Figure 6.

SAG13, BCB, ERD1, SAG20, and SAG21 transcript levels declined following a recovery period in O₃-free air. Fifteen-day-old Arabidopsis plants were exposed to 0.15 μL L⁻¹ O₃ for 6 h d⁻¹ or remained nontreated. The fifth and sixth leaves were harvested from six plants immediately following 6 h of exposure to O₃ or 18 h after removal of O₃. Samples were prepared as in Figure 3. The samples shown are one of two replicates. C, Control, nontreated plants; O₃, O₃-treated plants.