Study On Toxic Effects Of Lead, Mercury And Butachlor Combined Pollution On Lactuca Sativa L.

Heavy metals and herbicides are common and co-exist pollutions in the soil environment. They often interact and form a combined pollution which toxic effect is more complex than a single pollution. The pot experiment was conducted to study the toxic effects of individual and combined pollution of lead, mercury and herbicide Butachlor on Lactuca Sativa L. The results are as follows:(1) Single mercury (<4mg/kg) can promote the height of Lactuca Sativa L , and single Butachlor (<1mg/kg) can promote chlorophyll content of leaf . Higher concentration of mercury and Butachlor individualy inhibit the biomass, leaf area and chlorophyll content of leaf, and fortify destroy of cell membrane of Lactuca Sativa L. With their joint pollution, Butachlor plays a leading role in pollution effects, and their joint toxicity showed synergistic effects with higher concentration levels.(2) Single lead can promote plant height of Lactuca Sativa L, But with the culture time increased, the promotion on plant height decreased constantly. Single Butachlor and combined pollution of lead and Butachlor inhibited the plant height of Lactuca Sativa L , and with the concentration increased, the inbibitional effect was enhanced. The combined pollution of Butachlor and lead showed synergistic effects on plant height. The correlation between root weight and biomass of Lactuca Sativa L and lead concentration was positive, the correlation between root weight and biomass of Lactuca Sativa L and Butachlor concentration was negative. Low concentrations of lead promote the biomass of Lactuca Sativa L, high concentrations of lead inhibited biomass and root weight of Lactuca Sativa L. Single Butachlor inhibite the biomass and root weight of Lactuca Sativa L , and with the concentration increased, the inbibitional effect was enhanced.The combined pollution of Butachlor and lead inhibited biomass and root weight of Lactuca Sativa L, showed synergistic effects on biomass, and showed antagonistic on root weight.(3) There was a positive correlation between chlorophyll content of Lactuca Sativa L and concentration of lead and Butachlor,and a negative correlation between root activity, CAT and POD and the concentration of lead and Butachlor. Low concentration of combined pollution showed antagonistic effect on chlorophyll content, root activity , POD and CAT. High concentration of combined pollution showed antagonistic effects on chlorophyll content, POD and CAT, showed synergistic effects on root activity.(4) There was a significantly positive correlation between the lead content of Lactuca Sativa L leaves and roots and the concentration of lead and Butachlor. The correlation between Lead content in leaves and roots were significantly positive. The lead content of Lactuca Sativa L leaves and roots increased with the increase of lead concentration, and the lead content in root is higer than in leaves. The lead content of leaves and root increased with the increase of lead and Butachlor concentration, and the lead content in leaves is higer than in root. Lactuca Sativa L enrichment factor and transfer coefficient decreased with the increase of lead concentration in soil, But increased with the increase of Butachlor concentration in soil.