Study On Remedial Of Cd-contaminated Soil By Herbaceous Flowers

In recent years, the soil heavy metal pollution has been increasingly serious in ourcountry, mass contaminated soil needed to be repaired urgently, which severelyrestricted the sustainable development of agricultural production. As one of thesupervirulent and mobile heavy metal, cadmium can pose a great threat to the health ofhumans and animals and plants. Phytoremediation technology has gradually becomeone of the most effective methods for heavy metal contaminated soil repair because ofits low cost of “green” remediation. The research of adopting herbaceous flowers torepair plant has just risen, but the potential is tremendous. While repairing thecontaminated soil it could also bring huge economic and ecological benefits at the sametime.Using the herbaceous flowers with the features of wide distribution, strongresistances, more season sowing as screening plant source. Orychophragmus violaceusand Zinnia, dandelion, were chosen as the main research objects after preliminaryscreening through the seed germination experiments. Through the Cd concentrationgradient of outdoor pot experiment, studied tolerance and accumulation characteristicsof the four plants under the condition of the cadmium pollution, and used chemicalenhancement technology to explore flower plants restoration potential. The mainresearch results are as follows:1) The experiment showed that the orychophragmus violaceus had characteristicsas a Cd-hyperaccumulator. The removal rate of cd top to the maximum when theaddition concentration was100mg/kg, and the remediation effect came to the best inthis rage. Seeing from characterization, Orychophragmus violaceus didn’t show obviousphytotoxicity but showed a greater endurance; from the accumulation, the shoot Cdaccumulation was higher than the critical concentration of Cd accumulation100mg/kg;both TF and AF were higher than1. Under the condition of chemical reinforcement,when chelating agent-EDDS and soil conditioner were added in to Orychophragmusviolaceus, the repair efficiency of Cd contaminated soil was improved to a great extent,mainly displayed in the aboveground accumulation and biomass increasedsignificantly.2) The experiment showed that the dandelion were potential Cd-accumulator, theremoval rate of cd top to the maximum when the addition concentration was100mg/kg. The TF and AF were close to1, and showed great endurance to heavy metal Cd, whichshowed that the potential to become Cd-hyperaaccumulators. Under the condition ofchemical reinforcement, when chelating agent-EDDS was added into dandelion, itsaboveground accumulation increased significantly and more than the accumulation ofroots, and showed the characteristics of hyperaccumulator, repair efficiency of Cdcontaminated soil has been improved obviously.3) The experiment showed that the zinnia had some certain characteristics ofCd-hyperaccumulator in low concentration treatment (10mg/kg). From thecharacterization, with heavy metal Cd additive concentration increasing, Zinnia hasshown no phytotoxicity, and biomass didn’t obviously reduce, which showed superendurance; from accumulation, the heavy metal content of aboveground was more thanthat of the underground, and the ability to transfer was strong. When C1processing, theaccumulation of aboveground was close to the characteristic value of criticalconcentration, the TF was greater than1and enrichment capacity was better. Therefor,Zinnia can be used to do repair work under low pollution concentrations.