Abstract
About 80 days after full bloom, well-exposed fruit on the south part of the canopy of mature Liberty/M.9 apple trees were randomly assigned to one of the following two treatments. Some fruit were turned about 180 degrees to expose the original shaded side to full sun whereas the rest served as untreated controls. On day 0, 1, 2, 4, 7, and 10 after treatment, fruit peel samples were taken from the original shaded side of the treated fruit and both the sun-exposed side and the shaded side of the control fruit at midday to determine photosynthetic pigments and enzymatic and non-enzymatic antioxidants. Maximum photosystem II efficiency of the original shaded side decreased sharply after 1 day exposure to full sun, and then gradually recovered to a similar value of the sun-exposed side of the control fruit by day 10. The shaded side of the control fruit had much lower xanthophyll cycle pool size and conversion and antioxidant enzymes and soluble antioxidants of the ascorbate-glutathione cycle than the sun-exposed side. In response to full sun exposure, xanthophyll cycle pool size of the original shaded side increased, reaching a similar value of the sun-exposed side by day 10. Ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase and total pool size and reduction state of both ascorbate and glutathione of the original shaded side all increased to the corresponding values found in the sun-exposed side of the control fruit over a 10-day period. It is concluded that both xanthophyll cycle and the ascorbate-glutathione cycle in the original shaded side are up-regulated in response to fullsun exposure to minimize photo-oxidative damage and contributes to its re-acclimation to full sun.
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Claims 8
Claim · model-written summary
Maximum photosystem II efficiency in the formerly shaded peel fell after one day in full sun.
- Taxon
- Apple
Malus domesticat0 - Organ / stage
- original shaded sidee0
- Treatment
- exposure to full sune0
- Outcome
- Maximum photosystem II efficiencye0
- Direction
- decreasede0
- Value
- 1 daye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maximum photosystem II efficiency of the original shaded side decreased sharply after 1 day exposure to full sun”
t0“Apple Fruit”
Claim · model-written summary
The efficiency recovered to the sun-exposed control-side value by day 10.
- Taxon
- AppleMalus domesticat0
- Treatment
- exposure to full sune2
- Outcome
- Maximum photosystem II efficiencye1
- Direction
- recoverede0
- Qualifier
- by day 10e0
- Comparator
- sun-exposed side of the control fruite0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“then gradually recovered to a similar value of the sun-exposed side of the control fruit by day 10”
e1“Maximum photosystem II efficiency of the original shaded side”
e2“Maximum photosystem II efficiency of the original shaded side decreased sharply after 1 day exposure to full sun”
t0“Apple Fruit”
Claim · model-written summary
The shaded control side had lower xanthophyll cycle pool size and conversion than the exposed control side.
- Taxon
- AppleMalus domesticat0
- Outcome
- xanthophyll cycle pool size and conversione0
- Direction
- much lowere0
- Comparator
- sun-exposed sidee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The shaded side of the control fruit had much lower xanthophyll cycle pool size and conversion and antioxidant enzymes and soluble antioxidants of the ascorbate-glutathione cycle than the sun-exposed side”
t0“Apple Fruit”
Claim · model-written summary
The shaded control side had lower ascorbate-glutathione-cycle enzymes and soluble antioxidants than the exposed side.
- Taxon
- AppleMalus domesticat0
- Outcome
- antioxidant enzymes and soluble antioxidants of the ascorbate-glutathione cyclee0
- Direction
- much lowere0
- Comparator
- sun-exposed sidee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The shaded side of the control fruit had much lower xanthophyll cycle pool size and conversion and antioxidant enzymes and soluble antioxidants of the ascorbate-glutathione cycle than the sun-exposed side”
t0“Apple Fruit”
Claim · model-written summary
Full sun increased the xanthophyll-cycle pool in formerly shaded peel to the exposed-side value by day 10.
- Taxon
- AppleMalus domesticat0
- Treatment
- full sun exposuree0
- Outcome
- xanthophyll cycle pool sizee0
- Direction
- increasede0
- Qualifier
- by day 10e0
- Comparator
- sun-exposed sidee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In response to full sun exposure, xanthophyll cycle pool size of the original shaded side increased, reaching a similar value of the sun-exposed side by day 10”
t0“Apple Fruit”
Claim · model-written summary
Full sun increased the four named antioxidant enzyme activities in the formerly shaded side to control exposed-side values.
- Taxon
- AppleMalus domesticat0
- Treatment
- full sun exposuree1
- Outcome
- Ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductasee0
- Direction
- increasede0
- Qualifier
- over a 10-day periode0
- Comparator
- sun-exposed side of the control fruite0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase and total pool size and reduction state of both ascorbate and glutathione of the original shaded side all increased to the corresponding values found in the sun-exposed side of the control fruit over a 10-day period”
e1“full sun exposure”
t0“Apple Fruit”
Claim · model-written summary
Ascorbate pool size and reduction state rose in formerly shaded peel to exposed-side control values.
- Taxon
- AppleMalus domesticat0
- Treatment
- full sun exposuree1
- Outcome
- total pool size and reduction state of both ascorbate and glutathionee0
- Direction
- increasede0
- Qualifier
- over a 10-day periode0
- Comparator
- sun-exposed side of the control fruite0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total pool size and reduction state of both ascorbate and glutathione of the original shaded side all increased to the corresponding values found in the sun-exposed side of the control fruit over a 10-day period”
e1“full sun exposure”
t0“Apple Fruit”
Claim · model-written summary
The authors conclude that up-regulation of both antioxidant cycles helps limit photo-oxidative damage during reacclimation.
- Taxon
- AppleMalus domesticat0
- Treatment
- fullsun exposuree0
- Outcome
- photo-oxidative damagee0
- Qualifier
- both xanthophyll cycle and the ascorbate-glutathione cyclee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both xanthophyll cycle and the ascorbate-glutathione cycle in the original shaded side are up-regulated in response to fullsun exposure to minimize photo-oxidative damage and contributes to its re-acclimation to full sun”
t0“Apple Fruit”
The same questions in other papers
light · physiology: antioxidant enzymes · Malus domestica (apple)Positive and negative results
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- negative
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19 papers in the same direction as this paper · 12 in the opposite direction
- no effect
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28 papers more in this group
See all 32 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.