Figure 2. Effect of Se(IV) on endogenous total ROS (A–D), endogenous O₂ ^{• −} (E), lipid peroxidation (F), and the loss of plasma membrane integrity (G) in the roots of B. rapa.

The roots of seedlings were exposed to 0, 0.03, 0.06, 0.12, 0.23, and 0.46 mM of Se(IV) solution for 48 h. Afterwards, the roots were loaded with DCFH-DA for 15 min and immediately photographed (A). The relative DCF fluorescent density in roots was estimated (B). (C–D) The image and density of DCF fluorescence were obtained when the roots of seedlings were exposed to 0.06 mM of Se(IV) solution for 0, 1, 3, 6, 12, and 24 h, respectively. The roots of seedlings were exposed to 0, 0.03, 0.06, 0.12, 0.23, and 0.46 mM of Se(IV) solution for 48 h. Afterwards, the roots were stained with NBT (E), Schiff's reagent (F), and Evan blue (G), respectively. Asterisk indicates that mean values of three replicates are significantly different between the treatments of Se(IV) and the control group (CK) (P<0.05).