Effect of pH on the Activity of Some Respiratory Inhibitors.

Inhibition of respiration of cultured cells of Petunia hybrida by NaF, NaN(3), malonic acid, and salicylhydroxamic acid increased at low pH. This increase could be partially reversed by raising the pH of the medium. Uptake experiments show that the greater inhibition of malonic acid at low pH was not the result of greater uptake. The results suggest that the increase in inhibition at low pH could not be attributed to greater cell penetration.