Influence of phosphate and sulphate on the yield and arsenic accumulation of swamp-cabbage

Swamp-cabbage were planted in Hoagland^s solutions containing defferent concentrations of arsenate, sulphate and phosphate, and the effects of phosphate and sulpate on their yields and arsenic accumulation at defferent arsenate levels were evaluated. Significant and without significant adverse effects were found at 0.2-5mg·1~(-1) As on swampcabbage yield with 5mg·1~(-1)P and S and 30-100mg·1~(-1) P and S, respectively. The former was due to high arsenic accumulation by roots at low soluble P and S levels. The latter was caused by strong inhibition of higher levels of soluble P and S on arsenic accumulation in plant, increasing plant tolerance to arsenate toxicity. It was found that 0.2mg·1~(-1) As increased swamp-cabbage yield at 30mg·1~(-1) solution P and S, slightly increased at 100mg·1~(-1) soluble P and S. These results showed that trace arsenic might be helpful to swamp-cabbage growth, and excess P and S inhibited positive function of arsenic in swamp-cabbage.