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Hydraulic adjustments underlying drought resistance of Pinus halepensis
Year:
2011
Source of publication :
tree physiology (source)
Authors :
Cohen, Shabtai
;
.
Volume :
31
Co-Authors:
Klein, T., Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot 76100, Israel
Cohen, S., Institute of Soil, Water and Environmental Sciences, Volcani Center ARO, Beit Dagan 50250, Israel
Yakir, D., Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot 76100, Israel
Facilitators :
From page:
637
To page:
648
(
Total pages:
12
)
Abstract:
Drought-induced tree mortality has increased over the last decades in forests around the globe. Our objective was to investigate under controlled conditions the hydraulic adjustments underlying the observed ability of Pinus halepensis to survive seasonal drought under semi-arid conditions. One hundred 18-month saplings were exposed in the greenhouse to 10 different drought treatments, simulating combinations of intensities (fraction of water supply relative to control) and durations (period with no water supply) for 30 weeks. Stomata closed at a leaf water potential (Ψ l) of -2.8 MPa, suggesting isohydric stomatal regulation. In trees under extreme drought treatments, stomatal closure reduced CO 2 uptake to -1μmol m -2 s -1, indicating the development of carbon starvation. A narrow hydraulic safety margin of 0.3 MPa (from stomatal closure to 50% loss of hydraulic conductivity) was observed, indicating a strategy of maximization of CO 2 uptake in trees otherwise adapted to water stress. A differential effect of drought intensity and duration was observed, and was explained by a strong dependence of the water stress effect on the ratio of transpiration to evapotranspiration T/ET and the larger partitioning to transpiration associated with larger irrigation doses. Under intense or prolonged drought, the root system became the main target for biomass accumulation, taking up to 100% of the added biomass, while the stem tissue biomass decreased, associated with up to 60% reduction in xylem volume. © The Author 2011.
Note:
Related Files :
drought tolerance
evapotranspiration
Israel
Pinus
Pinus halepensis
Stomatal conductance
transpiration
Show More
Related Content
More details
DOI :
10.1093/treephys/tpr047
Article number:
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
24681
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:09
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Scientific Publication
Hydraulic adjustments underlying drought resistance of Pinus halepensis
31
Klein, T., Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot 76100, Israel
Cohen, S., Institute of Soil, Water and Environmental Sciences, Volcani Center ARO, Beit Dagan 50250, Israel
Yakir, D., Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot 76100, Israel
Hydraulic adjustments underlying drought resistance of Pinus halepensis
Drought-induced tree mortality has increased over the last decades in forests around the globe. Our objective was to investigate under controlled conditions the hydraulic adjustments underlying the observed ability of Pinus halepensis to survive seasonal drought under semi-arid conditions. One hundred 18-month saplings were exposed in the greenhouse to 10 different drought treatments, simulating combinations of intensities (fraction of water supply relative to control) and durations (period with no water supply) for 30 weeks. Stomata closed at a leaf water potential (Ψ l) of -2.8 MPa, suggesting isohydric stomatal regulation. In trees under extreme drought treatments, stomatal closure reduced CO 2 uptake to -1μmol m -2 s -1, indicating the development of carbon starvation. A narrow hydraulic safety margin of 0.3 MPa (from stomatal closure to 50% loss of hydraulic conductivity) was observed, indicating a strategy of maximization of CO 2 uptake in trees otherwise adapted to water stress. A differential effect of drought intensity and duration was observed, and was explained by a strong dependence of the water stress effect on the ratio of transpiration to evapotranspiration T/ET and the larger partitioning to transpiration associated with larger irrigation doses. Under intense or prolonged drought, the root system became the main target for biomass accumulation, taking up to 100% of the added biomass, while the stem tissue biomass decreased, associated with up to 60% reduction in xylem volume. © The Author 2011.
Scientific Publication
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