【作者】 陈亮；

【导师】 杨民和；

【作者基本信息】 福建师范大学 ， 微生物学， 2011， 硕士

【摘要】 近年来,外来植物入侵引起人们的关注,探索植物的入侵机制逐渐成为研究热点,而入侵地土壤微生物与入侵植物的互作关系是植物入侵机制的重要内容。本研究以紫茎泽兰(Ageratina adenophora)、薇甘菊(Mikania micrantha)、三叶鬼针草(Bidens pilosa)和空心莲子草(Alternanthera philoxeroides)等4种典型的外来入侵植物作为对象,对其入侵机制和防治进行了初步探索。主要研究结果如下：在云南紫茎泽兰、薇甘菊和三叶鬼针草等发生较为普遍的区域采集植株根际土壤样品,测量其理化性质和生化活性强度,以此来探讨3种菊科入侵植物的入侵对被入侵地土壤理化性质和生化活性的影响。土壤理化性质测定结果显示,各样品的含水量和PH无显著差异；3种菊科入侵植物入侵地域的土壤样品中有机质、全N、速效K的含量都显著高于本地植物混生地域的土壤样品,其中紫茎泽兰入侵地土壤样品有机质含量最高为30.42 g/1kg,本地植物混生最低,为16.35g/kg。紫茎泽兰入侵地域的土壤样品的各项理化指标都明显高于其他样品；薇甘菊入侵地域的土壤样品的有机质、全N和速效K的含量显著高于三叶鬼针草和本地植物混生地样品；三叶鬼针草入侵地域的土壤样品的有机质、全N、速效N和速效K的含量显著高于本地植物混生地样品。土壤生化活性的测定结果显示：3种菊科入侵植物入侵地域的土壤样品的硝化势和氨化作用强度均高于本地植物混生地域的土壤样品,其中薇甘菊入侵地域的土壤样品的硝化势最高,紫茎泽兰的次之；但紫茎泽兰入侵地域的土壤样品的氨化作用强度最高；三叶鬼针草入侵地域的土壤样品的反硝化作用强度最高,本地植物混生地域的土壤样品比紫茎泽兰和薇甘菊入侵地域的土壤样品的反硝化作用强度要高,紫茎泽兰入侵地域的土壤样品的反硝化作用强度最低。从总体来看,本地植物混生地域的土壤样品的各项理化和生化指标普遍低于被入侵地域的土壤样品。紫茎泽兰、三叶鬼针草和薇甘菊对土壤生态的影响比当地植物混合生长对土壤生态的影响更为显著,外来植物入侵能够引起土壤理化性状的改变,表明外来植物通过改善被入侵地的土壤养分水平,掠夺资源而排挤本地植物。利用PCR-DGGE技术研究了薇甘菊和三叶鬼针草在海口和广州两地不同入侵程度土壤中的细菌群落的变化。对DGGE图谱中不同入侵植物样品进行聚类分析显示：薇甘菊海口重度入侵和该地轻度入侵样品中的细菌种类的相似性较高；三叶鬼针草广州未入侵土壤和该地轻度入侵土壤样品中的细菌种类相似性为最高。对DGGE图谱中不同地域样品进行聚类分析显示：在广州,相对于被入侵的区域,本地植物混生区域所采的两个土样的细菌群落最为相近；在海口.薇甘菊重度入侵土壤和薇甘菊轻度入侵样品的细菌群落相似性最高。该两种入侵植物在海口和广州的样品分别聚为一簇,表明地域差别比覆盖植物差别对土壤中细菌种类的影响大。从特异性条带测序和比对的结果可以看出,薇甘菊和三叶鬼针草对广州和海口两地的入侵,可能造成了入侵地芽孢杆菌纲和变形菌纲等细菌群落的改变。上述结果表明：海口和广州两地的薇甘菊和三叶鬼针草根际土壤中的细菌种类在不同入侵程度土壤的差异,可能是由于该两种外来植物通过改变本地植物土壤的原始微生物群落结构来形成利于自身生长的微环境,便于进一步入侵扩张。从自然发病的空心莲子草病斑叶片上分离了11株致病真菌,其中1株对空心莲子草具有较强致病性,命名为NT008。在室内、室外条件下,测定了菌株NT008对空心莲子草的致病力、供试除草剂对菌株NT008菌落生长和孢子萌发的抑制作用,以及菌药混用的除草效果。试验结果表明,菌株NT008对空心莲子草具有较强的致病力；不同除草剂、同种除草剂不同浓度之间对空心莲子草NT008病原菌菌丝影响存在差异；根据生产厂家推荐最适浓度(草甘膦200ml/亩,2,4-D二胺盐水剂300mV亩,使它隆50ml/亩)进行试验,草甘膦浓度为2050μg/mL时,抑制率为43.23%,2,4-D二甲铵盐水剂浓度为2867μg/mL时,抑制率达96.30%,使它隆浓度为166.7μg/mL时,抑制率为37.07%。2,4-D二甲铵盐水剂对菌株NT008孢子萌发的抑制作用为20.4%,而草甘膦、使它隆的抑制作用分别为8.1%、3.1%,抑制作用较弱。菌药混用结果表明,草甘膦、使它隆与菌株NT008孢子混用都具有较好的效果,2,4-D二甲铵盐水剂次之。以上研究结果表明：外来入侵植物不仅能引起入侵地土壤理化性质的改变,也对土壤微生物群落造成影响。这种改变可能反过来影响入侵植物,从而有利于入侵植物在入侵地的生长和竞争。更多还原

【Abstract】 In order to investigate the soil physical and chemical properties and biochemical activity invased by three asteraceae plants and their possible invasion mechanisms, we collected soil samples from the rhizosphere of Ageratina adenophora、Mikania micrantha and Bidens pilosa to measure their physical and chemical properties and strength of the biochemical activity in Yunnan Province. From the results, we can find that there are no significant difference on PH and water content. Determination of soil physical and chemical properties showed that the organic matter, total N, available K levels of invased soil samples of three asteraceae invasive plants were significantly higher than that of mixed native plants. And soil samples which invaded by Ageratina adenophora have the highest organic matter content of 30.42g/kg, mixed native plants have the lowest organic matter content of 16.35g/kg. All values of physical and chemical properties of soil samples which invaded by Ageratina adenophora were significantly higher than that of other samples. Organic matter, total N and available K content of soil samples of Mikania micrantha invasion area were significantly higher than that of Mikania micrantha and mixed native plants; Organic matter, total N, available N and available K content of soil samples of Bidens pilosa invaded area were significantly higher than samples of mixed native plants. The results of biochemical activity of soil samples show that:The nitrification potential and ammonification intensity of soil samples of areas invaded by three invasive asteraceae plans were higher than that of mixed native plants soil samples. Ihe nitrification potential of soil sample of Mikania micrantha invasion area has the highest value, followed by Ageratina adenophora, but the ammonification of soil sample invaded by Ageratina adenophora has the highest intensity; the denitrification of soil sample of Bidens pilosa invasion area has the highest intensity, while the sample of mixed native plants area has the second highest intensity and the soil sample of Ageratina adenophora has the lowest denitrification intensity. Overall, the physical and chemical and biochemical parameters of the soil sample of mixed native plants were generally lower than that of the invaded soil samples. Present study suggests that the invasion by Ageratina adenophora、Mikania micrantha and Bidens pilosa had more significant effects on soil ecology than that of local plants. The invasion of alien plants can cause changes in soil physical and chemical properties. Alien plants can also improve the level of soil nutrients in invasion areas, plunder of resources and crowd out native plants.Interaction between invasive plant and soil microbial community is an important aspect to understand the plant invasiveness and susceptibility of receptive communities. In present study, PCR-DGGE was conducted to analyze the bacterial community in the rhizospheric soil, which were heavily invaded, newly invaded or non-invaded by two alien invasive weeds, Mikania micrantha and Bidens pilosain in Haikou and Guangzhou city. China. The analysis of DGGE showed some regularity .Firstly, we analysed soil samples invased by different invasive plants. From the samples of Mikania micrantha, we found that the soil samples from heavily invaded site and newly invaded site by Mikania micrantha in Haikou have the highest similarity. From the samples of Bidens pilosa, samples from heavily invaded site and non-invaded site by Bidens pilosa in Haikou have the highest similarity. Secondly, we analysed samples from different invaded sites. From the samples of Guangzhou, we found that the soil samples from non-invaded site by Bidens pilosa and non-invaded site by Mikania micrantha had the highest similarity. From the samples of Haikou, we found that the samples from heavily invaded site and newly invaded site by Mikania micrantha had the highest similarity. From the results of sequencing and alignment of the specific bands, we can infer that invasion of Mikania micrantha and Bidens pilosa in Guangzhou and Haikou may modified soil microbial community composition. The bacteria’s quantity of Bacilli、Proteobacteria and some other bacteria in the soil were changed. All those results suggested that the invasion of Mikania micrantha and Bidens pilosa can modify soil microbial community composition, probably creating favorable soil environment to benefit their invasion.From the natural Alternanthera leaves, we obtained 11 strains of pathogenic fungi. Among them, one strain named NT008 has a strong pathogenicity to Alternauthera. Under the control condition, we assayed the virulence of strain NTOO8, testing the influence of herbicides on NT008 mycelia growth and spore germination, and testing the influence of herbicide mixed with the pathogenic fungi. The results show that, strain NT008 has a strong virulence on Alternanthera. Different kinds of herbicides or differernt concentrations of one herbicide produced different virulence to Alternanthera. According to manufacturer’s recommendation, optimal concentration of 3 herbicides (glyphosate 200mL/mu. Butyl 2,4-dichlorophenoxy acetate 300mL/mu Starane 50mL/mu) were tested. With concentration of 2050μg/mL glyphosate,2867μg/mL 2,4-D dimethyl ammonium and 166.7μg/mL Starane, the inhibition rate on mycelia growth of strain NT008 were 43.23%,96.30% and 37.07%, respectively. The inhibition rate 2,4-D dimethyl ammoniumon on spore germination of strain NT008 was 20.4%, while the inhibition rate of glyphosate and Starane were 8.1% and 3.1%, respectively. The results of strain NT008 spores mixed with herbicides indicated that glyphosate mixed with strain NT008 spores had a good effect, and 2,4-D dimethyl ammonium agent second.更多还原