Protection of PSII from damage caused by drastic oxidative stress conditions.

<p>(<b>A</b>) The 35S:A9 seedlings survive drastic oxidative stress conditions. Representative results for the T₂/NT₂ line pair are shown. Differences in green color were evident between seedlings grown in control conditions (C). Most 35S:A9 seedlings (T₂) survived treatments for 24 h with 200 mM H₂O₂ (H₂O₂) that caused complete death of sibling NT₂ seedlings. The 3x-magnified inset shows bleaching of the cotyledons in the surviving T₂ seedlings. Scale bar, 1 cm. (<b>B</b>) Comparison of maximum quantum yield (F_v/F_m) of PSII between 35S:A9 (T) and NT seedlings after control (C) and H₂O₂ treatments (H₂O₂). Average values for nine independent experiments performed with three different T/NT line pairs. Statistical difference between the F_v/F_m values (F = 265.58, P = 0.0001) and rest of symbols indicated as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051443#pone-0051443-g002" target="_blank">Figure 2A</a>. (<b>C</b>) PSII membrane protein complexes of 35S:A9 seedlings partially resisted the H₂O₂ treatments. Thylakoids from control (C) and H₂O₂ treated seedlings (H₂O₂) were analyzed essentially as indicated in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051443#pone-0051443-g002" target="_blank">Figure 2B</a>. The H₂O₂ samples were prepared immediately after the treatment and the gel was photographed after BN-PAGE without further staining. Symbols for PSII complexes as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051443#pone-0051443-g002" target="_blank">Figure 2B</a>.