Water relations and hydraulic architecture of a tropical tree (Schefflera morototoni). Data, models, and a comparison with two temperate species (Acer saccharum and Thuja occidentalis)

• Published in: Plant physiology (Bethesda) Vol. 96; no. 4; pp. 1105 - 1113
• Main Authors: Tyree, M.T. (Northeastern Forest Experiment Station, Burlington, VT), Snyderman, D.A, Wilmot, T.R, Machado, J.L
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.08.1991
• Subjects: ACER SACCHARUM; Animal and plant ecology; Animal, plant and microbial ecology; ARALIACEAE; Architecture; Autoecology; Biological and medical sciences; Cavitation flow; Dry seasons; FEUILLE; Fundamental and applied biological sciences. Psychology; HOJAS; Hydraulics; Leaf area; Leaves; PANAMA; Petioles; Plants and fungi; PROPIEDADES FISICO-QUIMICAS; PROPRIETE PHYSICOCHIMIQUE; Rainy seasons; RELACIONES PLANTA AGUA; RELATION PLANTE EAU; THUJA OCCIDENTALIS; TRANSPIRACION; TRANSPIRATION; Water flow; Xylem; Central America; Panama; America; Tropical zone; Hydraulic conductivity; Plant leaf; Ecophysiology; Water potential; Cavitation; Aceraceae; Thuja occidentalis; Transpiration; Acer saccharum; Water regime; Dicotyledones; Morphology; Plant trunk; Angiospermae; Gymnospermae; Coniferales; Spermatophyta; Hardwood forest tree; Araliaceae
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.96.4.1105

The water relations and hydraulic architecture of a tropical tree (Schefflera morototoni) and of two temperate species (Acer saccharum and Thuja occidentalis) are reported. Among the water relations parameters measured were leaf and stem water storage capacity leaf water potential, transpiration, and vulnerability of stem to cavitation and loss of hydraulic conductivity by embolisms. Among the hydraulic architecture parameters measured were hydraulic conductivity per unit pressure gradient, specific conductivity, leaf-specific conductivity, and Huber value. In terms of vulnerability of stems to cavitation, stem and leaf capacitances, and leaf-specific conductivity, all three species followed the same sequence: Schefflera Acer Thuja. It is argued here that the high stem capacitance and high leaf-specific conductivity of Schefflera are necessary to compensate for its high vulnerability to cavitation. Extractable water storage per unit leaf area in Schefflera stems is 100 times that of Acer and may permit the species to survive unusually long, dry seasons in Panama. Although Schefflera frequently grows 20 meters, the biggest resistance to water flow in the shoots resides in the leaves