Lanthanum improves the cadmium tolerance of Zea mays seedlings by the regulation of ascorbate and glutathione metabolism

The effect of lanthanum on the metabolism of ascorbate (AsA) and glutathione (GSH) in the leaves of maize seedlings under cadmium stress was investigated. The findings showed that Cd remarkably increased electrolyte leakage (EL), the activities of ascorbate peroxidase, dehydroascorbate reductase, monodehydroascorbate reductase (MDHAR), glutathione reductase, L-galactono-1,4-lactone dehydrogenase, and γ-glutamylcysteine synthetase, and the content of reduced AsA, reduced GSH, total AsA, total GSH, malondialdehyde (MDA), and Cd, compared with control. However, Cd significantly decreased the dry biomass of roots and shoots. Treatment with La + Cd evidently increased the activities of above enzymes except MDHAR, the content of reduced AsA, reduced GSH, total AsA and total GSH, and the dry biomass of roots and shoots, compared with Cd stress alone. Meanwhile, treatment with La + Cd remarkably decreased EL and the content of Cd and MDA compared with Cd stress alone. Our results suggested that La could be used as a regulator to improve the Cd tolerance of maize for its role in the alleviation of Cd-induced oxidative damage by regulating the metabolism of AsA and GSH.