Heavy metal uptake and growth characteristics of Amaranthus caudatus L. under five different soils in a controlled environment

This study investigated the influence of soil types on morphological growth characteristics in Amaranthus caudatus. Seeds of A. caudatus were sown in soils formulated using USDA soil triangle technique and after germination, variabilities in the mean leaf area, shoot height, girth, mean number of branches and leaves per representative stand on different soils were measured. Also, heavy metal uptake characteristics of the plant were examined by comparing the concentrations of trace metals in the soil before and after planting with amount retained in the plant shoot. The results of soil mineral analysis indicated variabilities in the mineral content of the soil before and after planting. While some trace element concentrations got depleted after planting, some appreciated considerably. In addition, variabilities observed in the mean leaf area, shoot height, girth, mean number of branches and leaves per representative plant on different soils suggested the critical role of minerals present in each soil type in plant development. Some essential minerals such as calcium and magnesium were returned to the soil in three-fold of their initial concentrations. This suggested that the plant could serve as a phytoremediator of such minerals, particularly in mineral deficient areas. Also, reduced acidity of the post-harvest soils further showed the plant's capacity to mop up high acidity in an environment, thus; a good candidate for phytoremediation. For optimal yield in afore-mentioned growth parameters in a regulated environment, loam and silty clayey loam soils are recommended for cultivation of Amaranthus caudatus.