The mutual restraint effect between the expansion of Alternanthera philoxeroides (Mart.) Griseb and cadmium mobility in aquatic environment

Abstract

Alternanthera philoxeroides (Mart.) Griseb is one of the most malignant weeds in its invision habitats. While in the cadmium-contaminated aquatic environment, does A. philoxeroides possess good tolerance and adaptability? To demonstrate the effects of cadmium on A. philoxeroides in the polluted water bodies, a hydroponic stress experiment was conducted over a gradient of Cd concentrations (0, 2.5 and 5mg/l) in triplicate. The seedlings were cultured in a greenhouse and harvested on days 0, 10, 20, 30 and 40, respectively. The results showed the effects of mutual restraint between Cd and A. philoxeroides. The A. philoxeroides seedlings were enriched with large amounts of Cd, and the toxicity of Cd inhibited the rapid growth of A. philoxeroides and induced the rapid degradation of chlorophylls in its tissues. Furthermore, the use of iron plaque effectively immobilized Cd of 1123-2883mg/kg·DW on the root surface, thus it decreased the transferability of Cd in the aquatic environment. Due to its extensive adaptability, good Cd tolerance and the immobilization of Cd predominantly in the roots (the highest Cd concentration enriched was 7588.65±628.90mg/kg·DW in roots). A. philoxeroides effectively restrained the translocation of Cd and partitioned Cd in the roots within water bodies.

Capsule: The antagonistic effect exists between the invasion of A. philoxeroides and cadmium mobility in aquatic environments.

Keywords: Heavy metal; Hydrophyte; Iron plaque; Phytoremediation.