FIGURE 6.

Cold tolerance analysis of transgenic tobacco plants overexpressing PbeNAC1. (A) Plant phenotype of 30-days-old transgenic tobacco (OE3 and OE7) and WT before and after freezing treatment (0°C) for 24 h, followed by recovery growth for 10 days in an ambient environment. (B) Survival rates of PbeNAC1 overexpression lines and WT after 10 days of recovery from freezing treatment. (C) Photographs of 60-days-old WT and transgenic plants before and after freezing treatment, followed by recovery at room temperature for 10 days. (D–G) Cell death (D), Electrolyte leakage (EL) (E), chlorophyll content (F) and Proline content (G) in the transgenic lines and WT measured after freezing treatment. (H) Accumulation of O₂^- and H₂O₂ in the WT and transgenic lines (OE3 and OE7) under freezing treatment, as monitored with NBT (a,b) and DAB (c,d), respectively. Asterisks indicate that the value is significantly different from that of the WT at the same time point (^∗∗P < 0.01; ^∗∗∗P < 0.001).