Figure legends:
Figure 1 . Stomatal conductance (gs) of dehydrating leaves of Prunus dulcis (a) and Pyrus communis(b) treated with fusicoccin (orange) and abscisic acid (blue), and control leaves (green) at different leaf water potentials (Ψ). Thicker lines show average values for each treatment and thinner lines fit values recorded for each leaf. Black vertical lines show the average turgor loss point (solid lines) with 95% confidence intervals limits (dotted lines). Leaf replicates are n=10 (FC), n=7 (ABA), n=7 (control) in P. dulcis and n=7 (FC), n=6 (ABA), n=7 (control) in P. communis .
Figure 2 . Micrographs showing stomata of Prunus dulcis(a, c) and Pyrus communis (b, d) leaves treated with fusicoccin (a, b) and abscisic acid (c, d). Red segments show examples of pore width measured for stomatal aperture estimations (a, c, d). When the limits of cuticular ledges were not clearly observed, stomata were excluded from the analysis (b). Note surface roughness features such as furrows (more electron-dense) and folds (more electron-lucent) influencing water condensation.
Figure 3 . Cumulative change in mass (∆M ), water potential (ψ ) and estimated conductance (Ksur f) of Prunus dulcis (a, c, e) andPyrus communis (b, d, f) leaves treated with fusicoccin (orange triangles), abscisic acid (blue squares) and water (control; green circles) over time of fog exposure. Colored regions show 95% confidence intervals for the mean predicted value (solid lines) estimated by exponential models. Models in (a) and (b) correspond to the following equation:\(\Delta M=e^{A}\times(1-e^{\left(-B\ \times\ t^{2}\right)})\)where ∆M is the cumulative amount of water absorbed via the leaf surface calculated as the difference between initial leaf mass (time, t =0) and the mass after fog exposure (t=i ). Models in (c) and (d) correspond to the following equation:\(\Psi=A_{0}+e^{(B_{0}+B_{1}\times\ t^{2})}\) where Ψ is the leaf water potential at time t=i . Curves in (e) and (f) were calculated following Ohm’s law as Q / ψ, where Q is the instantaneous water flux into the leaf determined as the first derivative of the ∆M function. The parameters fit by each model are presented in the Supporting Information. Leaf replicates are n=21 (FC), n=22 (ABA), n=25 (control) in P. dulcis and n=18 (FC), n=22 (ABA), n=23 (control) in P. communis .
Figure 4. Micrographs of Prunus dulcis (a, c, e) andPyrus communis (b, d, f) leaf surface. a, b: Stomatal complex showing guard cells (GC), subsidiary cells (SC) and the cuticle (Cu) as the whitish layer at the most external part of the cells. Arrows indicate cuticular ledges over guard cells, and asterisks indicate the substomatal cuticle reaching and/or being part of parenchymatic cells. Red lines show the limits considered for measuring stomatal pore depth as the shortest distance between the intersection of the two lines at the inner side of the guard cells and the line at the cuticular ledges. c, d: Detail of the substomatal chamber showing the cuticle (Cu) of subsidiary cells (SC) and parenchymatic cells (PC). Asterisks are in the same position as in (a) and (b). e, f: Adaxial outer wall of ordinary epidermal cells (OEC) showing the cuticle (Cu) as the outermost cell wall (CW) region. Epicuticular waxes (EW) can be clearly observed inPyrus communis (f). The cytoplasm (Cy) is indicated as reference.