结合态氚在作物生态系统中的形成动态

采用模拟污染物的同位素示踪技术研究了氚水在玉米、大豆和水稻中结合态氚形成的动态过程,并探讨了结合态氚形成的机理.结果表明,土壤(或水)中的氚水通过作物根系吸收进入作物体内,并在作物各部位形成结合态氚;作物体中结合态氚的比活度随时间呈增加趋势;作物籽粒中的结合态氚的比活度约为2～3Bq/g,玉米籽和稻谷中结合态氚的比活度高于其余部位,而大豆籽则与其他部位相当.对3种作物中结合态氚比活度的变化动态进行指数回归分析得:玉米、大豆和水稻中的比活度分别为C_m(t)=1.14(1-e^-0.0509t)、C_s(t)=1.65(^1-e-0.0595t)和C_r>(t)=1.29(^1-e-0.1027t),经方差分析表明,各拟合方程较好地反映了氚水在玉米、大豆和水稻中结合态氚形成的动态.

The formative dynamics of bound tritium in the crop ecosystem.

The dynamic process of tritium water forming bound tritium in maize, soybean and rice was studied on simulated pollutants using the isotope-tracer techniques, and the formative mechanism of the bound tritium was discussed. The results showed that the tritium water in soil (or water) formed bound tritium in each departments of the crop when it entered the crop body through absorbing of root system. The specific activity of bound tritium in crop tended to increase with time. The specific activity of bound tritium in the seed of crop was about 2~3Bq/g. The specific activity in the seed of maize and paddy was higher than other departments, and that of soybean seed corresponded with other departments. The change dynamic for the specific activity of bound tritium in three kinds of crop showed Cm(t)=1.14(1-e-0.0509t), Cs(t)= 1.65(1-e-0.0595t) and Cr(t)=1.29(1-e-0.1027t) by analyzing with exponential regression method. The results of variance analysis showed that each regression equation could describe the formative dynamics of bound tritium in the maize, soybean and rice preferably.