水杨酸对蚕豆保卫细胞气孔运动及质膜内向K^+电流的影响

Effect of salicylic acid on stomatal movement and K^+ current on plasma membrane of guard cell in Vicia faba L.

【目的】研究逆境信号水杨酸(SA)刺激条件下,蚕豆气孔保卫细胞中H2O2的产生及其对气孔运动的影响。【方法】以蚕豆为材料,利用表皮条生物分析、膜片钳等方法研究SA诱导蚕豆气孔关闭过程中质膜内向K+电流的变化。【结果】SA可以浓度依赖的方式诱导蚕豆叶片的气孔关闭。质膜NADPH氧化酶抑制剂二亚苯基碘(DPI)可削弱SA作用的45%~60%。借助膜片钳手段记录SA处理条件下全细胞内向K+电流的变化,胞外0.1mmol/L SA处理后20 min可抑制内向K+电流的70%左右。电极液中10μmol/L DPI作用20 min可逆转SA抑制全细胞内向K+电流的46%左右。【结论】SA诱导的气孔关闭可能与H2O2的产生有关,DPI逆转SA对保卫细胞内向K+电流的抑制作用暗示,H2O2可能通过抑制质膜内向K+电流而介导SA诱导的气孔关闭过程。

[Objectivel The effect of salicylic acid on stomatal movement and K^＋ channel on plasma membrane of guard cell in Vicia faba L. was studied. [Method] Vicia faba L. as the material, epidermal strips bioassay and patch clamp were used to study Changes of Kt carrent on plasma meribrane in Vicia guard cells. [Result] Salicylic acid （SA） can induce stomatal closure with a concentration-dependent manner. DPI 10 μmol/L weakened the effect of SA on stomatal apertures by 45%--60% ,which indicated that the generation of H2O2 might be involved in the stomatal closure induced by SA. The voltage-dependent K^＋-selective channels in the plasma membrane were recorded by whole-cell configureuration by patch clamp. The whole-cell inward K^＋ currents were inhibited by 70% after 20 min treatment by SA 100 μmol/L. But intracellular application of DPI partly abolished SA-inhibited inward K^＋ current by 46 % after 20 rain treatment by SA. [Conclusion] This indicated that H2O2 mediated SA-induced stomatal closuring by targeting inward K^＋ channels on plasma membrane.