Saltbuch extract: a bio-solutionfor cadmium stress sorghum plants in germination and maturation.

Cadmium (Cd) is one of the dangerous factors that have negative impacts on plants and human health. Recently, many researchers have been looking for biostimulants to use as bioprotectants that can help or ameliorate plants' tolerance against abiotic stress, including Cd. To test the dangerousness of Cd accumulated in the soil, 200 µM of the latter was applied to sorghum seeds at germination and maturation stages. At the same time, Atriplex halimus water extract (0.1%, 0.25%, 0.5%) was applied to test its efficacy on Cd alleviation in sorghum plants. The obtained results showed that the tested concentrations enhanced the tolerance of sorghum to Cd by enhancing the germination indexes parameters such as germination percentage (GP), seedling vigor index (SVI), and reducing the mean germination time (MGT) of sorghum seeds grown under cadmium stress. On the other hand, the morphological parameters (height and weight) as well as the physiological parameters (chlorophyll and carotenoid) were stimulated in treated maturated sorghum plants under Cd stress. In addition, 0.5% and 0.25% of Atriplex halimus extract (AHE) stimulated the antioxidant enzymes, including superoxide dismutase, catalase, glutathione peroxidase, glutathione-s-transferase, and glutathione reductase. In the same time, an increase in carbon-nitrogen enzymes was recorded in the case of AHE treatment; phosphoenol pyruvate carboxylase, glutamine synthase, glutamate dehydrogenase, and amino acid transferase were all upregulated. These results suggest that using AHE as a biostimulant could be a better strategy to enhance the tolerance of sorghum plants to Cd stress.