Effect of selenium form and dose on camelthorn (Alhagi maurorum Medik) grown on a metal-contaminated soil

Selenium (Se) enhances the resistance of plants exposed to metal stress and can be used to lessen the impacts of toxic elements and to enhance the effectiveness of the plants used to clean up polluted sites. There is no information available about the optimum dose and form of Se to stimulate the camelthorn (Alhagi maurorum Medik) plant, which is one of the plants used in the phytostabilization of toxic elements. The impacts of selenate (Se-VI) and selenite (Se-IV) on the phytoremediation of toxic metals from loamy soils by camelthorn were investigated in a pot experiment. Se-VI and Se-IV were added to the soil at doses of 0, 5, and 10 mg Se kg^-1 soil, and each treatment was repeated five times. Se-VI and Se-IV, significantly increased plant growth and nutrient uptake. The addition of Se, either from Se-VI or Se-IV, significantly increased the superoxide dismutase (SOD) and peroxidase (POD) enzymes, and the non-enzymatic antioxidant compounds, i.e., proline and phenols, compared to the control. The addition of Se strengthened the defense against metal stress, and Se-VI outperformed Se-IV in boosting camelthorn's resistance to hazardous metal contamination. Selenium increased the accumulation of metal in the root of camelthorn and reduced root-shoot transfer. The best technique to boost camelthorn plants' capacity to clean up metal-contaminated soils is to supplement them with selenium in the form of selenate at a concentration of 10 mg Se kg^-1 soil.