Central Research and Development Department, Experimental Station, E. I. du Pont de Nemours and Company, Wilmington, Delaware 19898.
Plant Physiol. 1979 May;63(5):952-5. doi: 10.1104/pp.63.5.952.
Evidence is presented that K(+) uptake in corn root segments is coupled to an electrogenic H(+)/K(+) -exchanging plasmalemma ATPase while phosphate uptake is coupled to an OH(-)/Pi antiporter. The plasmalemma ATPase inhibitor, diethylstilbestrol, or the stimulator, fusicoccin, altered K(+) uptake directly and phosphate uptake indirectly. On the other hand, mersalyl, an OH(-)/Pi antiporter inhibitor, inhibited phosphate uptake instantly but only slightly affected K(+) uptake. Collapse of the proton gradient across the membrane by (p-trifluoromethoxy) carbonyl cyanide phenylhydrazone resulted in immediate inhibition of K(+) uptake but only later inhibited phosphate uptake. Changing the pH of the absorption solution had opposite effects on K(+) and phosphate uptake. In addition, a 4-hour washing of corn root tissue induced a 5-fold increase in the rate of K(+) uptake with little or no lag, but only a 2- to 3-fold increase in phosphate uptake with a 30- to 45-minute lag. Collectively these differences strongly support the coupling of an electrogenic H(+)/K(+) -exchanging ATPase to an OH(-)/Pi antiporter in corn root tissue.
有证据表明，玉米根段中的 K(+)摄取与电致性 H(+)/K(+)交换质膜 ATP 酶偶联，而磷酸盐摄取与 OH(-)/Pi 反向转运体偶联。质膜 ATP 酶抑制剂己烯雌酚或刺激剂腐霉利直接改变 K(+)摄取，间接改变磷酸盐摄取。另一方面，OH(-)/Pi 反向转运体抑制剂 mersalyl 立即抑制磷酸盐摄取，但仅轻微影响 K(+)摄取。质子梯度通过膜崩溃(p-trifluoromethoxy)羰基氰基苯腙导致 K(+)摄取立即抑制，但随后仅抑制磷酸盐摄取。改变吸收溶液的 pH 值对 K(+)和磷酸盐摄取有相反的影响。此外，玉米根组织 4 小时的洗涤导致 K(+)摄取速率增加 5 倍，几乎没有或没有滞后，但磷酸盐摄取仅增加 2 到 3 倍，滞后 30 到 45 分钟。这些差异强烈支持玉米根组织中电致性 H(+)/K(+)交换 ATP 酶与 OH(-)/Pi 反向转运体的偶联。
