Figure 2.

Plant hydraulic and gas-exchange responses to dehydration in Arabidopsis. Decline of the whole-plant hydraulic conductance (K_plant; A), g_s (B), and A_area (C) with dehydration are shown. Each point represents a different measured leaf. K_plant was obtained from the porometer data by dividing transpiration by Ψ_leaf (assuming that soil water potential was at full saturation). The black fitted line in each graph is the maximum likelihood function [exponential for and linear for and ]. The dotted gray line is the Ψ_leaf at 50% loss of maximum K_plant, g_s, or A_area. Because trait values above −0.1 MPa were especially low (white circles), likely representing stomatal closure at those high water potentials (see “Materials and Methods”), we did not include these points in the line fitting.