Figure 1.

A, Relation between Ψ_pd and Ψ_md in two V. vinifera varieties, Syrah (red) and Grenache (blue), in the field and during a drydown experiment in the greenhouse (Charrier et al., 2018). The piecewise linear regression was performed using the segmented function in R to estimate the values of breakpoints (Θ₁ and Θ₂) for each variety. The position of Θ₁ corresponds to the transition between anisohydric and isohydric behavior based on the change in stomatal sensitivity to VPD (for details see Charrier et al., 2018). B, Dependence of stomatal conductance (green), loss of hydraulic conductivity in petiole (purple) and stem (red), and leaf mortality (brown) on organ water potential in grapevine. Data were collected in both Syrah and Grenache, varieties but as none of the parameters defining the curves were statistically different, a mean curve was represented. Figure crafted de novo from results published in Charrier et al. (2016, 2018).