Analysis of Selenium (Ⅳ) Absorption Kinetics of Flue-cured Tobacco

In order to reveal the Se (Ⅳ) absorption and utilization rules of flue-cured tobacco, hydroponic experiments were carried out to study the kinetics characteristics of Se (Ⅳ) absorption of flue-cured tobacco cv. K326 and cv. Yunyan87, at different pH, accompanying ions and inhibitors by referring to the principles of nutrient absorption kinetics. The results indicated that: 1) At low Se (Ⅳ) level (100 g/L), the absorption and accumulation rate and affinity of K326 to Se (Ⅳ) was higher than those of Yunyan87. K326 was more adaptable to nutrient absorption at a low Se (Ⅳ) level. 2) Weak acidic or neutral condition (pH 5-7) facilitated to Se (Ⅳ) absorption and accumulation, while an alkaline condition did not. 3) Accompanying ions, such as SO₄^2-and PO₄^3-, inhibited the absorption and accumulation rate and decreased the affinity of flue-cured tobacco to Se (Ⅳ), especially PO₄^3-. 4) Both uncoupling metabolic inhibitor (CCCP) and Ca²⁺ channel inhibitor (LaCl₃) inhibited Se (Ⅳ) absorption of flue-cured tobacco, especially CCCP.