Abstract
Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest), a C 4 plant, was grown under different light regimes, after which the rate of photosynthesis and activities of several photosynthetic enzymes (per unit leaf chlorophyll) were measured at different light intensities. Plants were grown outdoors under direct sunlight or 23% of direct sunlight, and in growth chambers at photosynthetic photon flux densities of about 20% and 8% of direct sunlight. The plants grown under direct sunlight had a higher light compensation point than plants grown under lower light. At a light intensity about 25% of direct sunlight, plants from all growth regimes had a similar rate of photosynthesis. Under saturating levels of light the plants grown under direct sunlight had a substantially higher rate of photosynthesis than plants grown under the lower light regimes. The higher photosynthetic capacity in the plants grown under direct sunlight was accompanied by an increased activity of several photosynthetic enzymes and in the amount of the soluble protein in the leaf. Among five photosynthetic enzymes examined, RuBP carboxylase (EC 4.1.1.39) and pyruvate, Pi dikinase (EC 2.7.9.1) were generally just sufficient to account for rates of photosynthesis under saturating light; thus, these may be rate limiting enzymes in C 4 photosynthesis. Pyruvate, Pi dikinase and NADP‐malate dehydrogenase (EC 1.1.1.82) were the only enzymes examined which were light activated and increased in activity with increasing light intensity. In the low light grown plants the activity of pyruvate, Pi dikinase closely paralleled the photosynthetic rate measured under different light levels. With the plants grown under direct sunlight, as light intensity was increased the activation of pyruvate, Pi dikinase and NADP + ‐malate dehydrogenase proceeded more rapidly than photosynthesis.
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Claims 12
Claim · model-written summary
Sun-grown plants had a higher light compensation point than plants grown under lower light.
- Material
- Royal Creste0
- Treatment
- direct sunlighte1
- Outcome
- light compensation pointe1
- Direction
- highere1
- Comparator
- lower lighte1
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest)”
e1“The plants grown under direct sunlight had a higher light compensation point than plants grown under lower light”
Claim · model-written summary
At about one-quarter sunlight, plants from all growth regimes had similar photosynthesis rates.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest)”
e1“At a light intensity about 25% of direct sunlight, plants from all growth regimes had a similar rate of photosynthesis”
Claim · model-written summary
Under saturating light, sun-grown plants had substantially higher photosynthesis rates.
- Treatment
- direct sunlighte1
- Outcome
- rate of photosynthesise1
- Direction
- substantially highere1
- Qualifier
- saturating levels of lighte1
- Comparator
- lower light regimese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest)”
e1“Under saturating levels of light the plants grown under direct sunlight had a substantially higher rate of photosynthesis than plants grown under the lower light regimes”
Claim · model-written summary
Sun-grown plants had increased photosynthetic enzyme activity.
- Treatment
- direct sunlighte1
- Outcome
- activity of several photosynthetic enzymese1
- Direction
- increasede1
- Comparator
- lower light regimese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest)”
e1“The higher photosynthetic capacity in the plants grown under direct sunlight was accompanied by an increased activity of several photosynthetic enzymes and in the amount of the soluble protein in the leaf”
e2“lower light regimes”
Claim · model-written summary
Sun-grown plants had increased soluble leaf protein.
- Treatment
- direct sunlighte1
- Outcome
- amount of the soluble protein in the leafe1
- Direction
- increasede1
- Comparator
- lower light regimese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest)”
e1“The higher photosynthetic capacity in the plants grown under direct sunlight was accompanied by an increased activity of several photosynthetic enzymes and in the amount of the soluble protein in the leaf”
e2“lower light regimes”
Claim · model-written summary
RuBP carboxylase activity was generally just sufficient to account for saturating-light photosynthesis and may limit C4 photosynthesis.
- Gene
- RuBP carboxylasee1
- Outcome
- rates of photosynthesis under saturating lighte1
- Qualifier
- may be rate limiting enzymese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest)”
e1“RuBP carboxylase (EC 4.1.1.39) and pyruvate, Pi dikinase (EC 2.7.9.1) were generally just sufficient to account for rates of photosynthesis under saturating light; thus, these may be rate limiting enzymes in C 4 photosynthesis”
Claim · model-written summary
Pyruvate, Pi dikinase activity was generally just sufficient to account for saturating-light photosynthesis and may limit C4 photosynthesis.
- Gene
- pyruvate, Pi dikinasee1
- Outcome
- rates of photosynthesis under saturating lighte1
- Qualifier
- may be rate limiting enzymese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest)”
e1“RuBP carboxylase (EC 4.1.1.39) and pyruvate, Pi dikinase (EC 2.7.9.1) were generally just sufficient to account for rates of photosynthesis under saturating light; thus, these may be rate limiting enzymes in C 4 photosynthesis”
Claim · model-written summary
Pyruvate, Pi dikinase was light activated and increased in activity as light intensity rose.
- Treatment
- increasing light intensitye1
- Gene
- Pyruvate, Pi dikinasee1
- Outcome
- activitye1
- Direction
- increasede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest)”
e1“Pyruvate, Pi dikinase and NADP‐malate dehydrogenase (EC 1.1.1.82) were the only enzymes examined which were light activated and increased in activity with increasing light intensity”
Claim · model-written summary
NADP-malate dehydrogenase was light activated and increased in activity as light intensity rose.
- Treatment
- increasing light intensitye1
- Gene
- NADP‐malate dehydrogenasee1
- Outcome
- activitye1
- Direction
- increasede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest)”
e1“Pyruvate, Pi dikinase and NADP‐malate dehydrogenase (EC 1.1.1.82) were the only enzymes examined which were light activated and increased in activity with increasing light intensity”
Claim · model-written summary
In low-light-grown plants, pyruvate, Pi dikinase activity closely paralleled photosynthetic rate across light levels.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest)”
e1“In the low light grown plants the activity of pyruvate, Pi dikinase closely paralleled the photosynthetic rate measured under different light levels”
Claim · model-written summary
Under increasing light, pyruvate, Pi dikinase activation proceeded faster than photosynthesis in sun-grown plants.
- Gene
- pyruvate, Pi dikinasee1
- Outcome
- activation of pyruvate, Pi dikinasee1
- Direction
- more rapidlye1
- Comparator
- photosynthesise1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest)”
e1“With the plants grown under direct sunlight, as light intensity was increased the activation of pyruvate, Pi dikinase and NADP + ‐malate dehydrogenase proceeded more rapidly than photosynthesis”
Claim · model-written summary
Under increasing light, NADP-malate dehydrogenase activation proceeded faster than photosynthesis in sun-grown plants.
- Gene
- NADP + ‐malate dehydrogenasee1
- Outcome
- activation of pyruvate, Pi dikinase and NADP + ‐malate dehydrogenasee1
- Direction
- more rapidlye1
- Comparator
- photosynthesise1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize ( Zea mays L. Hybrid Sweet Corn, Royal Crest)”
e1“With the plants grown under direct sunlight, as light intensity was increased the activation of pyruvate, Pi dikinase and NADP + ‐malate dehydrogenase proceeded more rapidly than photosynthesis”
The same questions in other papers
light · physiology: osmolytes · Zea mays (maize)Positive and negative results
1 in the opposite direction
- negative
light · physiology: photosynthesis · Zea mays (maize)Positive and negative results
12 papers in the same direction as this paper · 15 in the opposite direction
- no effect
- no effect
- negative
24 papers more in this group
See all 28 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.