Figure 4.

The effect of short-term exposure of the source leaves to CO₂ enrichment on net photosynthesis and concurrent export rates expressed as absolute values (A) and as a percentage of photosynthesis (B). The species tested and assay conditions were those outlined in Figure 3, except that the source leaf was exposed to high CO₂ concentrations (inlet air of 90 Pa CO₂). Each point is an average of at least four leaves on four different plants. The se of the means are not shown for graphical clarity.