sHSP22 can promote hypocotyl elongation at high temperature. A, Hypocotyl elongation of 6-d-old No-0 wild type and shsp22 mutant grown at 22°C and 29°C. Plants were grown at 22°C for 2 d before being transferred to 29°C for 4 d. Bar = 0.5 cm. B, Quantitative analysis of hypocotyl length in seedlings shown in A. Values are means ± sd (n = 40), **P < 0.01. C, Hypocotyl elongation of 6-d-old sHSP22 transgenic and vector control plants grown at 22°C and 29°C. Plants were grown at 22°C for 2 d before being transferred to 29°C for 4 d. Bar = 0.5 cm. D, Quantitative analysis of hypocotyl length of 6-d-old sHSP22 transgenic and vector control plants grown in half-strength MS medium supplemented with 0 and 1.0 μm NPA at 22°C and 29°C, respectively. The values are means ± sd (n = 40), **P < 0.01. E, Hypocotyl elongation of 6-d-old sHSP22 OX, vector control, abi1-3, and abi1-3/sHSP22 plants grown at 22°C and 29°C. Plants were grown at 22°C for 2 d before being transferred to 29°C for 4 d. Bar = 0.2 cm. F, Quantitative analysis of hypocotyl length in seedlings shown in E. Values are means ± sd (n = 40), **P < 0.01.