Effects of inhibitors on ferricyanide uptake and assimilation by plants

Effects of inhibitors on uptake and assimilation of ferricyanide by different plants were investigated. Detached roots of plants were kept in a closed-dark hydroponic system with ferricyanide solution amended with various inhibitors. Dissociation of ferricyanide to free cyanide and iron in solution was negligible. The application of inhibitors affected both botanical assimilation and uptake of ferricyanide. Of the inhibitors tested, silver nitrate showed a significantly inhibitory effect on ferricyanide uptake by rice, soybean and maize (P < 0.01), while a negligible effect was found in willows spiked with the same inhibitor (P > 0.05). However, lanthanum chloride showed the most severe effect on botanical assimilation of ferricyanide by maize and rice (P < 0.01), whereas silver nitrate and tetraethylammonium chloride were the most sensitive inhibitors to soybean and willows, respectively (P < 0.01). Botanical assimilation of ferricyanide was observed positively in responses to temperatures, in which maize was more susceptible than other selected plants. In conclusion, application of inhibitors has a substantial influence on the uptake and assimilation of ferricyanide by plants, and the inhibitory efficiency is highly dependent on the species of inhibitors applied.