Figure 3.

Effect of low nutrient-solution pH during plant cultivation on the kinetic characteristics of corn root plasmalemma ATPase. Plasmalemma was isolated from 3-week-old corn roots grown at pH_e 6.0 (○) and 3.5 (•). Activity of plasmalemma ATPase was determined in an assay solution of pH 6.5, consisting of 100 mm KNO₃, 1 mm NaN₃, and 1 mm Na₂MoO₄. The concentration of Mg-ATP in the assay solution was kept constant in the range of 20 to 4000 μm. The inset represents a double-reciprocal plot of the effect of ATP concentration on ATPase activity. A representative example of four replications is presented.