Figure 2.

Computer-simulated leaf hydraulic vulnerability curves indicating the theoretical impact of reducing hydraulic conductance in the within-xylem and outside-xylem components for leaves with high and low resistance outside the xylem (A and B, respectively). Simulations were run for leaves with: (1) low vulnerability for xylem and outside-xylem components (P₅₀ for the vulnerability of each component = −1 MPa; black line), (2) high vulnerability for only the outside-xylem component (P₅₀ = −1 and −0.25 MPa for the within-xylem and outside-xylem components, respectively; dark gray dashed line), (3) high vulnerability for only the xylem component (P₅₀ = −0.25 and −1 MPa for the within-xylem and outside-xylem components, respectively; light gray dashed line), and (4) high vulnerability for both the xylem and outside-xylem components (P₅₀ = −0.25 MPa; gray solid line).