For estimation of lipid peroxidation, 0.2 g leaf sample was
homogenized in 10 ml 0.1% (w/v) trichloroacetic acid followed by
centrifugation. Supernatant was vertexed with 4 ml (v/w) 20% TCA
and 0.5% (w/v) 2-thiobarbituric acid (TBA), and then heated for
30 min at 95 C. Absorbance was measured at 600 and 532 nm and
lipid peroxidation was determined as malanoaldehyde (MDA)
content following the protocol of Heath and Packer (1968