Figure 5.

ABA-induced H₂O₂ accumulation and the effects of pretreatment with MAPKK inhibitors and PTP inhibitors on the production of H₂O₂ in leaves of detached maize plants exposed to ABA treatment. A, Histochemical detection of H₂O₂ production with DAB staining. B, Leaves were homogenized and H₂O₂ was assayed by spectrophotometry as described in “Materials and Methods.” The detached plants were treated as follows: 1, distilled water (control); 2, 0.1% DMSO; 3, 100 μm ABA; 4, 100 μm PD98059 + 100 μm ABA; 5, 10 μm U0126 + 100 μm ABA; 6, 25 μm PAO + 100 μm ABA; and 7, 25 μm 3,4 DP + 100 μm ABA. The detached plants were pretreated with various inhibitors or DMSO for 8 h, and then exposed to ABA or distilled water treatment for 2 h. In A, experiments were repeated at least five times with similar results. In B, the values are the means ± se (n = 6) of three different experiments. Means denoted by the same letter did not significantly differ at P < 0.05 according to Duncan's multiple range test.