Figure 4.
U-73122 blocks IP3 accumulation in salt-stressed plants. Myo-[2-3H]inositol-labeled plants were incubated in the absence (control) or presence of the PLC inhibitor (+ U-73122) and were then exposed to 0.25 m NaCl for 0 (□) or 15 (▪) min, respectively. A, The extracted and deacylated phosphoinositide head groups (organic) were separated by anion-exchange HPLC and the total number of counts in each PtdIns(4,5)P2 peak was calculated. B, The aqueous IP3-containing samples were analyzed by anion-exchange HPLC and the total number of counts in each IP3 peak was calculated. The aqueous and organic samples contained 1 × 106 and 3 × 106 cpm, respectively.