Figure 6From: Genome-wide analysis of the Populus Hsp90 gene family reveals differential expression patterns, localization, and heat stress responsesExpression analysis of PtHsp90 genes under heat stress. A. Conditions of heat stress. Seedlings were heated to 37°C for 3 h (pretreatment), returned to 23°C for 2 h, heated to 45°C for 3 h (treatment), and then allowed to recover 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. B-E. The corresponding relative densities of the RT-PCR signals generated from data in Additional file 12B, showing four different types of heat stress responses. Type I is induced by both pretreatment at 37°C and treatment at 45°C (B); Type II is induced by pretreatment at 37°C but is not affected by treatment at 45°C (C); Type III is not affected by pretreatment at 37°C but is negatively regulated by treatment at 45°C (D); and type IV is not affected by either pretreatment at 37°C or treatment at 45°C (E).Back to article page