Fig. 6
From: Stomatal conductance limited the CO2 response of grassland in the last century
Sensitivity of stomatal conductance (gs) to δ18Ocellulose. Relationship between the long-term change in δ18Ocellulose and the long-term change in stand-scale, growing season-integrated stomatal conductance, estimated as the ratio of C-yield of hay to the CO2 concentration gradient between the atmosphere and the leaf internal gas space (the “Methods” section) of individual treatments (a), and relationship between relative stomatal conductance change (in % gs change) and δ18O-increase (in permil) at the Park Grass Experiment for dicot-rich (n = 6) or grass-rich (n = 6) treatments (mean ± SE) compared to reports of δ18Ocellulose change versus leaf- or canopy-scale stomatal conductance change over a range of plant species or genotypes in different environmental conditions (see Additional file 1: Table S2 for details on reported studies) (b). The dashed line and the shaded area in a represent the regression line ± CI95%, while the continuous black line and the shaded area in b represent the mean sensitivity ± CI95% calculated from the reported studies