Fig. 4. Growth and sodium tolerance in ppz1,2 strains is pH dependent. Wild-type (DBY746) and ppz1,2 (DBY746 ppz1::URA3 ppz2::TRP1) strains were grown to saturation in selective media, serially diluted in sterile water and spotted on to YPD plates buffered to the indicated pH, without (A) or with (B) 1 M NaCl. Images were taken after 2–3 days (pH 6.5 and 7) or 5 days (pH 7.5) of incubation at 28°C. Identical results were obtained in two separate experiments.