Abstract
Soybean (Glycine max (L.) Merrill) is one of the most important oil and protein sources in the world. Interactive effect of elevated carbon dioxide (CO2) and soil water availability potentially impact future food security of the world under climate change. A rhizotron growth chamber experiment was conducted to study soil moisture interactions with elevated CO2 on gaseous exchange parameters of soybean under two CO2 concentrations (380 and 800 μmol·mol－1) with three soil moisture levels. Elevated CO2 decreased photosynthetic rate (11.1% and 10.8%), stomatal conductance (40.5% and 36.0%), intercellular CO2 concentration (16.68% and 12.28%), relative intercellular CO2 concentration (17.4% and 11.2%), and transpiration rate (43.6% and 39%) at 42 and 47 DAP. This down-regulation of photosynthesis was probably caused by low leaf nitrogen content and decrease in uptake of nutrients due to decrease in stomatal conductance and transpiration rate. Water use efficiency (WUE) increased under elevated CO2 because increase in total dry weight of plant was greater than that of water use under high CO2 conditions. Plants under normal and high soil moisture levels had significantly higher photosynthetic rate (7% to 16%) favored by optimum soil moisture content and high specific water content of soybean plants. Total dry matter production was significantly high when plants grown under elevated CO2 with normal (74.3% to 137.3%) soil moisture level. Photosynthetic rate was significantly and positively correlated with leaf conductance and intercellular CO2 concentration but WUE was significantly negatively correlated with leaf conductance, intercellular CO2 concentration and transpiration rate. However, the effect of high CO2 on plants depends on availability of nutrients and soil moisture for positive feedback from CO2 enrichment.
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Claims 10
Claim · model-written summary
Elevated CO2 decreased photosynthetic rate by 11.1% and 10.8% at 42 and 47 DAP.
- Taxon
- Soybean
Glycine maxt0 - Treatment
- Elevated CO2e0
- Outcome
- photosynthetic ratee0
- Direction
- decreasede0
- Value
- 11.1% and 10.8%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Elevated CO2 decreased photosynthetic rate (11.1% and 10.8%)”
t0“Soybean”
Claim · model-written summary
Elevated CO2 decreased stomatal conductance by 40.5% and 36.0%.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Elevated CO2e0
- Outcome
- stomatal conductancee0
- Direction
- decreasede0
- Value
- 40.5% and 36.0%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Elevated CO2 decreased photosynthetic rate (11.1% and 10.8%), stomatal conductance (40.5% and 36.0%)”
t0“Soybean”
Claim · model-written summary
Elevated CO2 decreased intercellular CO2 concentration by 16.68% and 12.28%.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Elevated CO2e0
- Outcome
- intercellular CO2 concentratione0
- Direction
- decreasede0
- Value
- 16.68% and 12.28%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Elevated CO2 decreased photosynthetic rate (11.1% and 10.8%), stomatal conductance (40.5% and 36.0%), intercellular CO2 concentration (16.68% and 12.28%)”
t0“Soybean”
Claim · model-written summary
Elevated CO2 decreased relative intercellular CO2 concentration by 17.4% and 11.2%.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Elevated CO2e0
- Outcome
- relative intercellular CO2 concentratione0
- Direction
- decreasede0
- Value
- 17.4% and 11.2%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Elevated CO2 decreased photosynthetic rate (11.1% and 10.8%), stomatal conductance (40.5% and 36.0%), intercellular CO2 concentration (16.68% and 12.28%), relative intercellular CO2 concentration (17.4% and 11.2%)”
t0“Soybean”
Claim · model-written summary
Elevated CO2 decreased transpiration rate by 43.6% and 39%.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Elevated CO2e0
- Outcome
- transpiration ratee0
- Direction
- decreasede0
- Value
- 43.6% and 39%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Elevated CO2 decreased photosynthetic rate (11.1% and 10.8%), stomatal conductance (40.5% and 36.0%), intercellular CO2 concentration (16.68% and 12.28%), relative intercellular CO2 concentration (17.4% and 11.2%), and transpiration rate (43.6% and 39%) at 42 and 47 DAP”
t0“Soybean”
Claim · model-written summary
Elevated CO2 increased water use efficiency.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- elevated CO2e0
- Outcome
- Water use efficiency (WUE)e0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water use efficiency (WUE) increased under elevated CO2”
t0“Soybean”
Claim · model-written summary
Normal and high soil moisture gave significantly higher photosynthetic rate by 7% to 16%.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- normal and high soil moisture levelse0
- Outcome
- photosynthetic ratee0
- Direction
- highere0
- Value
- 7% to 16%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants under normal and high soil moisture levels had significantly higher photosynthetic rate (7% to 16%)”
t0“Soybean”
Claim · model-written summary
Elevated CO2 with normal moisture significantly increased total dry matter production by 74.3% to 137.3%.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- elevated CO2 with normal (74.3% to 137.3%) soil moisture levele0
- Outcome
- Total dry matter productione0
- Direction
- highe0
- Value
- 74.3% to 137.3%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total dry matter production was significantly high when plants grown under elevated CO2 with normal (74.3% to 137.3%) soil moisture level”
t0“Soybean”
Claim · model-written summary
Photosynthetic rate correlated positively with leaf conductance and intercellular CO2 concentration.
- Taxon
- SoybeanGlycine maxt0
- Compound
- intercellular CO2 concentratione0
- Outcome
- Photosynthetic ratee0
- Direction
- positively correlatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Photosynthetic rate was significantly and positively correlated with leaf conductance and intercellular CO2 concentration”
t0“Soybean”
Claim · model-written summary
Water use efficiency correlated negatively with leaf conductance, intercellular CO2 concentration and transpiration rate.
- Taxon
- SoybeanGlycine maxt0
- Compound
- intercellular CO2 concentratione0
- Outcome
- WUEe0
- Direction
- negatively correlatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“WUE was significantly negatively correlated with leaf conductance, intercellular CO2 concentration and transpiration rate”
t0“Soybean”
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