Determination of lipid peroxidation, leaf water potential
and electrolyte leakage
Malondialdehyde (MDA) was measured as an end product of
lipid peroxidation using the 2-thiobarbituric acid (TBA) test.
Leaf samples (0.5 g) were homogenised in 5 ml 0.1% (w/v)
trichloroacetic acid (TCA). The homogenates were centrifuged
at 10,000 g for 10 min, and 4 ml 20% TCA containing 0.65%
(w/v) TBA were added to 1 ml of the supernatants. The
mixtures were heated in a hot water bath at 95 °C for 25 min and immediately placed in an ice bath to stop the reaction.
They were then centrifuged at 3000 g for 10 min, and the
absorbance of the supernatants was recorded at 440, 532 and
600 nm. The MDA equivalents were calculated according to
Hodges et al. (1999).