Abstract
Long-term and short-term effects of CO2 enrichment on dark respiration were investigated using soybean (Glycine max [L.] Merr.) plants grown at either 35.5 or 71.0 Pa CO2. Indirect effects, or effects of growth in elevated CO2, were examined using a functional model that partitioned respiration into growth and maintenance components. Direct effects, or immediate effects of a short-term change in CO2, were examined by measuring dark respiration, first, at the CO2 partial pressure at which plants were grown, and second, after equilibration in the reciprocal CO2 partial pressure. The functional component model indicated that the maintenance coefficient of respiration increased 34% with elevated CO2, whereas the growth coefficient was not significantly affected. Changes in maintenance respiration were correlated with a 33% increase in leaf total nonstructural carbohydrate concentration, but leaf nitrogen content of soybean leaves was not affected by CO2 enrichment. Thus, increased maintenance respiration may be a consequence of increased nonstructural carbohydrate accumulation. When whole soybean plants were switched from low CO2 to high CO2 for a brief period, leaf respiration was always reduced. However, this direct effect of CO2 partial pressure was approximately 50% less in plants grown in elevated CO2. We conclude from this study that there are potentially important effects of CO2 enrichment on plant respiration but that the effects are different for plants given a short-term increase in CO2 partial pressure versus plants grown in elevated CO2.
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Claims 7
Claim · model-written summary
Elevated CO2 increased the maintenance coefficient of respiration by 34%.
- Taxon
- soybean
Glycine maxe1 - Treatment
- elevated CO2e0
- Outcome
- maintenance coefficient of respiratione0
- Direction
- increasede0
- Value
- 34%e0
- Comparator
- 35.5e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the maintenance coefficient of respiration increased 34% with elevated CO2”
e1“soybean (Glycine max [L.] Merr.) plants grown at either 35.5 or 71.0 Pa CO2”
Claim · model-written summary
Elevated CO2 did not significantly affect the growth coefficient of respiration.
- Taxon
- soybeanGlycine maxe2
- Treatment
- elevated CO2e1
- Outcome
- growth coefficiente0
- Direction
- not significantly affectede0
- Comparator
- 35.5e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the growth coefficient was not significantly affected.”
e1“with elevated CO2”
e2“soybean (Glycine max [L.] Merr.) plants grown at either 35.5 or 71.0 Pa CO2”
Claim · model-written summary
Maintenance respiration changes correlated with a 33% increase in leaf total nonstructural carbohydrate concentration.
- Taxon
- soybeanGlycine maxe1
- Compound
- total nonstructural carbohydratee0
- Outcome
- maintenance respiratione0
- Direction
- increasee0
- Value
- 33%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Changes in maintenance respiration were correlated with a 33% increase in leaf total nonstructural carbohydrate concentration”
e1“soybean leaves”
Claim · model-written summary
CO2 enrichment did not affect soybean leaf nitrogen content.
- Taxon
- soybeanGlycine maxe0
- Treatment
- CO2 enrichmente0
- Outcome
- leaf nitrogen contente0
- Direction
- not affectede0
- Comparator
- 35.5e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“leaf nitrogen content of soybean leaves was not affected by CO2 enrichment.”
e1“35.5 or 71.0 Pa CO2”
Claim · model-written summary
Short switching of whole soybean plants from low to high CO2 always reduced leaf respiration.
- Taxon
- soybeanGlycine maxe0
- Treatment
- high CO2e0
- Outcome
- leaf respiratione0
- Direction
- reducede0
- Qualifier
- for a brief periode0
- Comparator
- low CO2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When whole soybean plants were switched from low CO2 to high CO2 for a brief period, leaf respiration was always reduced.”
Claim · model-written summary
The direct effect of CO2 partial pressure was approximately 50% less in plants grown in elevated CO2.
- Taxon
- soybeanGlycine maxe1
- Treatment
- elevated CO2e0
- Outcome
- direct effect of CO2 partial pressuree0
- Direction
- lesse0
- Value
- 50%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this direct effect of CO2 partial pressure was approximately 50% less in plants grown in elevated CO2.”
e1“soybean plants”
Claim · model-written summary
Increased maintenance respiration may result from increased nonstructural carbohydrate accumulation.
- Taxon
- soybeanGlycine maxe1
- Compound
- nonstructural carbohydratee0
- Outcome
- increased maintenance respiratione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased maintenance respiration may be a consequence of increased nonstructural carbohydrate accumulation.”
e1“soybean plants”
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See all 101 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.