Fig. 7.

Cytosolic oxaloacetate (OAA) at 1 mM activates S-type anion channel currents in wild-type (WT) Arabidopsis thaliana guard cells, whereas 0.1 mM OAA does not show activation. (a) Typical whole-cell recordings of S-type anion channel currents in guard cell protoplasts of wild type (WT) plants without OAA or with 0.1mM or 1 mM OAA added to the pipette solution. The pipette solutions contained 2 μM free Ca²⁺. (b) Steady state current-voltage relationships recorded as in (a). The number of guard cell is n = 6–9 for each condition. Data are mean ± SE. Note that Fig. 3 shares the same WT I–V curves, as data were obtained in the same experimental data sets (P < 0.01 for WT vs WT+1 mM OAA; P < 0.01 for WT+0.1 mM OAA vs WT+1 mM OAA at −145 mV).