Fig. 4

Analysis of H₂O₂ contents and antioxidant enzyme activity in WT and OP plants under low temperature stress. a H₂O₂ contents in leaves of WT and OP plants after 48 h low temperature stress treatment and 24 h recovery. b and c Changes in antioxidant enzyme activity in WT and OP plants after 48 h low temperature stress treatment and 24 h recovery. POD activity (b) and CAT activity (c). Data are shown as mean ± SD of three independent measurements. Asterisks indicate significant differences between WT and OP plants by ANOVA at * p < 0.05 and ** p < 0.01