Hydraulic Conductance and Water Potential Differences Inside Leaves of Tropical Evergreen and Deciduous Species

Several pieces of research suggest that leaf liquid-path conductance (K1) may be smaller in evergreen species (EG) than in deciduous species (DC), coexisting in tropical dry forests. This was investigated in four DC and two EG in a tropical dry forest in Venezuela. The K1 (kg m-2 MPa-1 s-1) were consistently lower in EG (8.4 × 10-5) than in DC (12 to 20 × 10-5). Differences in water potential (W) inside the leaves were calculated using K1 values in connection with maximum transpiration rates measured in the field. It was found that W was about 1.9 MPa in EG, intermediate for one DC (Pithecellobium dulce, 1.7 MPa) and minimum for other DC (1.0 to 1.3 MPa).