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为了解烟草对不同价态硒的吸收及耐性机制,以水培烟株为材料,研究了不同浓度(0、2、5、10、20 mg/L)Se(Ⅵ)和Se(Ⅳ)对烟株硒吸收及叶片硒亚细胞分布的影响。结果表明:(1)水培液中加入Se(Ⅵ)和Se(Ⅳ)处理,低浓度(<2 mg/L)对烟株生长有促进效果,高浓度(>5 mg/L)有抑制作用,且相同硒浓度下表现为Se(Ⅳ)毒性大于Se(Ⅵ);(2)施硒处理烟株各部位硒含量增加显著,叶片以有机硒为主,无机硒主要以Se(Ⅳ)形态存储;(3)烟株叶片和茎秆对Se(Ⅵ)的亲和力大于Se(Ⅳ),而根系对Se(Ⅳ)的亲和力大于Se(Ⅵ);(4)烟株叶片吸收的硒主要贮存在细胞质和细胞壁中,其次为线粒体和叶绿体;(5)同等硒用量下,Se(Ⅵ)处理叶片总硒及细胞壁、细胞质中硒含量大于Se(Ⅳ)处理。综合分析得出,水培条件下,烟株对Se(Ⅵ)的吸收能力和耐受性均大于Se(Ⅳ),原因为烟株吸收的Se(Ⅵ)更易合成含硒氨基酸或蛋白质等积累在细胞质中和被细胞壁固定,进而缓解了硒的毒性。
In order to understand the mechanisms of tobacco selenium uptake and tolerance to different valences, hydroponic tobacco plants were used to study the effects of different concentrations (0, 2, 5, 10 and 20 mg / L) of Se Effect of Selenium Absorption and Leaf Selenium Selenium Distribution in Tobacco Plants. The results showed that: (1) Se (¢ ö) and Se (¢ ò) were added into hydroponic solution, and the growth was inhibited at low concentration (<2 mg / L) Se (Ⅳ) toxicity was higher than that of Se (Ⅳ) under the same selenium concentration. (2) The content of selenium increased significantly in all parts of tobacco plants treated with selenium, (3) The affinity of leaves and stems to Se (Ⅵ) was higher than that of Se (Ⅵ), while the affinity of roots to Se (Ⅵ) was higher than that of Se (Ⅵ). (4) (5) Under the same amount of selenium, total selenium and cell wall were treated with Se (¢ ö), and the content of selenium in the cytoplasm was higher than that of Se (¢ ò). The results showed that Se (¢ ö) absorption capacity and tolerance of tobacco plants were higher than that of Se (¢ ñ) under hydroponics, because Se (VI) absorbed by tobacco plants was more likely to synthesize selenium-containing amino acids or proteins In the cytoplasm and the cell wall is fixed, and thus alleviate the toxicity of selenium.