Abstract
Abstract Many temperate grasses are both hyper‐accumulators of silicon (Si) and hosts of Epichloë fungal endophytes, functional traits which may alleviate environmental stresses such as herbivore attack. Si accumulation and endophyte infection may operate synergistically, but this has not been tested in a field setting, nor in the context of changing environmental conditions. Predicted increases in atmospheric CO 2 concentrations can affect both Si accumulation and endophyte function, but these have not been studied in combination. We investigated how elevated atmospheric CO 2 (eCO 2 ), Si supplementation, endophyte‐presence and insect herbivory impacted plant growth, stoichiometry (C, N, P and Si), leaf gas exchange (rates of photosynthesis, stomatal conductance, transpiration rates) and endophyte production of anti‐herbivore defences (alkaloids) of an important pasture grass (tall fescue; Lolium arundinaceum ) in the field. eCO 2 and Si supplementation increased shoot biomass (+52% and +31%, respectively), whereas herbivory reduced shoot biomass by at least 35% and induced Si accumulation by 24%. Shoot Si concentrations, in contrast, decreased by 17%–21% under eCO 2 . Si supplementation and herbivory reduced shoot C concentrations. eCO 2 reduced shoot N concentrations which led to increased shoot C:N ratios. Overall, shoot P concentrations were 26% lower in endophytic plants compared to non‐endophytic plants, potentially due to decreased mass flow (i.e. observed reductions in stomatal conductance and transpiration). Alkaloid production was not discernibly affected by any experimental treatment. The negative impacts of endophytes on P uptake were particularly strong under eCO 2 . We show that eCO 2 and insect herbivory reduce and promote Si accumulation, respectively, incorporating some field conditions for the first time. This indicates that these drivers operate in a more realistic ecological context than previously demonstrated. Reduced uptake of P in endophytic plants may adversely affect plant productivity in the future, particularly if increased demand for P due to improved plant growth under eCO 2 cannot be met. Read the free Plain Language Summary for this article on the Journal blog.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 12
Claim · model-written summary
Elevated CO2 increased shoot biomass by 52%.
- Taxon
- tall fescue
Lolium arundinaceume1 - Treatment
- eCO 2e0
- Outcome
- shoot biomasse0
- Direction
- increasede0
- Value
- +52%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“eCO 2 and Si supplementation increased shoot biomass (+52% and +31%, respectively)”
e1“tall fescue; Lolium arundinaceum”
Claim · model-written summary
Silicon supplementation increased shoot biomass by 31%.
- Taxon
- tall fescueLolium arundinaceume1
- Treatment
- Si supplementatione0
- Outcome
- shoot biomasse0
- Direction
- increasede0
- Value
- +31%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“eCO 2 and Si supplementation increased shoot biomass (+52% and +31%, respectively)”
e1“tall fescue; Lolium arundinaceum”
Claim · model-written summary
Herbivory reduced shoot biomass by at least 35%.
- Taxon
- tall fescueLolium arundinaceume1
- Treatment
- herbivorye0
- Outcome
- shoot biomasse0
- Direction
- reducede0
- Value
- at least 35%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“herbivory reduced shoot biomass by at least 35% and induced Si accumulation by 24%”
e1“tall fescue; Lolium arundinaceum”
Claim · model-written summary
Herbivory induced silicon accumulation by 24%.
- Taxon
- tall fescueLolium arundinaceume1
- Treatment
- herbivorye0
- Outcome
- Si accumulatione0
- Direction
- inducede0
- Value
- 24%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“herbivory reduced shoot biomass by at least 35% and induced Si accumulation by 24%”
e1“tall fescue; Lolium arundinaceum”
Claim · model-written summary
Elevated CO2 decreased shoot silicon concentrations by 17%–21%.
- Taxon
- tall fescueLolium arundinaceume1
- Treatment
- eCO 2e0
- Outcome
- Shoot Si concentrationse0
- Direction
- decreasede0
- Value
- 17%–21%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Shoot Si concentrations, in contrast, decreased by 17%–21% under eCO 2”
e1“tall fescue; Lolium arundinaceum”
Claim · model-written summary
Silicon supplementation reduced shoot carbon concentrations.
Not reportedTaxonComparator
Verbatim
e0“Si supplementation and herbivory reduced shoot C concentrations”
t0“plant phosphorus”
Claim · model-written summary
Herbivory reduced shoot carbon concentrations.
Not reportedTaxonComparator
Verbatim
e0“Si supplementation and herbivory reduced shoot C concentrations”
Claim · model-written summary
Elevated CO2 reduced shoot nitrogen concentrations.
Not reportedTaxonComparator
Verbatim
e0“eCO 2 reduced shoot N concentrations which led to increased shoot C:N ratios”
Claim · model-written summary
Elevated CO2 increased shoot carbon to nitrogen ratios.
Not reportedTaxonComparator
Verbatim
e0“eCO 2 reduced shoot N concentrations which led to increased shoot C:N ratios”
Claim · model-written summary
Endophytic plants had 26% lower shoot phosphorus than non-endophytic plants.
- Treatment
- endophytic plantse0
- Outcome
- shoot P concentrationse0
- Direction
- lowere0
- Value
- 26%e0
- Comparator
- non‐endophytic plantse0
Not reportedTaxon
Verbatim
e0“shoot P concentrations were 26% lower in endophytic plants compared to non‐endophytic plants”
Claim · model-written summary
Alkaloid production was not discernibly affected by treatments.
Not reportedTaxon
Verbatim
e0“Alkaloid production was not discernibly affected by any experimental treatment”
Claim · model-written summary
Endophyte-associated reductions in phosphorus uptake were particularly strong under elevated CO2.
Not reportedTaxon
Verbatim
e0“The negative impacts of endophytes on P uptake were particularly strong under eCO 2”
The same questions in other papers
silicon atom · growth · Lolium arundinaceum (tall fescue)Results agree
6 papers in the same direction as this paper
- positive
- positive
- positive
3 papers more in this group
See all 7 papers →co2 · growth · Lolium arundinaceum (tall fescue)Results differ
5 papers in the same direction as this paper · 3 in the opposite direction
- positive
- negative
- negative
5 papers more in this group
See all 9 papers →grazing · nutrient: content · Lolium arundinaceum (tall fescue)Results agree
1 paper in the same direction as this paper
- positive
grazing · growth · Lolium arundinaceum (tall fescue)Results agree
2 papers in the same direction as this paper
- no effect
- no effect
co2 · nutrient: content · Lolium arundinaceum (tall fescue)Results agree
2 papers in the same direction as this paper
- negative
- no effect
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.