Induction of cadmium-binding peptides in sorghum

Hydroponic experiments with sorghum were carried out in nutrient solution medium, under controlled environmental conditions for different periods of time. Cadmium (Cd ) was added at a final concentration of 0.1, 1 and 10 mg dm⁻³. The effect of time and cadmium concentration on the content of thiolic groups (TSH) in the "cell sap" of sorghum tissues are discussed in relation to plant resistance/tolerance to metal stress.

The increase in Cd level in the nutrient solution was associated with a higher total Cd accumulation in the plant (root and shoot), which produced a significant enhancement on the thiolic groups content. Furthermore, higher Cd concentrations in plant tissues induced not only an increase in sulphur-rich compounds but also enhanced the binding capacity of these compounds.