduced stomatal conductance.
- Taxon
- sugar mapleAcer saccharumt0
- Treatment
- Ozonee0
- Outcome
- stomatal conductancee0
- Direction
- reducede0
- Qualifier
- most pronounced under low lighte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ozone accelerated leaf senescence, and reduced net photosynthesis, 14 CO 2 uptake and stomatal conductance, with the effects being most pronounced under low light”
t0“sugar maple”
Claim · model-written summary
Intercellular space increased under elevated ozone and low light.
- Taxon
- sugar mapleAcer saccharumt0
- Organ / stage
- leavese0
- Treatment
- elevated ozone and low lighte0
- Outcome
- proportion of intercellular spacee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The proportion of intercellular space increased in leaves of seedlings grown under elevated ozone and low light”
t0“sugar maple”
Claim · model-written summary
Spongy mesophyll damage was especially frequent under elevated ozone and low light.
- Taxon
- sugar mapleAcer saccharumt0
- Treatment
- elevated ozone × low light treatmente0
- Outcome
- damage to spongy mesophyll cellse0
- Direction
- especially frequente0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“damage to spongy mesophyll cells in the elevated ozone × low light treatment was especially frequent”
t0“sugar maple”
Claim · model-written summary
14 CO 2 uptake was heterogeneous across areole regions in all treatments.
- Taxon
- sugar mapleAcer saccharumt0
- Organ / stage
- areole regionse0
- Outcome
- heterogeneous uptake of 14 CO 2e0
- Qualifier
- all treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“heterogeneous uptake of 14 CO 2 in well defined areole regions, suggesting patchy stomatal behaviour in all treatments”
t0“sugar maple”
Claim · model-written summary
Under elevated ozone and low light, highest 14 CO 2 uptake occurred along larger veins.
- Taxon
- sugar mapleAcer saccharumt0
- Organ / stage
- larger veinse0
- Outcome
- highest 14 CO 2 uptakee0
- Qualifier
- elevated ozone and low lighte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in seedlings grown under elevated ozone and low light, the highest 14 CO 2 uptake occurred along larger veins”
t0“sugar maple”
Claim · model-written summary
Under elevated ozone and low light, interveinal regions had little or no 14 CO 2 uptake.
- Taxon
- sugar mapleAcer saccharumt0
- Organ / stage
- interveinal regionse0
- Outcome
- little or no uptakee0
- Qualifier
- 14 CO 2e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“interveinal regions exhibited little or no uptake”
e1“14 CO 2 uptake occurred along larger veins”
t0“sugar maple”
Claim · model-written summary
Visible ozone injury symptoms were absent.
- Taxon
- sugar mapleAcer saccharumt0
- Outcome
- visible symptoms of ozone injury were not apparente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“visible symptoms of ozone injury were not apparent in these seedlings”
t0“sugar maple”
Claim · model-written summary
Ozone and low light accelerated senescence or similar injury.
- Taxon
- sugar mapleAcer saccharume0
- Treatment
- ozone × low light treatmente0
- Outcome
- senescence or senescence‐like injurye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the ozone × low light treatment accelerated senescence or senescence‐like injury in sugar maple”
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
- no effect
- positive
- negative
4 papers more in this group
See all 8 papers →ozone · quality: postharvest · Acer saccharum (sugar maple)Results agree
2 papers in the same direction as this paper
- no effect
- 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.