Figure 4.

S-Type Anion Channel Activation by [Ca²⁺]_cyt Is Similar in Wild-Type and era1-2 Guard Cell Protoplasts.

(A) S-type anion channel currents in a wild-type guard cell protoplast with [Ca²⁺]_cyt buffered to 2 μM.

(B) S-type anion channel currents in an era1-2 guard cell protoplast with [Ca²⁺]_cyt buffered to 2 μM.

(C) Current-voltage relationships for S-type anion currents recorded from wild-type (closed symbols; n = 8) or era1-2 (open symbols; n = 8) guard cell protoplasts with [Ca²⁺]_cyt buffered at 2 μM as in (A) and (B).

(D) Current-voltage relationships for S-type anion currents recorded from wild-type (closed symbols; n = 8) or era1-2 (open symbols; n = 7) guard cell protoplasts with [Ca²⁺]_cyt buffered to 500 nM.

In all experiments, protoplasts were preincubated in 40 mM [Ca²⁺]_ext and then perfused with 1 mM [Ca²⁺]_ext before patch clamping (see Results and Figure 2). mCol, Columbia.