Abstract:

Based on the serious situation of Cd pollution in the wetland of the Dongting Lake,a series of studies were conducted to evaluate the Cd enrichment characteristics and repairing effects of kinds of plants growing in the Dongting Lake area. The results show that Artemisia selengensis is an outstanding species to repair Cd pollution for its remarkable capacity to accumulate Cd from lake soil.Artemisia verlotorum shows a good capacity to absorb Cd and could be selected as a potential candidate to treat Cd pollution. Because of their higher Cd accumulation in the root parts and their higher biomass of stem and leave which could be harvested every year, Phragmites australis and Miscanthus lutarioriparius could also play a role in controlling Cd pollution in the wetland of the Dongting Lake.
In this study,a pot experiment was conducted to study the biological traits and the Cd accumulation characteristics of Artemisia selengensis to Cd stress during its growth period. The final results showed that the leaves were injured apparently associated with significant decrease of aboveground biomass when Cd concentrations in soil were higher than 40 mg/kg. Artemisia selengensis could complete its life cycle at a high Cd concentration (100 mg/kg) and showed a stronger resistence to soil Cd. The bioavailable Cd accounted for about 15.3%-37.1% of total soil Cd. There were no significant differences of Cd concentrations in the plants during their different growth phases, but a lower Cd accumulation was observed in stems and leaves at the seedling stage than the other stages because of low biomass. During the adult stage of Artemisia selengensis, Cd accumulation was up to 492-588 mg/kg under the Cd treatment of 40-60 mg/kg. These data suggested that Artemisia selengensis was an outstanding species that could be selected as a potential candidate to repair Cd pollution from lake soil.Using the Cdcontaminated soil as culture medium, a pot experiment was carried out to explore the affect by chelating agents on the biomass and Cd accumulation of Artemisia selengensis. The results showed that the biomass of stems and leaves decreased by the impact of HEDTA, EDTA and DTPA, but the content of Cd in aerial parts of plants increased respectively by 35.5%, 98.4% and 42.1%. Additionally, the effective content of Cd in soil, the opposite effect was observed in the add of lime. The growth of plants were promoted by the organic matter and fertilizer, however, the effect of Cd enrichment was not the case. Overall, the chelate applied at the seedling stage had a greater impact than the adult stage