Abstract
In this study, the physiological response of potted apple trees to combined drought and heat stress was evaluated. After establishing different levels of soil water availability, the trees were exposed to a five-day simulated heatwave with daily maximum temperatures of 40°C. Stem water potential, leaf gas exchange, chlorophyll fluorescence, and tree transpiration were monitored before, during and after the combined application of heat and water stress, therefore providing insights into the extent and rapidity of the recovery. Drought caused stomatal closure that limited net photosynthesis and transpiration both at leaf and at tree level, leading to structural damage through leaf loss. On drought-stressed plants, chlorophyll fluorescence was significantly reduced by heat stress, suggesting additional leaf damage although net photosynthesis was not lower than under drought stress alone. On the other hand, well-watered trees showed low midday stem water potentials and high transpiration rates during the heatwave, while net photosynthesis was not affected. Water use efficiency of well-watered trees at 33°C was reduced to 60% of that at 23°C. After the heatwave, transpiration rate in well-watered trees immediately declined to pre-stress levels, underscoring the strong atmospheric control on transpiration in apple trees. In drought-stressed trees, predawn stem water potential reached pre-stress values already on the first day of recovery. Stomatal conductance, net photosynthesis, and chlorophyll fluorescence, however, required a longer period to recover, indicating that drought stress induced transient hydraulic limitations. Nevertheless, all parameters fully recovered within five days after the end of the heatwave, showing that apple trees can withstand periods of combined heat and drought stress. The key role of water in modulating the response to heat stress highlights the need for improved irrigation management in apple orchards under climate change.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. 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 15
Claim · model-written summary
Drought induced stomatal closure in apple trees.
- Taxon
- apple tree
Malus domesticat0 - Treatment
- Droughte0
- Outcome
- stomatal closuree0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought caused stomatal closure”
t0“apple tree”
Claim · model-written summary
Drought limited net photosynthesis and transpiration at leaf and tree levels.
- Taxon
- apple treeMalus domesticat0
- Treatment
- Droughte0
- Outcome
- net photosynthesis and transpiratione0
- Direction
- limitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought caused stomatal closure that limited net photosynthesis and transpiration both at leaf and at tree level”
t0“apple tree”
Claim · model-written summary
Drought led to leaf loss.
- Taxon
- apple treeMalus domesticat0
- Treatment
- Droughte0
- Outcome
- leaf losse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought caused stomatal closure that limited net photosynthesis and transpiration both at leaf and at tree level, leading to structural damage through leaf loss.”
t0“apple tree”
Claim · model-written summary
Heat significantly reduced chlorophyll fluorescence in drought-stressed apple trees.
- Taxon
- apple treeMalus domesticat0
- Treatment
- heat stresse0
- Outcome
- chlorophyll fluorescencee0
- Direction
- reducede0
- Comparator
- drought-stressed plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On drought-stressed plants, chlorophyll fluorescence was significantly reduced by heat stress”
t0“apple tree”
Claim · model-written summary
Heat did not further lower net photosynthesis in drought-stressed trees.
- Taxon
- apple treeMalus domesticat0
- Treatment
- heat stresse0
- Outcome
- net photosynthesise0
- Direction
- not lowere0
- Comparator
- under drought stress alonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On drought-stressed plants, chlorophyll fluorescence was significantly reduced by heat stress, suggesting additional leaf damage although net photosynthesis was not lower than under drought stress alone.”
t0“apple tree”
Claim · model-written summary
Well-watered trees showed low midday stem water potentials during the heatwave.
- Taxon
- apple treeMalus domesticat0
- Treatment
- heatwavee0
- Outcome
- midday stem water potentialse0
- Direction
- lowe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“well-watered trees showed low midday stem water potentials and high transpiration rates during the heatwave”
t0“apple tree”
Claim · model-written summary
Well-watered trees showed high transpiration rates during the heatwave.
- Taxon
- apple treeMalus domesticat0
- Treatment
- heatwavee0
- Outcome
- transpiration ratese0
- Direction
- highe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“well-watered trees showed low midday stem water potentials and high transpiration rates during the heatwave”
t0“apple tree”
Claim · model-written summary
Heatwave exposure did not affect net photosynthesis in well-watered trees.
- Taxon
- apple treeMalus domesticat0
- Treatment
- heatwavee0
- Outcome
- net photosynthesise0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“well-watered trees showed low midday stem water potentials and high transpiration rates during the heatwave, while net photosynthesis was not affected.”
t0“apple tree”
Claim · model-written summary
Water use efficiency of well-watered trees at 33°C was 60% of the value at 23°C.
- Taxon
- apple treeMalus domesticat0
- Treatment
- 33°Ce0
- Outcome
- Water use efficiencye0
- Direction
- reducede0
- Value
- 60%e0
- Comparator
- 23°Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water use efficiency of well-watered trees at 33°C was reduced to 60% of that at 23°C.”
t0“apple tree”
Claim · model-written summary
After the heatwave, transpiration in well-watered trees immediately returned to pre-stress levels.
- Taxon
- apple treeMalus domesticat0
- Outcome
- transpiration ratee0
- Direction
- declinede0
- Comparator
- pre-stress levelse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transpiration rate in well-watered trees immediately declined to pre-stress levels”
t0“apple tree”
Claim · model-written summary
Predawn stem water potential in drought-stressed trees returned to pre-stress values on the first recovery day.
- Taxon
- apple treeMalus domesticat0
- Outcome
- predawn stem water potentiale0
- Direction
- reachede0
- Qualifier
- first day of recoverye0
- Comparator
- pre-stress valuese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“predawn stem water potential reached pre-stress values already on the first day of recovery.”
t0“apple tree”
Claim · model-written summary
Stomatal conductance, net photosynthesis, and chlorophyll fluorescence recovered more slowly.
- Taxon
- apple treeMalus domesticat0
- Outcome
- Stomatal conductance, net photosynthesis, and chlorophyll fluorescencee0
- Direction
- longer period to recovere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stomatal conductance, net photosynthesis, and chlorophyll fluorescence, however, required a longer period to recover”
t0“apple tree”
Claim · model-written summary
All measured apple tree parameters fully recovered within five days after the heatwave.
- Taxon
- apple treeMalus domesticat0
- Outcome
- all parameterse0
- Direction
- fully recoverede0
- Value
- five dayse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“all parameters fully recovered within five days after the end of the heatwave”
t0“apple tree”
Claim · model-written summary
The authors concluded that apple trees can withstand combined heat and drought stress.
- Taxon
- apple treesMalus domesticae0
- Outcome
- withstand periods of combined heat and drought stresse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“apple trees can withstand periods of combined heat and drought stress.”
Claim · model-written summary
The authors called for improved irrigation management in apple orchards under climate change.
- Taxon
- appleMalus domesticae0
- Outcome
- improved irrigation managemente0
- Qualifier
- under climate changee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“highlights the need for improved irrigation management in apple orchards under climate change.”
The same questions in other papers
drought · physiology: photosynthesis · Malus domestica (apple)Results differ
16 papers in the same direction as this paper · 4 in the opposite direction
- negative
- positive
- positive
17 papers more in this group
See all 21 papers →drought · physiology: gas exchange · Malus domestica (apple)Positive and negative results
8 papers in the same direction as this paper · 1 in the opposite direction
- positive
- negative
- negative
6 papers more in this group
See all 10 papers →heat · physiology: photosynthesis · Malus domestica (apple)Results agree
7 papers in the same direction as this paper
- negative
- negative
- negative
4 papers more in this group
See all 8 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.