【作者】 李艳；

【导师】 王开运；

【作者基本信息】 华东师范大学 ， 生态学， 2016， 硕士

【摘要】 土壤微生物(Soil microbes)作为生态系统中较为活跃的重要组成部分,对环境因子的变化较为敏感。大气温度升高会对湿地生态系统的土壤微生物产生重要影响。本文在运用开放式生长室(OTC)连续8年长期模拟增温的基础上,研究了崇明东滩滨海芦苇湿地(2015年)不同土壤深度不同季节土壤微生物数量及多样性,及代表植物芦苇、白茅根际、非根际的土壤微生物的数量及多样性对长期模拟增温的响应。结果表明：(1)OTC的增温效果：连续8年模拟增温使大气温度显著升高了1.53℃,同时也导致土壤温度显著升高1.04℃,土壤湿度无显著变化。长期的模拟增温使土壤的表层(0-20cm层)的总有机碳含量在7月产生显著性差异；对总氮(TN)和总磷(TP)的含量没有显著的影响。(2)8年长期模拟增温导致土壤微生物的总体数量显著增加了45.21%。细菌的数量显著增加了48.99%,对土壤微生物数量增长的贡献最大,贡献率为98.93%。真菌的数量增温比对照增加了21.38%,放线菌的数量的增加不显著。(3)长期模拟增温导致垂直层次上0-10cm层土壤微生物总体数量的增加率最大,为58.22%,在四层总体微生物数量的增加中贡献率最大,为45%。其中,细菌总体数量的增长率最大(63.81%),贡献率为44.64%。真菌的增加率在0-10cm层达到最大36.45%,而放线菌的总体数量则在10-20cm层的增加率最大,为22.68%。(4)长期模拟增温导致土壤微生物在7月份增加率(103.31%)最高,在土壤微生物总数的增加中贡献最大,贡献率为67.50%,7月份细菌数量增加的贡献率最大,贡献率为68.29%。对放线菌没有产生影响。(5)长期模拟增温对植物根际的土壤细菌数量的影响最显著,植物根际真菌的数量最高增加率为80.14%。增温对植物根际放线菌的数量变化没有显著影响。增温在0-10cm土层显著增加了非根际真菌数量(111.22%)。非根际放线菌的数量7月份显著增加,尤其在30-40cm土层。(6)长期的模拟增温导致不同土壤层次的植物根际的土壤菌群种类明显增多,且芦苇和白茅由于植物种类的差异,增加的菌群种类及数量在增温和对照中及不同土壤层次都不相同。而非根际土壤菌群在增温的作用下土壤微生物多样性减少。更多还原

【Abstract】 Soil microbes, as an important and active part in ecological system, were very sensitive to the changes of environmental factors. Increasing atmospheric temperature would have a very important influence on soil microorganisms of wetland ecosystem. By applying Open Top Chamber to simulate long term temperature enhangcement, this paper studied the soil microbes of different soil depth levels in different seasons, and rhizosphere soil microbial quantity and diversity of reeds, including Imperata cylindrica and Phragmites australis in Chongming dongtan Phragmites australis coastal wetland, as well as non-rhizosphere soil microbial number and diversity with the response to rising atmosphere temperature. It showed with the following results:(1)The warming effect of OTC:After 8-yeas simulating temperature continuously, atmospheric temperature rose about 1.53 degrees significantly, leading to the rise of 1.04 degrees of soil temperature and no significant change in soil moisture at the same time. Long-term simulation of rising temperature increased TOC significantly, in soil surface (0-20cm layer) in July, and had no effect on the content of TN and TP.(2) 8-years long-term simulation of rising temperature leaded to the increasing of total number of soil microorganisms by 45.21% significantly. With a dramatic increasing in the number of bacteria (48.99%), it made the biggest contribution to the growth of soil microorganism quantity, and the contribution rate was 98.93% in warming group. Compared with the control, fungi had a 21.38% increase in the number. The increase of actinomycetes number was not significant.(3) In the vertical level, the increasing rate of 0-10 cm layer soil microbial total quantity was the largest, as a result of long-term simulated temperature enhancement. The increasing rate of 58.22% made the contribution rate of 45% largest in general increasing of the number of microorganism. Among them, the biggest increasing rate of bacteria (63.81%), had the largest contribution rate of 44.64%. The fungi total quantity reached the biggest increasing rate (36.45%) in 0-10cm layer after long-term simulated temperature enhancement. Actinomycetes had the biggest increasing amplitude in the 10-20cm layer, with an increasing rate of 22.68%.(4) The seasonal change of soil microorganisms presented the highest increasing rate of 103.31% in July, with the biggest contribution of 67.50% in the total number of soil microorganisms, under the condition of long-term simulated temperature enhancement. The warming had the largest effects on bacteria, leading to the biggest increasement of bacteria number in July, with the biggest contribution rate of 68.29%. Warming made no difference in actinomycetes number.(5) During the entire study, the effect of long-term simulated temperature enhancement on the number of soil bacteria of plant rhizosphere was the most significant. The number of plant rhizosphere fungi increased highest at a rate of 80.14%. Warming showed no significant impact on the number of changes of plant rhizosphere actinomycetes. Temperature enhancement increased the number of non-rhizosphere fungi significantly in the 0-10 cm soil layer, with the increasing rate of 111.22%. The number of non-rhizosphere actinomycetes increased significantly in July, especially in the 30-40 cm layer.(6) Long-term simulation of the temperature enhancement resulted in plant rhizosphere soil bacteria diversity of different layers increased obviously. Because of the difference of plant species between Phragmites australis and Imperata cylindrica, the increase of the number and species of flora also were not identical in different soil layers between warming and control group. Instead, the diversity of non-rhizosphere bacteria under the action of raising temperature decreased obviously.更多还原