Abstract
ABSTRACT In this experiment, the photosynthetic acclimation of successive needle cohorts of Scots pine were studied during 3 years of growth at elevated CO 2 and temperature. Naturally regenerated Scots pine ( Pinus sylvestris L.) trees were subjected to elevated CO 2 concentration (+CO 2 , 700 p.p.m), elevated temperature (+T, ambient +2 to +6 °C) and to a combination of elevated CO 2 and temperature (+CO 2 + T) in closed‐top chambers, starting in August 1996. Trees growing in chambers with ambient CO 2 and ambient temperature served as controls (AmbC). Elevated CO 2 influenced the dark reactions more than the light reactions of photosynthesis, as in the 1996 and 1997 cohorts the carboxylation capacity of Rubisco was reduced in the first and second year of exposure, but there was no consistent change in chlorophyll fluorescence. Net photosynthesis measured at growth concentration of CO 2 was higher at +CO 2 than at AmbC on only one measuring occasion, was generally lower at +T and was not changed at +CO 2 + T. However, trees grown at +T tended to invest more nitrogen (N) in Rubisco, as Rubisco/chlorophyll and the proportion of the total needle N bound to Rubisco occasionally increased. The interaction of +CO 2 and +T on Rubisco was mostly negative; consequently, in the second and third year of the experiment the carboxylation capacity decreased at +CO 2 + T. In the 1996, 1997 and 1998 cohorts, the structural N concentration of needles was lower at +CO 2 than at AmbC. Elevated CO 2 and elevated temperature generally had a positive interaction on N concentration; consequently, N concentration in needles decreased less at +CO 2 + T than at +CO 2 . At +CO 2 + T, the acclimation response of needles varied between years and was more pronounced in the 1‐year‐old needles of the 1997 cohort than in those of the 1998 cohort. Thus, acclimation was not always greater in 1‐year‐old needles than in current‐year needles. In the +CO 2 + T treatment, elevated temperature had a greater effect on acclimation of needles than elevated CO 2 .
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Claims 11
Claim · model-written summary
Elevated CO2 reduced Rubisco carboxylation capacity in 1996 and 1997 needle cohorts during their first and second exposure years.
- Taxon
- Scots pine
Pinus sylvestrist0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Scots pine needles”
e0“in the 1996 and 1997 cohorts the carboxylation capacity of Rubisco was reduced in the first and second year of exposure”
e1“Elevated CO 2 influenced the dark reactions more than the light reactions of photosynthesis, as in the 1996 and 1997 cohorts the carboxylation capacity of Rubisco was reduced in the first and second year of exposure, but there was no consistent change in chlorophyll fluorescence. Net photosynthesis measured at growth concentration of CO 2 was higher at +CO 2 than at AmbC on only one measuring occasion, was generally lower at +T and was not changed at +CO 2 + T. However, trees grown at +T tended to invest more nitrogen (N) in Rubisco, as Rubisco/chlorophyll and the proportion of the total needle N bound to Rubisco occasionally increased.”
Claim · model-written summary
Elevated CO2 produced no consistent change in chlorophyll fluorescence.
- Taxon
- Scots pinePinus sylvestrist0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Scots pine needles”
e0“there was no consistent change in chlorophyll fluorescence”
e1“Elevated CO 2 influenced the dark reactions more than the light reactions of photosynthesis, as in the 1996 and 1997 cohorts the carboxylation capacity of Rubisco was reduced in the first and second year of exposure, but there was no consistent change in chlorophyll fluorescence. Net photosynthesis measured at growth concentration of CO 2 was higher at +CO 2 than at AmbC on only one measuring occasion, was generally lower at +T and was not changed at +CO 2 + T. However, trees grown at +T tended to invest more nitrogen (N) in Rubisco, as Rubisco/chlorophyll and the proportion of the total needle N bound to Rubisco occasionally increased.”
Claim · model-written summary
Net photosynthesis at growth CO2 was higher with elevated CO2 than in ambient chambers on only one occasion.
- Taxon
- Scots pinePinus sylvestrist0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Scots pine needles”
e0“Net photosynthesis measured at growth concentration of CO 2 was higher at +CO 2 than at AmbC on only one measuring occasion”
e1“Elevated CO 2 influenced the dark reactions more than the light reactions of photosynthesis, as in the 1996 and 1997 cohorts the carboxylation capacity of Rubisco was reduced in the first and second year of exposure, but there was no consistent change in chlorophyll fluorescence. Net photosynthesis measured at growth concentration of CO 2 was higher at +CO 2 than at AmbC on only one measuring occasion, was generally lower at +T and was not changed at +CO 2 + T. However, trees grown at +T tended to invest more nitrogen (N) in Rubisco, as Rubisco/chlorophyll and the proportion of the total needle N bound to Rubisco occasionally increased.”
Claim · model-written summary
Net photosynthesis was generally lower at elevated temperature.
- Taxon
- Scots pinePinus sylvestrist0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Scots pine needles”
e0“was generally lower at +T”
e1“Elevated CO 2 influenced the dark reactions more than the light reactions of photosynthesis, as in the 1996 and 1997 cohorts the carboxylation capacity of Rubisco was reduced in the first and second year of exposure, but there was no consistent change in chlorophyll fluorescence. Net photosynthesis measured at growth concentration of CO 2 was higher at +CO 2 than at AmbC on only one measuring occasion, was generally lower at +T and was not changed at +CO 2 + T. However, trees grown at +T tended to invest more nitrogen (N) in Rubisco, as Rubisco/chlorophyll and the proportion of the total needle N bound to Rubisco occasionally increased.”
Claim · model-written summary
Net photosynthesis was unchanged under combined elevated CO2 and temperature.
- Taxon
- Scots pinePinus sylvestrist0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Scots pine needles”
e0“was not changed at +CO 2 + T”
e1“Elevated CO 2 influenced the dark reactions more than the light reactions of photosynthesis, as in the 1996 and 1997 cohorts the carboxylation capacity of Rubisco was reduced in the first and second year of exposure, but there was no consistent change in chlorophyll fluorescence. Net photosynthesis measured at growth concentration of CO 2 was higher at +CO 2 than at AmbC on only one measuring occasion, was generally lower at +T and was not changed at +CO 2 + T. However, trees grown at +T tended to invest more nitrogen (N) in Rubisco, as Rubisco/chlorophyll and the proportion of the total needle N bound to Rubisco occasionally increased.”
Claim · model-written summary
At elevated temperature, the Rubisco to chlorophyll ratio and needle nitrogen allocation to Rubisco occasionally increased.
- Taxon
- Scots pinePinus sylvestrist0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Scots pine needles”
e0“Rubisco/chlorophyll and the proportion of the total needle N bound to Rubisco occasionally increased”
e1“Elevated CO 2 influenced the dark reactions more than the light reactions of photosynthesis, as in the 1996 and 1997 cohorts the carboxylation capacity of Rubisco was reduced in the first and second year of exposure, but there was no consistent change in chlorophyll fluorescence. Net photosynthesis measured at growth concentration of CO 2 was higher at +CO 2 than at AmbC on only one measuring occasion, was generally lower at +T and was not changed at +CO 2 + T. However, trees grown at +T tended to invest more nitrogen (N) in Rubisco, as Rubisco/chlorophyll and the proportion of the total needle N bound to Rubisco occasionally increased.”
Claim · model-written summary
Combined elevated CO2 and temperature decreased carboxylation capacity in experiment years two and three.
- Taxon
- Scots pinePinus sylvestrist0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Scots pine needles”
e0“in the second and third year of the experiment the carboxylation capacity decreased at +CO 2 + T”
e1“In the +CO 2 + T treatment, elevated temperature had a greater effect on acclimation of needles than elevated CO 2 .”
Claim · model-written summary
Structural needle nitrogen concentration was lower at elevated CO2 than ambient conditions across three cohorts.
- Taxon
- Scots pinePinus sylvestrist0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Scots pine needles”
e0“In the 1996, 1997 and 1998 cohorts, the structural N concentration of needles was lower at +CO 2 than at AmbC”
e1“In the +CO 2 + T treatment, elevated temperature had a greater effect on acclimation of needles than elevated CO 2 .”
Claim · model-written summary
Needle nitrogen concentration decreased less under combined elevated CO2 and temperature than under elevated CO2 alone.
- Taxon
- Scots pinePinus sylvestrist0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Scots pine needles”
e0“N concentration in needles decreased less at +CO 2 + T than at +CO 2”
e1“In the +CO 2 + T treatment, elevated temperature had a greater effect on acclimation of needles than elevated CO 2 .”
Claim · model-written summary
Combined-treatment needle acclimation was more pronounced in one-year-old 1997 cohort needles than in the 1998 cohort.
- Taxon
- Scots pinePinus sylvestrist0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Scots pine needles”
e0“was more pronounced in the 1‐year‐old needles of the 1997 cohort than in those of the 1998 cohort”
e1“At +CO 2 + T, the acclimation response of needles varied between years and was more pronounced in the 1‐year‐old needles of the 1997 cohort than in those of the 1998 cohort. Thus, acclimation was not always greater in 1‐year‐old needles than in current‐year needles.”
Claim · model-written summary
Temperature had a greater effect on needle acclimation than elevated CO2 in the combined treatment.
- Taxon
- Scots pinePinus sylvestrist0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Scots pine needles”
e0“elevated temperature had a greater effect on acclimation of needles than elevated CO 2”
e1“In the +CO 2 + T treatment, elevated temperature had a greater effect on acclimation of needles than elevated CO 2 .”
The same questions in other papers
co2 · physiology: photosynthesis · Pinus sylvestris (Scots pine)Positive and negative results
5 papers in the same direction as this paper · 2 in the opposite direction
- positive
- positive
- no effect
4 papers more in this group
See all 8 papers →co2 · nutrient: content · Pinus sylvestris (Scots pine)Results agree
2 papers in the same direction as this paper
- positive
- positive
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.