Fig. 8. O2 evolution at 1 % CO2 in peeled leaf discs sampled before or after dehydration of the tissue. Circles, Leaf discs obtained and peeled after the plants had developed various Ψw. Triangles, leaf discs obtained from plants with a high Ψw and peeled before subjecting the discs to various Ψw in the O2 electrode. Ψw was measured in the same discs immediately after each O2 evolution measurement. Individual data were pooled from three repeated experiments, and the discs were sampled from two adjacent leaves from each plant. Conditions during dehydration in the electrode were as described in Fig. 7 and during measurements in the electrode were as described in Fig. 5.