Abstract
Photosynthetic rates of outdoor-grown soybean (Glycine max L. Merr. cv. Bragg) canopies increased with increasing CO2 concentration during growth, before and after canopy closure (complete light interception), when measured over a wide range of solar irradiance values. Total canopy leaf area was greater as the CO2 concentration during growth was increased from 160 to 990 mm3 dm−3. Photosynthetic rates of canopies grown at 330 and 660 mm3 CO2 dm−3 were similar when measured at the same CO2 concentrations and high irradiance. There was no difference in ribulose bisphosphate carboxylase/oxygenase (rubisco) activity or ribulose 1,5-bisphosphate (RuBP) concentration between plants grown at the two CO2 concentrations. However, photosynthetic rates averaged 87% greater for the canopies grown and measured at 660 mm3 CO2 dm−3. A 10°C difference in air temperature during growth resulted in only a 4°C leaf temperature difference, which was insufficient to change the photosynthetic rate or rubisco activity in canopies grown and measured at either 330 or 660 mm3 CO2 dm−3. RuBP concentrations decreased as air temperature during growth was increased at both CO2 concentrations. These data indicate that the increased photosynthetic rates of soybean canopies at elevated CO2 are due to several factors, including: more rapid development of the leaf area index; a reduction in substrate CO2 limitation; and no downward acclimation in photosynthetic capacity, as occur in some other species.
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Claims 13
Claim · model-written summary
Canopy photosynthetic rates rose with growth CO2 before and after closure across irradiance values.
- Taxon
- soybean
Glycine maxe0 - Material
- Bragge0
- Outcome
- Photosynthetic ratese0
- Direction
- increasede0
- Qualifier
- before and after canopy closuree0
- Setting
- outdoor-growne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Photosynthetic rates of outdoor-grown soybean (Glycine max L. Merr. cv. Bragg) canopies increased with increasing CO2 concentration during growth, before and after canopy closure (complete light interception), when measured over a wide range of solar irradiance values.”
Claim · model-written summary
Total canopy leaf area increased as growth CO2 rose from 160 to 990 mm3 dm−3.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- CO2 concentration during growthe0
- Outcome
- Total canopy leaf areae0
- Direction
- greatere0
- Qualifier
- 160 to 990 mm3 dm−3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total canopy leaf area was greater as the CO2 concentration during growth was increased from 160 to 990 mm3 dm−3.”
t0“Soybean”
Claim · model-written summary
Canopies grown at 330 or 660 mm3 CO2 dm−3 had similar photosynthesis under common measurement CO2 and high irradiance.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- 660 mm3 CO2 dm−3e0
- Outcome
- Photosynthetic ratese0
- Direction
- similare0
- Qualifier
- same CO2 concentrations and high irradiancee0
- Comparator
- 330e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Photosynthetic rates of canopies grown at 330 and 660 mm3 CO2 dm−3 were similar when measured at the same CO2 concentrations and high irradiance.”
t0“Soybean”
Claim · model-written summary
Rubisco activity did not differ between the two growth CO2 levels.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- 660 mm3 CO2 dm−3e1
- Outcome
- ribulose bisphosphate carboxylase/oxygenase (rubisco) activitye0
- Direction
- no differencee0
- Comparator
- 330e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was no difference in ribulose bisphosphate carboxylase/oxygenase (rubisco) activity or ribulose 1,5-bisphosphate (RuBP) concentration between plants grown at the two CO2 concentrations.”
e1“330 and 660 mm3 CO2 dm−3”
t0“Soybean”
Claim · model-written summary
RuBP concentration did not differ between the two growth CO2 levels.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- 660 mm3 CO2 dm−3e1
- Outcome
- ribulose 1,5-bisphosphate (RuBP) concentratione0
- Direction
- no differencee0
- Comparator
- 330e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was no difference in ribulose bisphosphate carboxylase/oxygenase (rubisco) activity or ribulose 1,5-bisphosphate (RuBP) concentration between plants grown at the two CO2 concentrations.”
e1“330 and 660 mm3 CO2 dm−3”
t0“Soybean”
Claim · model-written summary
Canopies grown and measured at 660 mm3 CO2 dm−3 averaged 87% more photosynthesis.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- 660 mm3 CO2 dm−3e0
- Outcome
- photosynthetic ratese0
- Direction
- greatere0
- Value
- 87%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“photosynthetic rates averaged 87% greater for the canopies grown and measured at 660 mm3 CO2 dm−3.”
t0“Soybean”
Claim · model-written summary
A 10°C air temperature difference produced only a 4°C leaf temperature difference.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- 10°C difference in air temperature during growthe0
- Outcome
- leaf temperature differencee0
- Value
- 4°Ce0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A 10°C difference in air temperature during growth resulted in only a 4°C leaf temperature difference”
t0“Soybean”
Claim · model-written summary
The temperature difference did not change photosynthetic rate at either CO2 level.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- 10°C difference in air temperature during growthe1
- Outcome
- photosynthetic ratee0
- Direction
- insufficient to changee0
- Qualifier
- either 330 or 660 mm3 CO2 dm−3e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“which was insufficient to change the photosynthetic rate or rubisco activity in canopies grown and measured at either 330 or 660 mm3 CO2 dm−3.”
e1“A 10°C difference in air temperature during growth”
t0“Soybean”
Claim · model-written summary
The temperature difference did not change rubisco activity at either CO2 level.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- 10°C difference in air temperature during growthe1
- Outcome
- rubisco activitye0
- Direction
- insufficient to changee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“which was insufficient to change the photosynthetic rate or rubisco activity in canopies grown and measured at either 330 or 660 mm3 CO2 dm−3.”
e1“A 10°C difference in air temperature during growth”
t0“Soybean”
Claim · model-written summary
RuBP concentration declined with higher growth air temperature at both CO2 levels.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- air temperature during growthe0
- Outcome
- RuBP concentrationse0
- Direction
- decreasede0
- Qualifier
- both CO2 concentrationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RuBP concentrations decreased as air temperature during growth was increased at both CO2 concentrations.”
t0“Soybean”
Claim · model-written summary
Authors attribute enhanced photosynthesis at elevated CO2 partly to faster leaf area index development.
- Taxon
- soybeanGlycine maxe0
- Treatment
- elevated CO2e0
- Outcome
- increased photosynthetic ratese0
- Qualifier
- more rapid development of the leaf area indexe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increased photosynthetic rates of soybean canopies at elevated CO2 are due to several factors, including: more rapid development of the leaf area index”
Claim · model-written summary
Authors attribute enhanced photosynthesis at elevated CO2 partly to reduced substrate CO2 limitation.
- Taxon
- soybeanGlycine maxe0
- Treatment
- elevated CO2e0
- Outcome
- increased photosynthetic ratese0
- Qualifier
- a reduction in substrate CO2 limitatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increased photosynthetic rates of soybean canopies at elevated CO2 are due to several factors, including: more rapid development of the leaf area index; a reduction in substrate CO2 limitation”
Claim · model-written summary
Authors attribute enhanced photosynthesis at elevated CO2 partly to no downward acclimation in photosynthetic capacity.
- Taxon
- soybeanGlycine maxe0
- Treatment
- elevated CO2e0
- Outcome
- increased photosynthetic ratese0
- Qualifier
- no downward acclimation in photosynthetic capacitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increased photosynthetic rates of soybean canopies at elevated CO2 are due to several factors, including: more rapid development of the leaf area index; a reduction in substrate CO2 limitation; and no downward acclimation in photosynthetic capacity”
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