Antagonism between selenium (Se) and cadmium (Cd) has been demonstrated in plants. However, a mutual suppression threshold for Se and Cd has not been identified in previous studies using Cd or Se individually. To fill this knowledge gap, we determined the levels of Se and Cd in various tissues of rice under concentration gradients of Se and Cd with different Se application times via hydroponic experiments. The results showed that the application of exogenous Se or Cd reduced the uptake and transport of the other. When the molar ratio of Se/Cd (R (Se/Cd)) was higher than 1, the concentration and transfer factor of Cd (TF-Cd) in all parts of rice simultaneously reached the lowest values. The minimum Se absorption in rice was obtained at R (Cd/Se) greater than 20, while no inhibition threshold was found for Se transport. In addition, approximately 1:1 R (Se/Cd) was observed in roots and the addition of exogenous Cd or Se promoted the enrichment of the other element in roots. These data suggested a mutual inhibition of Se and Cd in their absorption, transportation and accumulation in rice, which might be related to the formation of insoluble Cd-Se complexes in roots. This study provided new insights into a plausible explanation of the interactions between Se and Cd and contributed to the remediation and treatment of combined Se and Cd pollution in farmland systems.

硒（Se）和镉（Cd）之间的拮抗作用已在植物中得到证明。但是，在以前的研究中，单独使用Cd或Se时，尚未确定Se和Cd的互抑制阈值。为填补这一知识空白，我们通过水培试验确定了在不同硒施用时间下，硒和镉的浓度梯度下，水稻各组织中硒和镉的含量。结果表明，外源硒或镉的施用降低了另一种硒的吸收和转运。当Se / Cd的摩尔比（R（Se / Cd））大于1时，水稻各部分中Cd的浓度和转移因子（TF-Cd）同时达到最低值。在R（Cd / Se）大于20的情况下，水稻对硒的最低吸收量，而未发现Se转运的抑制阈值。另外，约1：在根中观察到1 R（Se / Cd），外源Cd或Se的添加促进了根中其他元素的富集。这些数据表明，硒和镉在水稻中的吸收，运输和积累相互抑制，这可能与根中不溶性镉-硒配合物的形成有关。这项研究为合理解释硒和镉之间的相互作用提供了新的见解，并有助于对农田系统中硒和镉混合污染的修复和处理。