Abstract
Summary Upland rice ( Oryza sativa L.) was grown at both ambient (350 μmol mol −1 ) and elevated (700 μmol mol −1 ) CO 2 in either the presence or absence of the root hemi‐parasitic angiosperm Striga hermonthica (Del) Benth. Elevated CO 2 alleviated the impact of the parasite on host growth: biomass of infected rice grown at ambient CO 2 was 35% that of uninfected, control plants, while at elevated CO 2 , biomass of infected plants was 73% that of controls. This amelioration occurred despite the fact that O. sativa grown at elevated CO 2 supported both greater numbers and a higher biomass of parasites per host than plants grown at ambient CO 2 . The impact of infection on host leaf area, leaf mass, root mass and reproductive tissue mass was significantly lower in plants grown at elevated as compared with ambient CO 2 . There were significant CO 2 and Striga effects on photosynthetic metabolism and instantaneous water‐use efficiency of O. sativa . The response of photosynthesis to internal [CO 2 ] ( A / C i curves) indicated that, at 45 days after sowing (DAS), prior to emergence of the parasites, uninfected plants grown at elevated CO 2 had significantly lower CO 2 saturated rates of photosynthesis, carboxylation efficiencies and ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39) contents than uninfected, ambient CO 2 ‐grown O. sativa . In contrast, infection with S. hermonthica prevented down‐regulation of photosynthesis in O. sativa grown at elevated CO 2 , but had no impact on photosynthesis of hosts grown at ambient CO 2 . At 76 DAS (after parasites had emerged), however, infected plants grown at both elevated and ambient CO 2 had lower carboxylation efficiencies and Rubisco contents than uninfected O. sativa grown at ambient CO 2 . The reductions in carboxylation efficiency (and Rubisco content) were accompanied by similar reductions in nitrogen concentration of O. sativa leaves, both before and after parasite emergence. There were no significant CO 2 or infection effects on the concentrations of soluble sugars in leaves of O. sativa , but starch concentration was significantly lower in infected plants at both CO 2 concentrations. These results demonstrate that elevated CO 2 concentrations can alleviate the impact of infection with Striga on the growth of C 3 hosts such as rice and also that infection can delay the onset of photosynthetic down‐regulation in rice grown at elevated CO 2 .
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Claims 17
Claim · model-written summary
Elevated CO2 alleviated the impact of the parasite on rice growth
- Taxon
- rice
Oryza sativae2 - Treatment
- Elevated CO 2e1
- Interactor
- Striga hermonthica
Striga hermonthicae3parasite - Outcome
- the impact of the parasite on host growthe1
- Direction
- alleviatede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Elevated CO 2 alleviated the impact of the parasite on host growth”
e2“biomass of infected rice grown at ambient CO 2 was 35% that of uninfected, control plants”
e3“Striga hermonthica (Del) Benth.”
Claim · model-written summary
Infected rice grown at ambient CO2 had biomass of about 35% that of uninfected controls
- Taxon
- riceOryza sativae1
- Treatment
- ambient CO 2e1
- Interactor
- Striga hermonthicaStriga hermonthicae2parasite
- Outcome
- biomass of infected ricee1
- Direction
- lowerinferrede1
- Value
- 35%e1
- Comparator
- uninfected, control plantse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“biomass of infected rice grown at ambient CO 2 was 35% that of uninfected, control plants”
e2“Striga hermonthica (Del) Benth.”
Claim · model-written summary
Infected rice grown at elevated CO2 had biomass of about 73% that of uninfected controls
- Taxon
- riceOryza sativae2
- Treatment
- elevated CO 2e1
- Interactor
- Striga hermonthicaStriga hermonthicae3parasite
- Outcome
- biomass of infected plantse1
- Direction
- lowerinferrede1
- Value
- 73%e1
- Comparator
- controlse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“while at elevated CO 2 , biomass of infected plants was 73% that of controls”
e2“biomass of infected rice grown at ambient CO 2 was 35% that of uninfected, control plants”
e3“Striga hermonthica (Del) Benth.”
Claim · model-written summary
Elevated CO2 supported greater numbers and a higher biomass of Striga per rice host than ambient CO2
- Taxon
- O. sativaOryza sativae1
- Treatment
- elevated CO 2e1
- Interactor
- Striga hermonthicaStriga hermonthicae2parasite
- Outcome
- greater numbers and a higher biomass of parasites per hoste1
- Direction
- highere1
- Comparator
- plants grown at ambient CO 2e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This amelioration occurred despite the fact that O. sativa grown at elevated CO 2 supported both greater numbers and a higher biomass of parasites per host than plants grown at ambient CO 2”
e2“Striga hermonthica (Del) Benth.”
Claim · model-written summary
Under elevated CO2 the infection impact on host leaf area, leaf mass and root mass was lower than under ambient CO2
- Taxon
- O. sativaOryza sativae2
- Treatment
- elevatede1
- Outcome
- leaf area, leaf mass, root masse1
- Direction
- lowere1
- Comparator
- ambient CO 2e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The impact of infection on host leaf area, leaf mass, root mass and reproductive tissue mass was significantly lower in plants grown at elevated as compared with ambient CO 2”
e2“This amelioration occurred despite the fact that O. sativa grown at elevated CO 2 supported both greater numbers and a higher biomass of parasites per host than plants grown at ambient CO 2”
Claim · model-written summary
Under elevated CO2 the infection impact on host reproductive tissue mass was lower than under ambient CO2
- Taxon
- O. sativaOryza sativae2
- Treatment
- elevatede1
- Outcome
- reproductive tissue masse1
- Direction
- lowere1
- Comparator
- ambient CO 2e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The impact of infection on host leaf area, leaf mass, root mass and reproductive tissue mass was significantly lower in plants grown at elevated as compared with ambient CO 2”
e2“This amelioration occurred despite the fact that O. sativa grown at elevated CO 2 supported both greater numbers and a higher biomass of parasites per host than plants grown at ambient CO 2”
Claim · model-written summary
Elevated CO2 and Striga had significant effects on photosynthetic metabolism of rice
- Taxon
- O. sativaOryza sativae1
- Treatment
- CO 2 and Strigae1
- Outcome
- photosynthetic metabolisme1
StrigaNot reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“There were significant CO 2 and Striga effects on photosynthetic metabolism and instantaneous water‐use efficiency of O. sativa”
e2“This amelioration occurred despite the fact that O. sativa grown at elevated CO 2 supported both greater numbers and a higher biomass of parasites per host than plants grown at ambient CO 2”
Claim · model-written summary
Elevated CO2 and Striga had significant effects on instantaneous water-use efficiency of rice
- Taxon
- O. sativaOryza sativae1
- Treatment
- CO 2 and Strigae1
- Outcome
- instantaneous water‐use efficiencye1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“There were significant CO 2 and Striga effects on photosynthetic metabolism and instantaneous water‐use efficiency of O. sativa”
Claim · model-written summary
Uninfected rice grown at elevated CO2 had significantly lower CO2-saturated photosynthesis rates than at ambient CO2
- Taxon
- O. sativaOryza sativae4
- Treatment
- elevated CO 2e1
- Outcome
- CO 2 saturated rates of photosynthesise1
- Direction
- lowere1
- Qualifier
- at 45 days after sowing (DAS), prior to emergence of the parasitese3
- Comparator
- uninfected, ambient CO 2e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“uninfected plants grown at elevated CO 2 had significantly lower CO 2 saturated rates of photosynthesis”
e2“(Rubisco; EC 4.1.1.39) contents than uninfected, ambient CO 2”
e3“at 45 days after sowing (DAS), prior to emergence of the parasites”
e4“uninfected O. sativa grown at ambient CO 2”
Claim · model-written summary
Uninfected rice grown at elevated CO2 had significantly lower carboxylation efficiencies than at ambient CO2
- Taxon
- O. sativaOryza sativae4
- Treatment
- elevated CO 2e1
- Outcome
- carboxylation efficienciese2
- Direction
- lowere2
- Comparator
- uninfected, ambient CO 2e3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“uninfected plants grown at elevated CO 2 had significantly lower CO 2 saturated rates of photosynthesis”
e2“had significantly lower CO 2 saturated rates of photosynthesis, carboxylation efficiencies”
e3“uninfected, ambient CO 2”
e4“uninfected O. sativa grown at ambient CO 2”
Claim · model-written summary
Uninfected rice at elevated CO2 had Rubisco contents significantly lower than at ambient CO2
- Taxon
- O. sativaOryza sativae3
- Treatment
- elevated CO 2e1
- Gene
- Rubiscoe2
- Outcome
- (Rubisco; EC 4.1.1.39) contentse2
- Direction
- lowere1
- Comparator
- uninfected, ambient CO 2e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“uninfected plants grown at elevated CO 2 had significantly lower CO 2 saturated rates of photosynthesis”
e2“(Rubisco; EC 4.1.1.39) contents than uninfected, ambient CO 2”
e3“uninfected O. sativa grown at ambient CO 2”
Claim · model-written summary
Infection with S. hermonthica prevented down-regulation of photosynthesis in rice grown at elevated CO2
- Taxon
- O. sativaOryza sativae2
- Treatment
- infection with S. hermonthicae1
- Interactor
- S. hermonthicaStriga hermonthicae1parasite
- Outcome
- photosynthesise2
- Direction
- preventede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“infection with S. hermonthica prevented”
e2“in O. sativa grown at elevated CO 2 , but had no impact on photosynthesis of hosts grown at ambient CO 2”
Claim · model-written summary
Infection with S. hermonthica had no impact on photosynthesis of rice grown at ambient CO2
- Taxon
- O. sativaOryza sativae2
- Treatment
- infection with S. hermonthicae1
- Interactor
- S. hermonthicaStriga hermonthicae1parasite
- Outcome
- photosynthesis of hosts grown at ambient CO 2e2
- Direction
- no impacte2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“infection with S. hermonthica prevented”
e2“in O. sativa grown at elevated CO 2 , but had no impact on photosynthesis of hosts grown at ambient CO 2”
Claim · model-written summary
Infected rice grown at both elevated and ambient CO2 had lower carboxylation efficiencies and Rubisco contents than uninfected rice at ambient CO2 at 76 DAS
- Taxon
- O. sativaOryza sativae1
- Treatment
- infected plantse1
- Outcome
- carboxylation efficiencies and Rubisco contentse1
- Direction
- lowere1
- Qualifier
- At 76 DAS (after parasites had emerged)e2
- Comparator
- uninfected O. sativa grown at ambient CO 2e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“infected plants grown at both elevated and ambient CO 2 had lower carboxylation efficiencies and Rubisco contents than uninfected O. sativa grown at ambient CO 2”
e2“At 76 DAS (after parasites had emerged)”
Claim · model-written summary
Reductions in carboxylation efficiency and Rubisco content were accompanied by similar reductions in leaf nitrogen concentration of rice
- Taxon
- O. sativaOryza sativae1
- Organ / stage
- leavese1
- Outcome
- nitrogen concentratione1
- Direction
- reductionse1
- Qualifier
- both before and after parasite emergencee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The reductions in carboxylation efficiency (and Rubisco content) were accompanied by similar reductions in nitrogen concentration of O. sativa leaves, both before and after parasite emergence”
Claim · model-written summary
Elevated CO2 and infection had no significant effect on soluble sugar concentrations in rice leaves
- Taxon
- O. sativaOryza sativae1
- Organ / stage
- leavese1
- Treatment
- CO 2 or infectione1
- Outcome
- the concentrations of soluble sugars in leavese1
- Direction
- no significante1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“There were no significant CO 2 or infection effects on the concentrations of soluble sugars in leaves of O. sativa”
Claim · model-written summary
Infected rice had significantly lower starch concentration than uninfected rice at both CO2 concentrations
- Taxon
- O. sativaOryza sativae1
- Treatment
- infected plantse2
- Outcome
- starch concentratione2
- Direction
- lowere2
- Qualifier
- at both CO 2 concentrationse2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“There were no significant CO 2 or infection effects on the concentrations of soluble sugars in leaves of O. sativa”
e2“starch concentration was significantly lower in infected plants at both CO 2 concentrations”
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