中文摘要：

模拟土壤环境，采用109cd^2＋和65Zn^2＋核素双标记示踪技术，以玉米为指示植物研究了P、Cd、Zn间的交互作用，P的浓度设计为0．25（CK）、0．6、3．0mmol·L^-1，Cd的浓度为6．5×10^-3mmol·L^-1；Zn的浓度为0．1mmol·L^-1。研究结果表明，在P浓度为0．25和0．6mmol·L^-1时，植物根系和地上部对109Cd和。65Zn的吸收活度都呈增加趋势，当P浓度为3．0mmol·L^-1时，植物根系和地上部对109Cd和65Zn的吸收活度下降，说明P的浓度达到一定水平时，会使重金属Cd和Zn的有效态降低，从而降低了植物对重金属的吸收量。通过对植物根系和地上部吸收的Cd和Zn的比较，发现大多数的Cd和Zn积累在根系，从根部输送到地上部的很少。一是因为植物根系从溶液中吸收重金属后，P与Cd或Zn形成难溶物沉淀下来，使从根系输送到地上部的有效态Cd和Zn显著减少（P≤0．01）：二是因为根细胞壁表面带有较多的羧酸基团及少量带正电荷的氨基，Zn^2＋和Cd^2＋通过静电吸引而吸附在细胞壁上．减少了Cd和Zn向地上部的输送。从研究结果还可看出，根系吸附的Cd的量大于Zn的量，而茎叶与此相反，这是因为Cd为植物非必需元素，Zn为植物必需的微量元素，植物会把其所需要的元素优先输送到地上部，供其生长发育，所以大多数Zn通过木质部被输送到地上部，大多数Cd被滞留在根系中。利用统计方法分析了相同P水平条件下玉米不同部位吸收的Cd和Zn之间的相关性，结果表明根系吸收的Cd和Zn之间及茎叶吸收的Cd和Zn之间的相关性显著（P≤0．01），Cd与Zn之间存在着协同效应。

英文摘要：

Using isotopes tracer techniques, the simulated trial was conducted to study the interactions of phosphorus with zinc and cadmium under various phosphorus levels, with 0.25, 0.6 and 3.0 mmol. L^-1 phosphorus, 6.5×10-3 mmol. L^-1 cadmium, 0.1 mmol. L^-1 zinc. The results showed that the specific activity of cadmium and zinc of root and shoot in maize were increased at 0.25 and 0.6 mmol. L^-1 of P but decreased at 3.0 mmol·L^-1 of P, indicating that higher levels of Phosphorus could restrain the validity of cadmium and zinc. The absorption of Cd and Zn in the plant were reduced. Comparisons of the quantity of cadmium and zinc in root and shoot showed that the most of cadmium and zinc were accumulated in root and few of those were conveyed to shoot. On the one hand, after the heavy metal were absorbed from the solution, the deposit of phosphorus with cadmium and that with zinc were accumulated in root, less cadmium and zinc were transported from root to shoot （P≤0.01）; on the other hand, there were many COO and some NH4^＋in surface of the cell wall, cadmium and zinc were absorbed in the cell wall of root by static attraction. At the same time the concentration of cadmium in root was more than that of zinc, on the contrast the concentration of cadmium in shoot was less than that of zinc, illustrating that cadmium was one of the most toxic heavy metals and not an essential nutrient element for plant, however zinc was necessary element foe the plant, so more zinc could be prone to transit from root to shoot firstly and most of cadmium was resorted in root. There existed significant correlations between Cd and Zn in root and between Cd and Zn （P≤0.01） in shoot respectively, implied that there were synergistic effect between Cd and Zn.