Abstract
Thermostability of the photosynthetic apparatus of abscisic acid (ABA)-treated seedlings of barley (Hordeum vulgare) was studied by light-scattering and by fluorescence measurements of isolated chloroplasts. ABA treatment markedly decreased heat damage of the chloroplast ultrastructure; an exogenous ABA concentration of 10(-5) molar was most effective. Heat-induced increase of the 77 kilodalton fluorescence ratio F(740)/F(685) was also smaller at this ABA concentration. The heat-induced increase of the initial chlorophyll fluorescence level (F(o)) was virtually eliminated in ABA-treated (10(-5) molar) chloroplasts up to 45 degrees C and slightly increased at 50 degrees C, relative to control chloroplasts where F(o) increased even at 35 degrees C and reached its maximal value at 45 degrees C. In control chloroplasts, F(o) increased with a 5-minute pretreatment temperature, an effect observed as low as 35 degrees C. F(o) was maximal at 45 degrees C. In contrast, chloroplasts treated with 10(-5) molar ABA did not exhibit a heat-induced increase in F(o) until 50 degrees C.
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Claims 4
Claim · model-written summary
ABA reduced heat damage to chloroplast ultrastructure, most effectively at 10(-5) molar.
- Taxon
- barley (Hordeum vulgare)
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Hordeum vulgaret0 - Treatment
- ABA treatmente0
- Outcome
- heat damage of the chloroplast ultrastructuree0
- Direction
- decreasede0
- Value
- 10(-5) molare0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“ABA treatment markedly decreased heat damage of the chloroplast ultrastructure; an exogenous ABA concentration of 10(-5) molar was most effective.”
t0“seedlings of barley (Hordeum vulgare)”
Claim · model-written summary
ABA reduced the heat-induced rise of the fluorescence ratio.
- Taxon
- barley (Hordeum vulgare)Hordeum vulgaret0
- Treatment
- ABAe0
- Outcome
- 77 kilodalton fluorescence ratio F(740)/F(685)e0
- Direction
- smallere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Heat-induced increase of the 77 kilodalton fluorescence ratio F(740)/F(685) was also smaller at this ABA concentration.”
t0“seedlings of barley (Hordeum vulgare)”
Claim · model-written summary
At 10(-5) molar ABA, heat-induced F(o) increase was eliminated through 45 degrees C relative to controls.
- Taxon
- barley (Hordeum vulgare)Hordeum vulgaret0
- Treatment
- ABA-treated (10(-5) molar)e0
- Outcome
- initial chlorophyll fluorescence level (F(o))e0
- Direction
- virtually eliminatede0
- Qualifier
- up to 45 degrees Ce0
- Comparator
- control chloroplastse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The heat-induced increase of the initial chlorophyll fluorescence level (F(o)) was virtually eliminated in ABA-treated (10(-5) molar) chloroplasts up to 45 degrees C and slightly increased at 50 degrees C, relative to control chloroplasts where F(o) increased even at 35 degrees C and reached its maximal value at 45 degrees C.”
t0“seedlings of barley (Hordeum vulgare)”
Claim · model-written summary
ABA-treated chloroplast F(o) increased slightly at 50 degrees C.
- Taxon
- barley (Hordeum vulgare)Hordeum vulgaret0
- Outcome
- F(o)e1
- Direction
- increasede0
- Value
- 50 degrees Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“slightly increased at 50 degrees C”
t0“seedlings of barley (Hordeum vulgare)”
e1“chlorophyll fluorescence level (F(o)) was virtually eliminated”
The same questions in other papers
(+)-abscisic acid · physiology: photosynthesis · Hordeum vulgare (barley)Positive and negative results
1 paper in the same direction as this paper · 3 in the opposite direction
- negative
- negative
- negative
1 paper more in this group
See all 5 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.