Figure 5.

Modeled and measured recovery data for a C. rhomboidea plant subject to a stress sufficient to reduce K_leaf by approximately 90%. A, According to the hydraulic-stomatal limitation model, in fully hydrated soils E will be equal to the intersection of a hydraulic supply function (defined by K_plant) and the stomatal control function (determined empirically from the regression equations in Fig. 2). B, The observed recovery of whole-plant hydraulic conductivity after rewatering. C, The predicted (white circles, dotted line) recovery of midday E closely matches the observed (black circles, unbroken line) dynamic as the rewatered plant initially rehydrates rapidly to the edge of the stomatal control window (shown as the gray region, representing the Ψ_leaf range responsible for a 20% to 80% reduction in stomatal aperture) then slowly thereafter, thus limiting stomatal conductance and gas exchange. Predicted %E is calculated from entering the measured Ψ_leaf (triangles) into the stomatal control function equation %E = ƒ(Ψ_leaf) shown in A.