Figure 4

Decay in I _K,in and I _K,out from guard cells of wild-type Arabidopsis plants without (no pretreatment) and with opening buffer pretreatment (pretreatment) Decay in I _K,in and I _K,out from guard cells of wild-type Arabidopsis plants without (no pretreatment) and with opening buffer pretreatment (pretreatment). Voltage clamp scans were carried out at intervals following impalements. Raw current traces are shown in for scans at 10, 20, and 30 min time points from two guard cells for I_K,out (A) and I_K,in (C). Scale: vertical, 500 μA cm^-2; horizontal, 2 s. Clamp scans were from a holding voltage of −100 mV with tail steps to −100 mV. Test voltage steps were to voltages between −80 and +50 mV for I_K,out and to voltages between −100 and −240 mV for I_K,in. Data in (B) summarise the two current amplitude means ± SE (filled circles, no pretreatment; open circles, pretreatment) from 12 independent experiments with I_K,out determined at +40 mV and I_K,in determined at −220 mV. Note that currents recorded from guard cells in control experiments without OB pretreatment generally decayed with halftimes of 15–20 min.