不同重金属胁迫对乡土树种根际土壤微生物多样性的影响

Effects of Different Heavy Metal Stresses on Soil Microbial Diversity in Rhizosphere of Native Tree Species

摘要: 为了说明乡土树种为何能耐受重金属等不良环境因子的胁迫，以及乡土树种根际土壤微生物群落与环境因子的相互关系，用电感耦合等离子体质谱仪(ICP-MS)，分别测定了枫香、银杏、紫玉兰、国槐等乡土树种根际土壤Mn、Pb、Zn、Cu、Cd、As等重金属的含量，利用lltmina高通量测序手段，对乡土树种根际土壤细菌群落进行比较分析。结果表明：① 枫香、银杏、紫玉兰、国槐对重金属元素Mn、Zn、As、Pb有较强耐性；② KQ (矿区)组变形菌门、绿弯菌门、硝化螺旋菌门、芽单胞菌门的丰度明显高于FKQ (非矿区)组；③ 矿区乡土树种根际土壤特征微生物为硝化螺菌属与根瘤菌属，推测二者的作用主要是通过改变土壤中的氮环境，增强植物固氮循环，提高植物代谢能力，从而强化植物对重金属的耐受性。由此可见，重金属对乡土树种根际土壤微生物多样性和细菌群落结构具有重要的影响，根际土壤微生物对植物的重金属耐性及吸收能力具有重要的调控作用。

Abstract: In order to explain why native tree species can tolerate the stress of heavy metals and other adverse environmental factors, and the relationship between the rhizosphere soil microbial community of native tree species and environmental factors, the inductively coupled plasma mass spectrometer (ICP-MS) was used to detect the content of Mn, Pb, Zn, Cu, Cd, As and other heavy metals in the rhizosphere soil of native tree species such as Liquidambar formosana, Ginkgo biloba, Yulania liliiflora, and Styphnolobium japonicum. The lltmina high-throughput sequencing method was used to compare and analyze the bacterial communities in the rhizosphere soil of native tree species. The results showed that: 1). Liquidambar formosana, Ginkgo biloba, Yulania liliiflora and Styphnolobium japonicum had strong tolerance to heavy metal elements of Mn, Zn, As, Pb; 2). The abundance of Proteobacteria, Chloroflexomycota, Nitrospira and Blastomonas in KQ (Mining area) group is significantly higher than that of the FKQ (Non-mining area) group; 3). The characteristic microbes in the rhizosphere soil of the native tree species in the mining area are Nitrospira and Rhizobium. It is inferred that the role of the two is mainly to change the nitrogen environment in the soil, enhance the nitrogen fixation cycle of plants, and improve plant metabolism capacity, thereby strengthening the plant’s tolerance to heavy metals. It can be seen that heavy metals have an important effect on the rhizosphere soil microbial diversity and bacterial community structure of native tree species, and rhizosphere soil microorganisms have an important regulatory role on the plant’s heavy metal tolerance and absorption capacity.