Reduction of Arsenic Oxidative Toxicity By Phosphate Is Not Related To Arsenate Reductase Activity In Wheat Plants

ABSTRACT

Arsenic toxicity to plants is thought to be induced through the generation of reactive oxygen species. The response of arsenate reductase (AR) activity as well as the oxidative stress to the interaction of arsenate and phosphate in wheat seedlings was studied in this experiment. The results showed that AR activity increased by 108% with arsenate exposure under P-deficient condition and by 130% under P-sufficient condition; but AR activity showed no significant response to P treatment. Hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) concentrations increased significantly under arsenate exposure, especially in P-deficient plants, increasing by 180% for H₂O₂ and 51% for MDA. Superoxide dismutase (SOD) and peroxidase (POD) activity decreased significantly; catalase (CAT) activity decreased under P-deficient condition and increased under P-sufficient condition. Glutathione (GSH), Ascorbate (AsA) and Non-protein thiols (NPT) concentrations all increased when exposed to arsenate under P-deficient condition. Arsenate exposure induced oxidative stress in wheat and P-deprivation increased the damage of oxidative stress.

Keywords:

• arsenate
• arsenate reductase
• oxidative stress
• phosphate