Influence of Sulfur Supply on the Iron Accumulation in Rice Plants

The influence of sulfur (S) (0, 30, 60, and 120 mg S kg−1 soil) supply on iron (Fe) accumulation in rice was investigated in a soil (soil/sand = 4:1) culture experiment. Results showed that Fe concentration in brown rice stem/leaf increased initially and then decreased with the increase in S concentration from 30 to 120 mg kg−1. The greatest Fe concentration was achieved at 60 mg S kg−1, whereas Fe concentration in the roots decreased with the increase in S concentration. Possible mechanisms of S supply on Fe accumulation in rice were proposed. These results suggest that S fertilization is important in developing approaches to increase Fe accumulation in brown rice when cultivated in low-S soils. However, the S input in farmland, such as S-containing fertilizers (e.g., calcium superphosphate) and atmospheric S deposition may decrease Fe accumulation in brown rice when cultivated in high-S soils.