Abstract
We conducted greenhouse experiments to compare 14 lucerne (alfalfa, Medicago sativa L.) germplasms for their survival following freezing. Some are collections adapted to the Grand River National Grasslands in South Dakota. We hypothesised that these collections might have developed a tolerance to survive the frigid growth conditions common there. Two of these collections, River side (RS) and Foster ranch (FR), showed greater freezing tolerance than the other germplasms tested, based on their consistent survival rates with or without cold acclimation. In multiple freezing studies, RS and FR had average survival rates of 74% and 79%, respectively, in contrast to the commercial cultivars Apica and CUF-101 (CUF) (64% and 24%, respectively). The average temperature at which 50% of ions in plant tissues leak out (LT50) by freezing based on leaf electrolyte leakage was closely correlated with survival rates. Leaf LT50 improved 2–3-fold after 3 days of cold acclimation, based on leaf electrolyte leakage analysis, reaching -18°C, –9.6°C, –8.5°C, and -5°C for RS, FR, Apica, and CUF, respectively. Comparison of total soluble sugars and relative water content in shoots before and after cold acclimation showed that they were not well correlated with freezing tolerance and could not explain the superior responses of RS and FR during cold acclimation. Transcript analysis of cold-responsive MsCBF1, MsCBF2 and CAS15B genes showed that RS, FR, Apica and CUF exhibited distinct patterns of cold induction. Although RS, FR and Apica showed a rapid or greater increase in expression level of one or two of these genes, CUF showed only a moderate induction in MsCBF2 and CAS15B transcripts, suggesting that expression of these genes may be a good molecular marker for freezing tolerance in lucerne. The findings provide evidence that freezing tolerance in lucerne is a complex trait and that a combination of different mechanisms may greatly improve freezing tolerance. RS and FR are potential resources in breeding for improving freezing tolerance in lucerne.
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Claims 15
Claim · model-written summary
River side survived freezing at an average rate of 74%.
- Taxon
- lucerne
Medicago sativae2 - Material
- River sidee1
- Outcome
- survival ratese0
- Value
- 74%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RS and FR had average survival rates of 74% and 79%, respectively”
e1“River side (RS)”
e2“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
Foster ranch survived freezing at an average rate of 79%.
- Taxon
- lucerneMedicago sativae2
- Material
- Foster ranche1
- Outcome
- survival ratese0
- Value
- 79%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RS and FR had average survival rates of 74% and 79%, respectively”
e1“Foster ranch (FR)”
e2“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
Apica survived freezing at an average rate of 64%.
- Taxon
- lucerneMedicago sativae2
- Material
- Apicae0
- Outcome
- survival ratese1
- Value
- 64%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“commercial cultivars Apica and CUF-101 (CUF) (64% and 24%, respectively)”
e1“RS and FR had average survival rates”
e2“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
CUF-101 survived freezing at an average rate of 24%.
- Taxon
- lucerneMedicago sativae2
- Material
- CUF-101e0
- Outcome
- survival ratese1
- Value
- 24%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“commercial cultivars Apica and CUF-101 (CUF) (64% and 24%, respectively)”
e1“RS and FR had average survival rates”
e2“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
Leaf LT50 correlated closely with survival rate.
- Taxon
- lucerneMedicago sativae1
- Organ / stage
- leafe0
- Outcome
- survival ratese0
- Qualifier
- LT50e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The average temperature at which 50% of ions in plant tissues leak out (LT50) by freezing based on leaf electrolyte leakage was closely correlated with survival rates.”
e1“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
Cold acclimation improved leaf LT50 two to threefold.
- Taxon
- lucerneMedicago sativae1
- Treatment
- 3 days of cold acclimatione0
- Outcome
- Leaf LT50e0
- Direction
- improvede0
- Value
- 2–3-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf LT50 improved 2–3-fold after 3 days of cold acclimation”
e1“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
After acclimation, RS leaf LT50 reached -18°C.
- Taxon
- lucerneMedicago sativae2
- Material
- RSe0
- Outcome
- Leaf LT50e1
- Value
- -18°Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reaching -18°C, –9.6°C, –8.5°C, and -5°C for RS, FR, Apica, and CUF, respectively”
e1“Leaf LT50”
e2“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
After acclimation, FR leaf LT50 reached –9.6°C.
- Taxon
- lucerneMedicago sativae2
- Material
- FRe0
- Outcome
- Leaf LT50e1
- Value
- –9.6°Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reaching -18°C, –9.6°C, –8.5°C, and -5°C for RS, FR, Apica, and CUF, respectively”
e1“Leaf LT50”
e2“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
After acclimation, Apica leaf LT50 reached –8.5°C.
- Taxon
- lucerneMedicago sativae2
- Material
- Apicae0
- Outcome
- Leaf LT50e1
- Value
- –8.5°Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reaching -18°C, –9.6°C, –8.5°C, and -5°C for RS, FR, Apica, and CUF, respectively”
e1“Leaf LT50”
e2“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
After acclimation, CUF leaf LT50 reached -5°C.
- Taxon
- lucerneMedicago sativae2
- Material
- CUFe0
- Outcome
- Leaf LT50e1
- Value
- -5°Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reaching -18°C, –9.6°C, –8.5°C, and -5°C for RS, FR, Apica, and CUF, respectively”
e1“Leaf LT50”
e2“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
Shoot soluble sugars and water content were poorly correlated with freezing tolerance.
- Taxon
- lucerneMedicago sativae1
- Organ / stage
- shootse0
- Outcome
- freezing tolerancee0
- Qualifier
- not well correlatede0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total soluble sugars and relative water content in shoots before and after cold acclimation showed that they were not well correlated with freezing tolerance”
e1“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
The four germplasms had distinct cold induction patterns for the three named genes.
- Taxon
- lucerneMedicago sativae1
- Gene
- MsCBF1, MsCBF2 and CAS15Be0
- Outcome
- distinct patterns of cold inductione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transcript analysis of cold-responsive MsCBF1, MsCBF2 and CAS15B genes showed that RS, FR, Apica and CUF exhibited distinct patterns of cold induction.”
e1“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
RS, FR and Apica had rapid or greater expression increases for one or two cold response genes.
- Taxon
- lucerneMedicago sativae2
- Gene
- MsCBF1, MsCBF2 and CAS15Be1
- Outcome
- expression levele0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RS, FR and Apica showed a rapid or greater increase in expression level of one or two of these genes”
e1“MsCBF1, MsCBF2 and CAS15B genes”
e2“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
CUF showed moderate induction of MsCBF2 and CAS15B transcripts.
- Taxon
- lucerneMedicago sativae1
- Material
- CUFe0
- Gene
- MsCBF2 and CAS15Be0
- Outcome
- transcriptse0
- Direction
- inductione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CUF showed only a moderate induction in MsCBF2 and CAS15B transcripts”
e1“lucerne (alfalfa, Medicago sativa L.)”
Claim · model-written summary
RS and FR were identified as potential breeding resources for freezing tolerance.
- Taxon
- lucerneMedicago sativae0
- Material
- RS and FRe0
- Outcome
- potential resources in breeding for improving freezing tolerancee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RS and FR are potential resources in breeding for improving freezing tolerance in lucerne”
The same questions in other papers
cold · pest · Medicago sativa (alfalfa)Positive and negative results
1 paper in the same direction as this paper · 2 in the opposite direction
- no effect
- no effect
- 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.