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作 者 ：王玉倩, 汪晓丽, 单玉华, 盛海君, 封克

期 刊 ：植物营养与肥料学报 2010年 16卷 4期 页码：913-917

关键词：钾吸收；非选择性阳离子通道；温度；镉；铜；

Keywords:potassium uptake, nonselective cation channels(NSCCs), temperature, cadmium, copper,

摘 要 ：以石家庄8号小麦作为研究对象，通过添加钾载体抑制剂和钾专性通道抑制剂的方法，探讨了温度变化和重金属镉、铜对植物根系的非选择性阳离子通道（NSCCs）转运钾离子的影响。结果显示，NSCCs转运钾的最适温度在35℃左右，低温和高温都会使NSCCs的吸钾速率下降。较高的温度（40℃）对NSCCs转运钾的影响大于对专一性钾通道的影响; 而较低温度（20℃）对专一性钾通道活性的抑制比对NSCCs的抑制更强。重金属镉和铜均对小麦的钾吸收速率产生影响，浓度越大，抑制作用越强。其中，根系NSCCs对镉的敏感度相对于专一性钾通道来说要低，而对铜的敏感度相对较高。说明不同重金属对两类通道蛋白的影响机制不一样。

Abstract:The nonselective cation channels(NSCCs)in plant roots contribute to the potassium transport across cell membrane. However, the ratioa of NSCCs-mediated K⁺ uptake to total K⁺ absorption by crops, and whether this process is affected by the environmental factors are still unknown. In this paper, the wheat cultivar Shijiazhuang 8 was used as material to study the effects of temperature and heavy metals(cadmium and copper)on K⁺ transport by NSCCs. The results show that the optimum temperature for NSCCs K⁺ uptake is about 35℃, and lower or higher temperature reduces the rate of K⁺ uptake by NSCCs. NSCCs-mediated K⁺ uptake is more sensitive to higher temperature(40℃)compared with the specific K⁺ channels, while NSCCs-mediated K⁺ uptake is more tolerant to lower temperature(20℃). The effects of cadmium and copper on NSCCs-mediated K⁺ uptake are dependent on their concentrations. Compared with the specific K⁺ channels, NSCCs are less sensitive to Cd²⁺ and more sensitive to Cu²⁺, which indicates that different heavy metals may influence the two types of channel proteins in different ways.

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