增温和互花米草入侵对崇明东滩湿地 土壤碳循环功能基因的影响.

The carbon cycling process in wetland ecosystems has an important impact on global climate change. In this study, we used the GeoChip technology to detect the key functional genes of soil carbon cycle in the wetland soil of Chongming Dongtan, China. We also studied the effects of experimental warming and Spartina alterniflora invasion on carbon cycle of wetland soil and their relationships with environmental factors. The results showed that: 1) the number and abundance of functional genes in soil carbon cycle were higher than those in other categories; 2) the signal intensity of functional soil carbon cycle genes was higher in S. alterniflora community than in Phragmites australis community with the same temperature treatment; 3) warming significantly reduced the signal intensity of most functional genes in soil carbon cycle, including the basic processes of carbon degradation, carbon fixation, and methane metabolism, but the influence was not significant for the S. alterniflora invasion and its interaction with warming (P>0. 05) ;4) compared with the control, warming significantly reduced the abundance of functional genes of carbon cycle in the P. australis community, mainly including cda, exopolygalacturonase_fungi, rgh, xyla, xylanase, cellobiase and endoglucanase genes in the carbon degradation process and rubisco genes related to Calvin cycle during carbon fixation (P<0. 01), but the changes were not significant in the S. alterniflora community and their mixed community (P>0. 05) ;5) soil microbial carbon cycle functional genes were significantly and negatively correlated with soil reactive nitrogen gas emission and soil pH (P<0. 05) . In conclusion, warming significantly changes the functional gene abundances of soil carbon cycle. The research results provide data support for quantifying the impact of global warming on wetland carbon cycle and greenhouse gas emissions, and realizing carbon neutralization, and also provide scientific basis for the protection and management of wetland ecosystem. [ABSTRACT FROM AUTHOR]

湿地生态系统碳循环过程对全球气候变化具有重要影响.本文以崇明东滩湿地土壤为研究对象，采用 GeoChip 技术检测土壤碳循环关键功能基因，研究增温及互花米草入侵对湿地土壤碳循环的影响及其与环境因子之间的关系.结果表明：湿地土壤中碳循环功能基因数量及丰度均高于其他各类别的基因；在相同温度处理下，种植互花米草土壤的微生物群落碳循环功能基因信号强度均高于种植芦苇土壤；增温显著降低了大多数土壤碳循环功能基因信号强度，包括碳降解、碳固定和甲烷代谢等基本过程，但互花米草入侵及其与增温的交互作用无显著影响 (P>0.05) ;与对照相比，增温显著降低了种植芦苇土壤的微生物群落碳循环功能基因丰度，主要包括碳降解过程中的cda、exopolygalacturonase＿fungi、rgh、xyla、xylanase、cellobiase和endoglucanase基因，以及碳固定过程中与卡尔文循环相关的rubisco基因 (P<0.01),但对互花米草土壤的微生物群落以及互花米草与芦苇混种处理的影响不显著 (P>0.05) ;土壤微生物碳循环功能基因与土壤活性氮气体排放及土壤pH显著负相关 (P<0.05) .总之，增温显著地改变了土壤碳循环功能基因丰度，研究结果将为定量全球变暖对湿地碳循环和温室气体排放的影响、实现碳中和等提供数据支撑，也为湿地生态系统的保护和管理提供科学依据. [ABSTRACT FROM AUTHOR]