Effect of Cerium (Ce) on the Redox States of Ascorbate and Glutathione through Ascorbate-glutathione Cycle in the Roots of Maize Seedlings under Salt Stress

This study investigated the effect of cerium (Ce) on the ascorbate-glutathione (AsA-GSH) cycle in the roots of maize seedlings under salt stress. The results showed that salt stress significantly increased the activities of ascorbate peroxidase (APX) and monodehydroascorbate reductase (MDHAR), malondialdehyde (MDA) content and electrolyte leakage (EL) in the roots of maize seedlings, compared to the control. However, salt stress significantly decreased plant height, dry weight of root and shoot, the activities of glutathione reductase (GR) and dehydroascorbate reductase (DHAR), and the ratios of AsA/DHA and GSH/GSSG in the roots of maize seedlings, compared to the control. Pretreatment with cerium nitrate (Ce(NO3)(3)) significantly increased plant height, dry weight of root and shoot, the activities of above four enzymes, and the ratios of AsA/DHA and GSH/GSSG under salt stress, compared to salt stress alone. Pretreatment with Ce(NO3)(3) significantly decreased MDA content and EL induced by salt stress, compared to salt stress alone. Meanwhile, application of Ce(NO3)(3) to the control also significantly increased plant height, dry weight of root and shoot, the activities of above four enzymes and the ratios of AsA/DHA and GSH/GSSG, and decreased MDA content and EL, compared with control. Our results suggested that Ce(NO3)(3) alleviated salt stress-induced oxidative damage by improving AsA-GSH cycle in maize roots.