Figure 2.

Effects of H₂O₂ on the thermotolerance of WT and cngc6 seedlings. (A) About 8-day-old WT and cngc6 seedlings grown at 22°C were pre-treated with 2 ml of 0, 25, 50, 100, or 200 mM H₂O₂ for 8 h and then exposed to 45°C (HS) for 30 min. The H₂O₂ levels were then assessed by fluorescence microscopy in roots stained with CM-H2DCFDA. Bar = 100 mm. (B) Relative DCF fluorescence densities in the roots. The data presented are means ± SE of measurements taken from at least 10 roots for each treatment. ^*p < 0.05 and ^**p < 0.01 vs. 0 mM H₂O₂ (Student’s t-test). (C) Seedlings were exposed to 45°C for 100 min, then returned to 22°C and photographed 5 days later. (D) Survival ratios of the seedlings after HS treatment. The data presented are means ± SE of at least five independent experiments with 50 seedlings per experiment. ^*p < 0.05 vs. 0 mM H₂O₂ (Student’s t-test).