Figure 4. H₂O₂-induced [Ca²⁺]_i increases inhibits H₂O₂-activated channels more than NaCl-activated channels.

(A and C) Arabidopsis seedlings were subjected to a 4 mM H₂O₂ treatment once at 0 sec, and the solution was perfused by deionized water at 200 sec. Then, a second 4 mM H₂O₂ (A), or 200 mM NaCl (C) treatment was applied around 300 sec. Aequorin luminescence was recorded continuously through the treatments in the dark.

(B and D) Quantification of [Ca²⁺]_i increases for the 2^nd H₂O₂ (B) or 2^nd NaCl treatment (C) from experiments as in (A) to (C), respectively. Data for four independent experiments are shown (mean ± sd; n = 64; NS, not significant P > 0.05; *** P < 0.001).