采用膜片钳技术对烟草根皮层原生质体质膜上的钾通道进行全细胞记录,从而深入研究烟草K+的吸收机制和调控机理。结果表明,内向钾通道在膜电压低于-40 mV时,可以被K+激活。内向电流可以被钾通道的专一抑制剂TEA+抑制。动力学分析表明内向钾电流产生的K+表观解离常数(Km)≈15.2 mm o l/L,类似于低亲和性钾通道。该通道具有依赖于胞外K+浓度的特性,对胞外NH4+、C a2+、M g2+浓度变化反应敏感,内向K+电流可被不同程度地抑制。 Patch clamp technique was used to record the potassium channels in the plasma membrane of protoplast plasma of tobacco to further study the absorption mechanism and regulation mechanism of K + in tobacco. The results show that inward potassium channels can be activated by K + when the membrane voltage is below -40 mV. Inward current can be inhibited by potassium channel specific inhibitor TEA +. Kinetic analysis showed that K + apparent dissociation constant (Km) ≈15.2 mm o l / L produced by inward potassium current, similar to low affinity potassium channels. The channel is dependent on the extracellular K + concentration characteristics of the extracellular NH4 +, C a2 +, M g2 + concentration sensitive to changes in the inward K + current can be suppressed to varying degrees.