Abstract
The mechanistic basis for protection of exogenous ascorbate against photoinhibition at low temperature was examined in leaves of rice (Oryza sativa L.). Exposure of intact leaves to chilling temperature resulted in a drastic decrease in the speed of development of non-photochemical fluorescence quenching (NPQ). This was related to the low temperature-imposed restriction on the formation of the fast relaxing component of NPQ (qf). Feeding with 20 mM ascorbate markedly increased the rate of qf development at chilling temperature due primarily to the enhanced rate of zeaxanthin (Z) formation. On the other hand, ascorbate feeding had no influence on photosystem 2 (PS2)-driven electron flow. The reduced state of the PS2 primary electron acceptor QA decreased in ascorbate-fed leaves exposed to high irradiance at chilling temperature owing to the increased Z-associated thermal energy dissipation in the light-harvesting antenna system of PS2. Furthermore, ascorbate feeding increased the photosynthetic apparatus of rice leaves to resist photoinhibition at low temperature. The protective effect of exogenous ascorbate was fully accounted for by the enhanced xanthophyll cycle activity.
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Claims 9
Claim · model-written summary
Chilling temperature decreased the speed of NPQ development in rice leaves.
- Taxon
- rice
Oryza sativae1 - Treatment
- chilling temperaturee0
- Outcome
- speed of development of non-photochemical fluorescence quenching (NPQ)e0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“leaves of rice (Oryza sativa L.)”
e0“Exposure of intact leaves to chilling temperature resulted in a drastic decrease in the speed of development of non-photochemical fluorescence quenching (NPQ)”
Claim · model-written summary
Feeding with 20 mM ascorbate increased the rate of qf development at chilling temperature.
- Taxon
- riceOryza sativae1
- Treatment
- 20 mM ascorbatee2
- Outcome
- rate of qf developmente2
- Direction
- increasede2
- Qualifier
- at chilling temperaturee2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“leaves of rice (Oryza sativa L.)”
e2“Feeding with 20 mM ascorbate markedly increased the rate of qf development at chilling temperature due primarily to the enhanced rate of zeaxanthin (Z) formation”
Claim · model-written summary
The faster qf development under ascorbate feeding is attributed primarily to enhanced zeaxanthin formation.
- Taxon
- riceOryza sativae1
- Compound
- zeaxanthin (Z)e2
- Outcome
- rate of qf developmente2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“leaves of rice (Oryza sativa L.)”
e2“Feeding with 20 mM ascorbate markedly increased the rate of qf development at chilling temperature due primarily to the enhanced rate of zeaxanthin (Z) formation”
Claim · model-written summary
Ascorbate feeding had no influence on photosystem 2 driven electron flow in rice leaves.
- Taxon
- riceOryza sativae1
- Treatment
- ascorbate feedinge3
- Outcome
- photosystem 2 (PS2)-driven electron flowe3
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“leaves of rice (Oryza sativa L.)”
e3“ascorbate feeding had no influence on photosystem 2 (PS2)-driven electron flow”
Claim · model-written summary
Ascorbate-fed rice leaves exposed to high irradiance at chilling temperature had a decreased reduced state of the PS2 primary electron acceptor QA.
- Taxon
- riceOryza sativae1
- Treatment
- ascorbate-fed leaves exposed to high irradiance at chilling temperaturee4
- Outcome
- reduced state of the PS2 primary electron acceptor QAe4
- Direction
- decreasede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“leaves of rice (Oryza sativa L.)”
e4“The reduced state of the PS2 primary electron acceptor QA decreased in ascorbate-fed leaves exposed to high irradiance at chilling temperature owing to the increased Z-associated thermal energy dissipation in the light-harvesting antenna system of PS2”
Claim · model-written summary
The lower QA reduction in ascorbate-fed leaves is attributed to increased Z-associated thermal energy dissipation in the PS2 antenna.
- Taxon
- riceOryza sativae1
- Outcome
- reduced state of the PS2 primary electron acceptor QAe4
- Qualifier
- increased Z-associated thermal energy dissipation in the light-harvesting antenna system of PS2e4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“leaves of rice (Oryza sativa L.)”
e4“The reduced state of the PS2 primary electron acceptor QA decreased in ascorbate-fed leaves exposed to high irradiance at chilling temperature owing to the increased Z-associated thermal energy dissipation in the light-harvesting antenna system of PS2”
Claim · model-written summary
Ascorbate feeding increased the resistance of rice leaf photosynthetic apparatus to photoinhibition at low temperature.
- Taxon
- riceOryza sativae1
- Treatment
- ascorbate feedinge5
- Outcome
- resist photoinhibitione5
- Direction
- increasede5
- Qualifier
- at low temperaturee5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“leaves of rice (Oryza sativa L.)”
e5“ascorbate feeding increased the photosynthetic apparatus of rice leaves to resist photoinhibition at low temperature”
Claim · model-written summary
The protective effect of exogenous ascorbate against photoinhibition is fully accounted for by enhanced xanthophyll cycle activity.
- Taxon
- riceOryza sativae1
- Outcome
- protective effect of exogenous ascorbatee6
- Qualifier
- fully accounted for by the enhanced xanthophyll cycle activitye6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“leaves of rice (Oryza sativa L.)”
e6“The protective effect of exogenous ascorbate was fully accounted for by the enhanced xanthophyll cycle activity”
Claim · model-written summary
The reduced NPQ development at chilling temperature is related to restricted formation of the fast relaxing component qf.
- Taxon
- riceOryza sativae1
- Outcome
- fast relaxing component of NPQ (qf)e7
- Qualifier
- low temperature-imposed restriction on the formatione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“leaves of rice (Oryza sativa L.)”
e7“This was related to the low temperature-imposed restriction on the formation of the fast relaxing component of NPQ (qf)”
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See all 40 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.