Expression of the CBF pathway reduces the time to flowing of IT plants.

Plants were grown at 22°C or 4°C for vernalization under a 16-h photoperiod. (A, B) IT and it:cbf123; (C, D) SW and sw:cbf123. Flowering time was measured by either total leaf number including rosette and cauline leaves (A, C) or days taken for plants to bolt after transfer to 22°C (B, D). There are no data for SW plants at 22°C (i.e. no 0 weeks vernalization treatment data) because the SW and sw:cbf123 plants did not flower in the absence of a cold treatment. Error bars indicate SE (n = >9 plants). Asterisks indicate significant differences at each of the indicated time points between WT and mutant (Student t-test, P<0.01).