黔北赤水河流域不同林分土壤理化性质与微生物群落的构成特征及相关性研究

【作者】 袁小松；

【导师】 纳日碧力戈；

【作者基本信息】 贵州大学 ， 生态学， 2022， 博士

【摘要】 赤水河是长江水系的重要支流,黔北赤水河流域是世界著名的酱香型白酒核心产区,也是贵州经济增长的重要贡献地,当地酿酒技艺与酿酒产业对生态环境的依赖程度极高。因此,基于当地生态系统特征及发展变化机制选择生态管理策略,进而保护好黔北赤水河流域生态意义重大。而之前的黔北赤水河流域生态系统研究,多见于大气、河流生态等领域,极少有从森林生态角度开展。调查发现,黔北赤水河流域分布了大量以马尾松和栓皮栎作为优势树种形成的马尾松针叶林、栓皮栎阔叶林和马尾松+栓皮栎混交针阔混交林植被类型,这些森林植被广泛分布于赤水河河岸两侧,对赤水河流域生态功能以及区域生态平衡提供了重要的生态保障。然而,不同林分土壤的理化性质与微生物群落的构成特征以及二者之间的相关性尚不清楚。厘清这种构成特征及相关性,对于深入探索流域植被调控土壤演化的微生物功能以及植被演替机制、探索黔北赤水河流域乃至长江中上游生态保护和管理策略具有重要理论和实践价值。本研究选择黔北赤水河流域马尾松针叶林、栓皮栎纯阔叶林和马尾松+栓皮栎针阔混交林下的土壤理化性质和微生物为研究对象,在黔北赤水河流域选取6个典型森林样地设置10 m×10 m样方进行植物群落学调查,并在样方内按照对角线5点取样法进行土壤采集。采样时自上而下分A层(0 cm-10cm)、B层(10 cm-20cm)和C层(20 cm-30cm)各采集土壤样品1.5 kg,分别检测了马尾松针叶林、栓皮栎阔叶林及马尾松+栓皮栎针阔混交林3种类型森林土壤的理化性质,并采用第二代高通量分子测序方法分析了土壤真菌、细菌微生物α多样性、β多样性,通过Pearson相关性分析及CCA和RDA分析该区域微生物的群落的构成及相对丰度与土壤理化因子之间的关系。主要结果如下:(1)不同理化因子在不同林分下土壤及土层中的分布具有显著差异,并且重金属对土壤肥力因子的含量具有重要影响。14类理化因子(全磷、全钾、速效钾、缓效钾、铬、铅、铜、镍、汞、砷、p H值、镁、锌、钙)的含量在不同林分下的分布差异显著。其中,全磷、汞和砷在马尾松针叶林下土壤中的分布占显著优势,全钾、铜和钙在栓皮栎阔叶林下土壤中的含量优势显著,铅在马尾松+栓皮栎混交林下土壤中的含量占明显优势,而缓效钾、速效钾、镍、铬、锌和镁在栓皮栎阔叶林和马尾松+栓皮栎混交林下土壤中的含量均显著高于马尾松针叶林。全氮、碱解氮、全磷、有机质、砷、铅、汞、钙和镉趋向于分布在三类林分的A层土壤,而全钾、速效钾、缓效钾、铬、铜、镍、锌和镁主要分布在B层和C层土壤。三类林分下的土壤均属于酸性土壤,其中马尾松+栓皮栎混交林下的土壤酸性显著高于马尾松针叶林和栓皮栎阔叶林,三类林分下C层土壤的酸性高于A和B层土壤,马尾松针叶林下的这种差异最为显著。土壤中的氮素含量受到镉、汞和砷的显著影响,磷素受到铜、汞和砷的显著影响,钾素受到铬、镉、铜、镍和锌的显著影响,有机质主要受到汞和砷的显著影响,这些影响因林分的不同有显著差异。(2)真菌群落的构成及多样性随林分变化而具有显著差异。不同林分土壤真菌中的主要门类是子囊菌门和担子菌门,主要优势属是红菇属、乳菇属和革菌属等松属和栎属树种常见的外生菌根真菌类群。马尾松林的土壤真菌群落多样性显著高于栓皮栎阔叶林,针阔混交林与针叶林和阔叶林之间的土壤真菌群落多样性并不存在显著性差异。相同林分不同土层中,A层土壤真菌多样性均要大于B层和C层土壤,网络复杂性也均要高于B层和C层。(3)细菌群落的构成及多样性随林分变化而具有显著差异。不同林分土壤细菌中的主要门类是放线菌门、变形菌门、酸杆菌门和绿弯菌门,主要优势属是酸热菌属、康奈斯氏杆菌属、分枝杆菌属、慢生根瘤菌属、苔藓杆菌属、酸杆菌属、克洛氏菌属、念珠菌固体杆菌属等。栓皮栎林下的土壤细菌α多样性最高,混交林次之,马尾松林最低。相同林分不同土层中,A层土壤的细菌的β多样性均要高于B和C层土壤。(4)无论是真菌群落还是细菌群落在不同林分下土壤中的分布均受到理化因子的显著影响。CCA分析结果表明马尾松针叶林和栓皮栎阔叶林土壤真菌的分布主要受到土壤酸碱度的影响,而马尾松-栓皮栎真阔混交林土壤真菌群落的分布主要受到土壤重金属(主要是镉和铅)含量的影响。RDA分析结果表明,门水平的细菌类群对全磷、全氮、有机质、碱解氮和p H的响应比较显著,而在属水平上多数细菌类群对镁、铬、锌、镍和钙的响应比较显著,土壤阳离子交换量、有机质、全氮、全钾、p H以及土壤缓效钾、铝、钙和砷的含量对不同林分下土壤细菌ASV的分布产生了显著影响。马尾松林下土壤中细菌类群垂直分布受到土壤p H值和重金属元素铬的显著影响;栓皮栎林下土壤中细菌类群的垂直分布受到土壤酸碱度、全磷、铬、钙和铜的含量的显著影响。更多还原

【Abstract】 Chishui River is an important tributary of the Yangtze River system.Chishui River Basin in northern Guizhou is the world-famous core production area of sauce fragrant liquor and makes important contributions to the economic growth of Guizhou.The local winemaking techniques and the winemaking industry are highly dependent on the ecological environment.Therefore,it is of great significance to choose ecological management strategies based on local ecosystem characteristics and development and change mechanisms to protect the ecology of the Chishui River basin in northern Guizhou.However,the previous studies on the ecosystem of Chishui River basin are mostly found in the fields of atmosphere and river ecology,and few are carried out from the perspective of forest ecology.A large number of coniferous forests with Pinus massoniana as the dominant tree,broad-leaved forests with Quercus variabilis as the dominant tree,as well as their mixed forests mainly composed of P.massoniana and Q.variabilis are distributed in the Chishui River basin in northern Guizhou.These forests are widely distributed along the banks of the Chishui River,providing an important ecological safeguard for the ecological function and regional balance of nature of the Chishui River basin.However,the relationship between soil physicohemical properties and microbial community composition in different forest stands remains unclear.It is of great theoretical and practical value for further exploring the microbial function and vegetation succession mechanism of soil evolution regulated by vegetation in the basin,and for exploring ecological protection and management strategies in the Chishui River Basin and the middle and upper reaches of the Yangtze River Basin.Here,the soil physicochemical properties and microorganisms of coniferous forest,broad-leaved forest and mixed forest in the northern Chishui River basin of Guizhou province were studied,a 10 m × 10 m sampling plot was set up in six typical forest plots,and soil samples were collected according to the 5-point diagonal sampling method.Soil samples of 1.5 kg were collected from layer A(0 cm-10 cm),layer B(10cm-20 cm)and layer C(20 cm-30 cm)from top to bottom.Soil physicochemical properties of three forest types,namely coniferous forest,broad-leaved forest and their mixed forest were detected.The second generation high-throughput molecular sequencing was employed to analyze the α-diversity and β-diversity of soil fungi and bacterial microorganisms.Pearson correlation analysis,CCA and RDA were used to analyze the relationship between the composition and relative abundance of microbial communities and soil physicochemical factors.The main results are as follows:(1)There were significant differences in the distribution of different physicochemical factors in soil and soil layer under different stands,and heavy metals have an important influence on the content of soil fertility factors.The contents of 14 physicochemical factors(total phosphorus,total potassium,available potassium,slow potassium,chromium,lead,copper,nickel,mercury,arsenic,p H,magnesium,zinc,calcium)are significantly different in different stands.Among them,the distribution of total phosphorus,mercury and arsenic in the soil under coniferous forest is significantly dominant,the content of total potassium,copper and calcium in the soil under the broad-leaved forest is significantly dominant,and the content of lead in the soil under the mixed forest was evidently dominant.However,the contents of slow-available potassium,available potassium,nickel,chromium,zinc and magnesium in the soil of broad-leaved forest and mixed forest are significantly higher than those of coniferous forest.The total nitrogen,alkali-hydrolyzable nitrogen,total phosphorus,organic matter,arsenic,lead,mercury,calcium and cadmium tended to be distributed in the A layer soil of the three forest stands,while the total potassium,available potassium,slow available potassium,chromium,copper,nickel,zinc and magnesium are mainly distributed in the B layer and C layer soil.The soil under the three kinds of forest stands are all acidic soil,and the soil acidity under the mixed forest is significantly higher than that of coniferous forest and broad-leaved forest,and the soil acidity of layer C is higher than that of layer A and layer B under the three kinds of forest stands,and this difference is most significant under the coniferous forest.The nitrogen content in the soil is significantly affected by cadmium,mercury and arsenic,phosphorus is significantly affected by copper,mercury and arsenic,and potassium is significantly affected by chromium,cadmium,copper,nickel and zinc,organic matter is significantly affected by mercury and arsenic,which were significantly affected by different forest stands.(2)The composition and diversity of fungal communities varied significantly with the change of stand.Ascomycota and Basidiomycota are the main groups of soil fungi in different forest stands,and ectomycorrhizal fungi of Pinus and Quercus species,such as Russula,Lactarius and Tomentella.are the dominant genera.The diversity of soil fungal community in coniferous forest is significantly higher than that in broad-leaved forest.There is no significant difference in soil fungal community diversity between coniferous and broad-leaved forest as well as their mixed forest.In different soil layers of the same forest stand,soil fungal diversity in layer A is higher than that in layer B and C,and the network complexity is also the same.(3)The composition and diversity of bacterial communities are significantly different with the change of stand.The main groups of soil bacteria in different forest stands are Actinobacteria,Proteobacteria,Acidobacteria and Chlorobacteria,and the dominant genera were Acidothermus,Conexibacter,Mycobacterium,Bradyrhizobium,Bryobacter,Acidibacter,Crossiella,and Candidatus＿Solibacter,etc.Soil bacterial αdiversity under broad-leaved forest is the highest,followed by mixed forest and coniferous forest.In different soil layers of the same stand,the bacterial β-diversity of soil layer A was signifcantly higher than that of soil layer B and C.(4)The distribution of fungal and bacterial communities in soil under different stands is significantly affected by physicochemical factors.The results of CCA analysis showed that the distribution of soil fungi in coniferous forest and broad-leaved forest is mainly affected by soil p H,while the distribution of soil fungal community in mixed forest is mainly affected by soil heavy metals(mainly cadmium and lead).The results of RDA analysis showed that bacterial groups at phylum level had significant responses to total phosphorus,total nitrogen,organic matter,alkali-hydrolyzed nitrogen and p H,while most bacterial groups at genus level had significant responses to magnesium,chromium,zinc,nickel and calcium.Soil cation exchange capacity,organic matter,total nitrogen,total potassium,p H,and soil slow-available potassium,aluminum,calcium and arsenic have significant effects on the distribution of soil bacterial ASV in different stands.The vertical distribution of bacterial groups in the understory soil of coniferous forest is significantly affected by soil p H and heavy metal element chromium.The vertical distribution of bacterial groups in soils under broad-leaved forest is significantly affected by soil p H,total phosphorus,chromium,calcium and copper contents.更多还原