Single channel recording in the chloroplast envelope.

The patch-clamp technique was applied to study ion channels in the intact chloroplast envelope. Three channel types were characterized: two cation-selective, with a conductance (in 100 mM KCl) of 517 and 1016 pS, respectively, and one anion-selective with a conductance of 159 pS. All three channels showed voltage-dependent closures at both positive and negative membrane potentials.