Abstract
Modulated chlorophyll fluorescence, rapid fluorescence induction kinetics and the polyphasic fluorescence transients (OJIP) were used to evaluate PSII photochemistry in wheat plants exposed to water stress and/or heat stress (25–45°C). Water stress showed no effects on the maximal quantum yield of PSII photochemistry (Fv/Fm), the rapid fluorescence induction kinetics, and the polyphasic fluorescence transients in dark-adapted leaves, indicating that water stress had no effects on the primary photochemistry of PSII. However, in light-adapted leaves, water stress reduced the efficiency of excitation energycapture by open PSII reaction centres (F′v/F′m) and the quantum yield of PSII electron transport (φPSII), increased the non-photochemical quenching (qN) and showed no effects on the photochemical quenching (qP). This suggests that water stress modified the PSII photochemistry in the light-adapted leaves and such modifications may be a mechanism to down-regulate the photosynthetic electron transport to match a decreased CO2 assimilation. In addition, water stress also modified the responses of PSII to heat stress. When temperature was above 35°C, thermostability of PSII was strongly enhanced in water-stressed leaves, which was reflected in a less decrease in Fv/Fm, qP, F′v/F′m, and φPSII in water-stressed leaves than in well-watered leaves. There were no significant variations in the above fluorescence parameters between moder-ately and severely water-stressed plants, indicating that the moderate water stress treatment caused the same effects on thermostability of PSII as the severe treatment. It was found that increased thermostability of PSII may be associated with an improvement of resistance of the O2-evolving complex and the reaction centres in water-stressed plants to high temperature.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 7
Claim · model-written summary
Water stress did not alter dark-adapted PSII fluorescence measures.
- Taxon
- wheat plants
Triticum aestivumt0 - Organ / stage
- dark-adapted leavese0
- Treatment
- Water stresse0
- Outcome
- maximal quantum yield of PSII photochemistry (Fv/Fm), the rapid fluorescence induction kinetics, and the polyphasic fluorescence transientse0
- Direction
- no effectse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water stress showed no effects on the maximal quantum yield of PSII photochemistry (Fv/Fm), the rapid fluorescence induction kinetics, and the polyphasic fluorescence transients in dark-adapted leaves”
t0“wheat plants”
Claim · model-written summary
Water stress reduced excitation capture efficiency and PSII electron transport yield in light-adapted leaves.
- Taxon
- wheat plantsTriticum aestivumt0
- Organ / stage
- light-adapted leavese0
- Treatment
- water stresse0
- Outcome
- efficiency of excitation energycapture by open PSII reaction centres (F′v/F′m) and the quantum yield of PSII electron transport (φPSII)e0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in light-adapted leaves, water stress reduced the efficiency of excitation energycapture by open PSII reaction centres (F′v/F′m) and the quantum yield of PSII electron transport (φPSII)”
t0“wheat plants”
Claim · model-written summary
Water stress increased non-photochemical quenching.
- Taxon
- wheat plantsTriticum aestivumt0
- Treatment
- water stresse1
- Outcome
- non-photochemical quenching (qN)e0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased the non-photochemical quenching (qN)”
e1“water stress reduced the efficiency”
t0“wheat plants”
Claim · model-written summary
Water stress had no effect on photochemical quenching.
- Taxon
- wheat plantsTriticum aestivumt0
- Treatment
- water stresse1
- Outcome
- photochemical quenching (qP)e0
- Direction
- no effectse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“showed no effects on the photochemical quenching (qP)”
e1“water stress reduced the efficiency”
t0“wheat plants”
Claim · model-written summary
Water stress enhanced PSII heat stability above 35°C relative to well-watered leaves.
- Taxon
- wheat plantsTriticum aestivumt0
- Treatment
- water-stressed leavese0
- Outcome
- thermostability of PSIIe0
- Direction
- enhancede0
- Qualifier
- temperature was above 35°Ce0
- Comparator
- well-watered leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When temperature was above 35°C, thermostability of PSII was strongly enhanced in water-stressed leaves, which was reflected in a less decrease in Fv/Fm, qP, F′v/F′m, and φPSII in water-stressed leaves than in well-watered leaves”
t0“wheat plants”
Claim · model-written summary
Moderate and severe water stress produced similar fluorescence parameters.
- Taxon
- wheat plantsTriticum aestivumt0
- Treatment
- moder-atelye0
- Outcome
- above fluorescence parameterse0
- Direction
- no significant variationse0
- Comparator
- severely water-stressed plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There were no significant variations in the above fluorescence parameters between moder-ately and severely water-stressed plants”
t0“wheat plants”
Claim · model-written summary
Improved heat resistance of oxygen-evolving complex and reaction centers may relate to higher PSII thermostability.
- Taxon
- wheat plantsTriticum aestivumt0
- Outcome
- increased thermostability of PSIIe0
- Qualifier
- improvement of resistance of the O2-evolving complex and the reaction centrese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased thermostability of PSII may be associated with an improvement of resistance of the O2-evolving complex and the reaction centres in water-stressed plants to high temperature”
t0“wheat plants”
The same questions in other papers
drought · physiology: photosynthesis · Triticum aestivum (wheat)Positive and negative results
40 papers in the same direction as this paper · 204 in the opposite direction · 1 reporting no difference from an alternative
- negative
- negative
- negative
242 papers more in this group
See all 246 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.