Uptake and Distribution of Selenite and Selenate in Flue-cured Tobacco

In order to explore the production technologies of Se-rich tobacco and the rich mechanism of Se on tobacco, a pot experiment was conducted to study the characteristics of applying selenite and selenate on the uptake and distribution of selenium in flue-cured tobacco, and their effects on tobacco growth. The results showed that the morphological characters and the biomass of tobacco could be improved if Se concentration was 1-10 mg/kg, but higher Se concentration (20-30 mg/kg) had negative effects. The Se content in different parts of tobacco plant remarkably increased by applying selenite and selenate, and this increase was 3 to 30 times more with selenate than with selenite in the same application rate. The order of distribution density and enrichment ability of Se in different parts was leaves > roots > stalks with the treatment of selenite and selenate. Monod model fitting results indicated that estimated maximal selenium contents of leaves, stalks and roots in selenate-added soils were 1.83, 15.81 and 20.98 times higher than in selenite-added soils. The bioavailability and affinity of selenate was higher than selenite for tobacco plants.