Abstract
Abstract Elevated CO 2 enhances photosynthesis and growth of plants, but the enhancement is strongly influenced by the availability of nitrogen. In this article, we summarise our studies on plant responses to elevated CO 2 . The photosynthetic capacity of leaves depends not only on leaf nitrogen content but also on nitrogen partitioning within a leaf. In Polygonum cuspidatum , nitrogen partitioning among the photosynthetic components was not influenced by elevated CO 2 but changed between seasons. Since the alteration in nitrogen partitioning resulted in different CO 2 ‐dependence of photosynthetic rates, enhancement of photosynthesis by elevated CO 2 was greater in autumn than in summer. Leaf mass per unit area (LMA) increases in plants grown at elevated CO 2 . This increase was considered to have resulted from the accumulation of carbohydrates not used for plant growth. With a sensitive analysis of a growth model, however, we suggested that the increase in LMA is advantageous for growth at elevated CO 2 by compensating for the reduction in leaf nitrogen concentration per unit mass. Enhancement of reproductive yield by elevated CO 2 is often smaller than that expected from vegetative growth. In Xanthium canadense , elevated CO 2 did not increase seed production, though the vegetative growth increased by 53%. As nitrogen concentration of seeds remained constant at different CO 2 levels, we suggest that the availability of nitrogen limited seed production at elevated CO 2 levels. We found that leaf area development of plant canopy was strongly constrained by the availability of nitrogen rather than by CO 2 . In a rice field cultivated at free‐air CO 2 enrichment, the leaf area index (LAI) increased with an increase in nitrogen availability but did not change with CO 2 elevation. We determined optimal LAI to maximise canopy photosynthesis and demonstrated that enhancement of canopy photosynthesis by elevated CO 2 was larger at high than at low nitrogen availability. We also studied competitive asymmetry among individuals in an even‐aged, monospecific stand at elevated CO 2 . Light acquisition (acquired light per unit aboveground mass) and utilisation (photosynthesis per unit acquired light) were calculated for each individual in the stand. Elevated CO 2 enhanced photosynthesis and growth of tall dominants, which reduced the light availability for shorter subordinates and consequently increased size inequality in the stand.
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 16
Claim · model-written summary
In Polygonum cuspidatum, elevated carbon dioxide did not alter nitrogen partitioning among photosynthetic components.
- Taxon
- Polygonum cuspidatum
Polygonum cuspidatume0 - Treatment
- elevated CO 2e0
- Outcome
- nitrogen partitioning among the photosynthetic componentse0
- Direction
- not influencede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In Polygonum cuspidatum , nitrogen partitioning among the photosynthetic components was not influenced by elevated CO 2 but changed between seasons.”
Claim · model-written summary
Nitrogen partitioning in Polygonum cuspidatum changed between seasons.
- Taxon
- Polygonum cuspidatumPolygonum cuspidatume0
- Outcome
- nitrogen partitioning among the photosynthetic componentse0
- Direction
- changede0
- Qualifier
- between seasonse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In Polygonum cuspidatum , nitrogen partitioning among the photosynthetic components was not influenced by elevated CO 2 but changed between seasons.”
Claim · model-written summary
Elevated carbon dioxide enhanced photosynthesis more in autumn than summer.
- Taxon
- Polygonum cuspidatumPolygonum cuspidatumt0
- Treatment
- elevated CO 2e0
- Outcome
- photosynthesise0
- Direction
- greatere0
- Comparator
- summere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“enhancement of photosynthesis by elevated CO 2 was greater in autumn than in summer.”
t0“Polygonum cuspidatum”
Claim · model-written summary
Elevated carbon dioxide increased leaf mass per unit area.
- Taxon
- plantsViridiplantaee0
- Treatment
- elevated CO 2e0
- Outcome
- Leaf mass per unit area (LMA)e0
- Direction
- increasese0
Not reportedComparator
Verbatim
e0“Leaf mass per unit area (LMA) increases in plants grown at elevated CO 2 .”
Claim · model-written summary
Growth modeling suggested that increased LMA offsets reduced leaf nitrogen concentration under elevated carbon dioxide.
- Taxon
- plantsViridiplantaet0
- Outcome
- growthe0
- Direction
- advantageouse0
- Qualifier
- compensating for the reduction in leaf nitrogen concentration per unit masse0
Verbatim
e0“we suggested that the increase in LMA is advantageous for growth at elevated CO 2 by compensating for the reduction in leaf nitrogen concentration per unit mass.”
t0“plants grown at elevated CO 2”
Claim · model-written summary
Elevated carbon dioxide did not increase seed production in Xanthium canadense.
- Taxon
- Xanthium canadense
Xanthium strumarium var. canadensee0 - Treatment
- elevated CO 2e0
- Outcome
- seed productione0
- Direction
- did not increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In Xanthium canadense , elevated CO 2 did not increase seed production, though the vegetative growth increased by 53%.”
Claim · model-written summary
Elevated carbon dioxide increased vegetative growth of Xanthium canadense by 53%.
- Taxon
- Xanthium canadenseXanthium strumarium var. canadensee0
- Treatment
- elevated CO 2e0
- Outcome
- vegetative growthe0
- Direction
- increasede0
- Value
- 53%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In Xanthium canadense , elevated CO 2 did not increase seed production, though the vegetative growth increased by 53%.”
Claim · model-written summary
Seed nitrogen concentration remained constant across carbon dioxide levels.
- Taxon
- Xanthium canadenseXanthium strumarium var. canadenset0
- Treatment
- different CO 2 levelse0
- Outcome
- nitrogen concentration of seedse0
- Direction
- remained constante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nitrogen concentration of seeds remained constant at different CO 2 levels”
t0“Xanthium canadense”
Claim · model-written summary
The authors infer nitrogen availability limited seed production at elevated carbon dioxide.
- Taxon
- Xanthium canadenseXanthium strumarium var. canadenset0
- Outcome
- seed productione0
- Direction
- limitede0
- Qualifier
- availability of nitrogene0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“we suggest that the availability of nitrogen limited seed production at elevated CO 2 levels.”
t0“Xanthium canadense”
Claim · model-written summary
Canopy leaf area development was strongly constrained by nitrogen availability.
Verbatim
e0“leaf area development of plant canopy was strongly constrained by the availability of nitrogen rather than by CO 2 .”
Claim · model-written summary
Rice leaf area index increased as nitrogen availability increased.
- Taxon
- rice
Oryza sativae0 - Compound
- nitrogene0
- Outcome
- leaf area index (LAI)e0
- Direction
- increasede0
- Setting
- rice fielde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In a rice field cultivated at free‐air CO 2 enrichment, the leaf area index (LAI) increased with an increase in nitrogen availability but did not change with CO 2 elevation.”
Claim · model-written summary
Rice leaf area index did not change with carbon dioxide elevation.
- Taxon
- riceOryza sativae0
- Treatment
- CO 2 elevatione0
- Outcome
- leaf area index (LAI)e0
- Direction
- did not changee0
- Setting
- rice fielde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In a rice field cultivated at free‐air CO 2 enrichment, the leaf area index (LAI) increased with an increase in nitrogen availability but did not change with CO 2 elevation.”
Claim · model-written summary
Elevated carbon dioxide enhanced canopy photosynthesis more under high nitrogen availability than low.
- Taxon
- riceOryza sativat0
- Treatment
- elevated CO 2e0
- Outcome
- canopy photosynthesise0
- Direction
- largere0
- Comparator
- low nitrogen availabilitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“enhancement of canopy photosynthesis by elevated CO 2 was larger at high than at low nitrogen availability.”
t0“rice field”
Claim · model-written summary
Elevated carbon dioxide enhanced photosynthesis and growth of tall dominant plants.
- Taxon
- plantsViridiplantaet0
- Treatment
- Elevated CO 2e0
- Outcome
- photosynthesis and growth of tall dominantse0
- Direction
- enhancede0
Not reportedComparator
Verbatim
e0“Elevated CO 2 enhanced photosynthesis and growth of tall dominants, which reduced the light availability for shorter subordinates and consequently increased size inequality in the stand.”
t0“plants grown at elevated CO 2”
Claim · model-written summary
Dominant plant growth under elevated carbon dioxide reduced light for shorter plants.
- Taxon
- plantsViridiplantaet0
- Outcome
- light availability for shorter subordinatese0
- Direction
- reducede0
- Qualifier
- photosynthesis and growth of tall dominantse0
Verbatim
e0“Elevated CO 2 enhanced photosynthesis and growth of tall dominants, which reduced the light availability for shorter subordinates and consequently increased size inequality in the stand.”
t0“plants grown at elevated CO 2”
Claim · model-written summary
Elevated carbon dioxide increased size inequality in the stand.
- Taxon
- plantsViridiplantaet0
- Treatment
- Elevated CO 2e0
- Outcome
- size inequality in the stande0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“Elevated CO 2 enhanced photosynthesis and growth of tall dominants, which reduced the light availability for shorter subordinates and consequently increased size inequality in the stand.”
t0“plants grown at elevated CO 2”
The same questions in other papers
co2 · physiology: photosynthesis · Oryza sativa (rice)Results differ
44 papers in the same direction as this paper · 16 in the opposite direction · 1 reporting no difference from an alternative
- positive
- negative
- negative
58 papers more in this group
See all 62 papers →co2 · yield · Xanthium strumarium (cocklebur)Positive and negative results
1 paper in the same direction as this paper · 4 in the opposite direction
- positive
- positive
- positive
2 papers more in this group
See all 6 papers →co2 · physiology: photosynthesis · Viridiplantae (plants)Positive and negative results
7 papers in the same direction as this paper · 3 in the opposite direction
- negative
- no effect
- negative
7 papers more in this group
See all 11 papers →co2 · growth · Xanthium strumarium (cocklebur)Positive and negative results
11 papers in the same direction as this paper · 4 in the opposite direction
- no effect
- negative
- no effect
12 papers more in this group
See all 16 papers →co2 · growth · Viridiplantae (plants)Positive and negative results
11 papers in the same direction as this paper · 4 in the opposite direction
- negative
- negative
- no effect
12 papers more in this group
See all 16 papers →co2 · growth · Oryza sativa (rice)Positive and negative results
23 papers in the same direction as this paper · 100 in the opposite direction
- positive
- positive
- positive
120 papers more in this group
See all 124 papers →altitude · growth · Oryza sativa (rice)Results agree
2 papers in the same direction as this paper
- no effect
- negative
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.