不同荒漠植物根际土壤微生物群落结构特征

摘要

于2015年7月在甘肃安西极旱荒漠国家级自然保护区采集膜果麻黄(Ephedra przewalskii)、红砂(Reaumuria songarica)、合头草(Sympegma regelii)、泡泡刺(Nitraria sphaerocarpa)和珍珠猪毛菜(Salsola passerina)5种典型荒漠植物根际土壤样品,利用磷脂脂肪酸(PLFA)法结合Sherlock微生物鉴定系统分析了土壤微生物群落结构.结果表明,5种荒漠植物根际土壤微生物磷脂脂肪酸种类和组成差异显著,其中表征革兰氏阳性菌的18∶0 iso、16∶0 iso和17∶1 iso ω9c分别为红砂、珍珠猪毛菜特有表征放线菌的18∶1 ω7c 10-methyl仅在珍珠猪毛菜根际存在.总PLFAs、真菌、放线菌和真菌/细菌在珍珠猪毛菜中显著最高,革兰氏阳性菌、革兰氏阴性菌在膜果麻黄和珍珠猪毛菜根际显著高于其他植物,AM真菌在合头草根际有最高值.结构方程模型分析表明,与植物相比,土壤因子对微生物群落结构影响更为显著,其中易提取球囊霉素对放线菌有显著影响,土壤碱解氮是革兰氏阳性菌和革兰氏阴性菌的主要影响因子.同时,土壤微生物群落结构可用于检测不同荒漠植物根际微环境土壤退化状况.%To measure and manage plant growth in arid sandlands,improved understanding of the spatial patterns of desert soil resources and the role of soil microbes is required.The rhizosphere soils of Ephedra przewalskii,Reaumuria songarica,Sympegma regelii,Nitraria sphaerocarpa,and Salsola passerina in Anxi Extreme-arid Desert National Nature Reserve in Gansu Province,China were collected in July 2015.Soil microbial community structure in the rhizosphere of the studied five plants was analyzed by phospholipid fatty acid (PLFA) combined with Sherlock microbial identification system.The results showed that soil microbial PLFA species and composition in rhizosphere of five desert plants were significantly different.The characterizations of gram-positive bacteria 18∶0 iso,16∶0 iso and 17∶1 iso ω9c were unique in rhizosphereof R.songarica and S.passerina,respectively.18∶1 ω7c 10-methyl that indicated actinomycetes only existed in the rhizosphere of S.passerina.The total PLFA,fungi,actinomycetes and fungi/bacteria were the highest under S.passerina.However,grampositive and gram-negative bacteria were significantly higher under E.przewalskii and S.passerina than under the other plants.AM fungi had the highest value under S.regelii.Structural equation model analysis indicated that compared with plants,soil factors had more significant effects on microbial community structure.Easily extracted glomalin had a significant effect on actinomycetes.Soil available nitrogen was the major influencing factor of gram-positive and gram-negative bacteria.Moreover,soil microbial community structure can be used to monitor soil degradation in rhizosphere soil of different desert plants.