Figure 8.

Δ¹⁸O as a function of p_i/p_a (A) and p_m/p_a (B and C). In A, no correction was made for g_i, whereas in B and C, p_m was derived by assuming a g_i of 0.0.85 or 0.044 mol m⁻² s⁻¹ bar, respectively. The lines are not fitted to the data but represent the theoretical relationship of Δ¹⁸O and p_i/p_a or p_m/p_a at full isotopic equilibrium, where a = 7.7‰ and Δ_ea = 45‰ or 51‰ using either the average δ_t or δ_s values, respectively, in Equation 24. The value of g_i = 0.085 in B was estimated from minimizing the variance between measured and theoretical Δ¹⁸O calculated with the average δ_t. The CO₂ supplied to the leaf had a Δ¹⁸O of 24‰ relative to VSMOW. Data points in each section represent the individual samples collected during light (white circles) and dark (black circles) from three replicate leaves of K. daigremontiana (for details, see Figs. 2 and 5, legends above).