Abstract
Four eucalypt species were selected to represent two ecologically disparate groups which would be expected to contrast in seedling vigour and in the nature of growth responses to CO2 × nitrogen supply. Eucalyptus camaldulensis and E. cypellocarpa were taken as examples of fast-growing species with a wide distribution, that develop into large trees. By contrast, E. pauciflora and E. pulverulenta become smaller trees, and show a more limited distribution. Seedlings were established in pots (5 L) of a loamy soil and supplied with nutrient solution containing either 1.2 or 6.0 mM NO3- in both ambient (33 Pa) and CO2-enriched (66 Pa) greenhouses. Analysis of growth response to treatments (2 × 2 factorial) was based on destructive harvest of plants sampled on four occasions over 84 days for E. carnaldulensis and E. cypellocarpa, and 100 days for E. pulverulenta and E. pauciflora. A positive CO2 × N interaction on plant dry mass and leaf area was expressed in all species throughout the study period. In E. carnaldulensis and E. cypellocarpa, plant mass was doubled by high N at 33 Pa CO2, compared with a three to four-fold increase at 66 Pa to reach 34g by final harvest. In E. pulverulenta and E. pauciflora, slower growth resulted in about 50% less mass at a given age, but relative increases due to CO2 and N were of a similar order. A distinction can be made between N and CO2 effects on growth processes as follows. When trees were grown on low N, elevated CO2 increased nitrogen-use efficiency (NUE) at both leaf and whole plant levels. On high N, leaf NUE was increased in E. camaldulensis and E. cypellocarpa, but decreased in E. pulverulenta and E. pauciflora. Whole plant NUE showed no consistent response to elevated CO2 when plants were supplied high N. Net assimilation rate (NAR) was increased by elevated CO2 in all species on either N treatment. Moreover, high N increased NAR under either CO2 treatment in all species. There was a positive N × CO2 interaction on NAR in E. carnaldulensis and E. cypellocarpa, but not in E. pulverulenta and E. pauciflora. Growth indices for E. carnaldulensis and E. cypellocarpa species, and especially E. carnaldulensis, generally exceeded those for E. pulverulenta and E. pauciflora in terms of NAR, leaf NUE, N-enhancement of CO2 effects on leaf area and biomass, and non-structural carbohydrate content of foliage.
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Claims 16
Claim · model-written summary
A positive CO2 x N interaction on plant dry mass and leaf area occurred in all four eucalypt species throughout the study.
Verbatim
t0“Four Species of Eucalypt”
e0“A positive CO2 × N interaction on plant dry mass and leaf area was expressed in all species throughout the study period”
Claim · model-written summary
In E. camaldulensis and E. cypellocarpa, high N doubled plant mass at 33 Pa CO2.
- Taxon
- E. carnaldulensis and E. cypellocarpae0
- Treatment
- high N at 33 Pa CO2e0
- Outcome
- plant masse0
- Direction
- doublede0
Not reportedComparator
Verbatim
e0“In E. carnaldulensis and E. cypellocarpa, plant mass was doubled by high N at 33 Pa CO2, compared with a three to four-fold increase at 66 Pa to reach 34g by final harvest”
Claim · model-written summary
In E. camaldulensis and E. cypellocarpa, high N gave a three to four-fold increase in plant mass at 66 Pa CO2, reaching 34 g by final harvest.
- Taxon
- E. carnaldulensis and E. cypellocarpae0
- Treatment
- high Ne0
- Outcome
- plant masse0
- Direction
- three to four-fold increasee0
- Value
- 34ge0
- Qualifier
- 66 Pae0
Not reportedComparator
Verbatim
e0“In E. carnaldulensis and E. cypellocarpa, plant mass was doubled by high N at 33 Pa CO2, compared with a three to four-fold increase at 66 Pa to reach 34g by final harvest”
Claim · model-written summary
E. pulverulenta and E. pauciflora grew more slowly and had about 50% less mass at a given age.
- Taxon
- E. pulverulenta and E. pauciflora
Eucalyptus pauciflora_-_DSC03263.JPG?width=60)
Eucalyptus pulverulentae0 - Outcome
- masse0
- Direction
- lesse0
- Value
- about 50%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_-_DSC03263.JPG?width=500)
Verbatim
e0“In E. pulverulenta and E. pauciflora, slower growth resulted in about 50% less mass at a given age”
Claim · model-written summary
In E. pulverulenta and E. pauciflora, relative increases due to CO2 and N were of a similar order as in the faster-growing species.
- Taxon
- E. pulverulenta and E. paucifloraEucalyptus paucifloraEucalyptus pulverulentae0
- Treatment
- CO2 and Ne0
- Outcome
- relative increasese0
- Qualifier
- of a similar ordere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In E. pulverulenta and E. pauciflora, slower growth resulted in about 50% less mass at a given age, but relative increases due to CO2 and N were of a similar order”
Claim · model-written summary
On low N, elevated CO2 increased nitrogen-use efficiency at leaf and whole plant levels.
- Taxon
- treese0
- Treatment
- elevated CO2e0
- Outcome
- nitrogen-use efficiency (NUE)e0
- Direction
- increasede0
- Qualifier
- low Ne0
Not reportedComparator
Verbatim
e0“When trees were grown on low N, elevated CO2 increased nitrogen-use efficiency (NUE) at both leaf and whole plant levels”
Claim · model-written summary
On high N, leaf NUE was increased in E. camaldulensis and E. cypellocarpa.
- Taxon
- E. camaldulensis and E. cypellocarpa
Eucalyptus camaldulensis
Eucalyptus cypellocarpae0 - Outcome
- leaf NUEe0
- Direction
- increasede0
- Qualifier
- On high Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On high N, leaf NUE was increased in E. camaldulensis and E. cypellocarpa, but decreased in E. pulverulenta and E. pauciflora”
Claim · model-written summary
On high N, leaf NUE was decreased in E. pulverulenta and E. pauciflora.
- Taxon
- E. pulverulenta and E. paucifloraEucalyptus paucifloraEucalyptus pulverulentae0
- Outcome
- leaf NUEe0
- Direction
- decreasede0
- Qualifier
- On high Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On high N, leaf NUE was increased in E. camaldulensis and E. cypellocarpa, but decreased in E. pulverulenta and E. pauciflora”
Claim · model-written summary
Whole plant NUE showed no consistent response to elevated CO2 when plants received high N.
- Taxon
- plantsViridiplantaee0
- Treatment
- elevated CO2e0
- Outcome
- Whole plant NUEe0
- Direction
- no consistent responsee0
- Qualifier
- high Ne0
Not reportedComparator
Verbatim
e0“Whole plant NUE showed no consistent response to elevated CO2 when plants were supplied high N”
Claim · model-written summary
Net assimilation rate increased under elevated CO2 in all species on either N treatment.
- Taxon
- all speciese0
- Treatment
- elevated CO2e0
- Outcome
- Net assimilation rate (NAR)e0
- Direction
- increasede0
- Qualifier
- either N treatmente0
Not reportedComparator
Verbatim
e0“Net assimilation rate (NAR) was increased by elevated CO2 in all species on either N treatment”
Claim · model-written summary
High N increased NAR under either CO2 treatment in all species.
Not reportedComparator
Verbatim
e0“high N increased NAR under either CO2 treatment in all species”
Claim · model-written summary
There was a positive N x CO2 interaction on NAR in E. camaldulensis and E. cypellocarpa.
Verbatim
e0“There was a positive N × CO2 interaction on NAR in E. carnaldulensis and E. cypellocarpa, but not in E. pulverulenta and E. pauciflora”
Claim · model-written summary
No N x CO2 interaction on NAR was found in E. pulverulenta and E. pauciflora.
- Taxon
- E. pulverulenta and E. paucifloraEucalyptus paucifloraEucalyptus pulverulentae0
- Treatment
- N × CO2 interactione0
- Outcome
- NARe0
- Direction
- note0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was a positive N × CO2 interaction on NAR in E. carnaldulensis and E. cypellocarpa, but not in E. pulverulenta and E. pauciflora”
Claim · model-written summary
Growth indices of E. camaldulensis and E. cypellocarpa generally exceeded those of E. pulverulenta and E. pauciflora for NAR and leaf NUE.
Verbatim
e0“Growth indices for E. carnaldulensis and E. cypellocarpa species, and especially E. carnaldulensis, generally exceeded those for E. pulverulenta and E. pauciflora in terms of NAR, leaf NUE, N-enhancement of CO2 effects on leaf area and biomass, and non-structural carbohydrate content of foliage”
Claim · model-written summary
The N-enhancement of CO2 effects on leaf area and biomass was generally greater in E. camaldulensis and E. cypellocarpa than in E. pulverulenta and E. pauciflora.
Verbatim
e0“Growth indices for E. carnaldulensis and E. cypellocarpa species, and especially E. carnaldulensis, generally exceeded those for E. pulverulenta and E. pauciflora in terms of NAR, leaf NUE, N-enhancement of CO2 effects on leaf area and biomass, and non-structural carbohydrate content of foliage”
Claim · model-written summary
Non-structural carbohydrate content of foliage generally exceeded in E. camaldulensis and E. cypellocarpa the level in E. pulverulenta and E. pauciflora.
Verbatim
e0“Growth indices for E. carnaldulensis and E. cypellocarpa species, and especially E. carnaldulensis, generally exceeded those for E. pulverulenta and E. pauciflora in terms of NAR, leaf NUE, N-enhancement of CO2 effects on leaf area and biomass, and non-structural carbohydrate content of foliage”
The same questions in other papers
co2 · nutrient: efficiency · Viridiplantae (plants)Results agree
1 paper in the same direction as this paper
- 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.