Abstract
Elevated atmospheric CO2 concentration (e[CO2]) increases water use efficiency (WUE) while reducing nitrogen (N) concentration of crops particularly under drought conditions; yet the combined effects of e[CO2] and different N-fertigation regimes on WUE and crop N nutrition remain largely elusive. In this experiment, the growth and physiological responses of two barley genotypes, wild type barley Steptoe (WT) and its correspondent ABA-deficient mutant barley Az34, to three N-fertigation regimes at ambient CO2 (a[CO2]) (400 ppm) and e[CO2] (800 ppm) were investigated. From tillering to grain filling stage, the plants were subjected to three N-fertigation regimes: 1) N-fertigation at full irrigation volume (FIN); 2) N-fertigation at reduced irrigation volume (DIN); 3) alternate N-fertigation at reduced irrigation volume (PRDN). Although e[CO2] had little effect on gs, Tr and plant water use of WT, especially under DIN and PRDN, it increased An, resulting in an increased WUE at stomatal, leaf and whole plant levels. For Az34, the positive effect of e[CO2] on WUE was attributed to both significantly enhanced An and lowered gs and Tr. For both genotypes, e[CO2] increased 100-grain weight and shoot dry biomass but didn’t affect grain yield and WUE for grain production (WUEg). PRDN increased grain yield, HI and WUEg of both genotypes regardless of [CO2], compared to FIN. DIN and PRDN increased N uptake of both genotypes at e[CO2] compared to FIN. Compared to a[CO2], e[CO2] increased 15N uptake and 15N recovery rate of both genotypes by enhancing plant biomass. In addition, both genotypes grown under DIN and PRDN allocated more N to the grain compared to the FIN plants. Collectively, N-fertigation at reduced irrigation volume promoted N allocation to the grain and increased WUE, particularly under e[CO2]. Such information is conductive for optimizing WUE and N nutrition of crops in a future water-limited and CO2-enriched environment.
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Claims 15
Claim · model-written summary
Elevated CO2 had little effect on WT stomatal conductance, transpiration and water use.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaret0 - Material
- WTe0
- Treatment
- e[CO2]e0
- Outcome
- gs, Tr and plant water usee0
- Direction
- little effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Although e[CO2] had little effect on gs, Tr and plant water use of WT, especially under DIN and PRDN”
t0“barley”
Claim · model-written summary
Elevated CO2 increased WT net assimilation.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Although e[CO2] had little effect on gs, Tr and plant water use of WT, especially under DIN and PRDN, it increased An, resulting in an increased WUE at stomatal, leaf and whole plant levels.”
t0“barley”
Claim · model-written summary
Elevated CO2 increased WT water-use efficiency at stomatal, leaf and plant levels.
- Taxon
- barleyHordeum vulgaret0
- Material
- WTe0
- Treatment
- e[CO2]e0
- Outcome
- WUE at stomatal, leaf and whole plant levelse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Although e[CO2] had little effect on gs, Tr and plant water use of WT, especially under DIN and PRDN, it increased An, resulting in an increased WUE at stomatal, leaf and whole plant levels.”
t0“barley”
Claim · model-written summary
In Az34, elevated CO2 significantly enhanced assimilation.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For Az34, the positive effect of e[CO2] on WUE was attributed to both significantly enhanced An and lowered gs and Tr.”
t0“barley”
Claim · model-written summary
In Az34, elevated CO2 lowered gs and Tr.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For Az34, the positive effect of e[CO2] on WUE was attributed to both significantly enhanced An and lowered gs and Tr.”
t0“barley”
Claim · model-written summary
In Az34, elevated CO2 improved water-use efficiency.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For Az34, the positive effect of e[CO2] on WUE was attributed to both significantly enhanced An and lowered gs and Tr.”
t0“barley”
Claim · model-written summary
Elevated CO2 increased 100-grain weight and shoot biomass in both genotypes.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- e[CO2]e0
- Outcome
- 100-grain weight and shoot dry biomasse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For both genotypes, e[CO2] increased 100-grain weight and shoot dry biomass but didn’t affect grain yield and WUE for grain production (WUEg).”
t0“barley”
Claim · model-written summary
Elevated CO2 did not affect grain yield or WUEg in either genotype.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- e[CO2]e0
- Outcome
- grain yield and WUE for grain production (WUEg)e0
- Direction
- didn’t affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For both genotypes, e[CO2] increased 100-grain weight and shoot dry biomass but didn’t affect grain yield and WUE for grain production (WUEg).”
t0“barley”
Claim · model-written summary
PRDN increased grain yield, harvest index and WUEg relative to FIN in both genotypes.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- PRDNe0
- Outcome
- grain yield, HI and WUEge0
- Direction
- increasede0
- Comparator
- FINe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PRDN increased grain yield, HI and WUEg of both genotypes regardless of [CO2], compared to FIN.”
t0“barley”
Claim · model-written summary
DIN increased N uptake relative to FIN under elevated CO2.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“DIN and PRDN increased N uptake of both genotypes at e[CO2] compared to FIN.”
t0“barley”
Claim · model-written summary
PRDN increased N uptake relative to FIN under elevated CO2.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“DIN and PRDN increased N uptake of both genotypes at e[CO2] compared to FIN.”
t0“barley”
Claim · model-written summary
Elevated CO2 increased 15N uptake and recovery in both genotypes.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- e[CO2]e0
- Outcome
- 15N uptake and 15N recovery ratee0
- Direction
- increasede0
- Comparator
- a[CO2]e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to a[CO2], e[CO2] increased 15N uptake and 15N recovery rate of both genotypes by enhancing plant biomass.”
t0“barley”
Claim · model-written summary
Elevated CO2 increased plant biomass, which authors linked to greater 15N uptake.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- e[CO2]e0
- Outcome
- 15N uptake and 15N recovery ratee0
- Qualifier
- enhancing plant biomasse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“e[CO2] increased 15N uptake and 15N recovery rate of both genotypes by enhancing plant biomass.”
t0“barley”
Claim · model-written summary
DIN plants allocated more N to grain than FIN plants.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- DINe0
- Outcome
- N to the graine0
- Direction
- moree0
- Comparator
- FIN plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both genotypes grown under DIN and PRDN allocated more N to the grain compared to the FIN plants.”
t0“barley”
Claim · model-written summary
PRDN plants allocated more N to grain than FIN plants.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- PRDNe0
- Outcome
- N to the graine0
- Direction
- moree0
- Comparator
- FIN plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both genotypes grown under DIN and PRDN allocated more N to the grain compared to the FIN plants.”
t0“barley”
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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.