神农架大九湖不同生境表土磷脂脂肪酸揭示的微生物群落结构差异

磷脂脂肪酸(phospholipid fatty acid，PLFAs)是活体微生物细胞膜的重要组成部分，微生物通过改变细胞膜中PLFA组成，快速响应环境变化.目前，表土PLFAs研究主要集中于季节和植被群落变化对微生物群落结构影响，对于不同生境下表土PLFAs揭示的微生物群落结构的差异性尚不明确.基于此，对神农架大九湖7种不同生境表土进行PLFAs研究.结果表明，表土样品PLFAs集中分布于C₁₄到C₁₉；除湿生泥炭沼泽和湿生半退化沼泽生境外，其他生境以n16:0为主峰.不同生境的PLFAs含量差异较大，沼泽生境TPLFAs含量是草甸及阔叶林生境下的3~8倍.PLFAs组成还揭示出生境间主要受到pH和含水率的影响，微生物群落结构存在差异.不同生境下表层土壤PLFAs揭示的微生物丰度和群落结构具有一定的相似性及差异性.运用PLFAs对微生物量及微生物群落结构的划分将有助于更好的了解区域生态系统中微生物群落结构的变化，为研究微生物参与碳循环及古生态研究奠定基础. 

Comparison of Microbial Community in Topsoil among Different Habitats in Dajiuhu,Hubei Province: Evidence from Phospholipid Fatty Acids

As an important component of microbial cell membrane,phospholipid fatty acid (PLFAs) can respond sensitively to environmental changes,PLFAs can be altered by microorganisms changing their cell membrane composition by changing their metabolic or nutrient pathways. The current researches on soil PLFAs mainly focus on how changes in seasons and vegetation community affect microbial community structure. It is still not clear how habitats mediate the structure of soil microbial community revealed by topsoil PLFAs. In this study,soil PLFAs compositions were investigated among different habitats (including Sphagnum peat,herb peat,degraded peat,hygrophyte-mesophyte meadow,mesophyte-xeric meadow,xeric meadow,and deciduous broad-leaved forest) in Dajiuhu,Shennongjia. The results show that totally 26 PLFAs with carbon numbers ranging from C₁₄ to C₁₉ are common in the topsoil of the seven habitats. The concentration of total PLFAs in peats is 3-8 times higher than that in meadows. Because of pH and SWC (soil water content) PLFAs also reveal that microbial community structures are different among habitats. The microbial abundance and microbial community structure are similar and different in topsoil under different habitats. The results in this study shed light to better understand the changes of microbial community structure in regional ecosystem,and to facilitate the study of microbe's role in carbon cycle,paleoecology.