Wang Ying-Yan, Wang Fu-Hua, Luo Dong-Hai, Lü Sheng, Wang Zi-Fang, Gao Ming
College of Resources and Environment, Southwest University, Chongqing 400715, China.
Huan Jing Ke Xue. 2020 May 8;41(5):2445-2454. doi: 10.13227/j.hjkx.201910230.
To clarify the response of a nitrogen-related microbial community and function to different vegetation types in subtropical forest, soil samples were collected for analysis from the topsoil of five vegetation types in the Jinyun Mountain National Nature Reserve, i.e., coniferous forest, broadleaf forest, mixed broadleaf-coniferous forest, forest, and grassland. To analyze the microbial abundance, community, and function discrepancy between different vegetation soils, multiple molecular techniques, such as terminal restriction fragment length polymorphism (T-RFLP) and quantitative polymerase chain reaction (qPCR) analysis, and nitrogen-related microbial enzyme activity procedures were used. The results showed:① The denitrifying enzyme activity was much higher than nitrifying potential in Jinyun Mountain National Nature Reserve, and the two enzyme activities were much lower in coniferous forest soil than in the other vegetation soils (<0.05). In addition, dissolved organic carbon, soil water content, and total nitrogen were the key environmental factors controlling enzyme activity. ② The qPCR data showed that the abundance of nitrogen-related microbes was highest in forest, whereas it was lowest in coniferous forest. The abundances of the three nitrogen-related microbes were all significantly correlated with dissolved organic carbon, total nitrogen, available nitrogen, total potassium, and available potassium (<0.01). ③ Based on T-RFLP data, the -diversity of nitrogen-related microbes was highest in broadleaf forest, whereas it was lowest in forest. Principal co-ordinates analysis (PCoA) showed that the community structure of ammonia-oxidizing archaea responded significantly to different vegetations, and the community structure of nitrogen-related microbes showed the most difference in coniferous forest. In addition, distance-based redundancy analysis (db-RDA) showed that the community structure of nitrogen-related microbes was mainly shaped by dissolved organic carbon (<0.001), available nitrogen (<0.002), and soil water content (<0.001). ④ Soil-denitrifying enzyme activity was mainly affected by the abundance of -denitrifiers, ammonia-oxidizing archaea, and the community structure of nitrogen-related microbes, whereas nitrifying potential was only controlled by the abundance of ammonia-oxidizing archaea. Above all, subtropical forest vegetation significantly affects the abundance and community structure of soil nitrogen-related microbes, thereby changing their function of controlling the soil nitrogen cycle. This study can provide basic data for the coupling mechanism between soil microbes and NO release in subtropical forests in China.
为阐明亚热带森林中与氮相关的微生物群落和功能对不同植被类型的响应，从缙云山国家级自然保护区5种植被类型（即针叶林、阔叶林、针阔混交林、灌丛和草地）的表层土壤中采集土壤样本进行分析。为分析不同植被土壤间微生物丰度、群落和功能差异，采用了多种分子技术，如末端限制性片段长度多态性（T-RFLP）和定量聚合酶链反应（qPCR）分析，以及与氮相关的微生物酶活性测定方法。结果表明：①缙云山国家级自然保护区的反硝化酶活性远高于硝化潜力，且针叶林土壤中的这两种酶活性远低于其他植被土壤（<0.05）。此外，溶解有机碳、土壤含水量和总氮是控制酶活性的关键环境因素。②qPCR数据显示，与氮相关的微生物丰度在灌丛中最高，而在针叶林中最低。这三种与氮相关的微生物的丰度均与溶解有机碳、总氮、有效氮、全钾和有效钾显著相关（<0.01）。③基于T-RFLP数据，与氮相关的微生物的α多样性在阔叶林中最高，而在灌丛中最低。主坐标分析（PCoA）表明，氨氧化古菌的群落结构对不同植被有显著响应，且与氮相关的微生物的群落结构在针叶林中差异最大。此外，基于距离的冗余分析（db-RDA）表明，与氮相关的微生物的群落结构主要受溶解有机碳（<0.001）、有效氮（<0.002）和土壤含水量（<0.001）影响。④土壤反硝化酶活性主要受反硝化细菌、氨氧化古菌的丰度以及与氮相关的微生物的群落结构影响，而硝化潜力仅受氨氧化古菌丰度控制。综上所述，亚热带森林植被显著影响土壤中与氮相关的微生物的丰度和群落结构，从而改变其控制土壤氮循环的功能。本研究可为我国亚热带森林土壤微生物与NO释放的耦合机制提供基础数据。
