POTENTIAL OF Alternanthera bettzickiana (REGEL) G. NICHOLSON FOR REMEDIATION OF CADMIUM-CONTAMINATED SOIL USING CITRIC ACID

Abstract

The Alternanthera bettzickiana (Regel) G. Nicholson belongs to Amaranthaceae family and has great potential to decontaminate cadmium-affected soils. Organic acids including citric acids play a vital role in cadmium uptake and its detoxification. Thus, an experiment was performed to investigate the role of Alternanthera bettzickiana in phytoremediation of soils contaminated with Cd in the presence or absence of citric acids. Soils treated with different level of Cd (0, 25, 50, 100 mg kg(-1)) concentrations and citric acid (0, 250 and 500 mu M) were used to grow plants. The results indicated that more Cd was accumulated in aerial parts of the plant as compared to underground parts. Biomass, photosynthetic pigment, and plant growth enhanced with the increasing level of Cd concentration in soil but it decreased at the highest Cd concentration in the growth medium. With the maximum applied dose of CA (500 mu M), the plant height was significantly increased by 141, 107 and 90% at Cd level 25, 50 and 100 mg kg(-1), respectively. The activities of superoxide dismutase (SOD) and peroxidase (POD) enhanced with lower metal level (Cd 25, 50 mg kg(-1)), while reduced at the maximum Cd concentration (100 mg kg(-1)). With the maximum applied dose of (Cd 50+CA500), superoxide dismutase (SOD) in leaves and POD in leaves was significantly increased by 63 and 75%, respectively. It is concluded that Alternanthera bettzickiana has maximum ability to remediate moderately contaminated soils. Moreover, phytoremediation potential was further enhanced by the citric acid application. Enhancement of phytoremediation potential in Alternanthera bettzickiana was associated with citric acid-induced modulation in oxidative stress and antioxidant potential.