Figure 4. H₂O₂ accumulation in leaf discs of wild-type and ZmSO over-expressing plants in response to sulfite exposure.

(A) H₂O₂ production in leaf discs of wild-type and OE plants treated with 5 mM Na₂SO₃ was visualized by staining with 3, 3′-diaminobenzidine (DAB). The leaf discs were treated for 16 h, and were subsequently stained with DAB as described in the experimental procedures. (B) Relative total H₂O₂ production was quantified in leaf discs from two independent experiments. Error bars indicate SE (n = 10). The lower case letters (a, b, c, d) indicate P<0.05 for the differences within treatment between ecotypes.