Abstract
The function of chloroplast ferredoxin quinone reductase (FQR)-dependent flow was examined by comparing a wild type tobacco and a tobacco transformant (ΔndhB) in which the ndhB gene had been disrupted with their antimycin A (AA)-fed leaves upon exposure to chilling temperature (4 °C) under low irradiance (100 µmol m-2 s-1 photon flux density). During the chilling stress, the maximum photochemical efficiency of photosystem (PS) 2 (Fv/Fm) decreased markedly in both the controls and AA-fed leaves, and P700+ was also lower in AA-fed leaves than in the controls, implying that FQR-dependent cyclic electron flow around PS1 functioned to protect the photosynthetic apparatus from chilling stress under low irradiance. Under such stress, non-photochemical quenching (NPQ), particularly the fast relaxing NPQ component (qf) and the de-epoxidized ratio of the xanthophyll cycle pigments, (A+Z)/(V+A+Z), formed the difference between AA-fed leaves and controls. The lower NPQ in AA-fed leaves might be related to an inefficient proton gradient across thylakoid membranes (ΔpH) because of inhibiting an FQR-dependent cyclic electron flow around PS1 at chilling temperature under low irradiance.
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Claims 6
Claim · model-written summary
Chilling markedly decreased PS2 maximum photochemical efficiency in control and antimycin-fed tobacco leaves.
- Taxon
- tobacco
Nicotiana tabacumt0 - Organ / stage
- leavese0
- Treatment
- chilling stresse0
- Outcome
- maximum photochemical efficiency of photosystem (PS) 2 (Fv/Fm)e0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“During the chilling stress, the maximum photochemical efficiency of photosystem (PS) 2 (Fv/Fm) decreased markedly in both the controls and AA-fed leaves”
t0“tobacco leaves”
Claim · model-written summary
Antimycin-fed tobacco leaves had lower P700+ than controls during chilling.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- AA-fed leavese0
- Outcome
- P700+e0
- Direction
- lowere0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P700+ was also lower in AA-fed leaves than in the controls”
t0“tobacco leaves”
Claim · model-written summary
FQR-dependent cyclic flow was inferred to protect tobacco photosynthesis from chilling in low light.
- Taxon
- tobaccoNicotiana tabacumt0
- Gene
- FQRe0
- Outcome
- protect the photosynthetic apparatus from chilling stresse0
- Qualifier
- under low irradiancee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“FQR-dependent cyclic electron flow around PS1 functioned to protect the photosynthetic apparatus from chilling stress under low irradiance”
t0“tobacco leaves”
Claim · model-written summary
NPQ and its fast relaxing component differed between antimycin-fed and control tobacco leaves.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- AA-fed leavese0
- Outcome
- non-photochemical quenching (NPQ), particularly the fast relaxing NPQ component (qf)e0
- Direction
- differencee0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“non-photochemical quenching (NPQ), particularly the fast relaxing NPQ component (qf) and the de-epoxidized ratio of the xanthophyll cycle pigments, (A+Z)/(V+A+Z), formed the difference between AA-fed leaves and controls”
t0“tobacco leaves”
Claim · model-written summary
Xanthophyll-cycle pigment de-epoxidation ratio differed between antimycin-fed and control tobacco leaves.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- AA-fed leavese0
- Outcome
- de-epoxidized ratio of the xanthophyll cycle pigments, (A+Z)/(V+A+Z)e0
- Direction
- differencee0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the de-epoxidized ratio of the xanthophyll cycle pigments, (A+Z)/(V+A+Z), formed the difference between AA-fed leaves and controls”
t0“tobacco leaves”
Claim · model-written summary
Lower NPQ in antimycin-fed tobacco leaves may stem from inefficient thylakoid proton gradients after FQR-dependent flow inhibition.
- Taxon
- tobaccoNicotiana tabacumt0
- Gene
- FQRe0
- Outcome
- lower NPQe0
- Qualifier
- inefficient proton gradient across thylakoid membranes (ΔpH)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The lower NPQ in AA-fed leaves might be related to an inefficient proton gradient across thylakoid membranes (ΔpH) because of inhibiting an FQR-dependent cyclic electron flow around PS1 at chilling temperature under low irradiance”
t0“tobacco leaves”
The same questions in other papers
cold · physiology: photosynthesis · Nicotiana tabacum (tobacco)Positive and negative results
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- negative
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See all 14 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.