Effect of sulphate on selenium uptake and translocation in rape (Brassica napus L.) supplied with selenate or selenite

To clarify the effect of sulphate on the uptake and translocation of selenium (Se) by rape (Brassica napus L.) with Se applied as selenite or selenate. Three hydroponic experiments were conducted at the seedling stage of B. napus. Selenium concentrations in plant and culture solution samples were analyzed by hydride generation atomic fluorescence spectrometry (HG-AFS-8220). The Se absorption capacity of B. napus supplied with selenate or selenite was the same at 0.1 mM sulphate. The translocation factor of Se was significantly reduced by up to 46.4 % with increasing selenite in solution, while sulphate had no effect on Se translocation in selenite treatment. The translocation factor of Se was substantially increased by up to 60.5 % with increasing selenate in solution, and the application of sulphate appeared to facilitate Se translocation in selenate treatment. The positive effect of sulphate was more significant with extended treatment time, but unrelated to selenate or sulphate concentration. The Se absorption capacity of B. napus supplied with selenite or selenate depends on the concentration of sulphate. Sulphate is involved in the root-to-shoot translocation of Se in B. napus supplied with selenate, but not selenite. These results need confirming in pot and field trials.