TY  - JOUR
A1  - Lübbe, Torben
A1  - Lamarque, Laurent J.
A1  - Delzon, Sylvain
A1  - Torres Ruiz, José M.
A1  - Burlett, Régis
A1  - Leuschner, Christoph
A1  - Schuldt, Bernhard
T1  - High variation in hydraulic efficiency but not xylem safety between roots and branches in four temperate broad–leaved tree species
JF  - Functional Ecology
N2  - Xylem hydraulic safety and efficiency are key traits determining tree fitness in a warmer and drier world. While numerous plant hydraulic studies have focused on branches, our understanding of root hydraulic functioning remains limited, although roots control water uptake, influence stomatal regulation and have commonly been considered as the most vulnerable organ along the hydraulic pathway.
We investigated 11 traits related to xylem safety and efficiency along the hydraulic pathway in four temperate broad-leaved tree species.
Continuous vessel tapering from coarse roots to stems and branches caused considerable reduction in hydraulic efficiency. Wood density was always lowest in roots, but did not decline linearly along the flow path. In contrast, xylem embolism resistance (P50) did not differ significantly between roots and branches, except for one species. The limited variation in xylem safety between organs did not adequately reflect the corresponding reductions in vessel diameter (by ~70%) and hydraulic efficiency (by ~85%). Although we did not observe any trade-off between xylem safety and specific conductivity, vessel diameter, vessel lumen fraction and wood density were related to embolism resistance, both across and partly within organs.
We conclude that coarse roots are not highly vulnerable to xylem embolism as commonly believed, indicating that hydraulic failure during soil drying might be restricted to fine roots.
KW  - embolism resistance
KW  - wood density
KW  - wood anatomy
KW  - vulnerability curve
KW  - vessel tapering
KW  - flow path
KW  - hydraulic architecture
KW  - hydraulic conductivity
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318587
SN  - 0269-8463
VL  - 36
IS  - 3
SP  - 699
EP  - 712
ER  -