Abstract
The effects of elevated carbon dioxide concentration ([CO2]) and temperature and their interactions on leaf photosynthesis, reproductive processes, seed weight and seed nitrogen concentration ([N]) of soybeans (Glycine max (L.) Merr.) were investigated using temperature gradient chambers. Plants were grown under four regimes comprising two levels of [CO2], ambient (LC) and ambient +200 μmol mol-1 (HC), and two levels of temperature, low (LT) and high (HT, LT +∼3°C). Plant and seed weights were significantly increased by elevated [CO2] in both temperature regimes. Increased seed weight under elevated [CO2] was mainly because of the production of more nodes and seeds per plant. Increased temperature significantly increased the number of seeds per plant but decreased individual seed weight in both [CO2] regimes. Increased temperature therefore had no effect on seed weight. The increased seed number per plant in the HT regimes resulted from increased pod numbers per node. The light-saturated photosynthetic rate increased with increasing [CO2] and temperature, presumably resulting in more seeds per plant. The reduction in individual seed weight with increased temperature was attributed mainly to lower individual seed growth rate and fewer cotyledon cells per seed. The reduction in individual seed weight with increased temperature was less pronounced in the HC regime than in the LC regime, and there was a significant interaction between [CO2] and temperature. However, there was no interaction between [CO2] and temperature for seed weight. Neither individual effects nor interaction of [CO2] and temperature were observed for seed [N]. This study raises the possibility that projected increases in atmospheric [CO2] during the 21st century will increase the yield of soybeans without decreasing seed [N] in regions that have near or below optimum temperatures (near 25°C or above) for soybean yield.
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Claims 19
Claim · model-written summary
Elevated CO2 significantly increased plant weight in both temperature regimes.
- Taxon
- soybean
Glycine maxt0 - Treatment
- elevated [CO2]e0
- Outcome
- Plant and seed weightse0
- Direction
- increasede0
- Qualifier
- both temperature regimese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plant and seed weights were significantly increased by elevated [CO2] in both temperature regimes.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
Elevated CO2 significantly increased seed weight in both temperature regimes.
- Taxon
- soybeanGlycine maxt0
- Treatment
- elevated [CO2]e0
- Outcome
- seed weighte0
- Direction
- increasede0
- Qualifier
- both temperature regimese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plant and seed weights were significantly increased by elevated [CO2] in both temperature regimes.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
Elevated CO2 increased nodes, contributing to greater seed weight.
- Taxon
- soybeanGlycine maxt0
- Treatment
- elevated [CO2]e0
- Outcome
- nodese0
- Direction
- moree0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased seed weight under elevated [CO2] was mainly because of the production of more nodes and seeds per plant.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
Elevated CO2 increased seeds per plant, contributing to greater seed weight.
- Taxon
- soybeanGlycine maxt0
- Treatment
- elevated [CO2]e0
- Outcome
- seeds per plante0
- Direction
- moree0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased seed weight under elevated [CO2] was mainly because of the production of more nodes and seeds per plant.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
Higher temperature significantly increased seeds per plant in both CO2 regimes.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Increased temperaturee0
- Outcome
- number of seeds per plante0
- Direction
- increasede0
- Qualifier
- both [CO2] regimese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased temperature significantly increased the number of seeds per plant but decreased individual seed weight in both [CO2] regimes.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
Higher temperature decreased individual seed weight in both CO2 regimes.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Increased temperaturee0
- Outcome
- individual seed weighte0
- Direction
- decreasede0
- Qualifier
- both [CO2] regimese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased temperature significantly increased the number of seeds per plant but decreased individual seed weight in both [CO2] regimes.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
Increased temperature had no effect on total seed weight.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Increased temperaturee0
- Outcome
- seed weighte0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased temperature therefore had no effect on seed weight.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
Increased pod numbers per node explained greater seed number per plant at high temperature.
- Taxon
- soybeanGlycine maxt0
- Organ / stage
- pode0
- Outcome
- increased seed number per plante0
- Qualifier
- increased pod numbers per nodee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The increased seed number per plant in the HT regimes resulted from increased pod numbers per node.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
Light-saturated photosynthetic rate increased with rising CO2 and temperature.
- Taxon
- soybeanGlycine maxt0
- Treatment
- increasing [CO2] and temperaturee0
- Outcome
- light-saturated photosynthetic ratee0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The light-saturated photosynthetic rate increased with increasing [CO2] and temperature, presumably resulting in more seeds per plant.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
The authors propose that increased photosynthesis produced more seeds per plant.
- Taxon
- soybeanGlycine maxt0
- Outcome
- more seeds per plante0
- Qualifier
- light-saturated photosynthetic rate increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The light-saturated photosynthetic rate increased with increasing [CO2] and temperature, presumably resulting in more seeds per plant.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
The authors attribute reduced individual seed weight at higher temperature to lower individual seed growth rate.
- Taxon
- soybeanGlycine maxt0
- Treatment
- increased temperaturee0
- Outcome
- reduction in individual seed weighte0
- Qualifier
- lower individual seed growth ratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The reduction in individual seed weight with increased temperature was attributed mainly to lower individual seed growth rate and fewer cotyledon cells per seed.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
The authors attribute reduced individual seed weight at higher temperature to fewer cotyledon cells per seed.
- Taxon
- soybeanGlycine maxt0
- Treatment
- increased temperaturee0
- Outcome
- reduction in individual seed weighte0
- Qualifier
- fewer cotyledon cells per seede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The reduction in individual seed weight with increased temperature was attributed mainly to lower individual seed growth rate and fewer cotyledon cells per seed.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
High CO2 lessened the temperature-associated reduction in individual seed weight relative to low CO2.
- Taxon
- soybeanGlycine maxt0
- Treatment
- increased temperaturee0
- Outcome
- reduction in individual seed weighte0
- Direction
- less pronouncede0
- Qualifier
- HC regimee0
- Comparator
- LC regimee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The reduction in individual seed weight with increased temperature was less pronounced in the HC regime than in the LC regime, and there was a significant interaction between [CO2] and temperature.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
CO2 and temperature did not interact for seed weight.
- Taxon
- soybeanGlycine maxt0
- Treatment
- [CO2] and temperaturee0
- Outcome
- seed weighte0
- Direction
- no interactione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“However, there was no interaction between [CO2] and temperature for seed weight.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
CO2 had no observed individual effect on seed nitrogen concentration.
- Taxon
- soybeanGlycine maxt0
- Treatment
- [CO2]e0
- Outcome
- seed [N]e0
- Direction
- Neither individual effectse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Neither individual effects nor interaction of [CO2] and temperature were observed for seed [N].”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
Temperature had no observed individual effect on seed nitrogen concentration.
- Taxon
- soybeanGlycine maxt0
- Treatment
- temperaturee0
- Outcome
- seed [N]e0
- Direction
- Neither individual effectse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Neither individual effects nor interaction of [CO2] and temperature were observed for seed [N].”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
CO2 and temperature had no observed interaction for seed nitrogen concentration.
- Taxon
- soybeanGlycine maxt0
- Treatment
- [CO2] and temperaturee0
- Outcome
- seed [N]e0
- Direction
- Neither individual effects nor interactione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Neither individual effects nor interaction of [CO2] and temperature were observed for seed [N].”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
The authors suggest future atmospheric CO2 increases may raise soybean yield in regions near or below the optimum temperature.
- Taxon
- soybeanGlycine maxt0
- Outcome
- increase the yield of soybeanse0
- Qualifier
- regions that have near or below optimum temperatures (near 25°C or above)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This study raises the possibility that projected increases in atmospheric [CO2] during the 21st century will increase the yield of soybeans without decreasing seed [N] in regions that have near or below optimum temperatures (near 25°C or above) for soybean yield.”
t0“soybean (Glycine max (L.) Merr.)”
Claim · model-written summary
The authors suggest future atmospheric CO2 increases may avoid lowering seed nitrogen concentration.
- Taxon
- soybeanGlycine maxt0
- Outcome
- without decreasing seed [N]e0
- Qualifier
- regions that have near or below optimum temperatures (near 25°C or above)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This study raises the possibility that projected increases in atmospheric [CO2] during the 21st century will increase the yield of soybeans without decreasing seed [N] in regions that have near or below optimum temperatures (near 25°C or above) for soybean yield.”
t0“soybean (Glycine max (L.) Merr.)”
The same questions in other papers
co2 · yield · Glycine max (soybean)Positive and negative results
85 papers in the same direction as this paper · 10 in the opposite direction
- no effect
- positive
- positive
92 papers more in this group
See all 96 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.