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土壤氨氧化微生物是草地生态系统氮循环过程特别是氨氧化过程的主要驱动者,对全球变化具有响应、适应和反馈机制.通过采集在内蒙古温带草原设置的长期增温增雨野外控制实验的土壤样品,应用定量PCR、限制性末端片段长度多态性(terminal restriction fragment length polymorphism,T-RFLP)和克隆文库等方法研究氨氧化古菌和细菌的丰度、多样性和群落结构对增温增雨的响应.结果表明,增雨显著升高了土壤pH,而增温显著降低了土壤呼吸.氨氧化微生物丰度在各处理之间没有显著差异.T-RFLP结果表明,增雨显著影响土壤氨氧化细菌的群落结构,增温和增雨对土壤氨氧化微生物群落结构的交互作用并不显著.结构方程模型的结果显示植物多样性与氨氧化古菌和细菌的群落结构有显著的相关关系,表明气候变化-微生物-植物三者之间存在着一定的关系.研究结果预示土壤微生物对长期气候变化有一定的适应能力,这对预测未来生态系统的变化具有重要的参考价值.
Soil ammonia oxidizing microorganisms are the main drivers of the nitrogen cycle of grassland ecosystem, especially the process of ammonia oxidation, and have response, adaptation and feedback mechanisms to global changes. By collecting the soil samples from long-term warming and increasing rainfall control experiments in the temperate steppe of Inner Mongolia, The effects of abundance, diversity and community structure of archaea and ammonia-oxidizing bacteria on the warming and precipitation were studied by using quantitative PCR and T-RFLP and cloning libraries. The results showed that increasing rainfall significantly increased soil pH, while increasing temperature significantly decreased soil respiration. There was no significant difference in the abundance of ammonia oxidizing microorganisms among treatments. The results of T-RFLP showed that rainfall enhancement significantly affected soil ammonia oxidizing bacteria There was no significant interaction between community structure, warming and rainfall on the community structure of soil ammonia oxidizing microorganisms.The results of structural equation modeling showed that plant diversity had a significant correlation with the community structure of ammonia oxidizing archaea and bacteria, indicating that climate change - microorganisms - plants there is a certain relationship between the three.The results indicate that soil microorganisms Climate change has a certain ability to adapt, which is of great reference value to predict future changes in the ecosystem.