【作者】 焦舒梅；

【导师】 李金花；

【作者基本信息】 兰州大学 ， 生态学， 2013， 硕士

【摘要】 植物和土壤之间的反馈作用推动着植物群落演替和生态系统的恢复,植物可以改变土壤特性,反过来,土壤也会影响植物的表型、生产力、种群丰富度等。本文采集青藏高原东部亚高山草甸的土壤进行灭菌处理,同时选取六种当地植物物种,采集它们的种子,在人工气候室内,进行盆栽试验,添加不同浓度氮肥(NH4NO3溶液)并接种不同多样性梯度的微生物,观察植物和土壤微生物之间的反馈作用,同时进一步验证氮是否是亚高山草甸植物群落演替的限制因素。本文的研究结果表明：(1)植物对土壤的作用具有物种特异性。(2)土壤C矿化与土壤中微生物量C呈显著的正相关,微生物是土壤C矿化中的主要参与者,外源微生物的引入有利于土壤C矿化的进行,微生物的这种作用也依赖于土壤中N源的水平。本文研究显示高氮和高微生物条件最有利于土壤C矿化的进行。(3)氮素添加和微生物接种对植物群落的影响具有浓度依赖性。本文研究显示低氮不添加微生物条件有利于植物的生长,进一步验证氮是亚高山草甸植物群落演替的限制因素。更多还原

【Abstract】 The feedbacks between plant and soil can promote the succession of the plant communities and restoration of the ecosystem. Plant can change the characteristics of soil, on the contrary, soil can also effect plant performance, plant productivity and population abundance.In order to provide a basis for future decisions on effective grassland restoration programs and ecosystem management, as well as for further studies on carbon cycle under global change in this and other regions, we carry out an experiment to study the effect of nitrogen fertilization and inoculating microorganisms on plant-soil feedbacks in a sub-alpine meadow. We collected soil and seeds of six individual plant species from a sub-alpine meadow ecosystem in the eastern part of the Qing-Hai Tibetan Plateau. The soil was sterilized by y-irradiation (25kGy) and germinlated seeds were transplantd. We added N (NH4NO3solution) and inoculated microbes to study their effect on plant-soil feedbacks and to test whether soil N composition control plant community succession. The results of our study showed that:(1) Plants affected the characteristics of soil in a certain species-specific way.(2) Soil C mineralization rate was positively correlated with soil microbial biomass C. Soil microbe is a major player in the soil C mineralization, and inoculating microbiology promoted the process of soil C mineralization. However, this promotion effect depended on the level of N in the soil. Our study showed that high nitrogen and high microbial had the most rapid soil C mineralization rate.(3) Different concentrations of nitrogen and differdent combination of nitrogen and microbial community both have different effects of plants. Our study showed that low nitrogen and non-microbe inoculation were favorable for plant growth, further proved that the nitrogen was the limiting factor of plant community succession in sub-alpine meadow.更多还原