【摘要】 采用同位素示踪技术研究了土壤-青菜生态系统中125I的生物地球化学迁移与转化机制,并运用箱式模型分析了125I的动态变化。研究结果表明,引入土壤的125I随深度而衰减,绝大部分滞留在土壤0～10cm表层内,125I的滞留量与土壤质地有关;青菜通过根部能很快吸收土壤中的125I,并可将大部分转运至地上部分,青菜各部位125I的富集系数为根>茎>叶柄>叶,嫩叶中富集的125I明显大于老叶;土壤和青菜中125I的动态分布服从指数变化方程,土壤和青菜中的碘可以相向迁移,青菜中碘的积累量即为土壤和青菜中碘迁移量的差值。更多还原

【Abstract】 The behavior of biogeochemical transportation and translation of 125I in soil- Chinese cabbage ecosystem was studied by using isotope- tracer techniques, and the dynamic transformation of 125I was analyzed by application of model- box method. The results show that most of 125I concentrated in surface layer (0～ 10 cm from surface), and decreased rapidly with depth due to precipitation. The content of 125I in the soil related to the character of the soil. 125I could be absorbed rapidly by Chinese cabbage root and most of the absorbed 125I was transported to the shoot. The enrichment factor of 125I in different tissue types ranks as root > stem > petiole > leaf. The 125I taken up from surface soil concentrated more in the tender leaf than in the old leaf. The dynamic distribution of concentration of 125I in the soil- crop ecosystem can be described successfully using exponential equation. 125I in each compartment could move to each other and the content of 125I in crop was the difference of transportation.更多还原