Figure 3.

Knocking out NtGSNOR1a/1b leads to enhanced accumulation of both NO and H₂O₂. (A) NO level in the roots of 15-day-old plants was visualized by staining using 4,5-diaminoflorescein diacetate according to He et al. (2004). (B) The fluorescence intensity shown in (A) was quantified by ImageJ. (C) H₂O₂ was detected by staining the leaves of 40-day-old plants with 3,3'-diaminobenzidine (DAB) as described in section Materials and Methods. Oxidized DAB formed a reddish-brown deposit (examples of these deposits are indicated by the white arrows). (D) The intensity of the reddish-brown deposit shown in (C) was quantified by ImageJ. ** and *** indicate significant differences at 0.01 and 0.001 levels, respectively, by the Student's t-test.