Figure 8.

Effects of Short-Term Cold Stress on Photosynthetic Properties of PSII and Hydrogen Peroxide Production in Wild-Type and XVE:FBN5B Leaves.

Plants grown for 4 weeks at 22°C, with a 16/8-h light/dark photoperiod at 100 μmol m^–2 s^–1 illumination were considered to be cultivated under normal conditions. Plants were transferred to 5 to 7°C with a 16/8-h light/dark photoperiod under 60 μmol m^–2 s^–1 illumination for 5 d and then transferred to normal conditions to recover.

(A) F_v/F_m measurements after each treatment. Data are means ± sd (n = 3).

(B) Fraction of absorbed light consumed by photochemistry (Ф_PSII), ∆pH- and xanthophyll-regulated thermal dissipation (Ф_NPQ), and the sum of fluorescence and constitutive thermal dissipation (Ф_F,D). Asterisks denote significant differences between wild-type and XVE:FBN5B transgenic plants by Student’s t test: *P < 0.05 and ***P < 0.001. Data are means ± sd (n = 3).

(C) H₂O₂ detected in wild-type and XVE:FBN5B#17 leaves from normal and cold-stressed plants, determined with DAB solution staining.