Abstract
Plants of alfalfa ( Medicago sativa ) and orchard grass ( Dactylus glomerata ) were grown in controlled environment chambers at two CO 2 concentrations (350 and 700 μmol mol ‐1 ) and 4 constant day/night growth temperatures of 15, 20, 25 and 30°C for 50–90 days to determine changes in growth and whole plant CO 2 efflux (dark respiration). To facilitate comparisons with other studies, respiration data were expressed on the basis of leaf area, dry weight and protein. Growth at elevated CO 2 increased total plant biomass at all temperatures relative to ambient CO 2 , but the relative enhancement declined ( P ≤0.05) as temperature increased. Whole plant respiration (R d ) at elevated CO 2 declined at 15 and 20°C in D. glomerata on an area, weight or protein basis and in M. sativa on a weight or protein basis when compared to ambient CO 2 . Separation of R d into respiration required for growth (R g ) and maintenance (R m ) showed a significant effect of elevated CO 2 on both components. R m was reduced in both species but only at lower temperatures (15°C in M. sativa and 15 and 20°C in D. glomerata ). The effect on R m could not be accounted for by protein content in either species. R g was also reduced with elevated CO 2 ; however no particular effect of temperature was observed, i. e. R g was reduced at 20, 25 and 30°C in M. sativa and at 15 and 25°C in D. glomerata. For the two perennial species used in the present study, the data suggest that both R g and R m can be reduced by anticipated increases in atmospheric CO 2 ; however, CO 2 inhibition of total plant respiration may decline as a function of increasing temperature
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Claims 7
Claim · model-written summary
Elevated CO2 increased biomass in both species at all temperatures.
- Taxon
- alfalfa
Medicago sativat0 - Treatment
- elevated CO 2e0
- Outcome
- total plant biomasse0
- Direction
- increasede0
- Qualifier
- all temperaturese0
- Comparator
- ambient CO 2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Growth at elevated CO 2 increased total plant biomass at all temperatures relative to ambient CO 2 , but the relative enhancement declined ( P ≤0.05) as temperature increased.”
t0“Plants of alfalfa ( Medicago sativa )”
Claim · model-written summary
The biomass enhancement under elevated CO2 declined significantly with increasing temperature.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- temperaturee0
- Outcome
- relative enhancemente0
- Direction
- declinede0
- Value
- P ≤0.05e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the relative enhancement declined ( P ≤0.05) as temperature increased”
t0“Plants of alfalfa ( Medicago sativa )”
Claim · model-written summary
Elevated CO2 reduced orchard grass whole-plant respiration at 15 and 20°C on area, weight, and protein bases.
Verbatim
e0“Whole plant respiration (R d ) at elevated CO 2 declined at 15 and 20°C in D. glomerata on an area, weight or protein basis and in M. sativa on a weight or protein basis when compared to ambient CO 2 .”
Claim · model-written summary
Elevated CO2 reduced alfalfa whole-plant respiration at 15 and 20°C on weight and protein bases.
- Taxon
- M. sativaMedicago sativae0
- Treatment
- elevated CO 2e0
- Outcome
- Whole plant respiration (R d )e0
- Direction
- declinede0
- Qualifier
- weight or protein basise0
- Comparator
- ambient CO 2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Whole plant respiration (R d ) at elevated CO 2 declined at 15 and 20°C in D. glomerata on an area, weight or protein basis and in M. sativa on a weight or protein basis when compared to ambient CO 2 .”
Claim · model-written summary
Elevated CO2 significantly affected both growth and maintenance respiration.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- elevated CO 2e0
- Outcome
- respiration required for growth (R g ) and maintenance (R m )e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Separation of R d into respiration required for growth (R g ) and maintenance (R m ) showed a significant effect of elevated CO 2 on both components.”
t0“Plants of alfalfa ( Medicago sativa )”
Claim · model-written summary
Protein content did not account for the maintenance respiration response in either species.
- Taxon
- alfalfaMedicago sativat0
- Outcome
- effect on R me0
- Qualifier
- could not be accounted for by protein contente0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effect on R m could not be accounted for by protein content in either species.”
t0“Plants of alfalfa ( Medicago sativa )”
Claim · model-written summary
The authors interpreted elevated CO2 inhibition of total respiration as potentially declining with increasing temperature.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- increasing temperaturee0
- Outcome
- CO 2 inhibition of total plant respiratione0
- Direction
- declinee0
- Qualifier
- maye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CO 2 inhibition of total plant respiration may decline as a function of increasing temperature”
t0“Plants of alfalfa ( Medicago sativa )”
The same questions in other papers
co2 · growth · Medicago sativa (alfalfa)Positive and negative results
14 papers in the same direction as this paper · 5 in the opposite direction
- negative
- negative
- no effect
16 papers more in this group
See all 20 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.