Figure 10.

Transects of intercellular CO₂ concentration, C_i, across a 4-mm-diameter patch (limits indicated by dotted vertical lines) calculated from the diffusion model. A and B show results for different reduction factor values, φ, for the CO₂ diffusion coefficient D_c at fixed C_a (360 μmol mol⁻¹) and either high (A) or low (B) net CO₂ assimilation capacities (as indicated by the rate outside the patch of 23.5 and 12.1 μmol m⁻² s⁻¹, respectively). Numbers indicate φ in percentages. Model parameters were as follows: A, g_s^c = 200 mmol m⁻² s⁻¹, leaf thickness = 400 μm, a = 45 μmol m⁻² s⁻¹, b = 160 μmol mol⁻¹, c = 3.0 μmol m⁻² s⁻¹; and B, g_s^c = 140 mmol m⁻² s⁻¹, a = 20 μmol m⁻² s⁻¹, b = 90 μmol mol⁻¹, c = 3.0 μmol m⁻² s⁻¹ (see “Materials and Methods”). C shows C_i values for different C_a, using parameters from the high A case in A, with φ = 15%; C_a values are indicated.