Abstract
Naturally seeded Scots pine (Pinus sylvestris L.) trees, age 25-30 years, were subjected to two soil-nitrogen-supply regimes and to elevated atmospheric CO(2) concentrations by the branch-in-bag method from April 15 to September 15 for two or three years. Gas exchange in detached shoots was measured in a diffuse radiation field. Seven parameters associated with photosynthetic performance and two describing stomatal conductance were determined to assess the effects of treatments on photosynthetic components. An elevated concentration of CO(2) did not lead to a significant downward regulation in maximum carboxylation rate (V(cmax)) or maximum electron transport rate (J(max)), but it significantly decreased light-saturated stomatal conductance (g(sat)) and increased minimum stomatal conductance (g(min)). Light-saturated rates of CO(2) assimilation were higher (24-31%) in shoots grown and measured at elevated CO(2) concentration than in shoots grown and measured at ambient CO(2) concentration, regardless of treatment time or nitrogen-supply regime. High soil-nitrogen supply significantly increased photosynthetic capacity, corresponding to significant increases in V(cmax) and J(max). However, the combined elevated CO(2) + high nitrogen-supply treatment did not enhance the photosynthetic response above that observed in the elevated CO(2) treatment alone.
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Claims 7
Claim · model-written summary
Elevated CO2 did not significantly downregulate maximum carboxylation or electron transport rates.
- Taxon
- Scots pine
Pinus sylvestrise1 - Treatment
- elevated concentration of CO(2)e0
- Outcome
- maximum carboxylation rate (V(cmax)) or maximum electron transport rate (J(max))e0
- Direction
- did not lead to a significant downward regulatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“An elevated concentration of CO(2) did not lead to a significant downward regulation in maximum carboxylation rate (V(cmax)) or maximum electron transport rate (J(max))”
e1“Scots pine (Pinus sylvestris L.)”
Claim · model-written summary
Elevated CO2 significantly decreased light-saturated stomatal conductance.
- Taxon
- Scots pinePinus sylvestrise2
- Treatment
- elevated concentration of CO(2)e1
- Outcome
- light-saturated stomatal conductance (g(sat))e0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it significantly decreased light-saturated stomatal conductance (g(sat))”
e1“elevated concentration of CO(2)”
e2“Scots pine (Pinus sylvestris L.)”
Claim · model-written summary
Elevated CO2 significantly increased minimum stomatal conductance.
- Taxon
- Scots pinePinus sylvestrise2
- Treatment
- elevated concentration of CO(2)e1
- Outcome
- minimum stomatal conductance (g(min))e0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased minimum stomatal conductance (g(min))”
e1“elevated concentration of CO(2)”
e2“Scots pine (Pinus sylvestris L.)”
Claim · model-written summary
Light-saturated CO2 assimilation was 24-31% higher with elevated CO2 than ambient CO2 across treatment durations and nitrogen regimes.
- Taxon
- Scots pinePinus sylvestrise1
- Treatment
- elevated CO(2) concentratione0
- Outcome
- Light-saturated rates of CO(2) assimilatione0
- Direction
- highere0
- Value
- 24-31%e0
- Qualifier
- regardless of treatment time or nitrogen-supply regimee0
- Comparator
- ambient CO(2) concentratione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Light-saturated rates of CO(2) assimilation were higher (24-31%) in shoots grown and measured at elevated CO(2) concentration than in shoots grown and measured at ambient CO(2) concentration, regardless of treatment time or nitrogen-supply regime.”
e1“Scots pine (Pinus sylvestris L.)”
Claim · model-written summary
High soil nitrogen significantly increased photosynthetic capacity.
- Taxon
- Scots pinePinus sylvestrise1
- Treatment
- High soil-nitrogen supplye0
- Outcome
- photosynthetic capacitye0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“High soil-nitrogen supply significantly increased photosynthetic capacity”
e1“Scots pine (Pinus sylvestris L.)”
Claim · model-written summary
High soil nitrogen significantly increased maximum carboxylation and electron transport rates.
- Taxon
- Scots pinePinus sylvestrise2
- Treatment
- High soil-nitrogen supplye1
- Outcome
- V(cmax) and J(max)e0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significant increases in V(cmax) and J(max)”
e1“High soil-nitrogen supply”
e2“Scots pine (Pinus sylvestris L.)”
Claim · model-written summary
Adding high nitrogen to elevated CO2 did not further enhance the photosynthetic response.
- Taxon
- Scots pinePinus sylvestrise1
- Treatment
- combined elevated CO(2) + high nitrogen-supply treatmente0
- Outcome
- photosynthetic responsee0
- Direction
- did not enhancee0
- Comparator
- elevated CO(2) treatment alonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the combined elevated CO(2) + high nitrogen-supply treatment did not enhance the photosynthetic response above that observed in the elevated CO(2) treatment alone.”
e1“Scots pine (Pinus sylvestris L.)”
The same questions in other papers
nitrogen · physiology: photosynthesis · Pinus sylvestris (Scots pine)Positive and negative results
1 reporting no difference from an alternative
- positive
co2 · physiology: photosynthesis · Pinus sylvestris (Scots pine)Positive and negative results
1 paper in the same direction as this paper · 6 in the opposite direction
- positive
- positive
- positive
4 papers more in this group
See all 8 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.