Abstract
Spring wheat ( Triticum aestivum L. cv. Dragon) was exposed to elevated carbon dioxide (CO 2 ), alone (1995) or in combination with two levels of increased ozone (O 3 ) (1994) or increased irrigation (1996) during three successive growing seasons as part of the EU ESPACE‐wheat programme and conducted in open‐top chambers (OTCs) and ambient air (AA) plots at Östad, 50 km north‐east of Göteborg, Sweden. Doubling the CO 2 concentration had a positive effect on grain yield in all 3 years (+21, +7 and +11%, respectively), although only statistically significant in 1994. That year was characterised by a warm and dry summer in comparison with 1995 and 1996, in which the summers were more humid and typical for south‐west Sweden. In 1994, the CO 2 ‐induced increase in grain yield was associated with an increase in the duration of the green leaf area, a positive effect on straw yield and on the number of ears per square metre and a negative effect (−13%) on grain protein concentration. Harvest index was unaffected by the elevated CO 2 concentration. The only statistically significant effect of elevated CO 2 in 1995 was a decrease in the grain protein concentration (−11% in both CO 2 concentrations), and in 1996 an increase (+21%) in the straw yield. In 1996 the soil water potential was less negative in elevated CO 2 , which is likely to reflect a lower water consumption of these plants. Addition of extra O 3 significantly affected the grain yield (−6 and −10%, respectively) and the 1 000‐grain weight negatively (−3 and −6%). Statistically significant interactions between CO 2 and O 3 were obtained for the number of ears per unit area and for the 1 000‐grain weight. The 1 000‐grain weight was negatively affected by O 3 in low CO 2 , but remained unaffected in the high CO 2 treatment. There was a significant decrease (−6%) in the grain protein concentration induced by elevated irrigation. The chambers, compared with AA plots, had a positive effect on plant development and on grain yield in all 3 years.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 13
Claim · model-written summary
Doubling CO2 increased grain yield by 21%, 7%, and 11% in 1994, 1995, and 1996, respectively; only 1994 was significant.
- Taxon
- spring wheat
Triticum aestivumt0 - Treatment
- Doubling the CO 2 concentratione0
- Outcome
- grain yielde0
- Direction
- positive effecte0
- Value
- +21, +7 and +11%e0
- Qualifier
- only statistically significant in 1994e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Doubling the CO 2 concentration had a positive effect on grain yield in all 3 years (+21, +7 and +11%, respectively), although only statistically significant in 1994.”
t0“spring wheat”
Claim · model-written summary
In 1994 elevated CO2 increased duration of green leaf area, straw yield, and ears per square metre.
- Taxon
- spring wheatTriticum aestivumt0
- Treatment
- CO 2e0
- Outcome
- duration of the green leaf areae0
- Direction
- increasee0
- Qualifier
- In 1994e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 1994, the CO 2 ‐induced increase in grain yield was associated with an increase in the duration of the green leaf area, a positive effect on straw yield and on the number of ears per square metre”
t0“spring wheat”
Claim · model-written summary
Elevated CO2 reduced grain protein concentration by 13% in 1994.
- Taxon
- spring wheatTriticum aestivumt0
- Outcome
- grain protein concentratione0
- Direction
- negative effecte0
- Value
- −13%e0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a negative effect (−13%) on grain protein concentration”
t0“spring wheat”
Claim · model-written summary
Elevated CO2 left harvest index unaffected.
- Taxon
- spring wheatTriticum aestivumt0
- Treatment
- elevated CO 2 concentratione0
- Outcome
- Harvest indexe0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Harvest index was unaffected by the elevated CO 2 concentration.”
t0“spring wheat”
Claim · model-written summary
In 1995 elevated CO2 significantly decreased grain protein concentration by 11%.
- Taxon
- spring wheatTriticum aestivumt0
- Treatment
- elevated CO 2e0
- Outcome
- grain protein concentratione0
- Direction
- decreasee0
- Value
- −11%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The only statistically significant effect of elevated CO 2 in 1995 was a decrease in the grain protein concentration (−11% in both CO 2 concentrations)”
t0“spring wheat”
Claim · model-written summary
In 1996 elevated CO2 increased straw yield by 21%.
- Taxon
- spring wheatTriticum aestivumt0
- Outcome
- straw yielde0
- Direction
- increasee0
- Value
- +21%e0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in 1996 an increase (+21%) in the straw yield”
t0“spring wheat”
Claim · model-written summary
Soil water potential was less negative under elevated CO2 in 1996.
- Taxon
- spring wheatTriticum aestivumt0
- Treatment
- elevated CO 2e0
- Outcome
- soil water potentiale0
- Direction
- less negativee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 1996 the soil water potential was less negative in elevated CO 2”
t0“spring wheat”
Claim · model-written summary
Extra ozone significantly reduced wheat grain yield by 6% and 10% at the two levels.
- Taxon
- spring wheatTriticum aestivumt0
- Treatment
- extra O 3e0
- Outcome
- grain yielde0
- Direction
- −6 and −10%e0
- Value
- −6 and −10%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of extra O 3 significantly affected the grain yield (−6 and −10%, respectively)”
t0“spring wheat”
Claim · model-written summary
Extra ozone significantly reduced thousand-grain weight by 3% and 6% at the two levels.
- Taxon
- spring wheatTriticum aestivumt0
- Outcome
- 1 000‐grain weighte0
- Direction
- negativelye0
- Value
- −3 and −6%e0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the 1 000‐grain weight negatively (−3 and −6%)”
t0“spring wheat”
Claim · model-written summary
CO2 and ozone interacted significantly for ear number per area and thousand-grain weight.
- Taxon
- spring wheatTriticum aestivumt0
- Treatment
- CO 2 and O 3e0
- Outcome
- number of ears per unit areae0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Statistically significant interactions between CO 2 and O 3 were obtained for the number of ears per unit area and for the 1 000‐grain weight.”
t0“spring wheat”
Claim · model-written summary
Ozone reduced thousand-grain weight at low CO2 but not high CO2.
- Taxon
- spring wheatTriticum aestivumt0
- Treatment
- O 3e0
- Outcome
- 1 000‐grain weighte0
- Direction
- negatively affectede0
- Comparator
- high CO 2 treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The 1 000‐grain weight was negatively affected by O 3 in low CO 2 , but remained unaffected in the high CO 2 treatment.”
t0“spring wheat”
Claim · model-written summary
Elevated irrigation significantly reduced grain protein concentration by 6%.
- Taxon
- spring wheatTriticum aestivumt0
- Treatment
- elevated irrigatione0
- Outcome
- grain protein concentratione0
- Direction
- decreasee0
- Value
- −6%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was a significant decrease (−6%) in the grain protein concentration induced by elevated irrigation.”
t0“spring wheat”
Claim · model-written summary
Open-top chambers promoted plant development and grain yield relative to ambient air plots in all three years.
- Taxon
- spring wheatTriticum aestivumt0
- Treatment
- chamberse0
- Outcome
- plant development and on grain yielde0
- Direction
- positive effecte0
- Comparator
- AA plotse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The chambers, compared with AA plots, had a positive effect on plant development and on grain yield in all 3 years.”
t0“spring wheat”
The same questions in other papers
co2 · quality: protein · Triticum aestivum (wheat)Results differ
28 papers in the same direction as this paper · 3 in the opposite direction
- negative
- negative
- positive
28 papers more in this group
See all 32 papers →co2 · physiology: water · Triticum aestivum (wheat)Results differ
37 papers in the same direction as this paper · 4 in the opposite direction
- positive
- positive
- no effect
38 papers more in this group
See all 42 papers →ozone · yield · Triticum aestivum (wheat)Results differ
62 papers in the same direction as this paper · 7 in the opposite direction
- positive
- positive
- negative
66 papers more in this group
See all 70 papers →irrigation · quality: protein · Triticum aestivum (wheat)Results differ
29 papers in the same direction as this paper · 50 in the opposite direction
- positive
- positive
- positive
76 papers more in this group
See all 80 papers →co2 · growth · Triticum aestivum (wheat)Positive and negative results
123 papers in the same direction as this paper · 20 in the opposite direction · 1 reporting no difference from an alternative
- no effect
- positive
- positive
141 papers more in this group
See all 145 papers →co2 · yield · Triticum aestivum (wheat)Positive and negative results
173 papers in the same direction as this paper · 29 in the opposite direction
- no effect
- negative
- negative
199 papers more in this group
See all 203 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.