Abstract
ABSTRACT The response of Eucalyptus grandis seedlings to elevated atmospheric CO 2 concentrations was examined by growing seedlings at either 340 or 660 n mol CO 2 mol ‐1 for 6 weeks. Graded increments of phosphorus and nitrogen fertilizers were added to a soil deficient in these nutrients to establish if the growth response to increasing nutrient availability was affected by CO 2 concentration. At 660 μmol CO 2 mol ‐1 , seedling dry weight was up to five times greater than at 340 μmol CO 2 mol ‐1 . The absolute response was largest when both nitrogen and phosphorus availability was high but the relative increase in dry weight was greatest at low phosphorus availability. At 340 μmol CO 2 mol ‐1 and high nitrogen availability, growth was stimulated by addition of phosphorus up to 76 mg kg 1 soil. Further additions of phosphorus had little effect. However, at 660 μmol CO 2 mol ‐1 , growth only began to plateau at a phosphorus addition rate of 920mg kg ‐1 soil. At 340 μmol CO 2 mol ‐1 and high phosphorus availability, increasing nitrogen from 40 to 160mg kg ‐1 soil had little effect on plant growth. At high CO 2 , growth reached a maximum at between 80 and 160mg nitrogen kg ‐1 soil. Total uptake of phosphorus was greater at high CO 2 concentration at all fertilizer addition rates, but nitrogen uptake was either lower or unchanged at high CO 2 concentration except at the highest nitrogen fertilizer rate. The shoot to root ratio was increased by CO 2 enrichment, primarily because the specific leaf weight was greater. The nitrogen and phosphorus concentration in the foliage was lower at elevated CO 2 concentration partly because of the higher specific leaf weight. These results indicate that critical foliar concentrations currently used to define nutritional status and fertilizer management may need to be reassessed as the atmospheric CO 2 concentration rises.
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Claims 15
Claim · model-written summary
At elevated CO2, seedling dry weight was up to five times greater than at ambient CO2.
- Taxon
- Eucalyptus grandis
Eucalyptus grandise1 - Treatment
- 660 μmol CO 2 mol ‐1e0
- Outcome
- seedling dry weighte0
- Direction
- greatere0
- Value
- up to five timese0
- Comparator
- 340 μmol CO 2 mol ‐1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“At 660 μmol CO 2 mol ‐1 , seedling dry weight was up to five times greater than at 340 μmol CO 2 mol ‐1 .”
Claim · model-written summary
The absolute dry-weight response was largest with high nitrogen and phosphorus availability.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- nitrogen and phosphorus availability was highe0
- Outcome
- absolute responsee0
- Direction
- largeste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“The absolute response was largest when both nitrogen and phosphorus availability was high but the relative increase in dry weight was greatest at low phosphorus availability.”
Claim · model-written summary
The relative dry-weight increase was greatest at low phosphorus availability.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- low phosphorus availabilitye0
- Outcome
- relative increase in dry weighte0
- Direction
- greateste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“The absolute response was largest when both nitrogen and phosphorus availability was high but the relative increase in dry weight was greatest at low phosphorus availability.”
Claim · model-written summary
At ambient CO2 and high nitrogen, adding phosphorus stimulated growth up to 76 mg kg 1 soil.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- addition of phosphoruse0
- Outcome
- growthe0
- Direction
- stimulatede0
- Value
- 76 mg kg 1 soile0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“At 340 μmol CO 2 mol ‐1 and high nitrogen availability, growth was stimulated by addition of phosphorus up to 76 mg kg 1 soil.”
Claim · model-written summary
Further phosphorus addition had little effect on growth at ambient CO2.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- Further additions of phosphoruse0
- Outcome
- effecte0
- Direction
- little effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“Further additions of phosphorus had little effect.”
Claim · model-written summary
At elevated CO2, growth plateaued only at 920mg kg ‐1 soil phosphorus addition.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- phosphorus additione0
- Outcome
- growthe0
- Direction
- plateaue0
- Value
- 920mg kg ‐1 soile0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“However, at 660 μmol CO 2 mol ‐1 , growth only began to plateau at a phosphorus addition rate of 920mg kg ‐1 soil.”
Claim · model-written summary
At ambient CO2 and high phosphorus, raising nitrogen from 40 to 160mg kg ‐1 soil had little effect on growth.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- increasing nitrogen from 40 to 160mg kg ‐1 soile0
- Outcome
- plant growthe0
- Direction
- little effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“At 340 μmol CO 2 mol ‐1 and high phosphorus availability, increasing nitrogen from 40 to 160mg kg ‐1 soil had little effect on plant growth.”
Claim · model-written summary
At high CO2, growth reached a maximum between 80 and 160mg nitrogen kg ‐1 soil.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- high CO 2e0
- Outcome
- growthe0
- Direction
- maximume0
- Value
- between 80 and 160mg nitrogen kg ‐1 soile0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“At high CO 2 , growth reached a maximum at between 80 and 160mg nitrogen kg ‐1 soil.”
Claim · model-written summary
Total phosphorus uptake was greater at high CO2 across fertilizer rates.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- high CO 2 concentratione0
- Outcome
- Total uptake of phosphoruse0
- Direction
- greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“Total uptake of phosphorus was greater at high CO 2 concentration at all fertilizer addition rates”
Claim · model-written summary
Nitrogen uptake under high CO2 was lower or unchanged except at the highest nitrogen rate.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- high CO 2 concentratione0
- Outcome
- nitrogen uptakee0
- Direction
- lowere0
- Qualifier
- except at the highest nitrogen fertilizer ratee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“nitrogen uptake was either lower or unchanged at high CO 2 concentration except at the highest nitrogen fertilizer rate.”
Claim · model-written summary
CO2 enrichment increased the shoot-to-root ratio.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- CO 2 enrichmente0
- Outcome
- shoot to root ratioe0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“The shoot to root ratio was increased by CO 2 enrichment, primarily because the specific leaf weight was greater.”
Claim · model-written summary
Specific leaf weight was greater under CO2 enrichment.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- CO 2 enrichmente0
- Outcome
- specific leaf weighte0
- Direction
- greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“The shoot to root ratio was increased by CO 2 enrichment, primarily because the specific leaf weight was greater.”
Claim · model-written summary
Elevated CO2 lowered foliar nitrogen concentration.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- elevated CO 2 concentratione0
- Outcome
- nitrogen and phosphorus concentration in the foliagee0
- Direction
- lowere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“The nitrogen and phosphorus concentration in the foliage was lower at elevated CO 2 concentration partly because of the higher specific leaf weight.”
Claim · model-written summary
Elevated CO2 lowered foliar phosphorus concentration.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Treatment
- elevated CO 2 concentratione0
- Outcome
- phosphorus concentration in the foliagee0
- Direction
- lowere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“The nitrogen and phosphorus concentration in the foliage was lower at elevated CO 2 concentration partly because of the higher specific leaf weight.”
Claim · model-written summary
The authors recommend reassessing critical foliar nutrient concentrations as atmospheric CO2 rises.
- Taxon
- Eucalyptus grandisEucalyptus grandise1
- Outcome
- critical foliar concentrations currently used to define nutritional status and fertilizer management may need to be reassessede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Eucalyptus grandis”
e0“critical foliar concentrations currently used to define nutritional status and fertilizer management may need to be reassessed as the atmospheric CO 2 concentration rises.”
The same questions in other papers
nitrogen · growth · Eucalyptus grandis (rose gum)Positive and negative results
1 in the opposite direction
- positive
co2 · growth · Eucalyptus grandis (rose gum)Positive and negative results
1 paper in the same direction as this paper · 2 in the opposite direction
- no effect
- no effect
- positive
phosphorus · growth · Eucalyptus grandis (rose gum)Results agree
3 papers in the same direction as this paper
- positive
- 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.