Abstract
Premise Atmospheric carbon dioxide (CO 2 ) concentration is increasing, as is the frequency and duration of drought in some regions. Elevated CO 2 can decrease the effects of drought by further decreasing stomatal opening and, hence, water loss from leaves. Both elevated CO 2 and drought typically decrease plant nutrient concentration, but their interactive effects on nutrient status and uptake are little studied. We investigated whether elevated CO 2 helps negate the decrease in plant nutrient status during drought by upregulating nutrient‐uptake proteins in roots. Methods Barley ( Hordeum vulgare ) was subjected to current vs. elevated CO 2 (400 or 700 ppm) and drought vs. well‐watered conditions, after which we measured biomass, tissue nitrogen (N) and phosphorus (P) concentrations (%N and P), N‐ and P‐uptake rates, and the concentration of the major N‐ and P‐uptake proteins in roots. Results Elevated CO 2 decreased the impact of drought on biomass. In contrast, both drought and elevated CO 2 decreased %N and %P in most cases, and their effects were additive for shoots. Root N‐ and P‐uptake rates were strongly decreased by drought, but were not significantly affected by CO 2 . Averaged across treatments, both drought and high CO 2 resulted in upregulation of NRT1 (NO 3 − transporter) and AMT1 (NH 4 + transporter) per unit total root protein, while only drought increased PHT1 (P transporter). Conclusions Elevated CO 2 exacerbated decreases in %N and %P, and hence food quality, during drought, despite increases in the concentration of nutrient‐uptake proteins in roots, indicating other limitations to nutrient uptake.
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Claims 11
Claim · model-written summary
Elevated CO2 decreased the impact of drought on barley biomass.
- Taxon
- Barley
.jpg?width=60)
Hordeum vulgaree0 - Treatment
- Elevated CO 2e1
- Outcome
- impact of drought on biomasse1
- Direction
- decreasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Barley ( Hordeum vulgare )”
e1“Elevated CO 2 decreased the impact of drought on biomass”
Claim · model-written summary
Drought decreased tissue N and P concentrations (%N and %P) in barley in most cases.
- Taxon
- BarleyHordeum vulgaree0
- Treatment
- droughte1
- Outcome
- %N and %Pe1
- Direction
- decreasede1
- Qualifier
- in most casese1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Barley ( Hordeum vulgare )”
e1“both drought and elevated CO 2 decreased %N and %P in most cases, and their effects were additive for shoots”
Claim · model-written summary
Elevated CO2 decreased tissue N and P concentrations (%N and %P) in barley in most cases.
- Taxon
- BarleyHordeum vulgaree0
- Treatment
- elevated CO 2e1
- Outcome
- %N and %Pe1
- Direction
- decreasede1
- Qualifier
- in most casese1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Barley ( Hordeum vulgare )”
e1“both drought and elevated CO 2 decreased %N and %P in most cases, and their effects were additive for shoots”
Claim · model-written summary
The effects of drought and elevated CO2 on %N and %P were additive for shoots.
- Taxon
- BarleyHordeum vulgaree0
- Organ / stage
- shootse1
- Outcome
- their effects were additivee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Barley ( Hordeum vulgare )”
e1“both drought and elevated CO 2 decreased %N and %P in most cases, and their effects were additive for shoots”
Claim · model-written summary
Root N- and P-uptake rates were strongly decreased by drought.
- Taxon
- BarleyHordeum vulgaree0
- Treatment
- droughte1
- Outcome
- Root N‐ and P‐uptake ratese1
- Direction
- strongly decreasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Barley ( Hordeum vulgare )”
e1“Root N‐ and P‐uptake rates were strongly decreased by drought, but were not significantly affected by CO 2”
Claim · model-written summary
Root N- and P-uptake rates were not significantly affected by elevated CO2.
- Taxon
- BarleyHordeum vulgaree0
- Treatment
- CO 2e1
- Outcome
- Root N‐ and P‐uptake ratese1
- Direction
- not significantly affectede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Barley ( Hordeum vulgare )”
e1“Root N‐ and P‐uptake rates were strongly decreased by drought, but were not significantly affected by CO 2”
Claim · model-written summary
Drought upregulated NRT1 (NO3 transporter) and AMT1 (NH4 transporter) per unit total root protein, averaged across treatments.
- Taxon
- BarleyHordeum vulgaree0
- Treatment
- droughte1
- Gene
- NRT1 (NO 3 − transporter) and AMT1 (NH 4 + transporter)e1
- Outcome
- upregulatione1
- Direction
- upregulatione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Barley ( Hordeum vulgare )”
e1“both drought and high CO 2 resulted in upregulation of NRT1 (NO 3 − transporter) and AMT1 (NH 4 + transporter) per unit total root protein”
Claim · model-written summary
High CO2 upregulated NRT1 (NO3 transporter) and AMT1 (NH4 transporter) per unit total root protein, averaged across treatments.
- Taxon
- BarleyHordeum vulgaree0
- Treatment
- high CO 2e1
- Gene
- NRT1 (NO 3 − transporter) and AMT1 (NH 4 + transporter)e1
- Outcome
- upregulatione1
- Direction
- upregulatione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Barley ( Hordeum vulgare )”
e1“both drought and high CO 2 resulted in upregulation of NRT1 (NO 3 − transporter) and AMT1 (NH 4 + transporter) per unit total root protein”
Claim · model-written summary
Only drought increased PHT1 (P transporter) concentration.
- Taxon
- BarleyHordeum vulgaree0
- Treatment
- droughte1
- Gene
- PHT1 (P transporter)e1
- Outcome
- PHT1 (P transporter)e1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Barley ( Hordeum vulgare )”
e1“while only drought increased PHT1 (P transporter)”
Claim · model-written summary
Elevated CO2 exacerbated decreases in %N and %P, and hence food quality, during drought.
- Taxon
- BarleyHordeum vulgaree0
- Treatment
- Elevated CO 2e1
- Outcome
- decreases in %N and %Pe1
- Direction
- exacerbatede1
- Qualifier
- during droughte1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Barley ( Hordeum vulgare )”
e1“Elevated CO 2 exacerbated decreases in %N and %P, and hence food quality, during drought”
Claim · model-written summary
Despite increased concentrations of nutrient-uptake proteins in roots, nutrient uptake was limited by other factors.
- Taxon
- BarleyHordeum vulgaree0
- Outcome
- nutrient uptakee1
- Qualifier
- other limitations to nutrient uptakee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Barley ( Hordeum vulgare )”
e1“despite increases in the concentration of nutrient‐uptake proteins in roots, indicating other limitations to nutrient uptake”
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See all 22 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.