Wissenschaftsbereich Biophysik, Sektion Biologie, Friedrich-Schiller-Universität Jena, Philosophenweg 14a, DDR-6900, Jena, German Democratic Republic.
Planta. 1988 Mar;173(3):391-6. doi: 10.1007/BF00401026.
The fungal phytotoxin tentoxin and its natural derivative dihydrotentoxin impair light-induced stomatal opening in epidermal strips of broad bean (Vicia faba L.) incubated in a potassium-rich medium. Swelling of guard-cell protoplasts (GCPs) of the same species is inhibited in the presence of both substances. Swollen GCPs shrink after tentoxin or dihydrotentoxin treatment and these effects cannot be fully compensated by the phytoeffector fusicoccin. A comparison with the potassium carrier valinomycin shows that tentoxin acts in a different manner, because it is effective in the light only, whereas valinomycin causes shrinkage of GCPs also in the dark. Determination of adenine nucleotides in GCPs indicates a reduced ATP content and an enhanced ADP level after addition of tentoxin. At the same time, tentoxintreated GCPs contain more NADPH and less NAD(+) than the control (NADP(+) and NADH content does not differ). The results presented are consistent with the hypothesis that tentoxin closes stomata as a consequence of its inhibitory action on photophosphorylation.
真菌毒素 tentoxin 及其天然衍生物二氢 tentoxin 可抑制在富含钾的介质中孵育的蚕豆（Vicia faba L.）表皮条带的光诱导气孔开放。在这两种物质存在的情况下，同种的保卫细胞原生质体（GCP）的膨胀被抑制。在 tentoxin 或二氢 tentoxin 处理后，膨胀的 GCP 收缩，这些效应不能被植物效应物 fusicoccin 完全补偿。与钾载体缬氨霉素的比较表明，tentoxin 以不同的方式起作用，因为它仅在光下有效，而 valinomycin 即使在黑暗中也会导致 GCP 收缩。在 GCP 中测定腺嘌呤核苷酸表明，添加 tentoxin 后 ATP 含量降低，ADP 水平升高。同时，与对照相比，tentoxin 处理的 GCP 含有更多的 NADPH 和更少的 NAD（+）（NADP（+）和 NADH 含量没有差异）。所提出的结果与 tentoxin 通过抑制光合作用磷酸化而关闭气孔的假设一致。
