构树修复对重金属污染土壤环境质量的影响

通过温室盆栽试验，研究构树（Broussonetia papyrifera）生长对重金属污染土壤酶活性和微生物群落结构的影响.结果表明，构树修复污染土壤中酶活性和微生物多样性明显提高.经270d培养后，构树生长土壤中蔗糖酶和酸性磷酸酶活性与种植土壤相比分别显著（P<0.05）提高3.12倍和2.29倍；土壤脱氢酶与有效态As、Cd、Pb、Zn和Cu含量，蔗糖酶与有效态Cd含量，以及磷酸酶与有效态Cd和Cu含量之间呈显著负相关（P<0.05）.根据16S和18S rDNA PCR-DGGE分析表明，构树修复可提高污染土壤中细菌和丛枝菌根真菌多样性.上述结果表明，构树修复可有效改善重金属污染土壤的环境质量.然而，污染土壤中重金属有效态含量下降不明显，必须辅助物理和化学措施来强化构树对重金属污染土壤的生态修复潜力.

Effect of phytoremediation with Broussonetia papyrifera on the biological quality in soil contaminated with heavy metals

Effects of Broussonetia papyrifera on the enzyme activities and microbial community structure of heavy metal-contaminated soil were studied using greenhouse experiment. Results showed that the enzyme activities and microbial diversity were obviously enhanced in contaminated soil with B. papyrifera remediation. Compared with the soil without B. papyrifera, the contents of sucrase and acid phosphatase in soil remediated with B. papyrifera were significantly (P< 0.05) increased by 3.12 and 2.29 times, respectively, after 270 days of cultivation. Meanwhile, the relationship was significantly (P< 0.05) negative between the content of dehydrogenase and available As, Cd, Pb, Zn and Cu, that of sucrase and available Cd, that of acid phosphatase and available Cd and Cu, respectively. According to 16S and 18S rDNA PCR-DGGE analyses, the diversities of bacteria and arbuscular mycorrhizal fungus in contaminated soil were enhanced with the growth of B. papyrifera. The results suggested that the biological quality in heavy metals contaminated soil could be effectively improved with B. papyrifera remediation. However, the content of available heavy metals was scarcely declined in contaminated soil for 270 days of cultivation. Therefore, it is necessary to improve the potential of ecological remediation for metals-contaminated soil by combining B. papyrifera with additional physical and chemical methods.