非选择性阳离子通道对水稻幼苗镉吸收转运特性的影响

Effects of Nonselective Cation Channels on Accumulation and Transfer of Cd in Rice Seedlings

以高积累和低积累Cd的两种水稻幼苗为材料,对非选择性阳离子通道(NSCCs)在Cd吸收转运过程中的作用进行了研究。结果表明,水稻根系和地上部对Cd的吸收均存在高、低亲和两种转运系统,高积累品种幼苗的Cd吸收转运效率明显高于低积累品种;NSCCs在水稻Cd吸收转运过程中发挥了重要作用,对地上部Cd积累量的贡献率大于根系。在Cd浓度为0.1 mg·L-1的处理下,NSCCs对低积累水稻幼苗地上部Cd积累量的贡献率高达93.5%,显著高于对高积累品种的贡献率。环境中的Cd浓度越高,NSCCs的贡献率越低。NSCCs可能是水稻高亲和转运系统的重要组成部分,能将低浓度的Cd有效转运到地上部。

Research has shown that nonselective cation channels(NSCCs) play important roles in the accumulation and transfer of heavy metals in plants. Here seedlings from high and low cadmium(Cd)-accumulating rice varieties were used to study the effects of NSCCs on Cd absorption and accumulation. Experimental results indicated that two types of mechanisms, i.e. low-affinity transport system and highaffinity transport system, were responsible for the Cd uptake in rice root and shoot. The efficiency of Cd absorption and transport in seedlings from the high Cd-accumulating variety was apparently higher than that from low Cd-accumulating one. NSCCs played an important role in Cd absorption and transport in rice seedlings. The contribution rate of NSCCs to Cd accumulation in the rice shoots was greater than that in the roots. This rate was 93.5% for low Cd-accumulating variety at the Cd concentration of 0.1 mg·L-1, which was significantly greater than that of high Cd-accumulating variety. However, NSCCs contributed less to Cd accumulation under higher Cd concentrations. Therefore,NSCCs might be a part of the high-affinity transport system in rice, transporting Cd to the shoots effectively under low Cd concentrations.