Abstract
Photoinhibition of photosynthesis and its recovery were studied in wheat (Triticum aestivum L.) leaves grown at nonhardening (20 degrees C) and cold-hardening (5 degrees C) temperatures. Cold-hardened wheat leaves were less susceptible to photoinhibition at 5 degrees C than nonhardened leaves, and the winter cultivars, Kharkov and Monopol, were less susceptible than the spring cultivar, Glenlea. The presence of chloramphenicol, a chloroplastic protein synthesis inhibitor, increased the susceptibility to photoinhibition, but cold-hardened leaves still remained less susceptible to photoinhibition than nonhardened leaves. Recovery at 50 mumol m(-2) s(-1) photosynthetic photon flux density and 20 degrees C was at least biphasic, with a fast and a slow phase in all cultivars. Cold-hardened leaves recovered maximum fluorescence and maximum variable fluorescence in the dark-adapted state during the fast phase at a rate of 42% h(-1) compared with 22% h(-1) for nonhardened leaves. The slow phase occurred at similar rates (2% h(-1)) in cold-hardened and nonhardened leaves. Full recovery required up to 30 h. Fast-recovery phase was not reduced by either lowering the recovery temperature to 5 degrees C or by the presence of chloramphenicol. Slow-recovery phase was inhibited by both treatments. Hence, the fast phase of recovery does not require de novo chloroplast protein synthesis. In addition, only approximately 60% of the photochemical efficiency lost through photoinhibition at 5 degrees C was associated with lost [(14)C]atrazine binding and, hence, with damage to the secondary quinone electron acceptor for photosystem II-binding site. We conclude that the decrease in susceptibility to photoinhibition exhibited following cold hardening of winter and spring cultivars is not due to an increased capacity for repair of photoinhibitory damage at 5 degrees C but reflects intrinsic properties of the cold-hardened photosynthetic apparatus. A model to account for the fast component of recovery is discussed.
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Claims 14
Claim · model-written summary
Cold-hardened wheat leaves were less susceptible to photoinhibition at 5 degrees C than nonhardened leaves.
- Taxon
- wheat
Triticum aestivume0 - Treatment
- Cold-hardenede0
- Outcome
- susceptible to photoinhibitione0
- Direction
- less susceptiblee0
- Qualifier
- 5 degrees Ce0
- Comparator
- nonhardened leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cold-hardened wheat leaves were less susceptible to photoinhibition at 5 degrees C than nonhardened leaves”
Claim · model-written summary
The winter cultivars Kharkov and Monopol were less susceptible to photoinhibition than the spring cultivar Glenlea.
- Taxon
- WheatTriticum aestivumt0
- Material
- winter cultivars, Kharkov and Monopole0
- Outcome
- less susceptiblee0
- Direction
- less susceptiblee0
- Comparator
- spring cultivar, Glenleae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“the winter cultivars, Kharkov and Monopol, were less susceptible than the spring cultivar, Glenlea”
Claim · model-written summary
Chloramphenicol increased the susceptibility of wheat leaves to photoinhibition.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- chloramphenicole0
- Outcome
- susceptibility to photoinhibitione0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“The presence of chloramphenicol, a chloroplastic protein synthesis inhibitor, increased the susceptibility to photoinhibition”
Claim · model-written summary
Even in the presence of chloramphenicol, cold-hardened leaves remained less susceptible to photoinhibition than nonhardened leaves.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- cold-hardenede0
- Outcome
- susceptible to photoinhibitione0
- Direction
- less susceptiblee0
- Qualifier
- The presence of chloramphenicole0
- Comparator
- nonhardened leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“The presence of chloramphenicol, a chloroplastic protein synthesis inhibitor, increased the susceptibility to photoinhibition, but cold-hardened leaves still remained less susceptible to photoinhibition than nonhardened leaves”
Claim · model-written summary
Recovery of wheat leaves from photoinhibition was at least biphasic, with a fast and a slow phase in all cultivars.
- Taxon
- WheatTriticum aestivumt0
- Outcome
- at least biphasice0
- Qualifier
- a fast and a slow phase in all cultivarse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“Recovery at 50 mumol m(-2) s(-1) photosynthetic photon flux density and 20 degrees C was at least biphasic, with a fast and a slow phase in all cultivars”
Claim · model-written summary
During the fast recovery phase, cold-hardened leaves recovered maximum fluorescence and maximum variable fluorescence at 42% h(-1), compared with 22% h(-1) for nonhardened leaves.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- Cold-hardenede0
- Outcome
- recovered maximum fluorescence and maximum variable fluorescencee0
- Direction
- higherinferrede0
- Value
- 42% h(-1)e0
- Qualifier
- 22% h(-1)e0
- Comparator
- nonhardened leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“Cold-hardened leaves recovered maximum fluorescence and maximum variable fluorescence in the dark-adapted state during the fast phase at a rate of 42% h(-1) compared with 22% h(-1) for nonhardened leaves”
Claim · model-written summary
The slow recovery phase occurred at similar rates (2% h(-1)) in cold-hardened and nonhardened leaves.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- cold-hardenede0
- Outcome
- The slow phasee0
- Direction
- similare0
- Value
- 2% h(-1)e0
- Comparator
- nonhardened leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“The slow phase occurred at similar rates (2% h(-1)) in cold-hardened and nonhardened leaves”
Claim · model-written summary
The fast recovery phase was not reduced by lowering the recovery temperature to 5 degrees C.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- lowering the recovery temperature to 5 degrees Ce0
- Outcome
- Fast-recovery phasee0
- Direction
- not reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“Fast-recovery phase was not reduced by either lowering the recovery temperature to 5 degrees C or by the presence of chloramphenicol”
Claim · model-written summary
The fast recovery phase was not reduced by the presence of chloramphenicol.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- the presence of chloramphenicole0
- Outcome
- Fast-recovery phasee0
- Direction
- not reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“Fast-recovery phase was not reduced by either lowering the recovery temperature to 5 degrees C or by the presence of chloramphenicol”
Claim · model-written summary
The slow recovery phase was inhibited by lowering the recovery temperature to 5 degrees C.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- lowering the recovery temperature to 5 degrees Ce1
- Outcome
- Slow-recovery phasee0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“Slow-recovery phase was inhibited by both treatments”
e1“lowering the recovery temperature to 5 degrees C”
Claim · model-written summary
The slow recovery phase was inhibited by the presence of chloramphenicol.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- the presence of chloramphenicole1
- Outcome
- Slow-recovery phasee0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“Slow-recovery phase was inhibited by both treatments”
e1“the presence of chloramphenicol”
Claim · model-written summary
The fast phase of recovery does not require de novo chloroplast protein synthesis.
- Taxon
- WheatTriticum aestivumt0
- Outcome
- fast phase of recoverye0
- Qualifier
- does not require de novo chloroplast protein synthesise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“the fast phase of recovery does not require de novo chloroplast protein synthesis”
Claim · model-written summary
Only approximately 60% of the photochemical efficiency lost through photoinhibition at 5 degrees C was associated with lost atrazine binding at the secondary quinone electron acceptor site of photosystem II.
- Taxon
- WheatTriticum aestivumt0
- Compound
- [(14)C]atrazinee0
- Outcome
- photochemical efficiency lost through photoinhibitione0
- Value
- approximately 60%e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“only approximately 60% of the photochemical efficiency lost through photoinhibition at 5 degrees C was associated with lost [(14)C]atrazine binding”
Claim · model-written summary
The authors conclude that the lower photoinhibition susceptibility after cold hardening of winter and spring cultivars is not due to increased repair capacity at 5 degrees C but reflects intrinsic properties of the cold-hardened photosynthetic apparatus.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- cold hardeninge0
- Outcome
- decrease in susceptibility to photoinhibitione0
- Qualifier
- reflects intrinsic properties of the cold-hardened photosynthetic apparatuse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Wheat”
e0“the decrease in susceptibility to photoinhibition exhibited following cold hardening of winter and spring cultivars is not due to an increased capacity for repair of photoinhibitory damage at 5 degrees C but reflects intrinsic properties of the cold-hardened photosynthetic apparatus”
The same questions in other papers
cold · physiology: photosynthesis · Triticum aestivum (wheat)Results differ
10 papers in the same direction as this paper · 16 in the opposite direction
- no effect
- negative
- negative
23 papers more in this group
See all 27 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.