Abstract
Many studies demonstrate that elevated atmospheric carbon dioxide concentrations (eCO2) can promote root nodulation and biological nitrogen fixation (BNF) in legumes such as lucerne (Medicago sativa). But when elevated temperature (eT) conditions are applied in tandem with eCO¬2, a more realistic scenario for future climate change, the positive effects of eCO2 on nodulation and BNF in M. sativa are often much reduced. Silicon (Si) supplementation of M. sativa has also been reported to promote root nodulation and BNF, so could potentially restore the positive effects of eCO2 under eT. Increased nitrogen availability, however, could also increase host suitability for aphid pests, potentially negating any benefit. We applied eCO2 (+240ppm) and eT (+4ºC), separately and in combination, to M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-) to determine whether Si moderated the effects of eCO2 and eT. Plants were either inoculated with the aphid Acyrthosiphon pisum or insect-free. In Si- soils, eCO2 stimulated plant growth by 67% and nodulation by 42%, respectively, whereas eT reduced these parameters by 26% and 48%, respectively. Aphids broadly mirrored these effects on Si- plants, increasing colonization rates under eCO2 and performing much worse (reduced abundance and colonization) under eT when compared to ambient conditions, confirming our hypothesized link between root nodulation, plant growth and pest performance. Examined across all CO2 and temperature regimes, Si supplementation promoted plant growth (+93%), and root nodulation (+50%). Acyrthosiphon pisum abundance declined sharply under eT conditions and was largely unaffected by Si supplementation. In conclusion, supplementing M. sativa with Si had consistent positive effects on plant growth and nodulation under different CO2 and temperature scenarios. These findings offer potential for using Si supplementation to maintain legume productivity under predicted climate change scenarios without making legumes more susceptible to insect pests.
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Claims 11
Claim · model-written summary
In Si- soils, elevated CO2 (+240ppm) stimulated M. sativa plant growth by 67%.
- Taxon
- M. sativa
Medicago sativae1 - Treatment
- eCO2e0
- Outcome
- plant growthe0
- Direction
- stimulatede0
- Value
- 67%e0
- Setting
- Si- soilse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In Si- soils, eCO2 stimulated plant growth by 67% and nodulation by 42%, respectively, whereas eT reduced these parameters by 26% and 48%, respectively”
e1“M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-)”
Claim · model-written summary
In Si- soils, elevated CO2 stimulated M. sativa nodulation by 42%.
- Taxon
- M. sativaMedicago sativae1
- Treatment
- eCO2e0
- Outcome
- nodulatione0
- Direction
- stimulatede0
- Value
- 42%e0
- Setting
- Si- soilse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In Si- soils, eCO2 stimulated plant growth by 67% and nodulation by 42%, respectively, whereas eT reduced these parameters by 26% and 48%, respectively”
e1“M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-)”
Claim · model-written summary
In Si- soils, elevated temperature reduced M. sativa plant growth by 26%.
- Taxon
- M. sativaMedicago sativae1
- Treatment
- eTe0
- Outcome
- plant growthe0
- Direction
- reducede0
- Value
- 26%e0
- Setting
- Si- soilse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In Si- soils, eCO2 stimulated plant growth by 67% and nodulation by 42%, respectively, whereas eT reduced these parameters by 26% and 48%, respectively”
e1“M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-)”
Claim · model-written summary
In Si- soils, elevated temperature reduced M. sativa nodulation by 48%.
- Taxon
- M. sativaMedicago sativae1
- Treatment
- eTe0
- Outcome
- nodulatione0
- Direction
- reducede0
- Value
- 48%e0
- Setting
- Si- soilse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In Si- soils, eCO2 stimulated plant growth by 67% and nodulation by 42%, respectively, whereas eT reduced these parameters by 26% and 48%, respectively”
e1“M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-)”
Claim · model-written summary
Aphid colonization rates on Si- plants increased under elevated CO2 compared with ambient conditions.
- Taxon
- M. sativaMedicago sativae1
- Treatment
- eCO2e0
- Interactor
- AphidsAphidomorphae0pest
- Outcome
- colonization ratese0
- Direction
- increasinge0
- Comparator
- ambient conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Aphids broadly mirrored these effects on Si- plants, increasing colonization rates under eCO2 and performing much worse (reduced abundance and colonization) under eT when compared to ambient conditions”
e1“M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-)”
Claim · model-written summary
Aphid abundance and colonization on Si- plants were reduced under elevated temperature compared with ambient conditions.
- Taxon
- M. sativaMedicago sativae1
- Treatment
- eTe0
- Interactor
- AphidsAphidomorphae0pest
- Outcome
- abundance and colonizatione0
- Direction
- reducede0
- Comparator
- ambient conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Aphids broadly mirrored these effects on Si- plants, increasing colonization rates under eCO2 and performing much worse (reduced abundance and colonization) under eT when compared to ambient conditions”
e1“M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-)”
Claim · model-written summary
Across all CO2 and temperature regimes, Si supplementation promoted M. sativa plant growth by 93%.
- Taxon
- M. sativaMedicago sativae1
- Treatment
- Si supplementatione0
- Outcome
- plant growthe0
- Direction
- promotede0
- Value
- +93%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Si supplementation promoted plant growth (+93%), and root nodulation (+50%)”
e1“M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-)”
Claim · model-written summary
Across all CO2 and temperature regimes, Si supplementation promoted M. sativa root nodulation by 50%.
- Taxon
- M. sativaMedicago sativae1
- Treatment
- Si supplementatione0
- Outcome
- root nodulatione0
- Direction
- promotede0
- Value
- +50%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Si supplementation promoted plant growth (+93%), and root nodulation (+50%)”
e1“M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-)”
Claim · model-written summary
Acyrthosiphon pisum abundance declined sharply under elevated temperature.
- Taxon
- M. sativaMedicago sativae1
- Treatment
- eTe0
- Interactor
- Acyrthosiphon pisum
-PLoS.jpg?width=60)
Acyrthosiphon pisume0pest - Outcome
- Acyrthosiphon pisum abundancee0
- Direction
- declined sharplye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
-PLoS.jpg?width=500)
Verbatim
e0“Acyrthosiphon pisum abundance declined sharply under eT conditions”
e1“M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-)”
Claim · model-written summary
Acyrthosiphon pisum abundance was largely unaffected by Si supplementation.
- Taxon
- M. sativaMedicago sativae1
- Treatment
- Si supplementatione0
- Interactor
- Acyrthosiphon pisumAcyrthosiphon pisume0pest
- Outcome
- Acyrthosiphon pisum abundancee0
- Direction
- largely unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Acyrthosiphon pisum abundance declined sharply under eT conditions and was largely unaffected by Si supplementation”
e1“M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-)”
Claim · model-written summary
The authors conclude Si supplementation offers potential to maintain legume productivity under predicted climate change without making legumes more susceptible to insect pests.
Verbatim
e0“using Si supplementation to maintain legume productivity under predicted climate change scenarios without making legumes more susceptible to insect pests”
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