Lipid peroxides were extracted by grinding 0.5 g of shoot with ice-cold mortar and 5 mL of trichloroacetic acid (TCA) 5%. Homogenates were centrifuged at 12,290 × g for 10 min. The chro- mogen was formed by mixing 0.5 mL of supernatant with 1.5 mL of a reaction mixture containing 20% (w/v) TCA, 0.5% (w/v) TBA, and
by incubating the mixture at 95 ◦ C for 30 min (Minotti and Aust,
1987). After cooling at room temperature, absorbance of samples was measured at 532 nm. Lipid peroxidation was estimated as the content of TBARS and expressed as equivalents of MDA according to Halliwell and Gutteridge (1989). The calibration curve was made using MDA in the range of 0.1–100 mol. A blank for all samples was prepared by replacing the sample with extraction medium.