Abstract
Atmospheric CO2 concentration and temperature are increasing as a consequence of human activity. Periods of low water availability are expected to increase in Mediterranean ecosystems. Temperature gradient tunnels were used to provide near to ambient conditions and conditions simulating predicted increases in CO2 and temperature for an alfalfa crop. The performance, construction, and running costs of the tunnels are reported and discussed. Two levels of water supply were included in the treatments. Plants were grown in large, 13 L pots, keeping a fixed soil volumetric water content and with nodule fixation as the only nitrogen source for the plant. Regardless of water regime, the effect of elevated CO2 on plant growth was temperature dependent. Dry matter was enhanced when elevated CO2 and temperature were combined. Plant yield improvement was partly a result of increased photosynthetic rates. There were no effects on plant N concentration. Decreased specific nodule activity might suggest that lack of differences in plant N were a consequence of reduced nodule enzyme activity.
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Claims 6
Claim · model-written summary
The effect of elevated CO2 on alfalfa growth depended on temperature regardless of water regime.
- Taxon
- alfalfa
Medicago sativat0 - Treatment
- elevated CO2e0
- Outcome
- plant growthe0
- Qualifier
- Regardless of water regimee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Regardless of water regime, the effect of elevated CO2 on plant growth was temperature dependent.”
t0“alfalfa”
Claim · model-written summary
Combined elevated CO2 and temperature enhanced alfalfa dry matter.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- elevated CO2 and temperaturee0
- Outcome
- Dry mattere0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Dry matter was enhanced when elevated CO2 and temperature were combined.”
t0“alfalfa”
Claim · model-written summary
Alfalfa yield improvement was partly attributable to increased photosynthetic rates.
- Taxon
- alfalfaMedicago sativat0
- Outcome
- Plant yield improvemente0
- Qualifier
- increased photosynthetic ratese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plant yield improvement was partly a result of increased photosynthetic rates.”
t0“alfalfa”
Claim · model-written summary
Plant nitrogen concentration showed no effect.
- Taxon
- alfalfaMedicago sativat0
- Outcome
- plant N concentratione0
- Direction
- no effectse0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There were no effects on plant N concentration.”
t0“alfalfa”
Claim · model-written summary
Specific nodule activity decreased.
- Taxon
- alfalfaMedicago sativat0
- Outcome
- specific nodule activitye0
- Direction
- Decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Decreased specific nodule activity might suggest that lack of differences in plant N were a consequence of reduced nodule enzyme activity.”
t0“alfalfa”
Claim · model-written summary
The authors suggest reduced nodule enzyme activity may explain the lack of differences in plant nitrogen.
- Taxon
- alfalfaMedicago sativat0
- Outcome
- lack of differences in plant Ne0
- Qualifier
- reduced nodule enzyme activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lack of differences in plant N were a consequence of reduced nodule enzyme activity”
t0“alfalfa”
The same questions in other papers
co2 · growth · Medicago sativa (alfalfa)Positive and negative results
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See all 20 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.