Abstract
Chlorophyll a and carotenoids of spinach began to be destroyed 2 to 3 hr after fumigation with 2 ppm SO2 under light, whereas chlorophyll b was undamaged during 8 hr of exposure to SO2. Pheophytin a was not affected by the fumigation. When disks excised from leaves fumigated with SO2 at 2 ppm for 2 hr were illuminated, chlorophyll a and carotenoids were broken down, while they were not destroyed in darkness. The destruction of these pigments was suppressed under nitrogen. Chlorophyll a destruction was inhibited by l,2-dihydroxybenzene-3,5-disulfonate (tiron), hydro-quinone and ascorbate, but not by l,4-diazabicyclo-[2,2,2]-octane (DABCO), methio-nine, histidine, benzoate and formate. Chlorophyll a destruction was inhibited by phenazine methosulfate but stimulated by methyl viologen. Addition of superoxide dismutase (SOD) to the homogenate of SO2-fumigated leaves inhibited the chlorophyll a destruction. The activity of endogenous SOD was reduced to 40% by 2-hr fumigation before the loss of chlorophyll was observed. These results suggest that chlorophyll a destruction by SO2 was due to superoxide radicals (O2−). Moreover, malondialdehyde (MDA), a product of lipid peroxidation, was formed in SO2-fumigated leaves. MDA formation was inhibited by tiron, hydroquinone and DABCO but not by benzoate and formate. MDA formation was increased by D2O. These results suggest that lipid peroxidation in SO2-fumigated leaves was due to singlet oxygen 1O2 produced from O2−.
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Claims 17
Claim · model-written summary
SO2 under light destroyed chlorophyll a and carotenoids after 2 to 3 hours.
- Taxon
- spinach
Spinacia oleraceae0 - Treatment
- 2 ppm SO2 under lighte0
- Outcome
- Chlorophyll a and carotenoidse0
- Direction
- destroyede0
- Value
- 2 to 3 hre0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorophyll a and carotenoids of spinach began to be destroyed 2 to 3 hr after fumigation with 2 ppm SO2 under light”
Claim · model-written summary
Chlorophyll b remained undamaged during eight hours of SO2 exposure.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“chlorophyll b was undamaged during 8 hr of exposure to SO2”
t0“spinach”
Claim · model-written summary
Pheophytin a was unaffected by SO2 fumigation.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- SO2t0
- Outcome
- Pheophytin ae0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pheophytin a was not affected by the fumigation.”
t0“SO2-fumigated leaves of spinach”
Claim · model-written summary
Illuminating fumigated leaf disks broke down chlorophyll a and carotenoids, whereas darkness did not.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- illuminatede0
- Outcome
- chlorophyll a and carotenoidse0
- Direction
- broken downe0
- Comparator
- darknesse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When disks excised from leaves fumigated with SO2 at 2 ppm for 2 hr were illuminated, chlorophyll a and carotenoids were broken down, while they were not destroyed in darkness.”
t0“spinach”
Claim · model-written summary
Nitrogen suppressed pigment destruction.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- nitrogene0
- Outcome
- destruction of these pigmentse0
- Direction
- suppressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The destruction of these pigments was suppressed under nitrogen.”
t0“spinach”
Claim · model-written summary
Tiron, hydroquinone and ascorbate inhibited chlorophyll a destruction.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- tirone0
- Outcome
- Chlorophyll a destructione0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorophyll a destruction was inhibited by l,2-dihydroxybenzene-3,5-disulfonate (tiron), hydro-quinone and ascorbate”
t0“spinach”
Claim · model-written summary
DABCO, methionine, histidine, benzoate and formate did not inhibit chlorophyll a destruction.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- DABCOe0
- Outcome
- Chlorophyll a destructione1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but not by l,4-diazabicyclo-[2,2,2]-octane (DABCO), methio-nine, histidine, benzoate and formate.”
e1“Chlorophyll a destruction was inhibited by l,2-dihydroxybenzene-3,5-disulfonate (tiron)”
t0“spinach”
Claim · model-written summary
Phenazine methosulfate inhibited chlorophyll a destruction.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- phenazine methosulfatee0
- Outcome
- Chlorophyll a destructione0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorophyll a destruction was inhibited by phenazine methosulfate”
t0“spinach”
Claim · model-written summary
Methyl viologen stimulated chlorophyll a destruction.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- methyl viologene0
- Outcome
- Chlorophyll a destructione1
- Direction
- stimulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but stimulated by methyl viologen.”
e1“Chlorophyll a destruction was inhibited by phenazine methosulfate”
t0“spinach”
Claim · model-written summary
Added SOD inhibited chlorophyll a destruction in fumigated leaf homogenate.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- superoxide dismutase (SOD)e0
- Outcome
- chlorophyll a destructione0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of superoxide dismutase (SOD) to the homogenate of SO2-fumigated leaves inhibited the chlorophyll a destruction.”
t0“spinach”
Claim · model-written summary
Endogenous SOD activity fell to 40% after two hours of SO2 fumigation, before chlorophyll loss.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- 2-hr fumigatione0
- Outcome
- activity of endogenous SODe0
- Direction
- reducede0
- Value
- 40%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The activity of endogenous SOD was reduced to 40% by 2-hr fumigation before the loss of chlorophyll was observed.”
t0“spinach”
Claim · model-written summary
The authors attributed SO2-induced chlorophyll a destruction to superoxide radicals.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- chlorophyll a destructione0
- Qualifier
- superoxide radicals (O2−)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These results suggest that chlorophyll a destruction by SO2 was due to superoxide radicals (O2−).”
t0“spinach”
Claim · model-written summary
Malondialdehyde formed in SO2-fumigated leaves.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- SO2e0
- Outcome
- malondialdehyde (MDA)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“malondialdehyde (MDA), a product of lipid peroxidation, was formed in SO2-fumigated leaves.”
t0“spinach”
Claim · model-written summary
Tiron, hydroquinone and DABCO inhibited MDA formation.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- tirone0
- Outcome
- MDA formatione0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MDA formation was inhibited by tiron, hydroquinone and DABCO”
t0“spinach”
Claim · model-written summary
Benzoate and formate did not inhibit MDA formation.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- benzoate and formatee0
- Outcome
- MDA formatione1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but not by benzoate and formate.”
e1“MDA formation was inhibited”
t0“spinach”
Claim · model-written summary
D2O increased MDA formation.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- D2Oe0
- Outcome
- MDA formatione0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MDA formation was increased by D2O.”
t0“spinach”
Claim · model-written summary
The authors attributed lipid peroxidation to singlet oxygen generated from superoxide.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- lipid peroxidatione0
- Qualifier
- singlet oxygen 1O2 produced from O2−e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These results suggest that lipid peroxidation in SO2-fumigated leaves was due to singlet oxygen 1O2 produced from O2−.”
t0“spinach”
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1 paper in the same direction as this paper
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1 paper in the same direction as this paper
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formate · physiology: oxidative · Spinacia oleracea (spinach)Results agree
1 paper in the same direction as this paper
- no effect
nitrogen · physiology: pigments · Spinacia oleracea (spinach)Results differ
15 papers in the same direction as this paper · 3 in the opposite direction
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See all 5 papers →8 of 11 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
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.