HAL Id: hal-02734132
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Submitted on 2 Jun 2020
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The role of residual trnspiration in poplar drought tolerance
Lise-Marie Billon, Philippe Vernay, Stéphane Herbette, Cochard, Adnane Hitmi
To cite this version:
Lise-Marie Billon, Philippe Vernay, Stéphane Herbette, Cochard, Adnane Hitmi. The role of residual trnspiration in poplar drought tolerance. 3rd Xylem International Meeting, Sep 2017, Bordeaux, France. INRA, 2017, 3rd Xylem International Meeting. �hal-02734132�
The role of residual transpiration in poplar drought tolerance
Introduction
Xylem cavitation is a major health issue causing tree mortality under drought conditions. Xylem intrinsic resistance to cavitation is now well documented but the timing of cavitation formation in situ is still difficult to predict. During drought, cavitation occurs after stomatal closure which suggests a key, but yet unexplored, role of plant residual transpiration. This study aimed at defining an experimental design to measure accurately plant residual transpiration and at showing how far it plays a role in the timing of cavitation formation in poplar.
Experimental design : Pressure-Volume (A) and Vulnerability (B) curves were obtained to estimate Ptlp and P50 values:
Residual transpiration estimated gravimetrically on
well-watered (red) and water-stressed (yellow) poplars : Timing of cavitation induction for control (yellow) and 50% defoliated poplars (grey) :
Residual plant transpiration, remaining after stomatal closure during drought, can simply be estimated gravimetrically. Our work suggests that this trait plays a key role in the timing of cavitation induction during prolonged drought events, as demonstrated by our partial defoliation experiment. More information is needed on the intra and inter-specific variability of this trait and its structural and molecular basis if we are to better predict and model tree mortality under extreme drought conditions.
Conclusion
Billon Lise-Marie, Vernay Philippe, Herbette Stéphane, Cochard Hervé and Hitmi Adnane
UCA, INRA, PIAF, 63000 Clermont-Ferrand, France
lise-marie.billon@etudiant.univ-bpclermont.fr
Well-watered whole plants Water-stressed whole plants
30 40 50 60 70 80 90 0 6 14 PL C ( %)
Days after half defoliation
a a a c b b Water-stressed half-defoliated plants Water-stressed whole plants 0.3 0.8 1.3 1.8 2.3 2.8 0 10 20 30 40 50 60 1/ Ψ (MP a-1) 100-RWC (%)
Turgor loss point= -1,25 MPa
0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00 0 1 2 3 4 5 PL C ( %) Ψmin (- MPa) P50 P88 P12 - 2.71 - 3.44 - 1.97 3-4 month-old poplar trees Watered Stem Vulnerability curve P50 Water-stressed Leave Pressure-volume curve (Ptlp) Whole plant Gravimetric residual transpiration measurement Half defoliated plant Cavitation emergence study
Under our experimental conditions, residual transpiration
represented about 1,25% of the total transpiration of control plants.
-10 10 30 50 70 90 110 10 15 20 25 30 35 Tr an sp ira tio n g/ h Time (days) -10 0 10 20 30 40 50 22 22.5 23 23.5 24 Tr an sp ira tio n g/ h Days
Reducing plant residual transpiration by reducing plant leaf area after stomatal closure delayed significantly the induction of
cavitation in the stems. Means with the same letters are not significantly different at 5% probability level (n=3).
B
