Table I. Fittings for IK,in and IK,out from Arabidopsis guard cells to a Boltzmann function (see Eq. 1)

Fitted curves for wild-type and slac1-1 currents are as shown (for details, see Figs. 1 and 6). Best fittings were obtained with the voltage sensitivity coefficient (gating charge; δ), held in common in both cases, and with the voltage yielding half-maximal conductance (V1/2), held in common for IK,out, as indicated. Note the roughly 80% reduction in maximum conductance (gmax) for IK,in and its 60% enhancement for IK,out in the slac1-1 mutant.

ParameterWild Typeslac1-1pSLAC1
IK,in (δ, −1.9 ± 0.1)
gmax (μS cm−2)4.83 ± 0.080.99 ± 0.075.20 ± 0.09
V1/2 (mV)−187 ± 3−202 ± 2−189 ± 2
IK,out (δ, 2.0 ± 0.1; V1/2 −7 ± 2 mV)
gmax (μS cm−2)1.65 ± 0.072.83 ± 0.091.84 ± 0.08