Fig. 3.

Testing hypothesized rationales for the stomatal safety-efficiency trade-off. Relationships of maximum stomatal conductance (g_max) and the leaf water potential at 50% stomatal closure (Ψ_gs50) with (a) and (b) stomatal size (s; n = 12 species for which data were available); (c) and (d) osmotic potential at full turgor (π_o; n = 13 species for which data were available); and (e) and (f) leaf mass per area (LMA; n = 15 species). Lines are standard major axes for untransformed or log-transformed data, i.e., for linear or power-law fits, depending on which showed a stronger fit. Phylogenetic least squares regression r values for panels (a)–(f), respectively, were −0.56, 0.61, −0.82, 0.73, −0.61, and 0.56 (P = 0.0009–0.04). The g_max and Ψ_gs50 values were derived from fitted curves (Supplementary Fig. 1). Source data are provided as a Source Data file