Goh Chang-Hyo, Dietrich Petra, Steinmeyer Ralf, Schreiber Ulrich, Nam Hong-Gil, Hedrich Rainer
Julius-von-Sachs Institut für Biowissenschaften, Lehrstuhl für Molekulare Pflanzenphysiologie und Biophysik, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany.
Plant J. 2002 Nov;32(4):623-30. doi: 10.1046/j.1365-313x.2002.01451.x.
Stomata open in response to red and blue light. Red light-induced stomatal movement is mediated by guard cell chloroplasts and related to K+-uptake into these motor cells. We have combined a new type of microchlorophyll fluorometer with the patch-clamp technique for parallel studies of the photosynthetic electron transport and activity of plasma membrane K+ channels in single guard cell protoplast. In the whole-cell configuration and presence of ATP in the patch-pipette, the activity of the K+-uptake channels remained constant throughout the course of an experiment (up to 30 min) while photosynthetic activity declined to about 50%. In the absence of ATP inward K+ currents declined in a time-dependent manner. Under these ATP-free conditions, photosynthetic electron transport was completely blocked within 8 min. ADP together with orthophosphate was able to prevent inhibition of photosynthetic electron transport and run-down of K+-channel activity. The results demonstrate that the combination of these two techniques is suited to directly study cytosolic factors as common regulators of photosynthesis and plasma membrane transport within a single-cell.
气孔响应红光和蓝光而开放。红光诱导的气孔运动由保卫细胞叶绿体介导，并与钾离子进入这些运动细胞有关。我们将一种新型的微叶绿素荧光计与膜片钳技术相结合，用于在单个保卫细胞原生质体中并行研究光合电子传递和质膜钾离子通道的活性。在全细胞模式下且膜片吸管中存在ATP时，钾离子吸收通道的活性在整个实验过程（长达30分钟）中保持恒定，而光合活性下降至约50%。在没有ATP的情况下，内向钾离子电流呈时间依赖性下降。在这些无ATP的条件下，光合电子传递在8分钟内完全被阻断。ADP与正磷酸盐一起能够防止光合电子传递受到抑制以及钾离子通道活性的降低。结果表明，这两种技术的结合适合于直接研究作为单个细胞内光合作用和质膜转运共同调节因子的胞质因子。
