*2.5. Determination of Hydrogen Peroxide (H2O2)*

Hydrogen peroxide was determined by using the potassium iodide (KI) method. Three mL leaf extract supernatant was mixed with 0.5 mL trichloroacetic acid (TCA) (0.1%), 0.5 mL potassium phosphate buffer (100 mM), and 2 mL reagent 1 mL KI (1 M KI w/v in fresh double-distilled water). A blank probe was made using trichloroacetic acid (0.1%) in the absence of leaf extract. The reaction was developed for 1 h in darkness and absorbance measured at 390 nm. A standard curve was used to estimate the amount of hydrogen peroxide.

#### *2.6. Estimation of Ionic Content*

After harvesting, nine plants per treatment were separated into aboveground parts and roots. They were washed with de-ionized water, dried at 80 ◦C in 48 h, and stored at room temperature for further processing. The Na<sup>+</sup> and Cl<sup>−</sup> in roots and shoots were determined by using the method described by AcostaMotos et al. [21].
