Department of Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7622.
Plant Physiol. 1985 Nov;79(3):843-7. doi: 10.1104/pp.79.3.843.
Net electrolyte efflux from suspension-cultured tobacco cells undergoing the hypersensitive reaction to Pseudomonas syringae pv. pisi resulted from a specific efflux of K(+) which was accompanied by an equimolar net influx of H(+). These fluxes began 60 to 90 minutes after inoculation of tobacco cells with bacteria, reached maximum rates of 6 to 9 micromoles per gram fresh weight tobacco cells per hour within 2.5 to 3 hours, and dropped below 4 micromoles per gram per hour within 5 hours. Tobacco cells lost approximately 35% of total K(+) during this period, and average cellular pH declined by approximately 0.75 pH unit. These events were accompanied by a 30% decrease in cellular ATP. K(+) and H(+) fluxes were inhibited by the protonophore (p-trifluoromethoxy)carbonyl cyanide phenylhydrazone and by increasing the K(+) concentration of the external solution. Tobacco leaf discs inoculated with the bacterium also exhibited a specific net K(+) efflux and H(+) influx. These results suggest that induction of the hypersensitive reaction in tobacco proceeds through the activation of a passive plasmalemma K(+)/H(+) exchange mechanism. It is hypothesized that activation of this exchange is a major contributing factor in hypersensitive plant cell death.
悬浮培养的烟草细胞在对丁香假单胞菌 pv. pisi 产生过敏反应时，会导致净电解质流出，这是由于 K(+)的特异性流出，同时伴有等摩尔的 H(+)净内流。这些通量在烟草细胞接种细菌后 60 至 90 分钟开始，在 2.5 至 3 小时内达到每克新鲜烟草细胞 6 至 9 微摩尔/小时的最大速率，并在 5 小时内降至 4 微摩尔/克/小时以下。在此期间，烟草细胞失去了大约 35%的总 K(+)，平均细胞 pH 值下降了约 0.75 pH 单位。这些事件伴随着细胞 ATP 减少 30%。质子载体（对三氟甲氧基）羰基氰基苯腙和增加外部溶液中的 K(+)浓度抑制了 K(+)和 H(+)通量。用细菌接种的烟草叶片圆盘也表现出特定的净 K(+)流出和 H(+)流入。这些结果表明，烟草过敏反应的诱导是通过激活被动质膜 K(+)/H(+)交换机制进行的。据推测，这种交换的激活是植物细胞死亡过敏的主要因素。
