Antioxidant activity as a response to cadmium pollution in three durum wheat genotypes differing in salt-tolerance

Durum wheat is commonly used in various food industry industries and cultivated worldwide. A serious problem with the species cultivation is its capability to accumulate cadmium (Cd) in the grains. The aim of this study is to investigate whether antioxidant activity may be used as a marker of Cd tolerance in durum wheat. The experiment involved three durum wheat genotypes/lines differing in salt tolerance. The plant response to Cd was appraised based on the activity of ascorbate-glutathione (AsA-GSH) cycle enzymes, ascorbate-to-dehydroascorbate ratio, reduced-to-oxidized glutathione ratio (GSH:GSSG), as well as Cd content in the seeds. The highest activity of dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione reductase was noted in control plants of salt-sensitive cultivar "Tamaroi." In the presence of Cd, activity of these enzymes was considerably reduced. "Tamaroi" plants demonstrated also the highest Cd content in the grain. In conclusion, we identified the cultivar "Tamaroi" as most susceptible to cadmium, and the level of durum wheat sensitivity to the element can be evaluated based on a significant decrease in the activity of AsA-GSH cycle enzymes and GSH:GSSG ratio.