The Study Of Repairing Potential Of Sweet Potato To Pyrene, Cd, Pb Compound Polluted Soil

PAHs, heavy metals are the main pollutants in soil, those mostly remain on thesurface of the soil, threatening agricultural security and human health.This experimentused sweet potato as repairing material, and selected Pyr、Cd、Pb as pollutants,through indoor pot experiment, which used single and orthogonal designing, from theresult of sweet potatoes’ growth, the physiological effect, the absorption andaccumulation of heavy metals and mineral elements, Pyr degradation, the heavy metalforms in soil, etc, we had researched the single and composite effect of Pyr, Cd, andPb to the sweet potatoes’ toxic effects and the potential of sweet potatoes to repairPyr、Cd、Pb polluted soil, and the results showed that:(1) Single pollution and combined pollution reduced biomass of sweet potato, Pbwas the major factor affected the biomass of sweet potato. Leaf area and leafexpanding rate can be used as a quick indicator reflecting the growing changed ofsweet potatoed,when the sweet potatoes subjected to stress. Pyr and Pyr*Pb were themain two factors that affected sweet potato physiological characteristics, chlorophylla and chlorophyll b had different sensitivity toward different pollutants.(2) Main factors that affected the contents of Cd, Pb in sweet potatoes is thecontents of Cd and Pb in soil itself, under the single pollution, the concentration of Pbin sweet potatoes is greater than Cd, under the compound pollution, the concentrationof Cd in sweet potatoes is greater than Pb. Sweet potatoes had the potential to repairthe soil polluted by heavy metal Cd and Pb, but all pots of sweet potatoes hadexceeded the limits of pollutants standards in food. pollution stress affected theaccumulation of trace mineral elements in sweet potatoes more serious than the largenumber of mineral elements.(3) Residue Pyr in the soil gradually increased with the rising of its initialconcentration, the residual content in rhizosphere area was lower thannon-rhizosphere zones, Pyr degradation was reinforced by the rhizosphere of sweetpotato,and sweet potato had the potential to repair Pyr pollution soil, especially compound pollution soil. With the rising of concentrations of the soil, the contents ofall forms of Cd、Pb in sweet potato increased, the effectiveness of Pb in soil was lowerthan Cd, the sweet potato rhizosphere environment promotes passivation of Cd andPb.