Abstract
Drought stress applied to alfalfa seedlings (Medicago media Pers.) grown at 20–22 °C by reducing soil moisture from 100 to 30% of soil water holding capacity prior to freezing increased their LT 50 by 4–7 °C. The tests were performed in 12-cm pots containing either a greenhouse sandy loam potting mixture or material sampled in the Ap horizon of several soils of varying texture. Similar increases were obtained when identical soil water treatments were applied to plants hardened for 2 or 4 wk at 1 °C. Both stresses, drought and low temperature, have additive influences on plant survival following freezing. Low soil moisture increased both the level of cold hardening achieved and plant survival to freezing, but it had a larger effect on the freezing process than on the hardening process. Freezing tests carried out with insulated pots, in order to simulate field conditions where frost comes from above, did not affect the survival of alfalfa in spite of a delay in the cooling of the soil. Differences in cooling rates during freezing could not be correlated with the higher mortality observed with moist soils.
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Claims 7
Claim · model-written summary
Reducing soil moisture before freezing increased the LT50 of alfalfa seedlings by 4–7 °C.
- Taxon
- alfalfa
Medicago sativae0 - Treatment
- reducing soil moisture from 100 to 30% of soil water holding capacitye0
- Outcome
- LT 50e0
- Direction
- increasede0
- Value
- 4–7 °Ce0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought stress applied to alfalfa seedlings (Medicago media Pers.) grown at 20–22 °C by reducing soil moisture from 100 to 30% of soil water holding capacity prior to freezing increased their LT 50 by 4–7 °C”
Claim · model-written summary
Similar LT50 increases occurred when soil water treatments were applied to alfalfa hardened for 2 or 4 weeks at 1 °C.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- identical soil water treatmentse1
- Outcome
- LT 50e0
- Direction
- increasese1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought stress applied to alfalfa seedlings (Medicago media Pers.) grown at 20–22 °C by reducing soil moisture from 100 to 30% of soil water holding capacity prior to freezing increased their LT 50 by 4–7 °C”
e1“Similar increases were obtained when identical soil water treatments were applied to plants hardened for 2 or 4 wk at 1 °C”
Claim · model-written summary
Low soil moisture increased the level of cold hardening achieved by alfalfa.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- Low soil moisturee2
- Outcome
- level of cold hardeninge2
- Direction
- increasede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought stress applied to alfalfa seedlings (Medicago media Pers.) grown at 20–22 °C by reducing soil moisture from 100 to 30% of soil water holding capacity prior to freezing increased their LT 50 by 4–7 °C”
e2“Low soil moisture increased both the level of cold hardening achieved and plant survival to freezing, but it had a larger effect on the freezing process than on the hardening process”
Claim · model-written summary
Low soil moisture increased plant survival of alfalfa to freezing.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- Low soil moisturee2
- Outcome
- plant survival to freezinge2
- Direction
- increasede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought stress applied to alfalfa seedlings (Medicago media Pers.) grown at 20–22 °C by reducing soil moisture from 100 to 30% of soil water holding capacity prior to freezing increased their LT 50 by 4–7 °C”
e2“Low soil moisture increased both the level of cold hardening achieved and plant survival to freezing, but it had a larger effect on the freezing process than on the hardening process”
Claim · model-written summary
Low soil moisture had a larger effect on the freezing process than on the hardening process in alfalfa.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- Low soil moisturee2
- Outcome
- effect on the freezing processe2
- Direction
- largere2
- Comparator
- hardening processe2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought stress applied to alfalfa seedlings (Medicago media Pers.) grown at 20–22 °C by reducing soil moisture from 100 to 30% of soil water holding capacity prior to freezing increased their LT 50 by 4–7 °C”
e2“Low soil moisture increased both the level of cold hardening achieved and plant survival to freezing, but it had a larger effect on the freezing process than on the hardening process”
Claim · model-written summary
Freezing tests in insulated pots did not affect alfalfa survival despite a delay in soil cooling.
- Taxon
- alfalfaMedicago sativae3
- Treatment
- insulated potse3
- Outcome
- survivale3
- Direction
- did not affecte3
- Qualifier
- in spite of a delay in the cooling of the soile3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Freezing tests carried out with insulated pots, in order to simulate field conditions where frost comes from above, did not affect the survival of alfalfa in spite of a delay in the cooling of the soil”
Claim · model-written summary
Differences in cooling rates during freezing could not be correlated with higher alfalfa mortality in moist soils.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- moist soilse4
- Outcome
- mortalitye4
- Direction
- could not be correlatede4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought stress applied to alfalfa seedlings (Medicago media Pers.) grown at 20–22 °C by reducing soil moisture from 100 to 30% of soil water holding capacity prior to freezing increased their LT 50 by 4–7 °C”
e4“Differences in cooling rates during freezing could not be correlated with the higher mortality observed with moist soils”
The same questions in other papers
soil water · survival · Medicago sativa (alfalfa)Results agree
1 paper in the same direction as this paper
- 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.