Abstract
SUMMARY Rising atmospheric CO 2 profoundly influence plant physiology, yet integrated responses from molecular regulation to carbon allocation remain poorly characterized in C 4 cereals. We employed an integrated physiological, biochemical, and metabolomic approach to investigate how e [CO 2 ] (ambient +200 μmol mol −1 ) modulates carbon and nitrogen metabolism in leaves and stems of foxtail millet ( Setaria italica ). e [CO 2 ] significantly increased net photosynthetic rate (+27.4%) and photosynthetic pigment contents. This enhanced carbon gain was accompanied by increased cuticular wax deposition (+27.1%) and upregulation of wax biosynthesis genes. Stem structural carbohydrates were remodeled, with increased lignin and hemicellulose but reduced cellulose and pectin, suggesting carbon reallocation toward components enhancing lodging resistance. Metabolomic analysis revealed that e [CO 2 ] altered phenylpropanoid and flavonoid biosynthesis pathways, leading to accumulation of multiple flavonoids with potential antioxidant functions. Despite a significant reduction in leaf ABA content (0.05‐fold) and downregulation of ABA biosynthesis genes, stomatal conductance remained unchanged. Exogenous ABA dose–response experiments revealed that e [CO 2 ] increased the half‐maximal inhibitory concentration for ABA‐induced stomatal closure by 248.8%, demonstrating attenuated guard cell sensitivity to ABA. e [CO 2 ] also enhanced non‐structural carbohydrate accumulation while inducing a nitrogen dilution effect, characterized by reduced soluble protein and free amino acids in leaves. Our findings demonstrate that foxtail millet responds to e [CO 2 ] through coordinated reprogramming of primary and secondary metabolism, enhancing structural resilience and antioxidant capacity while maintaining stomatal conductance via reduced ABA sensitivity. These integrated responses provide mechanistic insights into C 4 cereal performance under future climate scenarios and offer potential targets for breeding climate‐resilient crops.
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Claims 15
Claim · model-written summary
Elevated CO2 increased net photosynthetic rate by 27.4%.
- Taxon
- foxtail millet
Setaria italicat0 - Treatment
- e [CO 2 ]e0
- Outcome
- net photosynthetic ratee0
- Direction
- increasede0
- Value
- +27.4%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“e [CO 2 ] significantly increased net photosynthetic rate (+27.4%) and photosynthetic pigment contents.”
t0“foxtail millet”
Claim · model-written summary
Elevated CO2 increased photosynthetic pigment contents.
- Taxon
- foxtail milletSetaria italicat0
- Treatment
- e [CO 2 ]e0
- Outcome
- photosynthetic pigment contentse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“e [CO 2 ] significantly increased net photosynthetic rate (+27.4%) and photosynthetic pigment contents.”
t0“foxtail millet”
Claim · model-written summary
Elevated CO2 increased cuticular wax deposition by 27.1%.
- Taxon
- foxtail milletSetaria italicat0
- Treatment
- e [CO 2 ]e1
- Outcome
- cuticular wax depositione0
- Direction
- increasede0
- Value
- +27.1%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased cuticular wax deposition (+27.1%) and upregulation of wax biosynthesis genes.”
e1“e [CO 2 ] significantly increased net photosynthetic rate (+27.4%) and photosynthetic pigment contents.”
t0“foxtail millet”
Claim · model-written summary
Wax biosynthesis genes were upregulated.
- Taxon
- foxtail milletSetaria italicat0
- Gene
- wax biosynthesis genese0
- Outcome
- upregulation of wax biosynthesis genese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“upregulation of wax biosynthesis genes.”
t0“foxtail millet”
Claim · model-written summary
Elevated CO2 increased stem lignin and hemicellulose.
- Taxon
- foxtail milletSetaria italicat0
- Organ / stage
- Steme0
- Treatment
- e [CO 2 ]e1
- Outcome
- lignin and hemicellulosee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stem structural carbohydrates were remodeled, with increased lignin and hemicellulose but reduced cellulose and pectin”
e1“e [CO 2 ] significantly increased net photosynthetic rate (+27.4%) and photosynthetic pigment contents.”
t0“foxtail millet”
Claim · model-written summary
Elevated CO2 reduced stem cellulose and pectin.
- Taxon
- foxtail milletSetaria italicat0
- Organ / stage
- Steme0
- Treatment
- e [CO 2 ]e1
- Outcome
- cellulose and pectine0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stem structural carbohydrates were remodeled, with increased lignin and hemicellulose but reduced cellulose and pectin”
e1“e [CO 2 ] significantly increased net photosynthetic rate (+27.4%) and photosynthetic pigment contents.”
t0“foxtail millet”
Claim · model-written summary
Elevated CO2 altered phenylpropanoid and flavonoid biosynthesis pathways.
- Taxon
- foxtail milletSetaria italicat0
- Treatment
- e [CO 2 ]e0
- Outcome
- phenylpropanoid and flavonoid biosynthesis pathwayse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“e [CO 2 ] altered phenylpropanoid and flavonoid biosynthesis pathways”
t0“foxtail millet”
Claim · model-written summary
Multiple flavonoids accumulated under elevated CO2.
- Taxon
- foxtail milletSetaria italicat0
- Treatment
- e [CO 2 ]e1
- Outcome
- accumulation of multiple flavonoidse0
- Direction
- accumulatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“leading to accumulation of multiple flavonoids with potential antioxidant functions.”
e1“e [CO 2 ] significantly increased net photosynthetic rate (+27.4%) and photosynthetic pigment contents.”
t0“foxtail millet”
Claim · model-written summary
Elevated CO2 reduced leaf ABA content to 0.05 fold.
- Taxon
- foxtail milletSetaria italicat0
- Treatment
- e [CO 2 ]e1
- Outcome
- leaf ABA contente0
- Direction
- reductione0
- Value
- 0.05‐folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a significant reduction in leaf ABA content (0.05‐fold) and downregulation of ABA biosynthesis genes”
e1“e [CO 2 ] significantly increased net photosynthetic rate (+27.4%) and photosynthetic pigment contents.”
t0“foxtail millet”
Claim · model-written summary
ABA biosynthesis genes were downregulated.
- Taxon
- foxtail milletSetaria italicat0
- Gene
- ABA biosynthesis genese0
- Outcome
- downregulation of ABA biosynthesis genese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“downregulation of ABA biosynthesis genes”
t0“foxtail millet”
Claim · model-written summary
Stomatal conductance remained unchanged.
- Taxon
- foxtail milletSetaria italicat0
- Outcome
- stomatal conductancee0
- Direction
- unchangede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“stomatal conductance remained unchanged.”
t0“foxtail millet”
Claim · model-written summary
Elevated CO2 increased the half maximal inhibitory concentration for ABA induced stomatal closure by 248.8%.
- Taxon
- foxtail milletSetaria italicat0
- Treatment
- e [CO 2 ]e0
- Outcome
- half‐maximal inhibitory concentration for ABA‐induced stomatal closuree0
- Direction
- increasede0
- Value
- 248.8%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“e [CO 2 ] increased the half‐maximal inhibitory concentration for ABA‐induced stomatal closure by 248.8%”
t0“foxtail millet”
Claim · model-written summary
Elevated CO2 enhanced nonstructural carbohydrate accumulation.
- Taxon
- foxtail milletSetaria italicat0
- Treatment
- e [CO 2 ]e0
- Outcome
- non‐structural carbohydrate accumulatione0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“e [CO 2 ] also enhanced non‐structural carbohydrate accumulation”
t0“foxtail millet”
Claim · model-written summary
Elevated CO2 reduced leaf soluble protein and free amino acids.
- Taxon
- foxtail milletSetaria italicat0
- Organ / stage
- leavese0
- Treatment
- e [CO 2 ]e1
- Outcome
- soluble protein and free amino acidse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reduced soluble protein and free amino acids in leaves.”
e1“e [CO 2 ] significantly increased net photosynthetic rate (+27.4%) and photosynthetic pigment contents.”
t0“foxtail millet”
Claim · model-written summary
Authors interpret reduced ABA sensitivity as maintaining stomatal conductance.
- Taxon
- foxtail milletSetaria italicat0
- Outcome
- stomatal conductancee0
- Qualifier
- reduced ABA sensitivitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maintaining stomatal conductance via reduced ABA sensitivity.”
t0“foxtail millet”
The same questions in other papers
co2 · physiology: photosynthesis · Setaria italica (foxtail millet)Results agree
2 papers in the same direction as this paper
- positive
- positive
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.