异丙甲草胺对根际土壤微生物数量的影响及其在根际环境中的降解研究  

Effect of Metolachlor on Soil Microbial Numbers in Rhizosphere and Its Degradtion

作　　者：陈波[1] 徐冬梅[2] 吴军林 刘广深[2] 刘维屏[2] 

机构地区：[1]杭州市余杭区环境监测站,浙江杭州311100 [2]浙江大学环境科学研究所,浙江杭州310029 [3]上虞市环境保护局,浙江上虞312300

出　　处：《农业环境科学学报》2006年第4期898-902,共5页Journal of Agro-Environment Science

基　　金：国家重点基础发展规划(973)资助项目(2002CB410800)

摘　　要：为探明根际微生物数量变化与有机污染物消解之间的关系,揭示根际环境中农药快速降解的机理,通过根际袋法土培试验,研究了异丙甲草胺对芹菜根际与非根际土壤微生物数量的影响及异丙甲草胺在根际与非根际土壤中的降解特性。结果表明,在试验初期,异丙甲草胺对细菌数量有一定的抑制作用,7d后土壤细菌数量增加,并高于对照土壤。异丙甲草胺对真菌的生长有一定的刺激作用,而且这种刺激作用随所用药剂浓度的提高而增强。在整个试验周期内,无论是处理土壤还是对照土壤,根际土中的微生物数量均要高于非根际土。各浓度处理条件下根际土中异丙甲草胺的半衰期均小于非根际土,1、2.5、5mg·kg-1浓度下根际土中异丙甲草胺的半衰期分别缩短为非根际土的86.22%、78.95%、77.97%,相应的降解速率常数分别为非根际土的1.16、1.27、1.28倍。在根际土壤中,异丙甲草胺更易降解。Rhizosphere was a special area around plant roots. As a result of release of organic substances by roots, microbial numbers and activities in rhizosphere were generally higher than in root free soil. In order to investigate the influence of plant roots and rhizosphere microorganisms on bioremediation of soils contaminated with organic pollutants, the effect of metolachlor on microbial numbers and its degradation in celery rhizosphere and non-rhizosphere soil were studied with rhizobag technique. The results showed that bacterial numbers were inhibited by metolachlor initially, but increased after 7 d. Fungi numbers were stimulated by metolachlor, and the higher the metolachlor concentration the greater the influence, which indicated that fungi can utilize metolachlor as carbon and energy sources. Both bacteria and fungi numbers in rhizosphere were higher than those in non-rhizosphere soil. The degradation of metolachlor in soil followed first- order kinetics. Half lives（t1/2） of metolachlor at 1 mg·kg^-1, 2.5 mg·kg^-1 and 5 mg·kg^-1 in rhizosphere were shorted to be 86.22%, 78.95% and 77.97% of those in non-rhizosphere soils, their corresponding degradation rates were 1.16, 1.27 and 1.28 times of those in non-rhizosphere soils, respectively. The results indicated that degradation of metolachlor was stimulated by plant roots in rhizosphere. Plants and their associated rhizosphere microorganisms could be a good method for bioremediation of soils contaminated with organic pollutants.

关 键 词：异丙甲草胺 根际 土壤微生物 降解 

分 类 号：X592[环境科学与工程—环境工程]