*2.10. Estimation of Oxidant and Antioxidant Enzyme Activities*

The plant tissue samples were collected in three replicates, wrapped in aluminum foil, and kept at −80 ◦C until the biochemical analyses. Two oxidant (hydrogen peroxide, H2O2 and malondialdehyde, MDA) and two antioxidant (catalase, CAT, and peroxidase, POD) enzyme activities were evaluated. According to the manufacturer's protocols, the extraction and spectrometric analysis of H2O2 and the antioxidant enzymes were achieved using their respective assay kits supplied by Beijing Solarbio Science and Technology, China [46]. As for the malondialdehyde (MDA), which is a byproduct of liquid metabolism, its cellular concentration was measured following the method described previously [49]. The physiological parameters that were measured are very significant for water stress tolerance in plants, and they have been used extensively in evaluating various field crops [50].
