Abstract
In outdoor common gardens, high latitude populations of deciduous tree species often display higher assimilation rates (A) than low latitude populations, but they accomplish less height. To test whether trends in A reflect adaptation to growing season length or, alternatively, are garden growth artefacts, we examined variation in height increment and ecophysiological traits in a range-wide collection of Populus balsamifera L. populations from 21 provenances, during unconstrained growth in a greenhouse. Rooted cuttings, maintained without resource limitation under 21 h photoperiod for 90 d, displayed increasing height growth, A, leaf mass per area and leaf N per area with latitude whereas stomatal conductance (g(s)) showed no pattern. Water-use efficiency as indicated by both gas exchange and delta(13)C increased with latitude, whereas photosynthetic nitrogen-use efficiency decreased. Differences in delta(13)C were less than expected based on A/g(s), suggesting coextensive variation in internal conductance (g(m)). Analysis of A-C(i) curves on a subset of populations showed that high latitude genotypes had greater g(m) than low-latitude genotypes. We conclude that higher peak rates of height growth in high latitude genotypes of balsam poplar are supported by higher A, achieved partly through higher g(m), to help compensate for a shorter growing season.
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Claims 7
Claim · model-written summary
Height growth and assimilation rate (A) of Populus balsamifera rooted cuttings increased with provenance latitude in a greenhouse.
- Taxon
- Populus balsamifera L.
Populus balsamiferat0 - Treatment
- latitudee0
- Outcome
- height growth, Ae0
- Direction
- increasinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“balsam poplar (Populus balsamifera L.)”
e0“displayed increasing height growth, A, leaf mass per area and leaf N per area with latitude”
Claim · model-written summary
Leaf mass per area and leaf N per area of Populus balsamifera rooted cuttings increased with provenance latitude in a greenhouse.
- Taxon
- Populus balsamifera L.Populus balsamiferat0
- Treatment
- latitudee0
- Outcome
- leaf mass per area and leaf N per areae0
- Direction
- increasinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“balsam poplar (Populus balsamifera L.)”
e0“displayed increasing height growth, A, leaf mass per area and leaf N per area with latitude”
Claim · model-written summary
Water-use efficiency, indicated by both gas exchange and delta13C, increased with latitude in Populus balsamifera.
- Taxon
- Populus balsamifera L.Populus balsamiferat0
- Treatment
- latitudee0
- Outcome
- Water-use efficiencye0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“balsam poplar (Populus balsamifera L.)”
e0“Water-use efficiency as indicated by both gas exchange and delta(13)C increased with latitude”
Claim · model-written summary
Photosynthetic nitrogen-use efficiency decreased with latitude in Populus balsamifera.
- Taxon
- Populus balsamifera L.Populus balsamiferat0
- Treatment
- latitudee0
- Outcome
- photosynthetic nitrogen-use efficiencye0
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“balsam poplar (Populus balsamifera L.)”
e0“Water-use efficiency as indicated by both gas exchange and delta(13)C increased with latitude, whereas photosynthetic nitrogen-use efficiency decreased”
Claim · model-written summary
High latitude Populus balsamifera genotypes had greater internal conductance (g(m)) than low-latitude genotypes, from A-Ci curves on a subset of populations.
- Taxon
- Populus balsamifera L.Populus balsamiferat0
- Material
- high latitude genotypese0
- Outcome
- g(m)e0
- Direction
- greatere0
- Comparator
- low-latitude genotypese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“balsam poplar (Populus balsamifera L.)”
e0“high latitude genotypes had greater g(m) than low-latitude genotypes”
Claim · model-written summary
Differences in delta13C were smaller than expected from A/g(s), suggesting coextensive variation in internal conductance (g(m)).
- Taxon
- Populus balsamifera L.Populus balsamiferat0
- Outcome
- Differences in delta(13)Ce0
- Qualifier
- coextensive variation in internal conductance (g(m))e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“balsam poplar (Populus balsamifera L.)”
e0“Differences in delta(13)C were less than expected based on A/g(s), suggesting coextensive variation in internal conductance (g(m))”
Claim · model-written summary
The authors conclude that higher peak rates of height growth in high latitude balsam poplar genotypes are supported by higher A, achieved partly through higher g(m), compensating for a shorter growing season.
- Taxon
- balsam poplarPopulus balsamiferae0
- Outcome
- peak rates of height growthe0
- Qualifier
- higher A, achieved partly through higher g(m)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“higher peak rates of height growth in high latitude genotypes of balsam poplar are supported by higher A, achieved partly through higher g(m)”