The Effects And Feedback Of Ageratina Adenophora Invasion On Arbuscular Mycorrhizal Fungi (AMF) Community

Soil microbe play a key role in competition exclusion local plant community succession process of exotic. arbuscular mycorrhizal fungi(AMF) was most important microorganism in soil which play an important role in the invasion of exotic plant, feedback of soil microbe is the focus of international research. In this study, we base on theories of interactions of soil and plant, and provided a thread of exotic plant Ageratina adenophora-AMF-native plant, we focus on A. adenophora which is an invasion on the southwest China, and investigated the effect of A. adenophora on the Soil microbe including AMF, and studied the interactions and response between AMF and A. adenophora. We studied that comparison of different sterilization methods, effect of A. adenophora invasion on diversity of Arbuscular mycorrhizal fungal in different habitats and AMF interaction with A. adenophora.Feedback of soil biota to the growth of Ageratina adenophora and its competitive ability with native plant: Comparison of different sterilization methodsSoil microbial communities play a vital role in the process that the exotic invasive plants competed and replaced the native plants, and then established communities. Soil sterilization is an useful method to explore the feedback effects of different soil microbe. In order to compare the differences of different the feedback that plants were cultured in the soils processed by different sterilization methods, we compared the differences of the biomasses of invasive plant A. adenophora and native plant Rabdosia amethystoides that growing in the soils processed by three sterilization methods(dry-heating sterilization, autoclaving sterilization and irradiation sterilization). Meanwhile, we took non-sterilized soil as control. As sterilization could change the physical properties of soil and affect the plant biomasses, another treatment adding vermiculite to each soil treatment. The results showed that all three sterilization methods significantly decreased the biomass of A. adenophora and R. amethystoides, no matter whether adding vermiculite or not. In three different sterilization methods, adding vermiculite to soil can promote the growth of A. adenophora and R. amethystoides, whereas the plant biomasses in non-sterilized soil was not affected by vermiculite. The biomass of plants in irradiation sterilization soil were the best among the three sterilization methods. Furthermore, through mixed pot experiment of A. adenophora and R. amethystoides in gamma irradiated soil added vermiculite and non-sterilized soil witf vermiculite, we found that soil microbes enhanced the competitive ability of A. adenophora over the local plant R. amethystoides. Based on our results, we found that pot experiment studies of the feedback effects of soil microbes on plants should use gamma irradiated soil with vermiculite. Soil microbes in the invaded range exert positive feedbacks on invasion plants A. adenophora.Ageratina adenophora invasion on diversity of Arbuscular mycorrhizal fungal in different habitatsAMF community characteristics were examined by A. adenophora in soil with different gradient contain abundant AMF resources. In addition, from the PD, Simpson index, Shannon index can get A. adenophora community diversity index of the highest, from Observed_species species, chao1 and rarefaction curves can be that A. adenophora community OTUs richness was reduced, and principal component analysis showed that the A. adenophora is affects the impact factor of AMF community composition, in summary show that soil of A. adenophora communities accumulated specific groups of AMF and make the diversity index is higher. From the soil chemical and physical properties and canonical correspondence analysis results show that with A. adenophora invaded soil significantly increase cotent of nitrogen, total carbon, total potassium; but reduce contain of phosphorus and p H value with the invasion of A. adenophora, we can draw the invasion of A. adenophora will lead to reduced AMF species, in the root gathered in the favor of the AMF species.Feedback of arbuscular mycorrhizal associations on the interspecific competition between Ageratina adenophora and Achyranthes bidentate in different fertility levelGreenhouse experiments study that arbuscular mycorrhizal associations on the interspecific competition between Ageratina adenophora and Achyranthes bidentate. The result show that microbial inoculum factor, fertility factor and cultivate pattern where microbial inoculum factor had the biggest impact on Ageratina adenophora and Achyranthes bidentate, fertility factor was the second major factor and cultivate pattern minmal impact, which interaction each other. Through comparing intercropping and nylon net split, Nutrient are absorbed mainly through root, AMF play a helpful role in assisting. Appropriate nutrient can improve positive feedback of AMF, but high nutrient had negative feedback of AMF that effect of positive feedback of AMF on A.adenophora which stated low negative of soil beneficial to A.adenophora growth and development. Adding microbial inoculum relative competitive advantage degree of A. adenophora was maximum in low fertility, as fertility increased, relative competitive advantage degree of A. adenophora gradual decrease. A. bidentate had the competitive advantages in non- microbial inoculum. This study shows that the A.adenophora in competition to replace the native plant process in AMF is the main positive feedback factor, fertility factor is a main influence factor; AMF microbial inoculum factor of A.adenophora role is greater than that of A. bidentate role in promoting, the competitiveness of A.adenophora stronger competition in A. bidentate; fertility factor and AMF inocula factor has a negative interaction; A.adenophora are more likely to invade barren soil.In conclusion, A.adenophora in the process of network competition, AMF to a decisive role, fertility is an important impact factor. we found that pot experiment studies of the feedback effects of soil microbes on plants should use gamma irradiated soil with vermiculite; Soil microbes in A.adenophora competition exclusion of native plants invasion process has a positive feedback effect; A.adenophora invasion changes the soil chemical and physical properties, influenced and changed the AMF community; effects of A.adenophora invasion significant interactions with the competition of several factors, including AMF microbial inoculum factor is the most important factor, was the second major factor and cultivate pattern minmal impact. In experiment, studying the AMF of the feedback of the invasive plant, the effect of the fertility level on the AMF feedback effect has played a decisive role, which indicates that in the future study, the fertility factors should be taken into account.