Fig. 9.

A comparison of IRGA measurements of WUE_i and calculated values of IWUE_i from images captured using the combined imaging system. WUE_i was measured from leaves (circles) of A. thaliana during a step-wise change in light at a CO₂ concentration of 400 µmol mol^–1 (see Fig. 8); data are means with standard errors (n=5–8). Measurements were taken from individual leaves (squares) at CO₂ concentrations between 100 µmol mol^–1 and 2000 µmol mol^–1. Air temperature and VPD were 25 °C and 1.2 kPa, respectively. The solid line represents a 1:1 relationship.