Botanical Laboratory, State University of Utrecht, Lange Nieuwstraat 106, 2501, Utrecht, The Netherlands.
Planta. 1979 Jan;145(1):77-82. doi: 10.1007/BF00379930.
Internode disks of tomato (Lycopersicon esculentum cv. Moneymaker) were shaken in glutamine and sucrose solutions. At low external pH (<±5.5), the uptake of these substances was accompanied with K(+) efflux, at high pH (>±5.5) with K(+) influx. Low concentrations of external K(+) (2 mmol l(-1)) stimulated the uptake of glutamine, which was strongly inhibited by the supply of high K(+) concentrations (20 mmol l(-1)). The effect of K(+) was particularly pronounced at high pH-values. Addition of CCCP in light reduced the uptake of glutamine to the same level as in the dark, and stopped the K(+) fluxes which coincided with the uptake. A model is presented wherein the movements of K(+) across the membrane are related to co-transport, depending on the membrane potential and the Nernst potential of K(+).
番茄（Lycopersicon esculentum cv. Moneymaker）的节间盘在谷氨酰胺和蔗糖溶液中被摇动。在外部 pH 值较低（<±5.5）时，这些物质的吸收伴随着 K(+)外流，在外部 pH 值较高（>±5.5）时伴随着 K(+)内流。低浓度的外部 K(+)（2 mmol l(-1)) 刺激了谷氨酰胺的吸收，而高浓度 K(+)（20 mmol l(-1)) 的供应则强烈抑制了谷氨酰胺的吸收。K(+) 的影响在高 pH 值下尤为明显。在光下添加 CCCP 将谷氨酰胺的吸收减少到与黑暗中相同的水平，并停止与吸收同时发生的 K(+)通量。提出了一种模型，其中跨膜的 K(+)运动与协同运输有关，这取决于膜电位和 K(+)的能斯特电位。
