Centre for Plant Biotechnology, Toronto, Ontario M5S 3B2, Canada.
Plant Physiol. 1992 Nov;100(3):1137-41. doi: 10.1104/pp.100.3.1137.
Patch-clamp techniques were employed to study the electrical properties of vacuoles from sugar beet (Beta vulgaris) cell suspensions at physiological concentrations of cytoplasmic Ca(2+). Vacuoles exposed to K(+) malate revealed the activation of instantaneous and time-dependent outward currents by positive membrane potentials. Negative potentials induced only instantaneous inward currents. The time-dependent outward currents were 10 times more selective for malate than for K(+) and were completely blocked by zinc. Vacuoles exposed to KCl developed instantaneous currents when polarized to positive or negative membrane potentials. The time-dependent outward channels could serve as the route for the movement of malate into the vacuole, whereas K(+) could move through the time-independent inward and outward channels.
采用膜片钳技术研究了在细胞质钙离子生理浓度下糖甜菜(Beta vulgaris)细胞悬浮液液泡的电学性质。液泡暴露在 K(+) 苹果酸中,在正膜电位下激活瞬间和时变外向电流。负电位仅诱导瞬间内向电流。时变外向电流对苹果酸的选择性比 K(+) 高 10 倍,完全被锌阻断。当液泡极化到正或负膜电位时,暴露在 KCl 中的液泡会产生瞬间电流。时变外向通道可作为苹果酸进入液泡的途径,而 K(+) 可通过非时变内向和外向通道移动。