Comparison of hydraulic architecture of woody plants of differing phylogeny and growth form with special reference to freestanding and hemi-epiphytic Ficus species from Panama.

Abstract

Hydraulic parameters were measured in seven species of Fiats (three free-standing and four hemi-epiphytic) on stem segments of 3-35 mm in wood diameter. Parameters measured included Kh (water flux per unit pressure gradient), Kh (leaf specific conductivity =Kh per unit leaf area), Ks (specific conductivity =Hh per unit wood cross section), and Hv (Huber value = wood cross section per unit leaf area). The hemi-epiphytes tended to have less conductive stems per unit leaf area (lower Ki and invested less wood cross section per unit leaf area (lower Hv ) than free-standing species. Hydraulic parameters of Ficus are compared to 21 other temperate and tropical species to see if there is any discernible pattern in hydraulic architecture that correlates with phylogeny, growth form or habitat occupied by diverse species. Figs, as a group, had relatively high hV . and relatively low hv compared to other tropical trees. A possible correlation between KL and transpiration and growth form is discussed.