Abstract
• Using the Poplar Free Air CO2 Enrichement (PopFACE) facility we investigated the effects of elevated [CO2] on the diurnal and growth cycle responses of photosynthesis and conductance in three poplar species. • In situ diurnal measurements of photosynthesis were made on Populus alba, P. nigra and P. ×euramericana and, in parallel, in vivo maximum capacity for carboxylation (Vc,max) and maximum rates of electron transport (Jmax) were determined by gas exchange measurement. • Light saturated (Asat) and daily integrated (A′) photosynthesis increased at elevated [CO2] in all species. Elevated [CO2] decreased Vc,max and Jmax for P. nigra and Jmax for P.¥euramericana but had no effect on stomatal conductance in any of the species throughout the first growth cycle. During post-coppice re-growth, elevated [CO2] did not increase Asat in P. nigra and P.×euramericana due to large decreases in Vc,max and Jmax. • A 50% increase in [CO2] under these open-air field conditions resulted in a large and sustained increase in Asat. Although there were some differences between the species, these had little effect on photosynthetic rates at the growth [CO2]. Nevertheless the results show that even fast growing trees grown without rooting volume restriction in the open may still show some down-regulation of photosynthetic potential at elevated [CO2].
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Claims 8
Claim · model-written summary
Elevated CO2 increased light-saturated and daily integrated photosynthesis in all three poplar species
- Treatment
- elevated [CO2]e1
- Outcome
- Light saturated (Asat) and daily integrated (A′) photosynthesise1
- Direction
- increasede1
PopulusNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Photosynthesis and stomatal conductance responses of poplars”
e0“the effects of elevated [CO2] on the diurnal and growth cycle responses of photosynthesis and conductance in three poplar species”
e1“Light saturated (Asat) and daily integrated (A′) photosynthesis increased at elevated [CO2] in all species”
Claim · model-written summary
Elevated CO2 decreased Vc,max and Jmax in P. nigra
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Photosynthesis and stomatal conductance responses of poplars”
e0“the effects of elevated [CO2] on the diurnal and growth cycle responses of photosynthesis and conductance in three poplar species”
e2“Elevated [CO2] decreased Vc,max and Jmax for P. nigra and Jmax for P.¥euramericana but had no effect on stomatal conductance in any of the species throughout the first growth cycle”
Claim · model-written summary
Elevated CO2 decreased Jmax in P.¥euramericana
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Photosynthesis and stomatal conductance responses of poplars”
e0“the effects of elevated [CO2] on the diurnal and growth cycle responses of photosynthesis and conductance in three poplar species”
e2“Elevated [CO2] decreased Vc,max and Jmax for P. nigra and Jmax for P.¥euramericana but had no effect on stomatal conductance in any of the species throughout the first growth cycle”
Claim · model-written summary
Elevated CO2 had no effect on stomatal conductance in any poplar species during the first growth cycle
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Photosynthesis and stomatal conductance responses of poplars”
e0“the effects of elevated [CO2] on the diurnal and growth cycle responses of photosynthesis and conductance in three poplar species”
e2“Elevated [CO2] decreased Vc,max and Jmax for P. nigra and Jmax for P.¥euramericana but had no effect on stomatal conductance in any of the species throughout the first growth cycle”
Claim · model-written summary
After coppice, elevated CO2 did not increase Asat in P. nigra, due to large decreases in Vc,max and Jmax
- Material
- P. nigrae3
- Treatment
- elevated [CO2]e3
- Outcome
- Asate3
- Direction
- did not increasee3
- Qualifier
- due to large decreases in Vc,max and Jmaxe3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Photosynthesis and stomatal conductance responses of poplars”
e0“the effects of elevated [CO2] on the diurnal and growth cycle responses of photosynthesis and conductance in three poplar species”
e3“During post-coppice re-growth, elevated [CO2] did not increase Asat in P. nigra and P.×euramericana due to large decreases in Vc,max and Jmax”
Claim · model-written summary
A 50% increase in CO2 caused a large and sustained increase in Asat under open-air field conditions
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Photosynthesis and stomatal conductance responses of poplars”
e0“the effects of elevated [CO2] on the diurnal and growth cycle responses of photosynthesis and conductance in three poplar species”
e4“A 50% increase in [CO2] under these open-air field conditions resulted in a large and sustained increase in Asat”
Claim · model-written summary
Species differences had little effect on photosynthetic rates at growth CO2 concentration
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Photosynthesis and stomatal conductance responses of poplars”
e0“the effects of elevated [CO2] on the diurnal and growth cycle responses of photosynthesis and conductance in three poplar species”
e5“Although there were some differences between the species, these had little effect on photosynthetic rates at the growth [CO2]”
Claim · model-written summary
Fast growing poplars grown in the open may still down-regulate photosynthetic potential at elevated CO2
- Treatment
- elevated [CO2]e6
- Outcome
- down-regulation of photosynthetic potentiale6
- Direction
- down-regulatione6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Photosynthesis and stomatal conductance responses of poplars”
e0“the effects of elevated [CO2] on the diurnal and growth cycle responses of photosynthesis and conductance in three poplar species”
e6“even fast growing trees grown without rooting volume restriction in the open may still show some down-regulation of photosynthetic potential at elevated [CO2]”
The same questions in other papers
co2 · physiology: gas exchange · Populus (poplar)Positive and negative results
2 papers in the same direction as this paper · 1 in the opposite direction
- negative
- positive
- no effect
co2 · physiology: photosynthesis · Populus (poplar)Positive and negative results
9 papers in the same direction as this paper · 1 in the opposite direction
- positive
- positive
- positive
7 papers more in this group
See all 11 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.