Figure 1.

Inhibition of ATP synthesis of tobacco cell cultures by SA. A, Separation and identification of ATP and ³²Pi on TLC plates. Separations were for supernatants from untreated cell cultures (lane 1) or the same supernatants that had been incubated at 30°C for 30 min in the presence (lane 2) or absence (lane 3) of 10 units of the ATP-hydrolyzing apyrase. B, Time course of inhibition of ATP synthesis by 1 mm SA. C, Concentration curve for inhibition of ATP synthesis after incubation for 10 min with 20 to 500 μm SA. The first two lanes in A and B are commercially purchased [γ-³²P]ATP and ³²Pi used as the standards.