Abstract
Tolerance of photosystem 2 (PS2) to high temperature in apple (Malus domestica Borkh. cv. Cortland) leaves and peel was investigated by chlorophyll a fluorescence (OJIP) transient after exposure to 25 (control), 40, 42, 44, and 46 °C in the dark for 30 min. The positive L-step was more pronounced in a peel than in leaves when exposed to 44 °C. Heat-induced K-step became less pronounced in leaves than in peel when exposed to 42 °C or higher temperature. Leaves had negative L-and K-steps relative to the peel. The decrease of oxygen-evolving complex (OEC) by heat stress was higher in the peel than in the leaves. OJIP transient from the 46 °C treated peel could not reach the maximum fluorescence (Fm). The striking thermoeffect was the big decrease in the relative variable fluorescence at 30 ms (VI), especially in the leaves. Compared with the peel, the leaves had less decreased maximum PS2 quantum efficiency (Fv/Fm), photochemical rate constant (KP), Fm and performance index (PI) on absorption basis (PIabs) and less increased minimum fluorescence (F0) and non-photochemical rate constant (KN), but more increased reduction of end acceptors at PS1 electron acceptor side per cross section (RE0/CS0) and per reaction center (RE0/RC0), quantum yield of electron transport from QA - to the end acceptors (ϕ R0) and total PI (PIabs,total) when exposed to 44 °C. In conclusion, PS2 is more thermally labile than PS1. The reduction of PS2 activity by heat stress primarily results from an inactivation of OEC. PS2 was more tolerant to high temperature in the leaves than in the peel.
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Claims 15
Claim · model-written summary
The positive L-step was more pronounced in apple peel than in leaves after exposure to 44 °C
- Taxon
- apple
Malus domesticae0 - Material
- Cortlande0
- Organ / stage
- peele0
- Treatment
- exposed to 44 °Ce1
- Outcome
- positive L-stepe1
- Direction
- more pronouncede1
- Comparator
- leavese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“The positive L-step was more pronounced in a peel than in leaves when exposed to 44 °C”
Claim · model-written summary
The heat-induced K-step was less pronounced in apple leaves than in peel after exposure to 42 °C or higher
- Taxon
- appleMalus domesticae0
- Organ / stage
- leavese1
- Treatment
- exposed to 42 °C or higher temperaturee1
- Outcome
- Heat-induced K-stepe1
- Direction
- less pronouncede1
- Comparator
- peele1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“Heat-induced K-step became less pronounced in leaves than in peel when exposed to 42 °C or higher temperature”
Claim · model-written summary
Apple leaves had negative L- and K-steps relative to the peel
- Taxon
- appleMalus domesticae0
- Organ / stage
- leavese1
- Outcome
- L-and K-stepse1
- Direction
- negativee1
- Comparator
- peele1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“Leaves had negative L-and K-steps relative to the peel”
Claim · model-written summary
The heat-stress decrease of the oxygen-evolving complex was higher in apple peel than in leaves
- Taxon
- appleMalus domesticae0
- Organ / stage
- peele1
- Treatment
- heat stresse1
- Outcome
- decrease of oxygen-evolving complex (OEC)e1
- Direction
- highere1
- Comparator
- leavese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“The decrease of oxygen-evolving complex (OEC) by heat stress was higher in the peel than in the leaves”
Claim · model-written summary
The OJIP transient of apple peel treated at 46 °C could not reach the maximum fluorescence (Fm)
- Taxon
- appleMalus domesticae0
- Organ / stage
- peele1
- Treatment
- 46 °Ce1
- Outcome
- OJIP transiente1
- Qualifier
- could not reach the maximum fluorescence (Fm)e1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“OJIP transient from the 46 °C treated peel could not reach the maximum fluorescence (Fm)”
Claim · model-written summary
Relative variable fluorescence at 30 ms (VI) showed a big decrease, especially in apple leaves
- Taxon
- appleMalus domesticae0
- Organ / stage
- leavese1
- Outcome
- relative variable fluorescence at 30 ms (VI)e1
- Direction
- decreasee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“The striking thermoeffect was the big decrease in the relative variable fluorescence at 30 ms (VI), especially in the leaves”
Claim · model-written summary
At 44 °C, apple leaves had less decreased Fv/Fm, KP and Fm than peel
- Taxon
- appleMalus domesticae0
- Organ / stage
- leavese1
- Treatment
- exposed to 44 °Ce1
- Outcome
- maximum PS2 quantum efficiency (Fv/Fm), photochemical rate constant (KP), Fme1
- Direction
- less decreasede1
- Comparator
- peele1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“Compared with the peel, the leaves had less decreased maximum PS2 quantum efficiency (Fv/Fm), photochemical rate constant (KP), Fm and performance index (PI) on absorption basis (PIabs) and less increased minimum fluorescence (F0) and non-photochemical rate constant (KN), but more increased reduction of end acceptors at PS1 electron acceptor side per cross section (RE0/CS0) and per reaction center (RE0/RC0), quantum yield of electron transport from QA - to the end acceptors (ϕ R0) and total PI (PIabs,total) when exposed to 44 °C”
Claim · model-written summary
At 44 °C, apple leaves had less decreased PIabs than peel
- Taxon
- appleMalus domesticae0
- Organ / stage
- leavese1
- Treatment
- exposed to 44 °Ce1
- Outcome
- performance index (PI) on absorption basis (PIabs)e1
- Direction
- less decreasede1
- Comparator
- peele1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“Compared with the peel, the leaves had less decreased maximum PS2 quantum efficiency (Fv/Fm), photochemical rate constant (KP), Fm and performance index (PI) on absorption basis (PIabs) and less increased minimum fluorescence (F0) and non-photochemical rate constant (KN), but more increased reduction of end acceptors at PS1 electron acceptor side per cross section (RE0/CS0) and per reaction center (RE0/RC0), quantum yield of electron transport from QA - to the end acceptors (ϕ R0) and total PI (PIabs,total) when exposed to 44 °C”
Claim · model-written summary
At 44 °C, apple leaves had less increased F0 and KN than peel
- Taxon
- appleMalus domesticae0
- Organ / stage
- leavese1
- Treatment
- exposed to 44 °Ce1
- Outcome
- minimum fluorescence (F0) and non-photochemical rate constant (KN)e1
- Direction
- less increasede1
- Comparator
- peele1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“Compared with the peel, the leaves had less decreased maximum PS2 quantum efficiency (Fv/Fm), photochemical rate constant (KP), Fm and performance index (PI) on absorption basis (PIabs) and less increased minimum fluorescence (F0) and non-photochemical rate constant (KN), but more increased reduction of end acceptors at PS1 electron acceptor side per cross section (RE0/CS0) and per reaction center (RE0/RC0), quantum yield of electron transport from QA - to the end acceptors (ϕ R0) and total PI (PIabs,total) when exposed to 44 °C”
Claim · model-written summary
At 44 °C, apple leaves had more increased reduction of PS1 end acceptors per cross section and per reaction center than peel
- Taxon
- appleMalus domesticae0
- Organ / stage
- leavese1
- Treatment
- exposed to 44 °Ce1
- Outcome
- reduction of end acceptors at PS1 electron acceptor side per cross section (RE0/CS0) and per reaction center (RE0/RC0)e1
- Direction
- more increasede1
- Comparator
- peele1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“Compared with the peel, the leaves had less decreased maximum PS2 quantum efficiency (Fv/Fm), photochemical rate constant (KP), Fm and performance index (PI) on absorption basis (PIabs) and less increased minimum fluorescence (F0) and non-photochemical rate constant (KN), but more increased reduction of end acceptors at PS1 electron acceptor side per cross section (RE0/CS0) and per reaction center (RE0/RC0), quantum yield of electron transport from QA - to the end acceptors (ϕ R0) and total PI (PIabs,total) when exposed to 44 °C”
Claim · model-written summary
At 44 °C, apple leaves had more increased electron-transport quantum yield (φR0) than peel
- Taxon
- appleMalus domesticae0
- Organ / stage
- leavese1
- Treatment
- exposed to 44 °Ce1
- Outcome
- quantum yield of electron transport from QA - to the end acceptors (ϕ R0)e1
- Direction
- more increasede1
- Comparator
- peele1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“Compared with the peel, the leaves had less decreased maximum PS2 quantum efficiency (Fv/Fm), photochemical rate constant (KP), Fm and performance index (PI) on absorption basis (PIabs) and less increased minimum fluorescence (F0) and non-photochemical rate constant (KN), but more increased reduction of end acceptors at PS1 electron acceptor side per cross section (RE0/CS0) and per reaction center (RE0/RC0), quantum yield of electron transport from QA - to the end acceptors (ϕ R0) and total PI (PIabs,total) when exposed to 44 °C”
Claim · model-written summary
At 44 °C, apple leaves had more increased total PI (PIabs,total) than peel
- Taxon
- appleMalus domesticae0
- Organ / stage
- leavese1
- Treatment
- exposed to 44 °Ce1
- Outcome
- total PI (PIabs,total)e1
- Direction
- more increasede1
- Comparator
- peele1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“Compared with the peel, the leaves had less decreased maximum PS2 quantum efficiency (Fv/Fm), photochemical rate constant (KP), Fm and performance index (PI) on absorption basis (PIabs) and less increased minimum fluorescence (F0) and non-photochemical rate constant (KN), but more increased reduction of end acceptors at PS1 electron acceptor side per cross section (RE0/CS0) and per reaction center (RE0/RC0), quantum yield of electron transport from QA - to the end acceptors (ϕ R0) and total PI (PIabs,total) when exposed to 44 °C”
Claim · model-written summary
PS2 is more thermally labile than PS1 in apple
- Taxon
- appleMalus domesticae0
- Outcome
- PS2 is more thermally labile than PS1e1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“In conclusion, PS2 is more thermally labile than PS1”
Claim · model-written summary
Heat-stress reduction of PS2 activity in apple primarily results from inactivation of the oxygen-evolving complex
- Taxon
- appleMalus domesticae0
- Outcome
- The reduction of PS2 activity by heat stresse1
- Qualifier
- primarily results from an inactivation of OECe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“The reduction of PS2 activity by heat stress primarily results from an inactivation of OEC”
Claim · model-written summary
PS2 was more tolerant to high temperature in apple leaves than in peel
- Taxon
- appleMalus domesticae0
- Organ / stage
- leavese1
- Treatment
- high temperaturee1
- Outcome
- tolerant to high temperaturee1
- Direction
- more tolerante1
- Comparator
- peele1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple (Malus domestica Borkh. cv. Cortland) leaves and peel”
e1“PS2 was more tolerant to high temperature in the leaves than in the peel”
The same questions in other papers
heat · disease · Malus domestica (apple)Positive and negative results
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