Figure 7.

Na⁺ transport in isolated vacuoles of nhx knockout mutant vacuoles. Na⁺-dependent uptake was calculated from fluorescence changes in SBFI-loaded vacuoles exposed to increasing Na⁺ concentrations as described in “Materials and Methods” and Figure 4. Values are means ± sd (n = 35–70) of each of three independent experiments. Insets show double-reciprocal plots of Na⁺-dependent SBFI fluorescence, represented as the change in fluorescence ratio following the addition of NaCl. A, The wild type. B, nhx2/3/4. C, nhx1/3/4. D, nhx1/2/4. E, nhx1/2/3. F, nhx1/2/3/4.