TheRelati磷饥饿时番茄幼苗根系质膜H^+- ATP酶活性的变化与磷吸收的关系(英文)

The Relationship Between Phosphate Uptake and Changes in Plasmalemma H^+-ATPase Activities from the Roots of Tomato Seedlings During Phosphate Starvation

磷饥饿提高了番茄幼苗质膜H+ ATP酶活性并促进了番茄幼苗根部的H+分泌。动力学分析表明 ,磷饥饿使番茄幼苗根部质膜H+ ATP酶的Km 值明显降低 ,亦即提高了该酶对其底物的亲和力 ,但对该酶的Vmax影响不大。另外 ,磷饥饿并不改变ATP酶的最适 pH值 (最适 pH值为 6.5)。钒酸盐显著抑制番茄幼苗根部质膜ATP酶的活性以及H+分泌 ,也显著抑制番茄幼苗的Pi吸收。与对照相比 ,上述抑制作用在饥饿处理的植物中表现得更强。以上结果表明 ,磷饥饿时高亲和性Pi传递系统的诱导很可能包含质膜H+ ATP酶的参与。

Phosphate starvation increased the activity of PM H + ATPase from tomato seedlings and enhanced the extrusion of H + from the roots of the seedlings (Figs.1,2). Kinetic analysis of the PM H + ATPase from the roots of tomato seedlings showed that phosphate starvation obviously lowered the K m value, which indicated that phosphate starvation increased the affinity of the enzyme to its substrate, but had no significant effect on the V max value of the enzyme (Fig.4). In addition, phosphate starvation did not alter the optimum pH (i.e., 6.5) of the ATPase (Fig.3). Vanadate, a specific inhibitor of PM H + ATPase, strongly inhibited not only phosphate uptake (Table 3) but also PM ATPase activity from (Table 2) and H + extrusion (Table 1) by the roots of tomato seedlings. These results demonstrated that the PM H + ATPase is involved in the induction of high affinity phosphate transport systems by phosphate starvation.[WT5”HZ]