Study On Accumulation And Degradation Characteristics Of Water Spinach Cultivars Under Hg-Cd-BDE209Combined Pollution

In order to research the accumulation and degradation characteristics of12cultivars ofwater spinach（Ipomoea aquatica Forsk）under the combined pollution of Hg-Cd-BDE209, potexperiments were carried out systematically to investigate the indexes of the growth, the shoot-root pollutant contents, the contents of mineral elements in shoot, the heavy metal effectivecontents in the rhizosphere, the residues of BDE209in the soil, soil enzyme activities, and therhizosphere microbial numbers of all12cultivars of water spinach, so that the support data setscould be provided for the research of variety screening for pollution-safe cultivars ofHg-Cd-BDE209combined pollution, and the safe use of under or less than mediumconcentrations of polluted soil. The main conclusions are as follows:1. The stress of combined pollution produced a toxic effect on the growth of all12kinds ofWater spinach, inhibiting plant heights, aboveground biomass and root biomass. The inhibitionsof Water spinach grown by Cd were stronger than by Hg.2. Under the condition of treatment a (adding concentration of Hg was1.5mg/kg, and thatof Cd was0.25mg/kg, hereinafter referred to as Ta), except No.5, all the other cultivars weredistinguished to be part of Cd-PSCs, No.3,4,5,6,7to be part of Hg-PSC cultivars, that is,under the condition of treatment a, No.3,4,6,7were the part of Hg+Cd-PSCs. In treatment b(adding concentration of Hg was0.75mg/kg, that of Cd was0.75mg/kg, hereinafter referred toas Tb), the concentrations of Cd in the edible parts of all the12cultivars of Water spinach wereexceeded the value of food safety standards, and No.3,4,5,6,9,12were of Hg-PSCs.3. The absorption of BDE-209in shoot between different treatments, different cultivars, andthe interaction of treatments and cultivars showed no significant difference. Concentration ofBDE-209residues in rhizosphere soil between different cultivars showed significantdifference(p<0.05). Under Ta, the highest concentration of BDE-209residues in rhizosphere soilappeared in No.4spinach, it was3.37times of the minimum value which appeared in No.11.4. The Max ratio of PBDEs in12spinach cultivars was BDE209and nona-BDE, the ratio ofpenta-BDE，hexa-BDE, hepta-BDE were small. The most proportions of PBDEs in rhizospherewere nona-BDE and deca-BDE (BDE209), and planting Water spinach could promote the BDE209in rhizosphere soil degrading to low PBDEs.5. The accumulation for Ca, Mg by Water Spinach was promoted under the stress ofcombined pollution; and the activity of urease, catalase, peroxidase in rhizosphere were inhibitedsome extent in all12cultivars.