A Field Study on the Uptake of Cd by Phytolacca americana L. (pokeweed）Supplied with Nitrogen and Organic Fertilizers in Red Soil Regions

Abstract

Abstract Application of fertilizers to enhance cadmium phytoextraction in light to moderately Cd-contaminated agricultural soils has become an increasingly common strategy. A randomized complete block design was used to examine Cd uptake and assess Cd accumulation by Phytolacca americanaL (pokeweed) treated with ammonium sulfate (AS treatment), urea (UR), organic fertilizer (OF) and no fertilizer (CK) under field conditions. The maximum aboveground dry biomass of 53.71 g, 51.40 g, 46.78 g and 39.36 g was recorded for the AS, UR, OF and CK treatments, respectively, within approximately 90 days and the biomass was in the order of leaf > stem > root for each treatment. No significant difference was almost observed in biomass between the four treatments at the current application rates. The Cd concentration in leaves was the highest for AS, UR, CK and OF with 31.64 mg/kg, 20.54 mg/kg, 16.70 mg/kg and 12.09 mg/kg, respectively. With regard to Cd concentration, leaves were significantly higher in AS than in the other treatments, stems displayed significant differences between AS and OF at three harvests and roots showed no significant difference between all treatments. The highest BCF and TF values were 16.36 and 2.44 for CK, 10.46 and 2.44 for OF, 19.26 and 2.54 for UR, and 31.14 and 3.67 for AS, respectively. The supply of ammonium sulfate significantly increased the BCF compared to CK. There was no significant difference in TF between all treatments. The highest level of Cd accumulation in pokeweed reached 1.34mg/plant in the AS treatment and was 2.6 times higher than in the CK in the about 90 days, suggesting that pokeweed could be used as a tool plant for phytoremediation of Cd-contaminated farmlands in red soil regions.