Dynamics of water transport and storage in conifers studied with deuterium and heat tracing techniques
- Resource Type
- Authors
- David R. Woodruff; J. R. Brooks; Ken Bible; David C. Shaw; Frederick C. Meinzer; Jean-Christophe Domec; Barbara L. Gartner; Jeffrey M. Warren
- Source
- Plant, Cell and Environment. 29:105-114
- Subject
- Hot Temperature
Time Factors
Water transport
biology
Physiology
Stable isotope ratio
Water
Biological Transport
Soil science
Plant Science
Deuterium
biology.organism_classification
Residence time (fluid dynamics)
Pseudotsuga
Tsuga
Volume (thermodynamics)
TRACER
Tracheid
Botany
Environmental science
Half-Life
- Language
- ISSN
- 1365-3040
0140-7791
The volume and complexity of their vascular systems make the dynamics of long-distance water transport in large trees difficult to study. We used heat and deuterated water (D 2 O) as tracers to characterize whole-tree water transport and storage properties in individual trees belonging to the coniferous species Pseudotsuga menziesii (Mirb.) Franco and Tsuga heterophylla (Raf.) Sarg. The trees used in this study spanned a broad range of height (13.5-58 m) and diameter (0.14-1.43 m). Sap flow was monitored continuously with heat dissipation probes near the base of the trunk prior to, during and following injec- tion of D 2 O. The transit time for D 2 O transport from the base of the trunk to the upper crown and the tracer resi- dence time were determined by measuring hydrogen iso- tope ratios in water extracted from leaves sampled at regular intervals. Transit times for arrival of D 2 O in the upper crown ranged from 2.5 to 21 d and residence times ranged from 36 to 79 d. Estimates of maximum sap veloc- ity derived from tracer transit times and path length ranged from 2.4 to 5.4 m d − 1 . Tracer residence time and half-life increased as tree diameter increased, independent of species. Species-independent scaling of tracer velocity with sapwood-specific conductivity was also observed. When data from this study were combined with similar data from an earlier study of four tropical angiosperm trees, species-independent scaling of tracer velocity and residence time with sapwood hydraulic capacitance was observed. Sapwood capacitance is an intrinsic tissue-level property that appears to govern whole-tree water trans- port in a similar manner among both tracheid- and vessel- bearing species.