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.