中文摘要：

植物的叶际存在各种类型微生物包括不同种类的细菌、丝状真菌、酵母、藻类等,它们发挥着重要的生态功能.本研究首次利用磷脂脂肪酸分析（PLFA）和末端限制性片断长度多态性分析（T-RFLP）2种非培养方法评价2种不同剂量的阿维菌素杀虫剂喷施甘蓝后对叶际微生物群落的影响.结果表明,低剂量阿维菌素农药处理对甘蓝叶际微生物的生物量和群落结构影响不显著,而高剂量阿维菌素杀虫剂处理明显地改变了甘蓝叶际微生物的群落结构和组成,减少了总叶际微生物生物量、细菌生物量和革兰氏阳性菌与革兰氏阴性菌特征磷脂脂肪酸之间的比值,而真菌生物量变化不大.PLFA分析结果表明经高剂量阿维菌素农药处理后增加了不饱和脂肪酸16：1ω9t、18：1ω7和环丙烷脂肪酸cy17：0、cy19：0的含量,而减少了饱和脂肪酸i15：0、a15：0、i16：0和a17：0的含量.T-RFLP分析结果表明经高剂量阿维菌素农药处理后出现一些新的酶切片段（如58、96、236和420 bp）,这些片段所属的微生物对甘蓝叶片上阿维菌素的降解可能发挥重要的作用;而一些酶切片段消失（如51、89、99、338、66、223和482 bp）,这些片段所属的微生物可能对阿维菌素类农药残留的指示具有重要意义.

英文摘要：

The indigenous microbial communities within the plant phyllosphere are highly diverse and include many different species of bacteria, filamentous fungi, yeasts and algae which play important ecological roles. This study was the first attempt to assess the impact of abamectin treatments on microbial communities of broccoli phyllosphere using two culture-independent techniques of phospholipid fatty acid analysis （PLFA） and terminal restriction fragment length polymorphism （T-RFLP）. Results showed that low concentration of abamectin treatments did not affect the microbial biomass and microbial community structure of broccoli phyllosphere significantly. However, high concentration of abamectin treatments significantly change the microbial community structure including a decrease of total and bacterial biomass, and a decrease in the ratio of Gram-positive bacteria to Gram-negative bacteria, but did not change the fungal biomass. Moreover, PLFA suggested that the number of unsaturated and cyclopropane phospholipid fatty acids （PLFAs： 16： lco9t, 18： 1ω7, cy17：0 and cy19：0） increased with high concentration abamectin treatment, while the saturated PLFAs i15：0, a15：0, i16：0 and a17：0 decreased. The appearance terminal restriction fragments （T-RFs： 58, 96, 236 and 420 bp） indicated that some bacteria might play a significant role in abamectin degradation in broccoli phylosphere, while the disappeared T-RFs （51, 89, 99, 338, 66, 223 and 482 bp） implied some other bacteria might potentially serve as microbial indicator of abamectin exposure.