Hyperaccumulator Of Copper Contaminated Soil Screening

In recent decades, excessive use of pesticide and chemical fertilizers, waste water or sewage for irrigation, industrial wastes and landfill leakage and atmospheric deposition caused by heavy metal pollution and the problem is becoming increasingly prominent. Many countries have recognized the seriousness of the problem and the Chinese government is no exception. People now pay widely attention to soil pollution as a basic problem which restricts sustainable development of human society. The heavy metal pollution prevention and control is imperative that people is actively taking effective measures to control and management of heavy metal pollution. As the soil is a special medium, to remove the pollutants is extremely difficult. Phytoremediation of thinking for this problem opens up new avenues. Based on relevant research at home and abroad, the writer select 9 species that predecessors have not studied set a different concentration gradient of Cu to carry out pot experiment. From the plant biomass, content of copper in plants, BCF, TF and so on, the writer study the influence of different copper concentrations in soil to the plant with the absorption and accumulation of copper. The main findings are as follows:(1) Toxic critical concentration of Cu to the different types of plants is of a difference. In the copper pollution soil, the toxic critical concentration of Cu to Callistephus chinensis (Linn.) Nees is about 1000 mg·kg-1, the remaining 8 plants could grow in the copper contaminated soil, showing strong patience, toxic critical concentration of Cu to them is greater than 1000 mg·kg-1(2) The effects on plant biomass caused by different Cu treatments are quite different, showing the following rules:①Different concentrations of Cu treatments on plant growth shows "promote inhibition" phenomenon, such as Callistephus chinensis (Linn.) Nees, Celosia cristata, Dahlia pinnate cv., Tagetes erecta L., Zinnia elegans;②With the increase of Cu concentration, plant biomass of aboveground or underground decreased, such as Pharbitis nil (Linn.) Choisy, Kochia scoparia (Linn.) Schrad.;③With increasing concentrations of Cu in soil, biomass in general is increasing, However, volatile, such as Brassica rapa pekinensis;④With the increase of Cu concentration, the size of the biomass is fluctuations, overall little changed, such as Tagetes patula L.(3) The absorption capacity of 9 tested plants to copper is varies by species. In 9 species, Tagetes patula L.and Brassica rapa pekinensis have strong absorption to copper; Callistephus chinensis (Linn.) Nees, Tagetes erecta L., Celosia cristata, Pharbitis nil (Linn.) Choisy, their absorptive capacity of the copper followed; and Kochia scoparia (Linn.) Schrad. and Zinnia elegans aboveground have the largest copper content of only 15.15 mg·kg-1,13.37 mg·kg-1, poor absorption of copper. In the same Cu treatment level, plant species with different Cu content are significantly different; Different levels of Cu treatment, the same plant with Cu content is different. Under the conditions of different copper concentrations, the variation of copper content in plants is as follows:①With the increase of Cu concentration, copper content in most of the tested plants aboveground and underground parts is increased, such as Tagetes patula L., Tagetes erecta L., Brassica rapa pekinensis and so on.②Distribution of Cu in the plant samples is the highest for the root and less for stem. The Cu content in most of plant samples is underground> aboveground.③The copper content of most plants aboveground is between 5～50 mg·kg-1.(4) BCF of copper about 9 species aboveground is almost less than 1, and it can not meet the conditions of hyperaccumulator.(5) TF of copper for the tested plants is generally small, and not a plant for copper shows superior ability. Variation of TF is as follows:①With the increase of the concentration of copper in the soil, TF first increases and then decreases volatility, such as Callistephus chinensis (Linn.) Nees and Celosia cristata;②With the increasing concentration of copper in the soil, TF reduces to a steep value and then the change tends to be stable, such as Pharbitis nil (Linn.) Choisy, Dahlia pinnate cv., Kochia scoparia (Linn.) Schrad., Brassica rapa pekinensis;③TF is increased trend, with Tagetes erecta L. showing the change characteristic.④TF is first increased and then decreased after decreasing trend, such as Tagetes patula L., Zinnia elegans.(6) After analyzing the experimental measure index and find that 9 species of the experiment plants do not meet the definition of the current international standard of copper hyperaccumulator. However, this test may provide valuable reference about the hyperaccumulator for the screening for later generations.