Cadmium and manganese accumulation in phytolacca americana l. and the roles of non-protein thiols and organic acids

• Published in: International journal of phytoremediation Vol. 15; no. 4; pp. 307 - 319
• Main Authors: Gao, Lu, Peng, Kejian, Xia, Yan, Wang, Guiping, Niu, Liyuan, Lian, Chunlan, Shen, Zhenguo
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis Group 01.01.2013; Taylor & Francis; Taylor & Francis Ltd
• Subjects: Biodegradation, Environmental; Cadmium; Cadmium - metabolism; Cadmium - pharmacology; Carboxylic Acids - analysis; Carboxylic Acids - metabolism; Cellular; cytosol; Detoxification; Dose-Response Relationship, Drug; Flowers & plants; Heavy metals; hydrochloric acid; Hydroponics; ions; Leaves; Lipid Peroxidation; Manganese; Manganese - metabolism; Manganese - pharmacology; Organ Specificity; Organic acid; Organic acids; Oxalic acid; Oxalic Acid - analysis; Oxalic Acid - metabolism; phytoaccumulation; Phytochelatins; Phytochelatins - metabolism; Phytolacca americana; Phytolacca americana - growth & development; Phytolacca americana - metabolism; Phytolacca americana - physiology; phytoremediation; Plant Leaves - growth & development; Plant Leaves - metabolism; Plant Leaves - physiology; Plant Roots - growth & development; Plant Roots - metabolism; Plant Roots - physiology; Plants; Polycarbonates; Proteins; Roots; soil; Soil contamination; Soil Pollutants; Stress, Physiological; Sulfhydryl Compounds - analysis; Sulfhydryl Compounds - metabolism; Thiols; Tissues
• ISSN: 1549-7879; 1522-6514; 1549-7879
• DOI: 10.1080/15226514.2012.702800

Phytolacca americana L. can accumulate large amounts of heavy metals in its aerial tissues, especially cadmium (Cd) and manganese (Mn). It has great potential for use in phytoextraction of metals from multi-metal-contaminated soils. This study was conducted to further investigate the Cd- and Mn-tolerance strategies of this plant. Concentrations of non-protein thiols (NPTs) and phytochelatins (PCs) in leaves and roots increased significantly as the concentration of Cd in solution increased. The molar ratios of PCs:soluble Cd ranged from 1.8 to 3.6 in roots and 8.1 to 31.6 in leaves, suggesting that the cellular response involving PC synthesis was sufficient to complex Cd ions in the cytosol, especially that of leaves. In contrast, excess Mn treatments did not result in a significant increase in NPT or PC concentrations in leaves or roots. Oxalic acid concentrations in leaves of plants exposed to 2 or 20 mM Mn reached 69.4 to 89.3 mg (0.771 to 0.992 mmol) g–¹ dry weight, respectively, which was approximately 3.7- to 8.6-fold higher than the Mn level in the 0.6 M HCl extract. Thus, oxalic acid may play an important role in the detoxification of Mn.