摘要
模拟根际根系分泌物梯度递减效应,研究了黑麦草根系分泌物剂量对污染土壤中芘降解特征和土壤微生物生态特征的影响.结果表明:污染土壤中芘残留量随根系分泌物添加剂量的增加呈现先下降后上升的非线性变化,达到最低芘残留量的添加剂量是总有机碳(TOC)32.75mg·kg-1,说明此浓度下根系分泌物显著促进了芘的降解;土壤微生物生物量碳和微生物熵的变化趋势与污染土壤中芘残留量变化趋势相反,表明土壤微生物与污染土壤中芘残留量存在密切关系.芘污染土壤中微生物群落以细菌占主导地位,且细菌变化趋势与芘降解变化一致,表明芘以细菌降解为主,根系分泌物主要通过影响细菌数量,进而影响芘的降解.能催化有机物质脱氢反应的土壤微生物胞内酶——脱氢酶活性的变化与土壤微生物变化趋势一致,进一步证明微生物及其生物化学特性变化是污染土壤中芘残留量随根系分泌物添加剂量变化的生态机制.
By simulating a gradually decreasing concentration of root exudates with the distance away from root surface in rhizosphere, this paper studied the effects of ryegrass （Lolium perenne） root exudates dose on the pyrene degradation and microbial ecological characteristics in a pyrene- contaminated soil. It was observed that with the increasing dose of ryegrass root exudates, the residual amount of soil pyrene changed nonlinearly, i.e., increased after an initial decrease. When the root exudates dose was 32.75 mg·kg-1 of total organic carbon, the residual pyrene was the minimum, indicating that the root exudates at this dose stimulated pyrene degradation significantly. In the meantime, soil microbial biomass carbon and microbial quotient had an opposite trend, suggesting the close relationship between pyrene degradation and soil microbes. In the test soil, microbial community was dominated by bacteria, and the bacteria had the same variation trend as the pyrene degradation, which indicated that the pyrene was degraded mainly by bacteria, and the effects of root exudates on pyrene degradation were mainly carried out through the effects on bacterial population. There was a similar variation trend between the activity of soil dehydrogenase, a microbial endoenzyme catalyzing the dehydrogenation of organic matter, and the soil microbes, which further demonstrated that the variations of soil microbes and their biochemical characteristics were the ecological mechanisms affecting the pyrene degradation in the pyrene-contaminated soil when the ryegrass root exudates dose increased.
出处
《应用生态学报》
CAS
CSCD
北大核心
2011年第10期2718-2724,共7页
Chinese Journal of Applied Ecology
基金
浙江省自然科学基金项目(Y5090001)
浙江省教育厅项目(Y200906259)资助
作者简介
作者简介谢晓梅，女，1970年生，博士，高级工程师．主要从事污染生态化学研究．E-mail：xiexiaomei@zju．edu．cn
通讯作者．E-mail：liaomin@zju．edu．cn
