Abstract
Long-term carbon dioxide enrichment, (14)CO(2) feeding, and partial defoliation were employed as probes to investigate source/sink limitations of photosynthesis during the development of symbiotically grown alfalfa. In the mature crop, long-term CO(2) enrichment does not affect the rates of net photosynthesis, relative growth, (14)C export to nonphotosynthetic organs, or the rates of (14)C label incorporation into leaf sucrose, starch, or malate. The rate of glycolate labeling is, however, substantially reduced under these conditions. When the mature crop was partially defoliated, a considerable increase in net photosynthesis occurred in the remaining leaves. In the seedling crop, long-term CO(2) enrichment increased dry matter accumulation, primarily as a result of increases in leaf starch content. Although the higher rates of starch synthesis are not maintained, the growth enhancement of the enriched plants persisted throughout the experimental period. These results imply a source limitation of seedling photosynthesis and a sink limitation of photosynthesis in more mature plants. Consequently, both the supply and the utilization of photosynthate may limit seasonal photosynthesis in alfalfa.
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Claims 11
Claim · model-written summary
Long-term CO2 enrichment did not affect net photosynthesis, relative growth or 14C export in the mature alfalfa crop.
- Taxon
- alfalfa
Medicago sativae1 - Organ / stage
- mature crope2
- Treatment
- long-term CO(2) enrichmente2
- Outcome
- rates of net photosynthesis, relative growth, (14)C export to nonphotosynthetic organse2
- Direction
- does not affecte2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“symbiotically grown alfalfa”
e2“In the mature crop, long-term CO(2) enrichment does not affect the rates of net photosynthesis, relative growth, (14)C export to nonphotosynthetic organs, or the rates of (14)C label incorporation into leaf sucrose, starch, or malate”
Claim · model-written summary
Long-term CO2 enrichment did not affect 14C label incorporation into leaf sucrose, starch or malate in the mature alfalfa crop.
- Taxon
- alfalfaMedicago sativae1
- Organ / stage
- mature crope2
- Treatment
- long-term CO(2) enrichmente2
- Outcome
- (14)C label incorporation into leaf sucrose, starch, or malatee2
- Direction
- does not affecte2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“symbiotically grown alfalfa”
e2“In the mature crop, long-term CO(2) enrichment does not affect the rates of net photosynthesis, relative growth, (14)C export to nonphotosynthetic organs, or the rates of (14)C label incorporation into leaf sucrose, starch, or malate”
Claim · model-written summary
Long-term CO2 enrichment substantially reduced the rate of glycolate labeling in the mature alfalfa crop.
- Taxon
- alfalfaMedicago sativae1
- Organ / stage
- mature crope2
- Treatment
- long-term CO(2) enrichmente2
- Outcome
- rate of glycolate labelinge3
- Direction
- substantially reducede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“symbiotically grown alfalfa”
e2“In the mature crop, long-term CO(2) enrichment does not affect the rates of net photosynthesis, relative growth, (14)C export to nonphotosynthetic organs, or the rates of (14)C label incorporation into leaf sucrose, starch, or malate”
e3“The rate of glycolate labeling is, however, substantially reduced under these conditions”
Claim · model-written summary
Partial defoliation of the mature alfalfa crop caused a considerable increase in net photosynthesis in the remaining leaves.
- Taxon
- alfalfaMedicago sativae1
- Organ / stage
- remaining leavese2
- Treatment
- partially defoliatede2
- Outcome
- net photosynthesise2
- Direction
- increasee2
- Qualifier
- considerablee2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“symbiotically grown alfalfa”
e2“When the mature crop was partially defoliated, a considerable increase in net photosynthesis occurred in the remaining leaves”
Claim · model-written summary
Long-term CO2 enrichment increased dry matter accumulation in the seedling alfalfa crop.
- Taxon
- alfalfaMedicago sativae1
- Organ / stage
- seedling crope2
- Treatment
- long-term CO(2) enrichmente2
- Outcome
- dry matter accumulatione2
- Direction
- increasede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“symbiotically grown alfalfa”
e2“In the seedling crop, long-term CO(2) enrichment increased dry matter accumulation, primarily as a result of increases in leaf starch content”
Claim · model-written summary
The dry matter gain in seedling alfalfa is primarily due to increased leaf starch content.
- Taxon
- alfalfaMedicago sativae1
- Compound
- starche2
- Outcome
- dry matter accumulatione2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“symbiotically grown alfalfa”
e2“In the seedling crop, long-term CO(2) enrichment increased dry matter accumulation, primarily as a result of increases in leaf starch content”
Claim · model-written summary
The higher rates of starch synthesis in enriched seedlings are not maintained.
- Taxon
- alfalfaMedicago sativae1
- Outcome
- rates of starch synthesise2
- Direction
- highere2
- Qualifier
- are not maintainede2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“symbiotically grown alfalfa”
e2“Although the higher rates of starch synthesis are not maintained, the growth enhancement of the enriched plants persisted throughout the experimental period”
Claim · model-written summary
The growth enhancement of CO2-enriched alfalfa plants persisted throughout the experimental period.
- Taxon
- alfalfaMedicago sativae1
- Treatment
- enriched plantse2
- Outcome
- growth enhancemente2
- Direction
- persistede2
- Qualifier
- throughout the experimental periode2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“symbiotically grown alfalfa”
e2“Although the higher rates of starch synthesis are not maintained, the growth enhancement of the enriched plants persisted throughout the experimental period”
Claim · model-written summary
Seedling alfalfa photosynthesis is source-limited (authors infer).
- Taxon
- alfalfaMedicago sativae1
- Organ / stage
- seedlinge2
- Outcome
- seedling photosynthesise2
- Qualifier
- source limitatione2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“symbiotically grown alfalfa”
e2“These results imply a source limitation of seedling photosynthesis and a sink limitation of photosynthesis in more mature plants”
Claim · model-written summary
Photosynthesis in more mature alfalfa plants is sink-limited (authors infer).
- Taxon
- alfalfaMedicago sativae1
- Organ / stage
- more mature plantse2
- Outcome
- photosynthesise2
- Qualifier
- sink limitation of photosynthesis in more mature plantse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“symbiotically grown alfalfa”
e2“These results imply a source limitation of seedling photosynthesis and a sink limitation of photosynthesis in more mature plants”
Claim · model-written summary
Supply and utilization of photosynthate may limit seasonal photosynthesis in alfalfa (hypothesis).
- Taxon
- alfalfaMedicago sativae1
- Outcome
- seasonal photosynthesise1
- Qualifier
- both the supply and the utilization of photosynthatee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Consequently, both the supply and the utilization of photosynthate may limit seasonal photosynthesis in alfalfa”
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See all 6 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.