Figure 5.

DHAR-OX plants maintain a higher apoplastic level of Asc following exposure to an acute episode of ozone. A, The levels of Asc and DHA were measured from the apoplastic fluid of the first fully expanded leaf of control (C), DHAR-OX (OX), and DHAR-KD (KD) tobacco collected prior to, immediately after, and 24 h following a 2-h exposure to 200 ppb ozone. The Asc redox state determined by [Asc]/[DHA] is also shown. B, The level of H₂O₂ was measured from the apoplastic fluid of the first fully expanded leaf collected prior to, immediately after, and 24 h following the ozone treatment.