Fig. 5

Enhanced heat tolerance of hmhsp70 overexpression transgenic tobaccos. a The survival numbers of heat-shocked WT and transgenic tobaccos after 7 days of recovery growth at 25 °C. The transgenic and WT tobaccos grew on normal temperature (25 °C) in tissue culture bottles were shifted to high temperature (46 °C, 48 °C, 50 °C, 52 °C) for 4 h. b The typical phenotype of heat-shocked WT and transgenic tobaccos after 7 days of recovery growth at 25 °C. The shock temperature was indicated in the photos. Each value is the mean from three parallel replicates ± SD. Two-tailed t test, performed by SPSS 18.0 (Chicago, Illinois, USA), was used to calculate statistical significance. Different letters in the same group of bars indicate a significant difference (P < 0.05)