Abstract
Mathematical growth analysis techniques were used to evaluate the effects of CO 2 concentrations of 350, 600, and 1000 ppm (v/v) on growth and biomass partitioning in corn (Zea mays L. ‘Dekalb XL 395’), itchgrass ( Rottboellia exaltata L. f.), soybean [ Glycine max (L.) Merr. ‘Tracy’], and velvetleaf ( Abutilon theophrasti Medic). Controlled environment chambers with day/night temperatures of 28/22 C and photosynthetic photon flux densities (PPFD) of 650 μE (microeinsteins) m -2 s -1 were used. Dry matter production in the two C 3 species (soybean and velvetleaf) was increased significantly by raising the CO 2 concentration above 350 ppm. In corn (a C 4 species), dry matter production was least at 1000 ppm CO 2 and did not differ between the 350 and 600 ppm treatments. In itchgrass (also C 4 ), dry matter production was greatest at 600 ppm CO 2 and did not differ between the 350 and 1000 ppm treatments. Increasing the CO 2 concentration increased the rate of dry matter production per unit leaf area (net assimilation rate or NAR) in soybean and velvetleaf but either decreased or did not alter NAR in corn and itchgrass. At 45 days after planting, the weed/crop ratios for total dry matter production for velvetleaf/corn and itchgrass/corn were significantly greater at both 600 and 1000 ppm than at 350 ppm CO 2 . The weed/crop ratio for itchgrass/soybean was less at 1000 ppm than at 350 or 600 ppm CO 2 . Compared to the value at 350 ppm, the weed/crop ratio for velvetleaf/soybean was greater at 600 ppm and less at 1000 ppm CO 2 . We conclude that atmospheric CO 2 enrichment probably will make weeds with the C 3 photosynthetic pathway more competitive with crops having the C 4 pathway. Weeds with the C 4 pathway may become less competitive with crops having the C 3 pathway.
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Claims 14
Claim · model-written summary
Elevated CO2 significantly increased soybean dry matter production.
- Taxon
- soybean
Glycine maxe0 - Treatment
- raising the CO 2 concentration above 350 ppme0
- Outcome
- Dry matter productione0
- Direction
- increasede0
- Comparator
- 350 ppme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Dry matter production in the two C 3 species (soybean and velvetleaf) was increased significantly by raising the CO 2 concentration above 350 ppm”
Claim · model-written summary
Elevated CO2 significantly increased velvetleaf dry matter production.
- Taxon
- velvetleaf
Abutilon theophrastie0 - Treatment
- raising the CO 2 concentration above 350 ppme0
- Outcome
- Dry matter productione0
- Direction
- increasede0
- Comparator
- 350 ppme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Dry matter production in the two C 3 species (soybean and velvetleaf) was increased significantly by raising the CO 2 concentration above 350 ppm”
Claim · model-written summary
Corn dry matter production was lowest at 1000 ppm CO2.
- Taxon
- corn
Zea mays subsp. mayse0 - Treatment
- 1000 ppm CO 2e0
- Outcome
- dry matter productione0
- Direction
- leaste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In corn (a C 4 species), dry matter production was least at 1000 ppm CO 2”
Claim · model-written summary
Corn dry matter production did not differ at 350 and 600 ppm.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- 600 ppme0
- Outcome
- dry matter productione0
- Direction
- did not differe0
- Comparator
- 350e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In corn (a C 4 species), dry matter production was least at 1000 ppm CO 2 and did not differ between the 350 and 600 ppm treatments”
Claim · model-written summary
Itchgrass dry matter production was greatest at 600 ppm.
Not reportedComparator
Verbatim
e0“In itchgrass (also C 4 ), dry matter production was greatest at 600 ppm CO 2”
Claim · model-written summary
Itchgrass dry matter production did not differ between 350 and 1000 ppm.
Verbatim
e0“In itchgrass (also C 4 ), dry matter production was greatest at 600 ppm CO 2 and did not differ between the 350 and 1000 ppm treatments”
Claim · model-written summary
Increasing CO2 increased soybean net assimilation rate.
- Taxon
- soybeanGlycine maxe0
- Treatment
- Increasing the CO 2 concentratione0
- Outcome
- net assimilation rate or NARe0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing the CO 2 concentration increased the rate of dry matter production per unit leaf area (net assimilation rate or NAR) in soybean and velvetleaf”
Claim · model-written summary
Increasing CO2 increased velvetleaf net assimilation rate.
- Taxon
- velvetleafAbutilon theophrastie0
- Treatment
- Increasing the CO 2 concentratione0
- Outcome
- net assimilation rate or NARe0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing the CO 2 concentration increased the rate of dry matter production per unit leaf area (net assimilation rate or NAR) in soybean and velvetleaf”
Claim · model-written summary
Increasing CO2 decreased or did not change corn and itchgrass NAR.
- Taxon
- cornZea mays subsp. mayse0
- Outcome
- NARe0
- Direction
- decreased or did not altere0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“either decreased or did not alter NAR in corn and itchgrass”
Claim · model-written summary
Velvetleaf to corn dry matter ratio was greater at 600 and 1000 ppm.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- 600 and 1000 ppme0
- Interactor
- velvetleafAbutilon theophrastie0weed
- Outcome
- weed/crop ratios for total dry matter production for velvetleaf/corne0
- Direction
- greatere0
- Comparator
- 350 ppme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the weed/crop ratios for total dry matter production for velvetleaf/corn and itchgrass/corn were significantly greater at both 600 and 1000 ppm than at 350 ppm CO 2”
Claim · model-written summary
Itchgrass to corn dry matter ratio was greater at 600 and 1000 ppm.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- 600 and 1000 ppme0
- Interactor
- itchgrasse0weed
- Outcome
- itchgrass/corne0
- Direction
- greatere0
- Comparator
- 350 ppme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the weed/crop ratios for total dry matter production for velvetleaf/corn and itchgrass/corn were significantly greater at both 600 and 1000 ppm than at 350 ppm CO 2”
Claim · model-written summary
Itchgrass to soybean ratio was lower at 1000 ppm than 350 or 600 ppm.
- Taxon
- soybeanGlycine maxe0
- Treatment
- 1000 ppme0
- Interactor
- itchgrasse0weed
- Outcome
- weed/crop ratio for itchgrass/soybeane0
- Direction
- lesse0
- Comparator
- 350 or 600 ppme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The weed/crop ratio for itchgrass/soybean was less at 1000 ppm than at 350 or 600 ppm CO 2”
Claim · model-written summary
Velvetleaf to soybean ratio was greater at 600 ppm than 350 ppm.
- Taxon
- soybeanGlycine maxe0
- Treatment
- 600 ppme0
- Interactor
- velvetleafAbutilon theophrastie0weed
- Outcome
- weed/crop ratio for velvetleaf/soybeane0
- Direction
- greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the weed/crop ratio for velvetleaf/soybean was greater at 600 ppm and less at 1000 ppm CO 2”
Claim · model-written summary
Velvetleaf to soybean ratio was lower at 1000 ppm than 350 ppm.
- Taxon
- soybeanGlycine maxe0
- Treatment
- 1000 ppm CO 2e0
- Interactor
- velvetleafAbutilon theophrastie0weed
- Outcome
- weed/crop ratio for velvetleaf/soybeane0
- Direction
- lesse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the weed/crop ratio for velvetleaf/soybean was greater at 600 ppm and less at 1000 ppm CO 2”
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See all 101 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.