Figure 4.

Antioxidant enzymatic activity. (A) Enzymatic activity of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) during drought. The enzymatic activity was spectrophotometrically determined in the whole protein extract, and total protein was determined by the Bradford method. SOD specific activity was expressed as U/total protein, and CAT and APX specific activities were expressed as µmol H₂O₂/min/mg protein and µmol ascorbate/min/mg protein, respectively. All analyses were conducted with 3 biological and 3 technical replicates. The bars indicate 5% standard error, and asterisks indicate t test statistical significance under 95% confidence. (B) Antioxidant enzyme transcript accumulation. The transcript accumulation of the enzyme genes was quantified by qRT-PCR. Fold change (FC) was calculated by the 2^−ΔΔCt method, and the results are expressed in a CTR-normalized manner. Gene expression analysis was conducted with 3 biological and 2 technical replicates. The bars indicate 5% standard error, and asterisks indicate t test statistical significance under 95% confidence.