Abstract: The action mechanism of Cu ²⁺ to Slow Vacuolar(SV) channels of Radish(Raphanus satirus L.) was investigated by using whole-vacuolar patch-clamp recording mode. It is shown that SV channel was a cation selective channel and it had voltage- and time-dependence. Cytoplasmic Ca ²⁺ could activate SV channel and the increase in cytoplasmic Ca ²⁺ led to enhancement of SV-type currents. The changes of SV current was shown after Cu ²⁺ with different concentrations was added to the bath. When CuCl₂ with different concentrations was added to the bath solution, SV currents have different effects. It was found that CuCl₂ with a lower concentration(<0.1 mmol/L) promoted the channel currents, while CuCl₂ with a higher concentration(>0.1 mmol/L) inhibited SV currents. When 1 μmol/L CuCl₂ was added to pipette solution, SV currents were inhibited remarkably. This result provides an important basis at the channel level for researching further the effects of Cu ²⁺ on physiological activities of plants and the effects of copper fertilizers on crops.

Key words: Whole-vacuolar recording, SV-type current, Cytoplasmic Ca²⁺, Cu ²⁺, Patch-clamp