采用水培法对不同浓度K-Cd 双重处理条件下籽粒苋(Amaranthus hypochondriacus Linn.)幼苗根、茎和叶干质量以及根和地上部分Cd、K、P、Ca、Zn、Fe、Mn 和Cu 含量的变化进行了分析。结果表明:在Cd 浓度相同的条件下,随K 浓度的提高(0. 0、2. 5 和20. 0 mmol·L^-1 ),籽粒苋根、茎和叶的干质量均呈逐渐增加的趋势;各部位的Cd 含量均呈现逐渐下降的趋势;根和地上部分的K 和Zn 含量增加、Ca 含量无明显变化、Fe 含量呈持续降低的趋势;根中Mn 含量无明显变化规律、Cu 含量逐渐降低,而地上部分Mn 含量总体上增加、Cu 含量则无明显的变化规律。在K 浓度相同的条件下,随Cd 浓度的提高(0、5、25 和45 μmol·L^-1 ),籽粒苋幼苗茎和叶的干质量逐渐降低、根的干质量在较高浓度Cd 处理条件下也均降低;不同部位Cd 含量均不断增加;根和地上部分的Ca、K、Zn 和Mn 含量基本呈逐渐降低的趋势、Fe 含量呈先增加后降低的趋势;根中P 和Cu 含量大体呈持续降低的趋势、地上部分P 和Cu含量则呈先增加后降低的趋势。在不同浓度K-Cd 双重处理条件下籽粒苋的根冠比差异不显著,其中5  μmol·L-1Cd 处理组幼苗的根冠比均最大。总体上看,在K-Cd 双重处理条件下籽粒苋幼苗根、茎和叶中Cd 含量的增幅均小于Cd 单一处理,Cd 的迁移系数也有所降低。研究结果显示:较高浓度的Cd 处理对籽粒苋幼苗的生长及体内营养元素积累均有一定的抑制作用,而添加K 能够减弱籽粒苋对Cd 的积累和迁移能力、减轻Cd 胁迫的伤害程度。据此,建议在用籽粒苋进行Cd 污染环境修复时施用适量的K 肥。

Under K-Cd double treatment with different concentrations, changes of dry weights of root, stem and leaf and contents of Cd, K, P, Ca, Zn, Fe, Mn and Cu in root and above-ground part of Amaranthus hypochondriacus Linn. seedling were researched by water culture method. The results show that under condition of same concentration of Cd, as rising of K concentration (0. 0, 2. 5 and 20. 0 mmol·L^-1), dry weights of root, stem and leaf of A. hypochondriacus appear the gradually increasing trend; Cd content in different organs appear the gradually decreasing trend, K and Zn contents increase, Ca content has no obvious change and Fe content appears the continuously reducing trend in root and above-ground part; Mn content has no regular change and Cu content gradually decreases in root; and Mn content generally increases, Cu content has no regular change in above-ground part. Under condition of same concentration of K, as rising of Cd concentration (0, 5, 25 and 45 μmol·L^-1 ), dry weights of stem and leaf of A. hypochondriacus appear the gradually decreasing trend, that of root also decreases under higher concentration of Cd; Cd content in different organs all increases continuously; generally, contents of Ca, K, Zn and Mn in root and above-ground part of A. hypochondriacus appear the gradually decreasing trend, Fe content appears the trend of firstly increasing and then decreasing; contents of P and Cu in root generally appear the continuously decreasing trend, while those in above-ground part appear the trend of firstly increasing and then decreasing. Generally, increasing range of Cd content in root, stem and leaf of A. hypochondriacus seedling under K-Cd double treatment condition is lower than that under Cd single treatment condition, and the transfer coefficient of Cd also reduces. It is concluded that Cd treatment with higher concentration has a certain inhibitory effect on growth and accumulation of nutrient elements in A. hypochondriacus seedling, while adding K can reduce the accumulation and transfer ability of A. hypochondriacus to Cd, and lightens the injury degree of Cd stress. Therefore, it is suggested that appropriate K fertilizer should be fertilized when using A. hypochondriacus to remediate Cdcontaminated environment.