Abstract
Abstract Ozone (O 3 ) and soil water deficit are two environmental stresses that significantly affect the growth and yield of alfalfa ( Medicago sativa L). However, little is known of the responses of field‐grown alfalfa to O 3 , and the effects of the interaction between O 3 and water stress on canopy temperature and water relations of alfalfa have not been previously reported. The objective of this 2‐yr study was to determine the interactive effects of O 3 and soil water deficits on canopy temperatures, water use, and water use efficiency (WUE) of alfalfa. Alfalfa (cv. WL‐514) was grown in 30‐3‐ by 5.5‐m plots on Wasco sandy loam (coarse‐loamy, mixed, nonacid, thermic Typic Torriorthents) in Shafter, CA, and was exposed in open‐top chambers to five levels of O 3 for 12 h daily, from March to October of 1984 and 1985. Ozone treatments ranged from charcoal‐filtered air (CF) to twice ambient O 3 concentrations. Each plot received either normal amounts of irrigation (NI) or 30% less than normal (WS). Canopy temperature‐air temperature differentials (T c ‐T a ) were significantly reduced by water stress an average of 27.9% in 1984 and 44.0% in 1985. Ozone also significantly reduced T c ‐ T a by 31% in NI and 37% in WS plots in 1984, but in 1985 O 3 had no effect on T c ‐ T a . Water use, rate of soil water depletion, or depth of effective rooting zone were not affected by O 3 , hereas water stress significantly reduced all three. Water use efficiency was significantly reduced by O 3 , averaging 12% lower in nonfiltered compared with CF plots. The effects of O 3 on WUE were attributed to premature senescence and abscission of older alfalfa leaves.
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Claims 9
Claim · model-written summary
Water stress reduced canopy-air temperature differential by 27.9% in 1984.
- Taxon
- Alfalfa
Medicago sativat0 - Treatment
- water stresse0
- Outcome
- Canopy temperature‐air temperature differentialse0
- Direction
- reducede0
- Value
- 27.9%e0
- Qualifier
- 1984e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Canopy temperature‐air temperature differentials (T c ‐T a ) were significantly reduced by water stress an average of 27.9% in 1984 and 44.0% in 1985”
t0“Alfalfa”
Claim · model-written summary
Water stress reduced canopy-air temperature differential by 44.0% in 1985.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- water stresse0
- Outcome
- Canopy temperature‐air temperature differentialse0
- Direction
- reducede0
- Value
- 44.0%e0
- Qualifier
- 1985e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Canopy temperature‐air temperature differentials (T c ‐T a ) were significantly reduced by water stress an average of 27.9% in 1984 and 44.0% in 1985”
t0“Alfalfa”
Claim · model-written summary
Ozone reduced the differential by 31% in normally irrigated plots in 1984.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- Ozonee0
- Outcome
- T c ‐ T ae0
- Direction
- reducede0
- Value
- 31%e0
- Qualifier
- NIe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ozone also significantly reduced T c ‐ T a by 31% in NI and 37% in WS plots in 1984”
t0“Alfalfa”
Claim · model-written summary
Ozone reduced the differential by 37% in water stressed plots in 1984.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- Ozonee0
- Outcome
- T c ‐ T ae0
- Direction
- reducede0
- Value
- 37%e0
- Qualifier
- WS plotse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ozone also significantly reduced T c ‐ T a by 31% in NI and 37% in WS plots in 1984”
t0“Alfalfa”
Claim · model-written summary
Ozone did not affect the differential in 1985.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in 1985 O 3 had no effect on T c ‐ T a”
t0“Alfalfa”
Claim · model-written summary
Ozone did not affect water use, soil water depletion rate or effective rooting depth.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- O 3e0
- Outcome
- Water use, rate of soil water depletion, or depth of effective rooting zonee0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water use, rate of soil water depletion, or depth of effective rooting zone were not affected by O 3”
t0“Alfalfa”
Claim · model-written summary
Water stress reduced water use, soil water depletion rate and effective rooting depth.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- water stresse0
- Outcome
- Water use, rate of soil water depletion, or depth of effective rooting zonee0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water use, rate of soil water depletion, or depth of effective rooting zone were not affected by O 3 , hereas water stress significantly reduced all three”
t0“Alfalfa”
Claim · model-written summary
Ozone reduced water use efficiency by 12% in nonfiltered versus filtered plots.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- O 3e0
- Outcome
- Water use efficiencye0
- Direction
- reducede0
- Value
- 12%e0
- Comparator
- CF plotse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water use efficiency was significantly reduced by O 3 , averaging 12% lower in nonfiltered compared with CF plots”
t0“Alfalfa”
Claim · model-written summary
Authors attribute ozone-related efficiency loss to early senescence and leaf abscission.
- Taxon
- alfalfaMedicago sativae0
- Outcome
- WUEe0
- Qualifier
- premature senescence and abscission of older alfalfa leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“effects of O 3 on WUE were attributed to premature senescence and abscission of older alfalfa leaves”
The same questions in other papers
ozone · physiology: water · Medicago sativa (alfalfa)Positive and negative results
1 in the opposite direction
- 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.