Cadmium- induced oxidative stress and its interrelationships with physiological characteristics of safflower genotypes

Abstract Cadmium (Cd) is easily absorbed by root system in many plant species and due to its solubility in water and toxicity is considered as a major pollutant. A factorial pot experiment was conducted on two cultivated and wild safflower species، in which four cultivated genotypes (Arak-2811، Saffire، C111، and AC-Sterling) and four wild genotypes (Arak، Shiraz، Isfahan and Azari) were treated by four levels of Cd (0، 1، 5، and 10 mg CdNo3/kg soil). Based on Cd Tolerance Index، chlorophyll (Chl) concentrations and lipid peroxidation Ac-Sterling، Isfahan، and Arak-2811 were ranked tolerant and Arak، C111 and Shiraz sensitive to the Cd stress. Wild and cultivated safflowers did not appear to differ in terms of the latter attributes. The greatest activities of ascorbate peroxidase (APX) and catalase (CAT) were observed to be at the 5 mgkg-1 level of Cd. The tolerant genotypes indicated a greater increase in their APX and CAT activity، compared to the sensitive genotypes. It was concluded that the enzymatic antioxidant defence system in safflower plays a major role in its response to Cd and APX and CAT antioxidants play a more crucial role in this regard، relative to GR.