Figure 8

qRT-PCR analysis of selected Populus Hsfs and Hsps under heat stress. The relative mRNA abundance of selected seven Hsfs, four sHsps, three Hsp60s, three Hsp70s, and three Hsp100s during heat stress were quantified. Seedlings were heated to 37°C for 3 h (pretreatment), return to 23°C for 2 h, heated to 45°C for 3 h (treatment), and then allowed to 23°C for 2 h. 1, control; 2, 30 min after pretreatment at 37°C; 3, 2 h after pretreatment at 37°C; 4, 1 h after recovery at 23°C; 5, 30 min after treatment at 45°C; 6, 2 h after treatment at 45°C; 7, 2 h after recovery at 23°C. Relative expression represents log2 expression values. Bars with the same letter are not significantly different according to Duncan’s test and Fisher’s protected LSD test (P < 0.05).