Figure 2.

Variability in stem vulnerability to xylem embolism among grapevine varieties. (a) Range of Ψ₅₀ (%) for the 30 grapevine varieties screened. Bars and errors represent means ± standard errors. Letters refer to the results of post-hoc tests. Different letters indicate significant differences among varieties. See Supplementary Table S1 for means ± SE. (b) Mean vulnerability curves (VCs), expressed as percentage loss of hydraulic conductivity (PLC, %), of grapevine variety types. n = 22, 5, and 3 for Vitis vinifera (V.v.) varieties, interspecific hybrid varieties, and Vitis rootstocks, respectively. Shaded bands represent standard deviations. (c) Mean vulnerability curves (VCs) for Vitis vinifera (V.v.) subspecies. n = 12, 7, and 3 for Vitis vinifera subsp. (proles) occidentalis, orientalis, and pontica, respectively. Shaded bands represent standard errors. All measurements were conducted in summer.