用膜片钳研究CuCl_2对萝卜液泡膜SV通道的影响

Effects of CuCl_2 on Slow Vacuolar Ion Channels in Radish by Patch-clamp

用膜片钳全液泡记录方式研究了 Cu Cl2 对萝卜 SV通道的影响 .研究表明 ,SV通道为阳离子选择性通道 ,细胞质钙可激活此通道 ,且其表现出钙依赖性 .细胞质钙达 2 mmol/ L时 ,SV通道电流基本上达到饱和 .当在外液中加入不同浓度的 Cu Cl2 时 ,SV通道电流有明显的变化 .高浓度的铜离子对通道电流有抑制作用 ,而低浓度 (<0 .1 mmol/ L)则增强通道电流 .电极内液中的 Cu Cl2 对 SV通道电流也有抑制作用 .

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 CuCl_2 with different concentrations was added to the bath solution, SV currents have different effects. It was found that CuCl_2 with a lower concentration(<0.1 mmol/L) promoted the channel currents, while CuCl_2 with a higher concentration(>0.1 mmol/L) inhibited SV currents. When 1 μmol/L CuCl_2 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.