Leaf-Conductance Patterns of Seven Palms in a Common Environment

Abstract

Leaf conductance was determined 10 times from November to June for small trees of the following palm species which grew together in cultivation in Taiwan: Caryota mitis, Dictyosperma alba, Elaeis guineensis, Ptychos perma macarthuri, Sabal umbraculifera, and Washingtonia filifera. Arenga engleri was sampled only in May and June. Two fan palms, with many stomata on both leaf surfaces, had average conductance of 0.45 and 0.35 cm s-1; conductance was similar on both surfaces and varied less than for the other species. Feather palms, which have most stomata on the lower surface, had mean conductance values of 0.12-0.27 cm s-1; conductance was greater on the lower leaf surface. Tall species which originated in open vegetation types in dry or seasonal climates had the highest conductances. Minimal conductance values were similar to those of many temperate dicotyledonous trees, but maximal values for four species matched or exceeded the maximum of 0.8 cm s-1 measured for temperate trees. Seasonal environmental v...