烟株对不同价态硒的吸收与分配
Uptake and Distribution of Selenite and Selenate in Flue-cured Tobacco
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摘要: 为了开发富硒烟叶生产技术和了解烟叶对硒的富集机理,采用水溶性Se(Ⅳ)(亚硒酸钠)和Se(Ⅵ)(硒酸钠)盆栽试验,探讨了烟株对硒的吸收和分配规律,以及不同价态和用量的硒对烟株生长发育的影响.结果表明,土壤施用适当浓度的两种价态硒(1~10 mg/kg)均有改善烟株形态性状和提高生物量的作用,高浓度硒(20~30 mg/kg)则有负面影响,且Se(Ⅵ)处理抑制效果大于Se(Ⅳ).相同浓度下,两种价态的硒均能有效提高烟株各部位硒含量,Se(Ⅵ)处理较Se(Ⅳ)提高了3~30倍.土壤中的硒优先富集和分布于叶片中,其次是根系,茎秆最小.Monod方程拟合结果表明,Se(Ⅵ)处理烟株叶片、茎秆和根系最大硒含量分别是Se(Ⅳ)处理的1.83、15.81和20.98倍,烟株对Se(Ⅵ)的亲和能力显著大于Se(Ⅳ),说明Se(Ⅵ)对烟株的生物有效性明显高于Se(Ⅳ).Abstract: 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.