机场草坪植被调控对土壤细菌群落结构与功能的影响

为了探究植被调控对土壤细菌群落结构和功能的影响，对天津滨海国际机场草地植被进行单一草坪植物建植和高强度刈割，在调控后第3年的春、夏、秋季节取调控区土壤样本，利用16S rRNA基因高通量测序和PICRUSt软件，分析了不同植被调控方式下土壤细菌组成、多样性及季节性变化，预测细菌功能特征。结果表明，各样地共有的优势菌门（相对丰度>5%）有变形菌门（Proteobacteria）、放线菌门（Actinobacteria）、酸杆菌门（Acidobacteria）、芽单胞菌门（Gemmatimonadetes）和绿弯菌门（Chloroflexi）。与对照区相比，刈割调控区土壤放线菌门相对丰度显著增加；单一草坪建植调控区，夏季土壤芽单胞菌门相对丰度显著增加（P<0.05）。刈割调控、高羊茅及黑麦草调控区，土壤细菌门之间相关性较对照分别减弱21.4%、46.4%和67.9%，使细菌网络结构更为简单。夏季和秋季3个调控区土壤细菌群落的Shannon指数和Chao1指数显著高于对照区，而秋季Simpson指数显著低于对照区（P<0.05）。KEGG代谢途径差异分析可知，刈割调控、高羊茅和黑麦草调控区，土壤细菌分别有25、24和23个代谢通路的功能基因丰度显著低于对照区，主要体现在聚糖的生物合成与代谢、细胞运动、细胞生长与死亡、核苷酸代谢等通路上。可见，机场植被调控改变了土壤细菌群落的组成，简化了细菌网络结构，代谢功能也明显下降。

Lawn vegetation regulation changes the structure and function of soil bacterial community at airport

In order to explore the effects of vegetation regulation on the structure and function of soil bacterial community, a natural plant community at Tianjin Binhai International Airport was subjected to single turfgrass establishment or high-intensity mowing. Soil samples were collected during the spring, summer and autumn in the third year of the regulation measure. The composition, diversity and seasonal changes of soil bacterial community under different vegetation regulations were analyzed, and the functional characteristics of bacteria were predicted by using 16S rRNA gene high-throughput sequencing and PICRUSt software. The results showed that Proteobacteria, Actinobacteria, Acidobacteria, Gemmatimonadetes and Chloroflexi were the dominant phyla (relative abundance >5%) in all sampling plots. Compared with the control area, the relative abundance of soil Actinobacteria phylum significantly increased in the mowing area whereas the relative abundance of soil Gemmatimonadetes significantly increased in Festuca arundinacea and Lolium perenne areas in summer (P<0.05). The correlations between soil bacterial phyla were reduced by 21.4%, 46.4% and 67.9%, respectively, in the mowing, F. arundinacea and L. perenne plots compared with the control plot, which made bacterial networks simpler. The Shannon and Chao1 indices of the soil bacterial community in the regulated plots were significantly higher than those in the control plot in summer and autumn, whereas the Simpson index was significantly lower (P<0.05) in autumn. Difference analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways revealed that 25, 24 and 23 pathways in soil bacteria had significantly lower functional gene abundance in the mowing, F. arundinacea and L. perenne plots, respectively, compared with the control plot, mainly in glycan biosynthesis and metabolism, cell motility, cell growth and death, nucleotide metabolism. The findings suggest that vegetation regulation altered the structure of soil bacterial community, simplified bacterial network, and decreased the metabolic function.