近年来植物黄酮类次生代谢物质已成为外来植物入侵机制研究的热点。黄顶菊（Flaveria bidentis）自2001年入侵我国以来，已对自然生态系统及农业生产造成了严重危害。紫云英苷是黄顶菊植株体内含量最高的黄酮类次生代谢物质，可抑制种子萌发，影响植物生长，目前对其被分泌到土壤后，在土壤中的迁移性及降解等行为尚不清楚。本文研究了紫云英苷在不同土壤中的迁移及降解规律，并以潮土为例，通过土壤酶活性测定与高通量测序技术，试图揭示紫云英苷在土壤中的降解机制。结果表明：紫云英苷在不同土壤中的迁移值Rf为0.14~0.51，呈现弱至中等移动特性；紫云英苷在不同土壤中的降解符合一级动力学方程，降解半衰期为2.68~18.55 h，在灭菌潮土中的半衰期为111.8 h；紫云英苷加入土壤后土壤脱氢酶、多酚氧化酶及β-葡萄糖苷酶活性均表现出一定程度的升高；高通量测序结果表明，紫云英苷改变了土壤细菌群落结构，其中诺卡氏菌属（Nocardioides）、鞘氨醇单胞菌属（Sohingomonas）、新鞘氨醇杆菌属（Novosphingobium）、脂肪杆菌属（Pimelobacter）、Aeromicrobium属、Pedobacter属、溶杆菌属（Lysobacter）、热单胞菌属（Thermomonas）、枝动菌属（Mycoplana）、类芽孢杆菌属（Paenibacillus）、红球菌属（Rhodococcus）、支原体属（Mycoplasma）等菌群在紫云英苷加入土壤后表现出较高的丰度，可能在紫云英苷降解过程中起重要作用。%The secondary metabolites of plant flavonoids have become one research hotspot on the invasion mechanism of alien plant in recent years. An exotic weed native to South America,Flaveria bidentis, is spreading in northern China where it forms dense monospecific patches threatening native aboveground biodiversity and agricultural production from 2001.F. bidentiscontains high amounts of astragalin, one flavonoid metabolite, which can inhibit seed germination and affect growth of neighboring plants, the movement and degradation of astragalin in the soil remain unclear after being released into the soil. The regular of the movement and degradation of astragalin in five soils was study. The mechanism of degradation astragalin was evaluated with soil enzyme activity and the high-throughput sequencing method. Results showed that theRf of astragalin was 0.14~0.51 with weak to moderate- mobility in five soils; The degradation of astragalin fitted well with a first-order kinetic equation, with astragalin concentrations decreasing rapidly and then maintaining relatively constant thereafter. The half-lives of astragalin in the non-sterilized soils were 2.68~18.55 h, and 111.8 h in the sterilized fluvo-aquic soil. The activities ofsoil dehydrogenase, polyphenol oxidase and β-glycosidase were all increased after adding astragalin. The high-throughput sequencing results showed that the diversity of soil microbial communities was changed and the relative abundances ofNocardioides,Sohingomonas,Novosphingobium,Pimelobacter,Aeromicrobium, Pedobacter,Lysobacter,Thermomonas,Mycoplana,Paenibacillus,Rhodococcus andMycoplasma was increased, these bacteria may be involved in the degradation of astragalin in soils.
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