Is the effect of silicon on rice uptake of arsenate (AsV) related
to internal silicon concentrations, iron plaque and
phosphate nutrition?
Abstract
Solution culture experiments were conducted to investigate the effects of silicon (Si) on arsenate (AsV) uptake by rice. The addition of Si to
the pretreatment or uptake solution significantly decreased shoot and root As concentrations (P < 0.001 and P < 0.05). The presence of Si in the
pretreatment or uptake solution also significantly decreased shoot P concentrations (P < 0.001). The data demonstrated that both internal and
external Si inhibited the uptake of As and P. Results of As uptake kinetics showed that the mechanism of the effect of Si on arsenate uptake is not
caused by direct competition for active sites of transporters with As. The effect of Si on As uptake was not entirely mediated through the effect of
Si on P uptake. Although the addition of Si to pretreatment solutions still significantly decreased shoot and root As concentrations, the extent of
reduction became smaller when rice roots were coated with iron plaque.