Abstract
The influence of temperature on the oil content and composition of sunflower was studied on plants grown under field conditions and in a range of controlled environments. Traces of oil were detectable in cypsela (seed) almost immediately after pollination. Much of this appeared to be present in the hull (pericarp), which is well developed at this stage. Significant production of oil commenced with the development of the embryo about 150 day-degrees after pollination, and the oil content reached a maximum value just prior to physiological maturity of the seed. Linoleic acid constituted the major component of the oil at all stages of seed development, and under favourable temperature conditions increased from c. 50% soon after pollination to over 70% at physiological maturity. High temperature during the development of the seed was associated with a reduction in total oil yield. However, under field conditions this effect was variable owing to confounding with other environmental factors such as moisture stress, which also influence the yield of oil through their effects on growth and development of seed. Elevated temperatures, and in particularly high night temperatures, caused a marked reduction in the percentage of linoleic acid, apparently due to the effect of temperature on the activity of the desaturase enzymes which are responsible for the conversion of oleic to linoleic acid. These results support the hypothesis that reduced yields and altered composition of sunflower oil from crops matured under high temperature conditions in midsummer are due to the effects of heat stress on the biosynthesis of fatty acids.
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Claims 10
Claim · model-written summary
Oil traces were detectable in sunflower seed almost immediately after pollination.
- Taxon
- sunflower
Helianthus annuust0 - Organ / stage
- cypsela (seed)e0
- Outcome
- Traces of oile0
- Qualifier
- almost immediately after pollinatione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Traces of oil were detectable in cypsela (seed) almost immediately after pollination”
t0“sunflower seed”
Claim · model-written summary
Much early seed oil appeared to be in the hull.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- hull (pericarp)e0
- Outcome
- present in the hull (pericarp)e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Much of this appeared to be present in the hull (pericarp), which is well developed at this stage”
t0“sunflower seed”
Claim · model-written summary
Significant oil production began with embryo development about 150 day-degrees after pollination.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- embryoe0
- Outcome
- production of oile0
- Direction
- commencede0
- Value
- 150 day-degreese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Significant production of oil commenced with the development of the embryo about 150 day-degrees after pollination”
t0“sunflower seed”
Claim · model-written summary
Seed oil content peaked just before physiological maturity.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- physiological maturity of the seede0
- Outcome
- oil contente0
- Direction
- maximume0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the oil content reached a maximum value just prior to physiological maturity of the seed”
t0“sunflower seed”
Claim · model-written summary
Linoleic acid was the major seed-oil component throughout development.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- seed developmente0
- Outcome
- Linoleic acid constituted the major component of the oile0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Linoleic acid constituted the major component of the oil at all stages of seed development”
t0“sunflower seed”
Claim · model-written summary
Under favorable temperatures, seed-oil linoleic acid rose from about 50% after pollination to over 70% at maturity.
- Taxon
- sunflowerHelianthus annuust0
- Outcome
- Linoleic acide0
- Direction
- increasede0
- Value
- over 70%e0
- Qualifier
- under favourable temperature conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Linoleic acid constituted the major component of the oil at all stages of seed development, and under favourable temperature conditions increased from c. 50% soon after pollination to over 70% at physiological maturity”
t0“sunflower seed”
Claim · model-written summary
High temperature during seed development was associated with lower total oil yield.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- High temperaturee0
- Outcome
- total oil yielde0
- Direction
- reductione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“High temperature during the development of the seed was associated with a reduction in total oil yield”
t0“sunflower seed”
Claim · model-written summary
The high-temperature effect on oil yield varied in field conditions with confounding environmental factors including moisture stress.
- Taxon
- sunflowerHelianthus annuust0
- Outcome
- this effect was variablee0
- Qualifier
- moisture stresse0
- Setting
- field conditionse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“under field conditions this effect was variable owing to confounding with other environmental factors such as moisture stress”
t0“sunflower seed”
Claim · model-written summary
Elevated temperatures, particularly high night temperatures, markedly reduced the percentage of linoleic acid.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- Elevated temperaturese0
- Outcome
- percentage of linoleic acide0
- Direction
- reductione0
- Qualifier
- high night temperaturese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Elevated temperatures, and in particularly high night temperatures, caused a marked reduction in the percentage of linoleic acid”
t0“sunflower seed”
Claim · model-written summary
The authors attributed reduced linoleic acid percentage to temperature effects on desaturase enzymes.
- Taxon
- sunflowerHelianthus annuust0
- Gene
- desaturase enzymese0
- Outcome
- conversion of oleic to linoleic acide0
- Qualifier
- effect of temperature on the activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apparently due to the effect of temperature on the activity of the desaturase enzymes which are responsible for the conversion of oleic to linoleic acid”
t0“sunflower seed”
The same questions in other papers
heat · quality: oil · Helianthus annuus (common sunflower)Positive and negative results
2 papers in the same direction as this paper · 2 in the opposite direction
- positive
- positive
- 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.