Effects of arsenic on maize growth, antioxidant system, and ion distribution

A greenhouse sand culture experiment was conducted to study the effects of arsenic (As) on the biomass accumulation, photosynthetic pigments, antioxidant system, and the absorption and distribution of As and mineral ions in maize Zhengdan 958. At lower concentrations (4 mg As x L(-1)), As inhibited the seedlings growth severely. At 2 mg As x L(-1), the chlorophyll a, b, and a+b contents reached their peaks; but with increasing As concentration, the chlorophyll contents decreased gradually. At 10 mg As x L(-1), the destruction of chloroplast structure and the dissolution of thylakoid membrane were observed by electron microscopy. With increasing As concentration, the activities of antioxidant enzymes SOD, POD, and CAT in root increased, and those in leaf reached the maximum at 8 mg As x L(-1). The sensibility of the enzymes in leaf to