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.