Influence of Ionizing Radiation on Antioxidant Enzymes in Three Species of Trigonella

The response of three species of Trigonella, namely, Trigonella stellata, Trigonella hamosa and Trigonella anguina to gamma irradiation stress was investigated with respect to antioxidant enzyme induction. When dry seeds were subjected to gamma rays (0, 40, 60, 80, 100 Krad) from a cobalt source ⁶⁰Co at a dose rate of 233.5 rad/ min, a dose dependent increase in the activities of ascorbate peroxidase (APOX), superoxide dismutase (SOD) and glutathione reductase (GR) was observed in both shoots and roots of the studied species. On the contrary, catalase activity was repressed, particularly at the higher applied doses. Shoots were more significantly affected by irradiation than roots. The three species differed in their radio-sensitivity with respect to the characters concerned. Changes in the activity of the key antioxidant enzymes which confer tolerance to irradiation stress were discussed.