Abstract
The Emerson enhancement effect was evaluated in the intact spinach (Spinacia oleracea var. Long Standing Bloomsdale) chloroplast by monitoring the uptake of (14)CO(2) during illumination by 640 nm and 720 nm lights. Low levels (about 10 mum) of fructose 1,6-diphosphate, ribose 5-phosphate, and glycerate 3-phosphate stimulated the rate of photosynthesis and abolished enhancement values observed in their absence. Concentrations of the two sugar phosphates at levels of 1 mm responded similarly. In contrast, 1 mm glycerate 3-phosphate inhibited the rate of photosynthesis and increased enhancement. The exchange of glycerate 3-phosphate for glyceraldehyde 3-phosphate was speculated to be a factor underlying the decrease in photosynthesis and the increase in enhancement. Glucose 6-phosphate, NADPH, and l-malate did not influence photosynthesis or enhancement.The uncoupler, p-trifluoromethoxyphenylhydrazone, decreased the rate of photosynthesis but did not change the enhancement values. ATP (0.2 to 1 mm) had an occasional stimulating effect on CO(2) fixation but no effect on enhancement. Magnesium ions inhibited photosynthesis and decreased the enhancement values. It was concluded that the enhancement phenomenon reflects events of the photosynthetic carbon reduction cycle as well as the photochemical act.
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Claims 8
Claim · model-written summary
Low concentrations of three phosphate metabolites stimulated photosynthesis and abolished enhancement.
- Taxon
- spinach
Spinacia oleraceat0 - Treatment
- fructose 1,6-diphosphate, ribose 5-phosphate, and glycerate 3-phosphatee0
- Outcome
- rate of photosynthesis and abolished enhancement valuese0
- Direction
- stimulatede0
- Value
- about 10 mume0
- Comparator
- their absencee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Low levels (about 10 mum) of fructose 1,6-diphosphate, ribose 5-phosphate, and glycerate 3-phosphate stimulated the rate of photosynthesis and abolished enhancement values observed in their absence.”
t0“Spinach”
Claim · model-written summary
At 1 mm the two sugar phosphates responded similarly.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- two sugar phosphatese0
- Outcome
- responded similarlye0
- Value
- 1 mme0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Concentrations of the two sugar phosphates at levels of 1 mm responded similarly.”
t0“Spinach”
Claim · model-written summary
At 1 mm glycerate 3-phosphate inhibited photosynthesis and increased enhancement.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- 1 mm glycerate 3-phosphatee0
- Outcome
- rate of photosynthesis and increased enhancemente0
- Direction
- inhibitede0
- Value
- 1 mme0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In contrast, 1 mm glycerate 3-phosphate inhibited the rate of photosynthesis and increased enhancement.”
t0“Spinach”
Claim · model-written summary
Glucose 6-phosphate, NADPH and l-malate did not influence photosynthesis or enhancement.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- Glucose 6-phosphate, NADPH, and l-malatee0
- Outcome
- photosynthesis or enhancemente0
- Direction
- did not influencee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Glucose 6-phosphate, NADPH, and l-malate did not influence photosynthesis or enhancement.”
t0“Spinach”
Claim · model-written summary
The uncoupler decreased photosynthesis but did not change enhancement.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- p-trifluoromethoxyphenylhydrazonee0
- Outcome
- rate of photosynthesis but did not change the enhancement valuese0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The uncoupler, p-trifluoromethoxyphenylhydrazone, decreased the rate of photosynthesis but did not change the enhancement values.”
t0“Spinach”
Claim · model-written summary
ATP occasionally stimulated carbon dioxide fixation but did not affect enhancement.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- ATP (0.2 to 1 mm)e0
- Outcome
- CO(2) fixation but no effect on enhancemente0
- Direction
- stimulatinge0
- Qualifier
- occasionale0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ATP (0.2 to 1 mm) had an occasional stimulating effect on CO(2) fixation but no effect on enhancement.”
t0“Spinach”
Claim · model-written summary
Magnesium ions inhibited photosynthesis and reduced enhancement.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- Magnesium ionse0
- Outcome
- photosynthesis and decreased the enhancement valuese0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Magnesium ions inhibited photosynthesis and decreased the enhancement values.”
t0“Spinach”
Claim · model-written summary
The authors concluded that enhancement reflects carbon reduction cycle events and photochemistry.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- enhancement phenomenone0
- Qualifier
- photosynthetic carbon reduction cycle as well as the photochemical acte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It was concluded that the enhancement phenomenon reflects events of the photosynthetic carbon reduction cycle as well as the photochemical act.”
t0“Spinach”
The same questions in other papers
magnesium ion · physiology: photosynthesis · Spinacia oleracea (spinach)Results agree
1 paper in the same direction as this paper
- 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.