锰矿区大叶胡枝子灌丛土壤的丛枝菌根真菌多样性

大叶胡枝子(Lespedeza davidii)为一种豆科灌木,具有较强耐受重金属胁迫及固氮能力,也是矿区一种重要修复植物。丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)是一类植物共生真菌,它在矿区与植物共生可促进植物生长、提高植物的抗逆性;但其种类、分布及其影响机制尚不够清楚。以大叶胡枝子灌丛土壤AMF群落为研究对象,采集矿区与非矿区大叶胡枝子冠下及其相邻空旷地土壤进行内部转录间隔区(ITS)测序,分析土壤理化性质,揭示不同样地土壤AMF群落的多样性及其影响因素。研究结果表明:(1)土壤样本共得到2961个可操作分类单元(OTU),其中属于AMF的OTU为66个;Silva数据库比对发现AMF有7目10科16属24种。AMF总体物种丰度为矿区相邻空旷地土壤>矿区冠下土壤>非矿区冠下土壤>非矿区相邻空旷地土壤,Shannon指数和Simpson指数与该趋势保持一致。(2)矿区土壤AMF群落以内养囊霉属(Entrophospora)等为优势属,非矿区冠下以斗管囊霉属(Funneliformis)等为优势属。稀有内养囊霉(Entrophospora infrequens)是4个样地共有的优势种,该种为广谱生态型种;Archaeospora sp.和Paraglomerales sp.为矿区冠下的优势种,它们对锰胁迫有较强的耐受性;Funneliformis sp.为非矿区冠下的优势种。(3)冗余分析(RDA)表明,AMF的种类和数量受到锰含量、土壤pH值以及全磷含量的显著影响。本研究结果说明AMF种类及多样性受到土壤理化性质的影响;矿区一些耐性AMF的存在提高了AMF多样性,它们有利于逆境条件下植物的生长。

Diversity of arbuscular mycorrhizal fungi in the soil of Lespedeza davidii scrub in manganese mining area

Lespedeza davidii is a shrub belonging to Fabaceae, which is also an important phytoremediation candidant plant in mining areas because of its strong tolerance to heavy metal stress and the ability of nitrogen-fixation. Arbuscular mycorrhizal fungi (AMF) is a kind of symbiotic fungi for plants, and its symbiosis with plants in the mining area can promote the plant growth and improve the plant resistance to stress. However, its species composition, distributions and influencing factors are still unclear. The AMF community of L. davidii scrub soil was selected as the study object, and the soil under L. davidii canopy and adjacent open land in mining and non-mining areas were collected to carry out internal transcribed spacer (ITS) sequencing and physical and chemical characteristics, aiming to reveal the diversity of soil AMF community in different sample sites and its influencing factors. The results showed that: (1) A total of 2961 operational taxonomic units (OTUs) were obtained from soil samples, among which 66 OTUs belonged to AMF. By consulting Silva database, 7 orders, 10 families, 16 genera and 24 AMF species were obtained. Total species abundance of AMF was the soil in the adjacent open land of mining area>soil under the crown of mining area>soil under the crown of non-mining area>soil in the adjacent open land of non-mining area. The trend of Shannon Index and Simpson Index was the same as that of species abundance. (2) Entrophospora and so on were the dominant genera in the AMF community of the soil in mining area, while Funneliformis and so on were the dominant genera in the AMF community of the soil under the crown of non-mining area. Entrophospora infrequens was the common dominant species in four sample sites, which belonged to a broad-spectrum ecotype species. Archaeospora sp. and Paraglomerales sp. were the dominant species in the AMF community of the soil under the crown of mining area, with strong adaptability to heavy metal stress. Funneliformis sp. was the dominant species in the AMF community of the soil under the crown of non-mining area. (3) Redundancy analysis (RDA) illustrated that the species and amounts of AMF were significantly affected by Mn content, soil pH value, and total phosphorus content. All these results showed that AMF species and diversity were effected by soil physicochemical properties. The presence of some AMF, which had strong tolerance in mining area, improved the species diversity, and they can help plant grow under adverse conditions.