Abstract
Chilling temperatures (5 degrees C) and high irradiance (1000 microeinsteins per square meter per second) were used to induce photooxidation in detached leaves of cucumber (Cucumis sativus L.), a chilling-sensitive plant. Chlorophyll a, chlorophyll b, beta carotene, and three xanthophylls were degraded in a light-dependent fashion at essentially the same rate. Lipid peroxidation (measured as ethane evolution) showed an O(2) dependency. The levels of three endogenous antioxidants, ascorbate, reduced glutathione, and alpha tocopherol, all showed an irradiance-dependent decline. alpha-Tocopherol was the first antioxidant affected and appeared to be the only antioxidant that could be implicated in long-term protection of the photosynthetic pigments. Results from the application of antioxidants having relative selectivity for (1)O(2), O(2) (-), or OH indicated that both (1)O(2) and O(2) (-) were involved in the chilling- and light-induced lipid peroxidation which accompanied photooxidation. Application of D(2)O (which enhances the lifetime of (1)O(2)) corroborated these results. Chilling under high light produced no evidence of photooxidative damage in detached leaves of chilling-resistant pea (Pisum sativum L.). Our results suggest a fundamental difference in the ability of pea to reduce the destructive effects of free-radical and (1)O(2) production in chloroplasts during chilling in high light.
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Claims 7
Claim · model-written summary
Chilling with high irradiance degraded chlorophyll a, chlorophyll b, beta-carotene and three xanthophylls in cucumber detached leaves in a light-dependent fashion.
- Taxon
- cucumber (Cucumis sativus L.)
Cucumis sativuse0 - Organ / stage
- detached leavese0
- Treatment
- Chilling temperatures (5 degrees C) and high irradiancee0
- Outcome
- Chlorophyll a, chlorophyll b, beta carotene, and three xanthophyllse1
- Direction
- degradede1
- Qualifier
- light-dependent fashione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chilling temperatures (5 degrees C) and high irradiance (1000 microeinsteins per square meter per second) were used to induce photooxidation in detached leaves of cucumber (Cucumis sativus L.), a chilling-sensitive plant”
e1“Chlorophyll a, chlorophyll b, beta carotene, and three xanthophylls were degraded in a light-dependent fashion at essentially the same rate”
Claim · model-written summary
Lipid peroxidation in cucumber leaves measured as ethane evolution showed an oxygen dependency.
- Taxon
- cucumber (Cucumis sativus L.)Cucumis sativuse0
- Outcome
- Lipid peroxidation (measured as ethane evolution)e2
- Qualifier
- O(2) dependencye2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chilling temperatures (5 degrees C) and high irradiance (1000 microeinsteins per square meter per second) were used to induce photooxidation in detached leaves of cucumber (Cucumis sativus L.), a chilling-sensitive plant”
e2“Lipid peroxidation (measured as ethane evolution) showed an O(2) dependency”
Claim · model-written summary
Ascorbate, reduced glutathione and alpha-tocopherol levels declined with irradiance in cucumber leaves.
- Taxon
- cucumber (Cucumis sativus L.)Cucumis sativuse0
- Treatment
- irradiancee3
- Outcome
- ascorbate, reduced glutathione, and alpha tocopherole3
- Direction
- irradiance-dependent declinee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chilling temperatures (5 degrees C) and high irradiance (1000 microeinsteins per square meter per second) were used to induce photooxidation in detached leaves of cucumber (Cucumis sativus L.), a chilling-sensitive plant”
e3“The levels of three endogenous antioxidants, ascorbate, reduced glutathione, and alpha tocopherol, all showed an irradiance-dependent decline”
Claim · model-written summary
Alpha-tocopherol was the first antioxidant affected in cucumber leaves and appeared to be the only one implicated in long-term protection of photosynthetic pigments.
- Taxon
- cucumber (Cucumis sativus L.)Cucumis sativuse0
- Outcome
- alpha-Tocopherol was the first antioxidant affectede4
- Qualifier
- the only antioxidant that could be implicated in long-term protection of the photosynthetic pigmentse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chilling temperatures (5 degrees C) and high irradiance (1000 microeinsteins per square meter per second) were used to induce photooxidation in detached leaves of cucumber (Cucumis sativus L.), a chilling-sensitive plant”
e4“alpha-Tocopherol was the first antioxidant affected and appeared to be the only antioxidant that could be implicated in long-term protection of the photosynthetic pigments”
Claim · model-written summary
Singlet oxygen and superoxide were both involved in chilling- and light-induced lipid peroxidation in cucumber leaves.
- Taxon
- cucumber (Cucumis sativus L.)Cucumis sativuse0
- Compound
- (1)O(2) and O(2) (-)e5
- Outcome
- chilling- and light-induced lipid peroxidatione5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chilling temperatures (5 degrees C) and high irradiance (1000 microeinsteins per square meter per second) were used to induce photooxidation in detached leaves of cucumber (Cucumis sativus L.), a chilling-sensitive plant”
e5“Results from the application of antioxidants having relative selectivity for (1)O(2), O(2) (-), or OH indicated that both (1)O(2) and O(2) (-) were involved in the chilling- and light-induced lipid peroxidation which accompanied photooxidation”
Claim · model-written summary
D2O, which enhances singlet oxygen lifetime, corroborated the antioxidant-based results in cucumber leaves.
- Taxon
- cucumber (Cucumis sativus L.)Cucumis sativuse0
- Compound
- D(2)Oe6
- Outcome
- corroborated these resultse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chilling temperatures (5 degrees C) and high irradiance (1000 microeinsteins per square meter per second) were used to induce photooxidation in detached leaves of cucumber (Cucumis sativus L.), a chilling-sensitive plant”
e6“Application of D(2)O (which enhances the lifetime of (1)O(2)) corroborated these results”
Claim · model-written summary
Chilling under high light produced no evidence of photooxidative damage in detached pea leaves.
- Taxon
- pea (Pisum sativum L.)
Lathyrus oleraceuse7 - Organ / stage
- detached leavese7
- Treatment
- Chilling under high lighte7
- Outcome
- photooxidative damagee7
- Direction
- no evidence ofe7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“Chilling under high light produced no evidence of photooxidative damage in detached leaves of chilling-resistant pea (Pisum sativum L.)”
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See all 28 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.