Long-term expression of NF-YA2 confers tolerance to freezing and heat.

(A) Images of eight-day-old WT, P35S:NF-YA2 and PXVE:NF-YA2 seedlings grown on 0.1× MS that were transferred to 0.1× MS+ β-estradiol (7 µM) for 24 h or 7 days prior to stress. Photographs were taken after four and seven days of recovery time for freezing (−7°C/4 h, lids off) and heat (45°C/2 h, lids on) treatments, respectively. (B) Weight of 12 seedlings of each line was determined at the indicated induction times. Data represent means and SD of three replicates statistically treated using a student t-test (*P<0.05). (C) Average survival rate of each plant line subsequent to the stress assay (n>50). Data represent means and SD of three replicates statistically treated using a student t-test (*P<0.05).