Figure 3.

Freeze-induced damage to chloroplasts in F₃ lines of nonacclimated A. thaliana plants that either did (diagonal bars) or did not (solid bars) constitutively express COR15a. Leaves from nonacclimated plants were frozen to either −5°C or −6°C, thawed, and damage to chloroplasts was assessed by determining F_v/F_m. The percentage decrease in F_v/F_m was determined by dividing the mean F_v/F_m values for the frozen leaves (values presented in Table 1) by the mean F_v/F_m values for nonfrozen leaves (and multiplying by 100). The values for the nonfrozen leaf samples for COR15am positive and negative lines (six lines for each; three leaves for each line) were 0.808 ± 0.005 and 0.804 ± 0.004, respectively.