2.3.2 Lipid Peroxidation
The levels of lipid peroxidation in S. hieraciifolia and T. parvula shoots were determined to assess the membrane damage in terms of thiobarbituric acid reactive substances (TBARS) according to the method by Heath and Packer (1968). The shoot samples (0.1 g) were homogenized 0.1% (w/v) trichloroacetic acid (TCA) and the homogenate was centrifuged at 15.000 g for 5 min. The supernatant (1 ml) was mixed with 4 ml 0.5% (w/v) thiobarbituric acid in 20 % TCA. The mixture was heated at 95 °C for 30 min and then cooled on ice bath. The absorbance of the supernatant 532 and 600 nm was read and the value of 600 nm was subtracted from 532 nm value. The amount of MDA-TBA complex was calculated from the extinction of 155 mM-1cm-1.