以水稻( Oryza sativa Linn.) 高 Cd 积累品种 ‘T 优 705’ (‘T You 705’) 和低 Cd 积累品种‘湘早籼 24’ (‘Xiangzaoxian 24’)为实验材料,采用水培法对不同浓度 Cd(0. 0 和 2. 7  μmol· L^-1 Cd)和 K(0、30 和 60 mmol· L^-1K)处理条件下 2 个品种幼苗的相对生长量、根系和地上部的 Cd 含量及其亚细胞分布特征进行了比较,并分析了添加离子通道活性抑制剂 TEA 和 LaCl₃后幼苗根系和地上部的 Cd 和 K 含量;在此基础上，比较了 NSCCs(非选择性阳离子通道) 和K专性通道对2个品种幼苗根系和地上部 Cd 和K吸收贡献率的影响。结果表明:与 Cd 单一处 理 组(2. 7  μmol· L^-1 Cd)相比, Cd-K 双 重 处 理 组(2. 7  μmol· L^-1 Cd-30 mmol· L^-1 K 和 2. 7  μmol· L^-1 Cd-60 mmol· L^-1 K)2 个品种幼苗的相对生长量显著提高，而幼苗根系和地上部的 Cd 含量显著下降;随 K 浓度的提高，2 个品种幼苗根系细胞壁和细胞液中的 Cd 含量显著下降,但细胞壁中 Cd 含量的分配比例增大而细胞液中 Cd含量的分配比例则减小。在含 2. 7  μmol· L^-1 Cd 和 30 mmol· L^-1 K 的培养 液 中 分 别 添 加 5 mmol· L^-1 TEA 或0. 2 mmol· L^-1 LaCl₃后，2 个品种幼苗根系和地上部的 Cd 和 K 含量均显著下降，其中，LaCl₃处理组的根系 Cd 含量降幅高于 TEA 处理组,但 LaCl₃处理组的根系 K 含量降幅则低于 TEA 组。 NSCCs 对品种‘T 优 705’幼苗根系和地上部 Cd 吸收的贡献率显著低于品种‘湘早籼 24’幼苗,而 K 专性通道对品种‘T 优 705’幼苗根系 K 吸收和地上部Cd 吸收的贡献率则显著低于品种‘湘早籼 24’幼苗。研究结果显示:添加外源 K 可缓解 Cd 对水稻幼苗生长的抑制作用,并通过提高细胞壁与 Cd 的结合能力来降低细胞液中 Cd 的积累,以此减弱幼苗对 Cd 的吸收和转运能力；幼苗体内的 K 和 Cd 均可通过 K 专性通道和 NSCCs 转运，其中，K 吸收和转运主要通过 K 专性通道完成,而 Cd 吸收和转运主要通过 NSCCs 完成。 此外，品种‘T 优 705’可能具有多种离子通道参与 Cd 的吸收和转运,而品种‘湘早籼 24’主要依赖 NSCCs 参与 Cd 的吸收和转运，且后者对 K 的吸收和积累强于前者。

Taking high-Cd-accumulation cultivar ‘T You 705’ and low-Cd-accumulation cultivar ‘Xiangzaoxian 24’ of Oryza sativa Linn. as experimental materials, relative growth amount, Cd contentand its subcellular distribution characteristics in root and above-ground part of two cultivar seedlings under treatment conditions of Cd (0. 0 and 2. 7 μmol· L-1 Cd) and K (0, 30 and 60 mmol· L-1 K) with different concentrations were compared by hydroponics, and Cd and K contents in root and above-ground part of seedling after added ion channel activity inhibitor TEA and LaCl3 were analyzed. On this basis, effects of NSCCs (nonselective cation channels) and K specific channel on contribution rate to Cd and K absorption of root and above-ground part of two cultivar seedlings were compared. The results show that compared with single Cd treatment group (2. 7 μmol · L-1 Cd), relative growth amount of two cultivar seedlings in Cd-K double treatment groups (2. 7 μmol· L-1 Cd-30 mmol· L-1 K and 2. 7 μmol· L-1 Cd-60 mmol· L-1 K) increases significantly, while Cd content in root and above-ground part of seedling decreases significantly. With increasing of K concentration, Cd content in cell wall and cell sap of root of two cultivar seedlings decreases significantly, but allocation proportion of Cd content in cellwall increases, while that in cell sap decreases. After added 5 mmol· L-1 TEA or 0. 2 mmol· L-1 LaCl3 in culture solution containing 2. 7 μmol· L-1 Cd and 30 mmol· L-1 K, respectively, Cd and K contents in root and above-ground part of two cultivar seedling decrease significantly, in which, decreasing range of Cd content in root in LaCl3 treatment group is higher than that in TEA treatment group, but decreasing range of K content in root in LaCl3 treatment group is lower than that in TEA treatment group. Contribution rate of NSCCs to Cd absorption of root and above-ground part of cultivar ‘ T You 705’ seedling is significantly lower than that of cultivar ‘Xiangzaoxian 24’seedling, while contribution rate of K specific channel to K absorption of root and to Cd absorption of above-ground part of cultivar ‘T You 705’ seedling is significantly lower than that of cultivar ‘Xiangzaoxian 24’ seedling. It is suggested that adding exogenous K can relieve inhibition of Cd to growth of O. sativa seedling, and through increasing binding ability of cell wall with Cd to decrease Cd accumulation in cell sap, so as to reduce absorption and transport capacities of seedling to Cd. K and Cd in seedling both can be transported by K specific channel and NSCCs, in which, K absorption and transport is mainly finished by K specific channel, while Cd absorption and transport is mainly finished by NSCCs. In addition, cultivar ‘T You 705’ may possess many ion channels to participate Cd absorption and transport, while cultivar ‘Xiangzaoxian 24’ mainly depends on NSCCs to participate Cd absorption and transport, and K absorption and accumulation of the latter are stronger than those of the former.