Figure 1.

Time course for Suc content changes in the guard cell symplast (●) and the guard cell apoplast (○). Broad bean plants were cultured at a constant 60% RH in a growth chamber (14-h day, 20°C/25°C, 600 μmol photons m⁻² s⁻¹). Control plants (upper; n = 16 [two experiments]) were maintained at 60% RH (Lu et al., 1995), whereas the RH-shifted plants (lower; n = 40 [five experiments]) were transferred to 90% RH 8 h before the onset of the photoperiod. Corresponding stomatal aperture sizes (n = 48–120) are represented by the histogram. Errors are se.