Fig. 6

The thermotolerance phenotypes, survival rate and the chlorophyll contents of TaHsfA2–10 transgenic Arabidopsis seedlings and wild type (WT) under the normal conditions and subjected to HS. aTaHsfA2–10 relative expression in WT and three transgenic lines of T3 generation by semi-RT-PCR. There were total 50 individual plants of each line of each plate, and the experiment was repeated three times. Single and double asterisks indicate the significant differences between WT and overexpressing lines at P < 0.05 and P < 0.01 level (t-test), respectively. B-E: WT controls and three lines of TaHsfA2–10 overexpressed Arabidopsis (line 2_22, line 10_5 and line 11_26) were used to analyse the basal (BT) and acquired thermotolerances (AT). Five-day-old seedlings (grown in the greenhouse with temperature of 22 °C/18 °C, 16 h light/8 h dark cycles and light of 100 mmol photons m^− 2 s^− 1) were treated with different HS regimes listed under each phenotype picture, and the seedlings were recovered at 22 °C for 8 days, then the phenotypes were observed and photographed. b-c: assays for BT, d-e: assays for the AT. b, d: seedlings under the normal conditions; c, e: seedlings treated with different HS regimes. After above, the survival rates (g) were measured and the rosettes of each line were collected for measurement of chlorophyll contents (f). Total 50 individual plants of each line were divided into three parts and used for chlorophyll contents measurement; three plates were performed for each heat treatment. Each bar value represents mean ± SD of triplicate experiments; raw data refer to Additional file 2 and Additional file 3. Single and double asterisks indicate the significant differences between WT and overexpressing lines at P < 0.05 and P < 0.01 level (t-test), respectively