| 外源亚硒酸盐和硒酸盐在土壤中的价态转化及其生物有效性 |
| 摘要点击 4387 全文点击 2955 投稿时间：2010-06-24 修订日期：2010-09-28 |
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| 中文关键词 亚硒酸盐 硒酸盐 小白菜(Brassica rapa L.Chinensis Group) 硒价态 生物有效性 |
| 英文关键词 selenite selenate pakchoi (Brassica rapa L.Chinensis Group) selenium valence state bioavailability |
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| 中文摘要 |
| 采用土培盆栽试验和化学分析方法相结合的方法，研究了外源亚硒酸盐和硒酸盐态硒在土壤中的价态转化及其生物有效性，旨在为富硒蔬菜的开发和硒污染土壤的生物修复提供依据.结果表明，当土壤中外源施入亚硒酸盐时，小白菜不同生长时期土壤总硒、Se(Ⅳ)和Se(0)含量均随外源硒浓度的增加显著升高(p< 0.05)；而当土壤外源施入硒酸盐时，小白菜不同生长时期土壤总硒、Se(Ⅳ)、Se(Ⅵ)和Se(0)含量均随外源硒浓度的增大显著升高(p< 0.05).土壤中外源添加亚硒酸(Se(Ⅳ))或硒酸盐(Se(Ⅵ))后，土壤不同价态硒发生了相互转化，部分施入的Se(Ⅳ)和Se(Ⅵ)转化为Se(0).当施入外源亚硒酸盐态硒浓度≤20 mg·kg-1时对小白菜的生长无显著影响，而外源硒酸盐态硒浓度≥1 mg·kg-1 时，小白菜根部生物量即显著下降，当硒浓度≥10 mg·kg-1时，显著抑制了小白菜根的伸长及地上部的生长(p< 0.05)，而高浓度硒酸盐对小白菜生长的毒害作用大于亚硒酸盐.土壤外源添加亚硒酸盐时，小白菜根部为硒的主要累积部位；而外源添加硒酸盐时，小白菜地上部更易累积硒.硒酸盐态硒的生物有效性及其在小白菜体内的迁移能力大于亚硒酸盐态硒，因此硒酸盐处理的小白菜地上部和根部硒含量均显著高于亚硒酸盐处理(p< 0.05).在土壤中硒的各种价态中以Se(Ⅵ)对小白菜硒含量的贡献最大.高浓度硒酸盐和亚硒酸盐对小白菜生长的影响不同，源于小白菜对不同形态硒吸收、转运和累积的差异，而不同形态硒在土壤中的价态转化又反过来进一步影响到小白菜对硒的吸收及转运. |
| 英文摘要 |
| Pot experiments were conducted to study valence state changes and bioavailability of selenium in soil treated with selenite and selenate.The objective of the study was to provide information for bioavailability,biogeochemical cycling and environmental action of selenium in soil.The results showed that the total selenium,Se(Ⅳ) and Se (0) concentration of the soil treated with slenite increased significantly with the increase of selenium concentration at different growth stages of pakchoi.In different growth phases,soil total selenium,Se(Ⅳ),Se (VI) and Se (0) concentration increased remarkably when selenate concentration increased.The valence state changes of selenium were observed in soil treated with selenite and selenate.Se(Ⅳ) and Se (VI) were transformed into Se (0) with the growth of pakchoi.Roots were the dominant sites for selenium accumulation in slelenite-supplied pakchoi,whereas shoots were the major sinks for selenate accumulation.Shoots and roots seleniun content in selenate-treated pakchoi were significantly higher than that in selenite-treated pakchoi.The bioavaibility and mobility efficiency of selenate in pakchoi were greater than selenite.Selenium accumulation in pakchoi was more contributed to soil Se (VI) concentration than other valence selenium. |
