Figure 11.

Effects of salinity and leaf age on the SV channel activity in quinoa mesophyll vacuoles. A, Typical whole-vacuole records of time- and voltage-dependent SV currents in vacuoles of young and old leaves from quinoa plants grown under control conditions (50 mm NaCl) and of old leaves from plants grown under saline conditions (400 mm NaCl). For symmetric 100 mm KCl, 1 mm free Ca²⁺ was added to the cytosolic side to activate SV and inhibit FV currents. B and C, Mean numbers of open SV channels in quinoa tonoplast as a function of membrane voltage. Solid lines are the best fits to the Boltzmann equation. D, Same data as in B and C, but only the points within the physiological tonoplast potential range (±20 mV) are considered. Data with different lowercase letters are significantly different at P < 0.05. O, Old leaves; Y, young leaves. Values are means ± se (n = 4–6 vacuoles).