Effects of foliar and soil application of sodium silicate on arsenic toxicity and accumulation in rice (Oryza sativa L.) seedlings grown in As-contaminated paddy soils

ABSTRACTSilicon (Si) and arsenite (iAsIII) share the same pathway of uptake and translocation in rice (Oryza sativa L.), and it has been reported that Si can decrease arsenic (As) uptake by rice in hydroponic culture. Due to the competitive sorption between Si and As for the soil minerals, different extents of effects on As toxicity and uptake by rice as influenced by soil Si application were found. In order to avoid the competitive sorption between Si and As for the soil minerals, foliar applications of Si might be a more efficient alternative to reduce As uptake by rice. Therefore, the aim of this study was to investigate the effects of Si foliar and soil applications on the growth and As accumulation in rice seedlings. In this study, three application rates of Si (as sodium silicate) were applied to (1) the foliage and (2) the soil, of rice grown in two soils with different Si retention capacities and As contents. The results showed that there were no significant differences in Si concentrations in sho...