Effect of Isosteviol on Wheat Seed Germination and Seedling Growth under Cadmium Stress

Cadmium (Cd) contamination of agricultural soil has become a serious threat to global food security. The present study highlights the effect of added isosteviol in modulating growth physiology and antioxidant defense systems conferring tolerance against cadmium (Cd) stress in wheat. Wheat growth, chlorophyll content, malondialdehyde (MDA) content of leaves, dehydrogenase activity of root, and antioxidant enzyme activity were determined to get an overview of cellular response in conquering Cd-induced oxidative stress damages. The results indicated that wheat germination was inhibited under Cd(2+) concentration at 10 µM. The presence of isosteviol and gibberellic acid (GA) significantly alleviated the inhibitory effect on the growth of wheat seedling under 10 µM Cd(2+) stress. Moreover, different concentrations of isosteviol and GA regulated the physiological changes of wheat under Cd stress: more chlorophyll a + b content; less MDA content; and higher dehydrogenase activity of root and antioxidant enzyme activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), as compared to Cd alone in wheat seedling. The present study thus suggests a possible role of isosteviol in amelioration of Cd stress by increasing chlorophyll content and root dehydrogenase activity, which also could reduce oxidative damage of the cell membrane by regulating the activities of antioxidant enzymes in wheat seedling.