The Influences Of Heavy Metals And Pesticide On Soil Enzyme Activitie And The Plant Enrichment Of Cd,Zn

This paper studied the influence of Zn, Cd on the soil enzyme activity of Chlorophytum malayense and Pharbitis nil(L.) Choisy. The results showed that under the experimental conditions of Cd, Zn single and combined pollution, the urease activities of plant rhizosphere soil of two groups was inhibited the largest, and also the most sensitive, followed by invertase and catalase. Therefore, urease can be used as one of the indexes of Cd, Zn pollution. Under the conditions of the Cd, Zn single and combined pollution, compared with Pharbitis nil(L.) Choisy, Chlorophytum malayense had strong resistance and adaptability, it showed that Chlorophytum malayense had repairing potential of Cd, Zn pollution soil. Cd, Zn combined pollution had weak antagonism effect on the urease of two plant groups. Under the concentration of Cd50 + Zn1000, it showed a synergistic effect. Under the concentration of Cd1 + Zn200, Cd5 + Zn400, it had antagonism effect on invertase activity, the other groups showed antagonistic effect. Cd and Zn combined pollution on catalase showed a synergistic effect. Combined pollution on soil enzyme inhibition was Cd > Zn.Secondly, this paper selected Chlorophytum malayense as the repair plant, to study its adsorption capacity of Cd, Zn and growth condition. The results showed that the low concentration of Cd(CCd = 5 mg·kg- 1) can promote the bracketplant chlorophyll synthesis, high concentration of Cd(> 5 mg·kg- 1) inhibited the synthesis of chlorophyll. The resistance and transfer ability of Chlorophytum malayense were weak, and enrichment coefficient was low. It showed that Chlorophytum malayense did not have Cd hyperaccumulator potential, but still has some accumulation ability. Low concentration of Zn(≤400 mg·kg-1) had a positive effect on plant growth. The migration and enrichment coefficient of Chlorophytum malayense were low, it can not be used as a Zn hyperaccumulator. Chlorophytum malayense’s transport capacity of Cd was weaker than Zn.Then, this paper studied the influence of two pesticide bactericide on soil enzyme activities. The results showed that the curve of three kinds of enzyme activity variation was promotion, reduction, flatness during the incubation period(1 to 12 days) under different concentrations of Mancozeb and Chlorothalonil. Low concentrations of Mancozeb and Chlorothalonil had activation effect on urease, invertase and catalase activities, but high concentrations had inhibitory effect on three kinds of soil enzyme activity. The inhibition rates of three kinds of soil enzyme activity Mancozeb were higher than Chlorothalonil. Under different concentrations of Mancozeb, the inhibition rates were urease > invertase > catalase. Under different concentrations of Chlorothalonil, the inhibition rates were urease > invertase > catalase. It showed that urease was sensitive to Mancozeb and Chlorothalonil, it can be considered as one of indexes of soil pollution.Finally, this paper studied the effects of Mancozeb and Cd combined pollution on farmland and greenhouse soil enzyme activity. The results showed that the low concentration of Mancozeb and Cd combined treatment had activation effect on urease and catalase activity of farmland and greenhouse soil. High concentration combined treatment had inhibitory effect, and the concentration was higher, the inhibitory effect was stronger. Different concentrations of Mancozeb and Cd combined treatment on the two kinds of soil invertase were inhibitory effect. The effects of Mancozeb and Cd combined treatment on three soil enzyme activities were urease > invertase > catalase for farmland soil, for greenhouse soil the effects were urease > catalase> invertase. Compared with greenhouse soil, farmland soil had strong resistance to Mancozeb and Cd combined pollution.