© 1997 Heron Publishing—Victoria, Canada
Hydraulic architecture and water relations of a flood-tolerant tropical tree, Annona glabra
Gerhard Zotz (1, 2, 3, 4), Melvin T. Tyree (1, 2, 3) and Sandra Patiño (3)
1. USDA Forest Service, 705 Spear Street, Burlington, VT 05402, USA / 2. Department of Botany, University of Vermont, Burlington, VT 05405, USA / 3. Smithsonian Tropical Research Institute, Apdo. 2072, Balboa, Republic of Panama / 4. Julius-von-Sachs-Institut für Biowissenschaften, mit Botanischem Garten der Universität Würzburg, Lehrstuhl für Botanik II,
Mittlerer Dallenbergweg 64, D-97082 Würzburg, Germany / Received May 28, 1996
Summary
Hydraulic architecture parameters, water relation parameters and wood anatomy were studied in roots and shoots of the flood-tolerant
tree Annona glabra L. on Barro Colorado Island, Panama. Hydraulic conductivity, leaf specific conductivity, and Huber value were similar to
the corresponding values for tree species living in non-flooded habitats. The vulnerability of stems to loss of hydraulic
conductivity resulting from embolism was low (50% loss of conductivity at –3.3 MPa). The lowest leaf water potential measured
in the field was about –1.0 MPa, indicating that A. glabra has a large margin of safety from embolism, which may provide protection against rare drought events, or may be an adaptation
to brackish mangrove habitats. Low absolute conductivity of roots was compensated for by an increase in the number of roots.
More than two-thirds of whole-plant resistance to water flow was located in the roots.
Keywords:
flooding, Huber value, hydraulic conductivity, leaf specific conductivity, vulnerability curve.
