Liang Yue-Ming, Su Yi-Rong, He Xun-Yang, Chen Xiang-Bi
Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China.
Key Laboratory of Karst Dynamics, Ministry of Land and Resources & Guangxi Zhuangzu Autonomy Region, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin 541004, China.
Huan Jing Ke Xue. 2017 Mar 8;38(3):1253-1261. doi: 10.13227/j.hjkx.201606215.
Lithology is a key factor when used to restore vegetation in karst degraded ecosystems, and arbuscular mycorrhizal (AM) fungi and nitrogen-fixing bacteria play an important role in improving plant growth. However, little information is available regarding the effects of lithology on these two groups of microorganisms. To test whether these microbial communities are impacted by lithology, the abundance and composition of soil AM fungal and nitrogen-fixing bacteria communities were determined through terminal restriction fragment length polymorphism (T-RFLP) and real-time fluorescence-based quantitative PCR (real-time PCR). Three types of lithology (dolomite, limestone and dolomite-limestone) were selected in this study. The diversity, richness, and evenness of plant species were evaluated through field surveys and soil properties were measured. The results showed that the abundances of soil nitrogen-fixing bacteria and arbuscular mycorrhizal fungal communities were significantly influenced by lithology. The abundances of these two groups of microorganisms were the lowest in dolomite soil, inferior to dolomite-limestone soil, while highest in limestone soil. Similarly, the composition of soil nitrogen-fixing bacteria and AM fungi communities varied among lithology. A significant linear correlation was observed among soil organic carbon, available phosphorus, clay content and nitrogen-fixing bacterial abundance (<0.05), and a significant linear correlation among total nitrogen, clay content and AM fungal abundance (<0.05). Redundancy analysis showed that the composition of nitrogen-fixing bacterial community was closely linked to plant evenness, and the AM fungal community composition was closely linked to plant diversity (plant evenness, Shannon-wiener and richness). These results indicated that lithology influenced the abundances and compositions of soil nitrogen-fixing bacteria and arbuscular mycorrhizal (AM) fungal communities mainly through plant and soil properties.
岩性是喀斯特退化生态系统植被恢复的关键因素，丛枝菌根（AM）真菌和固氮细菌在促进植物生长方面发挥着重要作用。然而，关于岩性对这两类微生物影响的信息却很少。为了测试这些微生物群落是否受到岩性的影响，通过末端限制性片段长度多态性（T-RFLP）和基于实时荧光的定量PCR（实时PCR）测定了土壤AM真菌和固氮细菌群落的丰度和组成。本研究选择了三种岩性类型（白云岩、石灰岩和白云岩-石灰岩）。通过实地调查评估了植物物种的多样性、丰富度和均匀度，并测量了土壤性质。结果表明，土壤固氮细菌和丛枝菌根真菌群落的丰度受岩性显著影响。这两类微生物的丰度在白云岩土壤中最低，低于白云岩-石灰岩土壤，而在石灰岩土壤中最高。同样，土壤固氮细菌和AM真菌群落的组成在不同岩性之间也有所不同。土壤有机碳、有效磷、粘粒含量与固氮细菌丰度之间存在显著线性相关（<0.05），全氮、粘粒含量与AM真菌丰度之间存在显著线性相关（<0.05）。冗余分析表明，固氮细菌群落组成与植物均匀度密切相关，AM真菌群落组成与植物多样性（植物均匀度、香农-威纳指数和丰富度）密切相关。这些结果表明，岩性主要通过植物和土壤性质影响土壤固氮细菌和丛枝菌根（AM）真菌群落的丰度和组成。
