Figure 5.

SME1 Negatively Regulates the Cold Acclimation Process in Arabidopsis.

(A) and (B) Freezing tolerance of nonacclimated (A) and cold-acclimated (7 d, 4°C) (B) 2-week-old wild-type (WT), sme1-1, and sme1-2 plants exposed for 6 h to the indicated freezing temperatures. Freezing tolerance was estimated as the percentage of plants surviving each specific temperature after 7 d of recovery under control conditions.

(C) and (D) Representative nonacclimated (C) and cold-acclimated (D) plants 7 d after being exposed to −6°C and −11°C, respectively, for 6 h.

(E) Tolerance to dehydration of 2-week-old wild-type, sme1-1, and sme1-2 plants. The rates of dehydration were established as the percentages of initial fresh weights that remained after allowing rosettes to dehydrate on filter papers for the indicated times.

(F) Tolerance to salt stress of 5-day-old wild-type, sme1-1, and sme1-2 seedlings. Tolerances were calculated as the relative main root lengths of seedlings exposed for 7 d to 120 or 150 mM NaCl with respect to seedlings grown under control conditions.

In (A), (B), (E), and (F), data represent the mean of three independent experiments. Asterisks indicate significant differences (***P < 0.0001) between sme1 mutants and wild-type plants, as determined by one-way ANOVA (Dunnett’s post-hoc test). Error bars indicate the SD.