Abstract
Most studies involving photosynthetic efficiency have compared species or cultivars that were grown under fixed day/night temperature regimes. Researchers attempting to improve photosynthetic efficiency and productivity of a crop may also need to consider genotype response to adverse factors, such as temporary chilling, which have been shown to reduce subsequent photosynthetic rates. Three alfalfa ( Medicago sativa L.) cultlvars, representing a range of environmental adaptation, were grown in a greenhouse at 22/18 C (day/night), and then were exposed for one night to 5 or 18 C to determine the effect of low temperature on physiological processes the following morning. The CO 2 exchange rate (CER) of all three cultivars was reduced following a 5 C night. A greater reduction in CER occurred in ‘Mesa‐Sirsa’ and ‘Saranac’ (69.1 and 60.2% less than 18 C, respectively) than in ‘Kane’ (36.7% less than 18 C). Transpiration rates were significantly reduced following chilling exposure of Mesa‐Sirsa only (75.5% less than 18 C). This reduction in transpiration was associated with a 50% increase in leaf diffusive resistance and a 4.3 bar decrease in xylem water p6tential. Increased leaf diffusive resistance was not observed in Saranac and Kane following a chilling night. A greater leaf carbohydrate concentration and reduced l4 C‐photosynthate translocation from leaf tissue was noted in all cultivars following a 5 C night. These data suggest a feedback inhibition of CER in alfalfa following one 5 C chilling night. A water stress inducing an increased leaf diffusion resistance and decreased transpiration was found in Mesa‐Sirsa only.
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Claims 11
Claim · model-written summary
CO2 exchange rate of all three alfalfa cultivars was reduced following a 5 C night.
- Taxon
- Alfalfa
Medicago sativat0 - Treatment
- 5 C nighte0
- Outcome
- CO 2 exchange rate (CER)e0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Three Alfalfa Cultivars”
e0“The CO 2 exchange rate (CER) of all three cultivars was reduced following a 5 C night”
Claim · model-written summary
CER of Mesa-Sirsa was reduced 69.1% relative to the 18 C night after a 5 C night.
- Taxon
- AlfalfaMedicago sativat0
- Material
- Mesa‐Sirsae0
- Outcome
- CERe0
- Direction
- reductione0
- Value
- 69.1e0
- Comparator
- 18 Ce0
Not reportedTreatment
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Three Alfalfa Cultivars”
e0“A greater reduction in CER occurred in ‘Mesa‐Sirsa’ and ‘Saranac’ (69.1 and 60.2% less than 18 C, respectively)”
Claim · model-written summary
CER of Saranac was reduced 60.2% relative to the 18 C night after a 5 C night.
- Taxon
- AlfalfaMedicago sativat0
- Material
- Saranace0
- Outcome
- CERe0
- Direction
- reductione0
- Value
- 60.2%e0
- Comparator
- 18 Ce0
Not reportedTreatment
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Three Alfalfa Cultivars”
e0“A greater reduction in CER occurred in ‘Mesa‐Sirsa’ and ‘Saranac’ (69.1 and 60.2% less than 18 C, respectively)”
Claim · model-written summary
CER of Kane was reduced less (36.7% below the 18 C night) than in Mesa-Sirsa and Saranac after a 5 C night.
- Taxon
- AlfalfaMedicago sativat0
- Material
- Kanee1
- Outcome
- CERe0
- Direction
- reductione0
- Value
- 36.7%e1
- Comparator
- 18 Ce1
Not reportedTreatment
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Three Alfalfa Cultivars”
e0“A greater reduction in CER”
e1“than in ‘Kane’ (36.7% less than 18 C)”
Claim · model-written summary
Transpiration rate was significantly reduced by 75.5% relative to 18 C following chilling in Mesa-Sirsa only.
- Taxon
- AlfalfaMedicago sativat0
- Material
- Mesa‐Sirsae0
- Treatment
- chilling exposuree0
- Outcome
- Transpiration ratese0
- Direction
- reducede0
- Value
- 75.5%e0
- Comparator
- 18 Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Three Alfalfa Cultivars”
e0“Transpiration rates were significantly reduced following chilling exposure of Mesa‐Sirsa only (75.5% less than 18 C)”
Claim · model-written summary
In Mesa-Sirsa, the reduction in transpiration was associated with a 50% increase in leaf diffusive resistance.
- Taxon
- AlfalfaMedicago sativat0
- Outcome
- leaf diffusive resistancee0
- Direction
- increasee0
- Value
- 50%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Three Alfalfa Cultivars”
e0“a 50% increase in leaf diffusive resistance”
Claim · model-written summary
In Mesa-Sirsa, the reduction in transpiration was associated with a 4.3 bar decrease in xylem water potential.
- Taxon
- AlfalfaMedicago sativat0
- Outcome
- xylem water p6tentiale0
- Direction
- decreasee0
- Value
- 4.3 bare0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Three Alfalfa Cultivars”
e0“a 4.3 bar decrease in xylem water p6tential”
Claim · model-written summary
Increased leaf diffusive resistance was not observed in Saranac and Kane following a chilling night.
- Taxon
- AlfalfaMedicago sativat0
- Material
- Saranac and Kanee0
- Treatment
- chilling nighte0
- Outcome
- leaf diffusive resistancee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Three Alfalfa Cultivars”
e0“Increased leaf diffusive resistance was not observed in Saranac and Kane following a chilling night”
Claim · model-written summary
Leaf carbohydrate concentration was greater in all three cultivars following a 5 C night.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- 5 C nighte1
- Outcome
- leaf carbohydrate concentratione0
- Direction
- greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Three Alfalfa Cultivars”
e0“A greater leaf carbohydrate concentration”
e1“in all cultivars following a 5 C night”
Claim · model-written summary
Translocation of 14C photosynthate from leaf tissue was reduced in all three cultivars following a 5 C night.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- 5 C nighte0
- Outcome
- photosynthate translocation from leaf tissuee0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Three Alfalfa Cultivars”
e0“reduced l4 C‐photosynthate translocation from leaf tissue was noted in all cultivars following a 5 C night”
Claim · model-written summary
The authors suggest a feedback inhibition of CER in alfalfa following one 5 C chilling night.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- one 5 C chilling nighte0
- Outcome
- CERe0
- Qualifier
- feedback inhibitione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These data suggest a feedback inhibition of CER in alfalfa following one 5 C chilling night”
The same questions in other papers
cold · physiology: gas exchange · Medicago sativa (alfalfa)Results agree
1 paper in the same direction as this paper
- negative
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.