Cosgrove D J, Hedrich R
Pflanzenphysiologisches Institut der Universität, Göttingen, Federal Republic of Germany.
Planta. 1991 Dec;186(1):143-53. doi: 10.1007/BF00201510.
Mechanosensitive ion channels in the plasma membrane of Vicia faba guard cell protoplasts were studied by use of the patch clamp technique. Stretch-activated (SA) channels in outside-out patches were analyzed for channel conductance, kinetics and ion selectivity. We found three distinct SA channels, permeable to Cl-, K+ and Ca2+ and distinguishable from spontaneous (non-SA) channels for these ions on the basis of conductance, kinetics, and voltage-dependence, as well as sensitivity to membrane stretch. In the attached patch configuration, light suction (2 to 10 kPa) reversibly induced channel opening with multiple amplitudes and complex kinetics. The open probability for SA channels increased nonlinearly with pipette suction. In guard cells in situ, these SA channels may mediate ion transport across the plasma membrane directly, as well as influence the activity of non-SA channels via effects on membrane voltage and cytoplasmic calcium. Through such effects, SA channels likely influence volume and turgor regulation of guard cells, and thereby control of leaf gas exchange.
利用膜片钳技术研究了蚕豆保卫细胞原生质体质膜中的机械敏感离子通道。对向外膜片上的牵张激活（SA）通道进行了通道电导、动力学和离子选择性分析。我们发现了三种不同的SA通道，它们对Cl-、K+和Ca2+具有通透性，并且基于电导、动力学、电压依赖性以及对膜拉伸的敏感性，可与这些离子的自发（非SA）通道区分开来。在膜片钳的吸附式膜片配置中，轻微抽吸（2至10 kPa）可可逆地诱导通道开放，具有多种幅度和复杂的动力学。SA通道的开放概率随移液管抽吸呈非线性增加。在原位保卫细胞中，这些SA通道可能直接介导离子跨质膜的运输，以及通过对膜电压和细胞质钙的影响来影响非SA通道的活性。通过这些作用，SA通道可能影响保卫细胞的体积和膨压调节，从而控制叶片气体交换。
