皖北淮河平原幼龄‘中山杉118'根际与非根际细菌特征分析

Rhizosphere and non-rhizosphere bacterial characteristics analysis of young Taxodium ‘Zhongshanshan 118'in Huaihe Plain of North Anhui

关键词:  中山杉118', 根际, 非根际, 细菌, 土壤养分, 高通量测序

Key words:   Taxodium ‘Zhongshanshan 118', rhizosphere, non-rhizosphere, bacterial, soil nutrients, high throughput sequencing

摘要:

为探究生态景观绿化树种‘中山杉118'对皖北淮河平原土壤生态系统的影响,该研究分析了其根际与非根际土壤养分差异、微生物类群及其影响因子。结果表明:(1)4年生‘中山杉118'根际对大量元素的富集能力较弱,水解性氮和有效磷出现亏欠现象,全氮与非根际持平,对全磷、全钾和速效钾有低程度的富集; ‘中山杉118'根际对微量元素铁、铜、锰的富集能力较强,其中根际有效锰含量显著高于非根际; ‘中山杉118'根际与非根际土壤均为碱性,根际pH略小于非根际,而根际的电导率则大于非根际,根际对速效钠、速效镁、速效钙有一定程度的富集,对有机碳和有机质也有一定的富集性。(2)Anosim组间群落结构差异显著性检验R值为0.224(P=0.022),R值显著大于0,表明‘中山杉118'根际与非根际细菌群落差异显著。‘中山杉118'根际与非根际共有5 283个OTUs,根际特有1 307个,非根际特有1 265个。(3)根际细菌多样性略小于非根际,两者的优势菌种为厚壁菌门、变形菌门、酸杆菌门、拟杆菌门、绿弯菌门、粘球菌门、放线菌门、泉古菌门,其中仅酸杆菌门与有效磷呈显著正相关,丰度较高的菌种中厚壁菌门、拟杆菌门在根际的含量分别为17.94%、5.21%,高于非根际1.84%、3.90%,并且两者与环境因子相关性不显著; 梭菌纲、拟杆菌纲和芽孢杆菌纲在根际的丰度比非根际分别高出14.05%、1.32%、2.06%。(4)UPGMA聚类树表明,‘中山杉118'根际R4样品独聚一枝,非根际样品NR4和NR5聚为一枝,NR1、NR2和NR3与根际R1、R2、R3、R5聚为一枝,R4的物种多样性及物种丰度明显低于其他样品且分布不均匀。综上认为,尽管幼龄‘中山杉118'根际效应较弱,但其是根际厚壁菌门和拟杆菌门富集的主要因素,栽培过程中应多补充微量元素,适量补充大量元素。

Abstract:

In order to explore the effects of ecological landscaping tree species Taxodium ‘Zhongshanshan 118' on soil microbial ecosystem in Huaihe Plain of north Anhui Province, the differences in soil nutrients levels, microbial communities structures and their influencing factors between the rhizosphere(R)and non-rhizosphere(NR)were analyzed. The results were as follows:(1)The 4-year-old Taxodium ‘Zhongshanshan 118' rhizosphere had a low enrichment capacity for macronutrients, resulting in a deficiency of hydrolyzable nitrogen and available phosphorus. The R had similar levels of total nitrogen, and lower levels of total phosphorus, total potassium and available potassium than the NR soil. The R had a strong enrichment ability for microelements(iron, copper, manganese). And the available manganese content in the R was significantly higher than that in the NR. Both the R and the NR soils of Taxodium ‘Zhongshanshan 118' were alkaline. The R had a slightly lower pH and a higher electrical conductivity than the NR. The R had a certain degree of enrichment for available sodium, available magnesium and available calcium, as well as for organic carbon and organic matter.(2)Based on the Anosim analysis of community structure between groups, the R value was 0.224(P=0.022), which was significantly greater than 0, indicating significant differences between the bacterial communities of the R and the NR of Taxodium ‘Zhongshanshan 118'. The total number of OTUs in the R and the NR was 5 283. There were 1 307 unique OTUs in R and 1 265 OTUs in NR.(3)The R had a slightly lower bacterial diversity than the NR. The dominant phylum in both the R and the NR were Firmicutes, Proteobacteria, Acidobacteriota, Bacteroidetes, Chloroflexi, Myxococcota, Actinobacteria, and Crenarchaeota. Among them, only Acidobacteriota showed a significant positive correlation with available phosphorus. The R had higher abundances of Firmicutes(17.94%)and Bacteroidetes(5.21%)than the NR(1.84% and 3.90%), respectively. Neither of them had a significant correlation with environmental factors. The R had higher abundances of Clostridia, Bacteroidia and Bacilli than the NR by 14.05%, 1.32% and 2.06%, respectively.(4)The UPGMA clustering analysis showed that R4 was isolated from the other samples. NR4 and NR5 formed a cluster, NR1, NR2 and NR3 clusted with R1, R2, R3 and R5. R4 had lower species diversity and abundance than the other samples, and had an uneven distribution of taxa. In conclusion, despite the weak rhizosphere effect of young Taxodium ‘Zhongshanshan 118', it was the main factor for the enrichment of Firmicutes and Bacteroidetes in the rhizosphere. And more microelements and a moderate amount of macroelements should be applied in the cultivation process.