Patch-clamp study of vascular plant chloroplasts: ion channels and photocurrents

This article presents direct measurements of large-conductance cation channel (G = 730 pS in 100/50 mM KCl; PK+/PCl- = 2.8) and light-induced current (photocurrent) in chloroplasts from C4 plants, Amaranthus hybridus and Zea mays, using the conventional patch-clamp technique. It was shown that preillumination of chloroplast gave rise to a fast decaying transient (tau approximately equal to 6 ms) in the light-induced current for the second and following light pulses. This transient increase of photocurrent was interpreted as a consequence of photoreducing of the redox pool between photosystems.