Abstract
Net photosynthetic rate, CO(2) compensation concentration, and starch and soluble sugar concentrations were measured in soybean (Glycine max [L.] Merrill) leaves in an attempt to evaluate the effect of carbohydrate concentration on rate of CO(2) assimilation.Plants were grown in a controlled environment room at 23.5 C, 50% relative humidity, 16-hour photoperiod, and quantum flux (400-700 nm) of 510 mueinsteins/m(2).sec (30,090 lux) at plant level. On the 21st day after seeding, plants were subjected for 12.5 hours to one of three CO(2) concentrations (50, 300, or 2000 mul/l) in an attempt to alter leaf carbohydrate levels. Following the CO(2) treatment, gas exchange measurements were made at a CO(2) concentration of 300 mul/l on the lowermost trifoliolate leaf. Immediately after measurement, the leaf was removed and stored at -20 C until carbohydrate analyses were performed.Increasing the CO(2) concentration for 12.5 hours significantly increased leaf starch concentration but not soluble sugar concentration. There was a strong negative correlation between net photosynthetic rate and starch concentration. Net photosynthetic rate declined from approximately 38 to 22 mg CO(2)/dm(2) leaf area.hr as starch concentration increased from 0.5 to 3 mg/cm(2) leaf area. Carbohydrate concentrations had no effect on compensation concentration.The decrease in net photosynthetic rate as starch concentration increased resulted from an increase in mesophyll (liquid phase) CO(2) diffusion resistance. This suggests that starch accumulation may reduce net photosynthetic rate by impeding intracellular CO(2) transport.
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Claims 6
Claim · model-written summary
Higher CO(2) significantly increased leaf starch concentration.
- Taxon
- soybean
Glycine maxt0 - Treatment
- Increasing the CO(2) concentration for 12.5 hourse0
- Outcome
- leaf starch concentratione0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing the CO(2) concentration for 12.5 hours significantly increased leaf starch concentration but not soluble sugar concentration.”
t0“Soybean”
Claim · model-written summary
Higher CO(2) did not change soluble sugar concentration.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Increasing the CO(2) concentration for 12.5 hourse0
- Outcome
- soluble sugar concentratione0
- Direction
- note0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing the CO(2) concentration for 12.5 hours significantly increased leaf starch concentration but not soluble sugar concentration.”
t0“Soybean”
Claim · model-written summary
Net photosynthetic rate correlated negatively with starch concentration.
- Taxon
- soybeanGlycine maxt0
- Compound
- starche0
- Outcome
- net photosynthetic ratee0
- Direction
- negativee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was a strong negative correlation between net photosynthetic rate and starch concentration.”
t0“Soybean”
Claim · model-written summary
Net photosynthetic rate fell from about 38 to 22 mg CO(2)/dm(2) leaf area.hr as starch rose.
- Taxon
- soybeanGlycine maxt0
- Compound
- starche0
- Outcome
- Net photosynthetic ratee0
- Direction
- declinede0
- Value
- 38 to 22 mg CO(2)/dm(2) leaf area.hre0
- Qualifier
- 0.5 to 3 mg/cm(2) leaf areae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Net photosynthetic rate declined from approximately 38 to 22 mg CO(2)/dm(2) leaf area.hr as starch concentration increased from 0.5 to 3 mg/cm(2) leaf area.”
t0“Soybean”
Claim · model-written summary
Carbohydrate concentration did not affect compensation concentration.
- Taxon
- soybeanGlycine maxt0
- Compound
- Carbohydratee0
- Outcome
- compensation concentratione0
- Direction
- no effecte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Carbohydrate concentrations had no effect on compensation concentration.”
t0“Soybean”
Claim · model-written summary
The authors attribute the photosynthetic decline with starch accumulation to increased mesophyll CO(2) diffusion resistance.
- Taxon
- soybeanGlycine maxt0
- Compound
- starche0
- Outcome
- decrease in net photosynthetic ratee0
- Qualifier
- increase in mesophyll (liquid phase) CO(2) diffusion resistancee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The decrease in net photosynthetic rate as starch concentration increased resulted from an increase in mesophyll (liquid phase) CO(2) diffusion resistance.”
t0“Soybean”
The same questions in other papers
co2 · physiology: osmolytes · Glycine max (soybean)Positive and negative results
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- positive
- no effect
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11 papers in the same direction as this paper · 6 in the opposite direction
- positive
- negative
- no effect
14 papers more in this group
See all 18 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.