Diversity of soil bacteria and fungi communities in artificial forests of the sandy-hilly region of Northwest China

Soil erosion is a serious issue in the sandy-hilly region of Shanxi Province,Northwest China.There has been gradual improvement due to vegetation restoration,but soil microbial community characteristics in different vegetation plantation types have not been widely investigated.To address this,we analyzed soil bacterial and fungal community structures,diversity,and microbial and soil environmental factors in Caragana korshinskii Kom.,Populus tomentosa Carr.,Populus simonii Carr.,Salix matsudana Koidz,and Pinus tabulaeformis Carr.forests.There were no significant differences in the dominant bacterial community compositions among the five forest types.The alpha diversity of the bacteria and fungi communities showed that ACE(abundance-based coverage estimator),Chao1,and Shannon indices in C.korshinskii forest were significantly higher than those in the other four forest types(P<0.05).Soil organic matter,total nitrogen,and urease had a greater impact on bacterial community composition,while total nitrogen,β-glucosidase,and urease had a greater impact on fungal community composition.The relative abundance of beneficial and pathogenic microorganisms was similar across all forest types.Based on microbial community composition,diversity,and soil fertility,we ranked the plantations from most to least suitable as follows:C.korshinskii,S.matsudana,P.tabulaeformis,P.tomentosa,and P.simonii.

Resistance of Microbial Community of Artemisia annua L.to Pathogenic Fungi

[Objectives]This paper was to figure out whether the dominant bacterial community has the role and effect of bacterial community and its defense mechanism against potential pathogenic fungi in Artemisia annua,and thus establish a systematic model of bacteria-fungus-plant.[Methods]Fifty-eight strains of bacteria and one strain of pathogenic fungi,Globisporangium ultimatum,were used for the experiments.These 58 bacterial strains were assembled into a bacterial community,and the bacteria with abundance in the top 1%were reassembled into a dominant bacterial community as measured by 16S rDNA.[Results]The growth of A.annua seedlings inoculated with bacterial communities and pathogenic fungi or dominant bacterial communities and pathogenic fungi was significantly better than that of A.annua seedlings inoculated with pathogenic fungi during in vitro confrontation,which was evident in both enzymatic and non-enzymatic antioxidant assays.[Conclusions]The results suggest that the dominant bacterial community has a crucial role as a representative core microbial community of synthetic bacterial community,which can protect plants by interfering with the growth of phytopathogenic fungi mediated by chemical signals,and can be used as the main synthetic community of biocides to achieve the effect of biocontrol.

Effect of Arbuscular Mycorrhizal Fungi and Their Partner Bacteria on the Growth of Sesame Plants and the Concentration of Sesamin in the Seeds

Arbuscular mycorrhizal fungi (AMF) can stimulate the plant growth. Pseudomonas sp. (KCIGC01) NBRC109613 isolated from the spores of Glomus clarum IK97, an AMF, is reported to support the plant growth and development as partner bacteria (PB) for AMF REF _Ref399417929 \r \h \* MERGEFORMAT [1]. In order to investigate the effect of G. clarum IK97 and Pseudomonas sp. (KCIGC01) NBRC109613 on the secondary metabolites, these microorganisms were inoculated to sesame plants. The inoculation of these microorganisms stimulated the growth of sesame. The rate of sesame root colonization in G. clarum IK97 + Pseudomonas sp. (KCIGC01) NBRC109613 inoculated plants (66.4% ± 4.4%) was higher than that in G. clarum IK97 alone inoculated plants (39.2% ± 5.8%). Furthermore, the content of sesamin in sesame seeds was increased by the inoculation of these microorganisms. In particular, the content of sesamin in the treatment inoculated with G. clarum IK97 and Pseudomonas sp. (KCIGC01) NBRC-109613 was 11.4 ± 1.5 mg/g seed. The results suggest that AMF and their partner bacteria can stimulate the growth and development of sesame plants and increase the content of sesamin in the seeds.

Straw bio-degradation by acidogenic bacteria and composite fungi

A composite microbial system, including a strain of Candida tropicalis(W3), a strain of Lactobacillus plantarm(WY3) and three strains of basidiomycete pL104, pL113 and C33, was chosen to degrade corn straw. The final pH was acid owing to the inoculation of acidogenic bacteria, and under this condition the composite fungi system could produce complex enzyme to destroy the compact structure of corn straw. The experimental results showed that the biomass of composite fungi could reach up to maximum when the pH value was 4.5. Through the bio-degradation by combining acidogenic bacteria with the composite fungi system, the cellulose, hemi-cellulose and lignin degradation rates of corn straw powder were 26.36%, 43.30% and 26.96%, respectively. And the gross crude protein content increased 60.41%. This study provided the evidence for the feasibility of developing a composite microbial system with high capability of degrading straw lignocelluloses in order to make reasonable use of straw resource and protect rural eco-environment.

BIOLOGICAL NITROGEN REMOVAL FROM WASTEWATER BY DENITRIFICATION OF MIX-CULTURING FUNGI AND BACTERIA

Denitrification has been long thought to be a unique characteristic of prokaryotes, but in recent years, several filamentous fungi and yeasts were found to exhibit denitrifying activities. This paper deals with the examination of denitrification capabilities by mix-cultures of the fungus (Fusarium oxysporum) and the bacterium (Pseudomonas stutzeri TR2) in combination with a specific medium and using a synthetic wastewater of defined quality. The results revealed that P. stutzeri TR2 has strong and fast denitrifying capabilities under anaerobic conditions, and that co-denitrification of mix-cultures with F. oxysporum and P. stutzeri TR2 was more effective to remove nitrate under limited oxygen conditions. P. stutzeri TR2 was able to remove nitrate completely during cultivation for 12 hr in the specific medium and in mixed culture with F. oxysporum. A rapid N 2 evolution by mixed culture with F. oxysporum and P. stutzeri TR2 was observed in both mixed culture medium and synthetic wastewater. Using synthetic wastewater with a defined composition, about 87% of the nitrate was eliminated to form about 420μmol of N 2 from 1.0mmol of NO-3 by co-denitrification of F. oxysporum and P. stutzeri TR2 after incubation for 6days. In co-cultures of F. oxysporum and P. stutzeri TR2, N2O produced by F. oxysporum was rapidly consumed by P. stutzeri TR2. This indicated that mixed culture of F. oxysporum and P. stutzeri TR2 can be used to remove nitrate and nitrite from wastewater effectively.

Response of arbuscular mycorrhizal fungi and phosphorus solubilizing bacteria to remediation abandoned solid waste of coal mine

Coal is the vital resource of energy in China,but abandoned coal ash and gangue lead to the degradation of vegetation cover and reduce soil quality.Both arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) play a key role in biogeochemical cycle such as soil organic matter decomposition,nutrition release,and energy flow.To improve and reclamation the soil quality and ecological efficiency of the coal mining waste,we investigated the effects of an AMF strain (Glomus mosseae) and a PSB strain (Pantoesstewarti) on phytate mineralization and subsequent transfer to the host plant (Medicago sativa L.) using a two-compartment microcosm with a central 30 mm nylon mesh barrier.The results showed that significantly higher available P (AP),above ground biomass (AGB) and underground biomass (UGB) were in combined inoculation of AMF-PSB than other treatments in root and hyphae compartment.The microbial inoculum of the AMF or PSB had a significant influence on soil acid phosphatase activities (ACP).AMF-PSB enhanced phytate mineralization,improved plant biomass.AP and ACP positively influenced the AGB and UGB.AMF-PSB could be used as bioinoculant to enhance sustainable production of the plant in abandoned solid waste of coal mine.

Uniform categorization of biocommunication in bacteria,fungi and plants

This article describes a coherent biocommunication categorization for the kingdoms of bacteria,fungi and plants. The investigation further shows that,besides biotic sign use in trans-,inter-and intraorganismic communication processes,a common trait is interpretation of abiotic influences as indicators to generate an appropriate adaptive behaviour.Far from being mechanistic interactions,communication processes within organisms and between organisms are sign-mediated interactions.Sign-mediated interactions are the precondition for every cooperation and coordination between at least two biological agents such as cells,tissues,organs and organisms.Signs of biocommunicative processes are chemical molecules in most cases.The signs that are used in a great variety of signaling processes follow syntactic(combinatorial) ,pragmatic(context-dependent) and semantic(contentspecific) rules.These three levels of semiotic rules are helpful tools to investigate communication processes throughout all organismic kingdoms.It is not the aim to present the latest empirical data concerning communication in these three kingdoms but to present a unifying perspective that is able to interconnect transdisciplinary research on bacteria,fungi and plants.

The effect of soil moisture on the response by fungi and bacteria to nitrogen additions for N_(2)O production

In addition to bacteria,the contribution of fungi to nitrous oxide(N_(2)O)production has been recognized but the responses of these two broad and unrelated groups of microorganisms to global environmental changes,atmospheric nitrogen(N)deposition,and precipitation in terms of N_(2)O production are unclear.We studied how these two microbial-mediated N_(2)O production pathways responded to soil moisture conditions and to N addition in an N-limited temperate forest.Soils from a long-term N addition experiment in Changbai Mountain,northeastern China were incubated.Varied concentrations of cycloheximide and streptomycin,both inhibitors of fungal and bacterial activity,were used to determine the contributions of both to N_(2)O production in 66%,98%and 130%water-filled pore spaces(WFPS).The results showed that N_(2)O production decreased significantly with increasing cycloheximide concentration whereas streptomycin was only inhibiting N_(2)O emissions at 98%and 130%WFPS.The bacterial pathway of N_(2)O production in N-addition(Nadd)soil was significantly more dominant than that in untreated(Namb)soil.The difference in the fungal pathway of N_(2)O production between the soil with nitrogen addition and the untreated soil was not significant.Net N_(2)O emissions increased with increasing soil moisture,especially at 130%WFPS,a completely flooded condition.Bacteria dominated carbon dioxide(CO_(2))and N_(2)O emissions in Nadd soil and at 130%WFPS regardless of N status,while fungi dominated CO_(2)and N_(2)O emissions in soil without N addition at 66%and 98%WFPS.The results suggest that flooded soil is an important source of N_(2)O emissions and that bacteria might be better adapted to compete in fertile soils under anoxic conditions.

Shifting cultivation effects on soil fungi and bacterial population in Chittagong Hill Tracts, Bangladesh

A study was conducted at two pair sites of Chittagong Hill Tracts in Bangladesh to find out the effects of shifting cultivation on soil fungi and bacterial population. The first pair of sites with shifting culti-vation and village common forest-managed by indigenous community was at Madhya Para in Rangamati district and the second pair of sites with the shifting cultivated land and village common forest at Ampu Para in Bandarban district of Chittagong Hill Tracts. At both the locations with two different land uses, soil textures in surface （0？10 cm） and sub-surface （10？20 cm） soils varied from sandy loam to sandy clay loam. Soil pH and moisture content were lower in shifting cultivated land com-pared to village common forest. The results also showed that both fungal and bacterial population in surface and subsurface soils was significantly （p ≤ 0.05） lower, in most cases, in shifting cultivated land compared to village common forest at both Madhya Para and Ampu Para. At Ranga-mati and Bandarban in shifting cultivated lands, Colletrotrichum and Fusarium fungi were absent and all the bacterial genus viz. Coccus, Bacillus and Streptococcus common in two different locations with dif-ferent land uses. Common identified fungi at both the land uses and locations were Aspergillus, Rhizopus, Trichoderma and Penicillium. Further study can be done on the other soil biota to understand the extent of environmental deterioration due to shifting cultivation.

Isolation and Screening of Silicate Bacteria from Various Habitats for Biological Control of Phytopathogenic Fungi

Silicate solubilizing bacteria (SSB) can play an efficient role in soil by solubilizing insoluble forms of silicates. In addition to this some SSB can also solubilize potassium and phosphates, hence increasing soil fertility and enhancing plant defense mechanisms. A total of 111 bacterial strains were isolated from various habitats of Pakistan and screened for solubilization of silicate, phosphate and potassium on respective media. Out of these, 35 bacterial isolates were capable of solubilizing either silicate, phosphate or potassium. Amongst these 7 bacterial isolates were capable of solubilizing all three minerals tested. The highest silicate (zone diameter 54 mm) and phosphate solubilization (zone diameter 55 mm) was observed for bacterial isolate NR-2 while the highest potassium solubilization was observed for NE-4b (zone diameter 11 mm). Dual culture antagonistic assays were carried out by using these bacterial isolates against four plant pathogenic fungi Magnaporthae grisae, Rhizoctonia solani, Altarnaria alternata and Macrophomina pheasolina. Mean zone of inhibition of these bacterial isolates against the four pathogenic fungi ranged between 4 mm to 39 mm. The largest zone of inhibition against all four bacterial strains was recorded for bacterial isolate NR-2 followed by NE-4b. These strains will be further investigated for their plant growth promoting activities in the future.

Plant growth-promoting properties and anti-fungal activity of endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta in arid lands

Endophytes,as crucial components of plant microbial communities,significantly contribute to enhancing the absorption of nutrients such as nitrogen and phosphorus by their hosts,promote plant growth,and degrade pathogenic fungal mycelia.In this study,an experiment was conducted in August 2022 to explore the growth-promoting potential of endophytic bacterial strains isolated from two medical plant species,Thymus altaicus and Salvia deserta,using a series of screening media.Plant samples of Thymus altaicus and Salvia deserta were collected from Zhaosu County and Habahe County in Xinjiang Uygur Autonomous Region,China,in July 2021.Additionally,the inhibitory effects of endophytic bacterial strains on the four pathogenic fungi(Fusarium oxysporum,Fulvia fulva,Alternaria solani,and Valsa mali)were determined through the plate confrontation method.A total of 80 endophytic bacterial strains were isolated from Thymus altaicus,while a total of 60 endophytic bacterial strains were isolated from Salvia deserta.The endophytic bacterial strains from both Thymus altaicus and Salvia deserta exhibited plant growth-promoting properties.Specifically,the strains of Bacillus sp.TR002,Bacillus sp.TR005,Microbacterium sp.TSB5,and Rhodococcus sp.TR013 demonstrated strong cellulase-producing activity,siderophore-producing activity,phosphate solubilization activity,and nitrogen-fixing activity,respectively.Out of 140 endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta,104 strains displayed anti-fungal activity against Fulvia fulva,Alternaria solani,Fusarium oxysporum,and Valsa mali.Furthermore,the strains of Bacillus sp.TR005,Bacillus sp.TS003,and Bacillus sp.TSB7 exhibited robust inhibition rates against all the four pathogenic fungi.In conclusion,the endophytic bacterial strains from Thymus altaicus and Salvia deserta possess both plant growth-promoting and anti-fungal properties,making them promising candidates for future development as growth-promoting agents and biocontrol tools for plant diseases.

设施西瓜连作土壤生化性质及微生物群落变化

为探索设施连作西瓜土壤微生态环境变化,通过高通量测序对连作组(连作10年设施西瓜土壤)和对照组(连作10年设施西瓜棚外相同土质的露天西瓜土壤)样品进行测序分析,比较2组土壤细菌和真菌的群落结构差异,测定土壤理化性质及酶活性。结果表明,连作组土壤pH、铵态氮、速效钾、微生物量碳、土壤酶活性极显著低于对照,而硝态氮和有效磷极显著高于对照组。连作组土壤中细菌ACE指数和Chaol指数均极显著高于对照组,土壤中真菌ACE指数、Chaol指数、Simpson指数和Shannon指数均低于对照组。土壤微生物优势物种组成改变,连作组土壤细菌变形菌门、芽单胞菌门、绿弯菌门及硝化螺旋菌门相对丰度较对照组分别增加了9.80%、20.83%、21.76%和27.12%(P<0.05),而酸杆菌门和疣微菌门较对照组分别减少了21.7%和26.27%(P<0.05);连作组土壤真菌子囊菌门相对丰度较对照组增加了10.96%(P<0.05),担子菌门和罗兹菌门的相对丰度分别较对照组减少了13.42%和93.77%(P<0.05)。相关性分析显示,优势菌门除Latescibacteria和己科河菌门丰度与所有土壤环境因子相关性均不显著外,其他优势菌群都与所测土壤环境因子(有机质除外)存在密切相关关系,土壤pH、铵态氮、有效磷、速效钾是影响土壤中微生物群落的主要因素,担子菌门和绿弯菌门能够指示土壤微生物量,微生物群落结构的变化对土壤酶活性有较大的影响。综上,设施西瓜连作10年土壤理化性质、酶活性及微生物群落结构皆显著变化,西瓜连作障碍是多种因素综合作用的结果。

增施微生物肥对设施黄瓜土壤微生物多样性的影响

【目的】研究增施微生物肥对土壤微生物群落结构和功能的影响,为设施蔬菜栽培过程中微生物肥的使用、土壤改良及提高蔬菜产量提供理论基础。【方法】选择蔬菜为黄瓜,以土壤微生物为研究对象,以不施用微生物肥土壤为对照,采用16S rRNA和真菌ITS区测序,分析微生物肥对土壤微生物群落结构和功能的影响。【结果】增施微生物肥可增加拟杆菌门、绿弯菌门和厚壁菌门的细菌丰度和担子菌门的真菌丰度,降低子囊菌门和被孢霉门的真菌丰度;增加土壤中微生物的均匀度和细菌的多样性,降低真菌多样性;通过增加有益细菌的含量、减少病源真菌、丰富种群,有效改善土壤微生物群落功能,微生物群落的代谢功能强于对照土壤。【结论】施用微生物肥料可以改善土壤营养环境,为土壤微生物的生命活动提供充足的养分和能源,从而促进微生物生长繁殖,丰富种群,有效改善土壤微生物群落功能。

浙江九龙山香果树生境土壤微生物多样性及其影响因素

【目的】揭示珍稀植物香果树Emmenopteryshenryi生境土壤微生物多样性变化信息及其影响因素,为香果树的保护和繁育提供参考。【方法】通过高通量测序技术检测了34个香果树群落生境的土壤细菌和真菌种类,分析海拔、坡向、土壤理化性质和香果树群落特征对土壤细菌和真菌多样性的影响。【结果】α多样性分析表明:九龙山香果树生境土壤细菌Shannon-Wiener指数均值为5.87,Simpson指数均值为0.98;土壤真菌Shannon-Wiener指数均值为4.88,Simpson指数均值为0.97。细菌Shannon-Wiener指数当量(H')随海拔升高而显著降低(P<0.05),随土壤pH(4.62~5.83)升高而显著升高(P<0.05);土壤细菌Simpson指数当量(D')与土壤速效钾呈显著负相关(P<0.05)。真菌H'和D'都随着海拔上升呈先下降后上升的趋势,且随碱解氮的升高而显著降低(P<0.05);真菌D'还与样地中心香果树胸高断面积呈显著正相关(P<0.05)。β多样性分析表明:细菌Sorenson相异性指数均值为0.39,其中物种周转组分贡献为70.2%,真菌Sorenson相异性指数均值为0.72,其中物种周转组分贡献为85.1%;细菌和真菌的Sorenson相异性指数各自存在显著空间自相关(P<0.05),且与土壤理化性质以及树种组成差异显著相关(P<0.05)。偏Mantel检验结果表明:细菌的物种周转组分与土壤理化性质和样地树种组成显著相关(P<0.05),而其物种丰富度组分仅与取样年份显著相关(P<0.05);真菌的物种周转组分存在显著空间自相关且与土壤理化性质差异显著相关(P<0.05),而其物种丰富度组分与取样年份、海拔都显著相关(P<0.05)。【结论】九龙山香果树生境土壤真菌多样性较高,细菌多样性较低;香果树生境土壤微生物多样性存在时空异质性,海拔、土壤碱解氮和香果树胸高断面积是土壤微生物α多样性的主要影响因素,土壤理化性质和样地树种组成是土壤微生物β多样性的主要影响因素。图4表2参32.

秀珍菇病害种类调查和病原菌鉴定

近年来,病害频发对秀珍菇产量和品质产生了严重的影响,对其病原菌的鉴定和特性研究非常重要。此次采集了不同时期的患病秀珍菇样本,通过分离纯化获得病原菌,采用科赫法则、显微特征、ITS或16S rRNA测序等方法进行病原菌鉴定。结果表明,真菌病原菌主要有木霉属、青霉属、链孢霉属、毛霉属和毛壳菌属菌类,引发绿霉病、红粉病等真菌性病害,多发生于秀珍菇营养期。细菌病原菌主要有假单胞菌属、欧文菌属、伯克氏菌属、窄食单胞菌属及噬几丁质菌属菌类,引发黄菇病、枯萎病等细菌性病害,多发生于秀珍菇生殖生长期。

土地利用方式对低山丘陵区土壤理化性质及微生物群落的影响

为探究土地利用方式对辽西北低山丘陵区土壤性质的影响,以喀左县为研究样点,采集毗邻草地、林地和农田的土壤,测定其理化性质和微生物群落结构。结果表明:草地土壤的全磷、速效磷和硝态氮含量最低,农田土壤全氮、铵态氮和全碳含量最低。细菌群落中,林地土壤根瘤菌目的相对丰度最高,农田土壤鞘脂单胞菌目的相对丰度最高;真菌群落中,农田土壤粪壳菌目的相对丰度最高,林地格孢腔菌目的相对丰度最高。农田土壤细菌和真菌的Chao1指数和观测物种数显著地低于林地(P<0.05)。农田土壤微生物的乙醛酸循环和碳水化合物降解等途径丰度较高,但磷酸戊糖途径和碳水化合物合成等途径的丰度较低。综上,与草地和林地相比,农田土壤氮素流失严重,土壤微生物多样性下降,微生物群落趋向于增强土壤氮挥发和碳分解,不利于氮积累和碳固存。

短期OTC增温对晋北农牧交错带温性草地土壤微生物的影响

土壤微生物作为参与生物地球化学循环的重要生物类群,对陆地生态系统至关重要,但温度升高如何影响农牧交错带温性草地土壤微生物群落的丰度仍不清楚。本研究依托山西右玉黄土高原草地生态系统定位观测研究站2017年建立的开顶式同化箱(Open-Top chamber,OTC)增温实验平台,处理5年后进行土壤样品的采集,测定土壤真菌和细菌的丰度以及土壤微生物生物量碳(Microbial biomass carbon,MBC)和氮(Microbial biomass nitrogen,MBN)含量等指标,探讨农牧交错带温性草地土壤微生物对不同增温处理的响应。结果表明:增温显著降低土壤真菌丰度,对土壤微生物生物量碳、氮含量没有产生显著影响,细菌丰度随着增温处理的温度上升呈现先上升再下降的趋势;增温处理下,微生物生物量与土壤全磷、硝态氮和可溶性有机氮含量呈正相关关系。未来需要加强针对气候变化对该类脆弱生态系统影响的监测,为农牧交错带温性草地管理提供预警及科学依据。

丛枝菌根真菌和解磷细菌双接种对小麦磷肥利用率的影响

试验采用单因素随机区组设计,以接种复合灭活菌剂为对照,分析了2种丛枝菌根真菌(Rhizoph-agus irregularis,RI;Glomus intraradices,GI)和4种解磷细菌(Bacillus amyloliquefaciens,BA;Bacillus megate-rium,BM;Arthrobacter pascens,AP;Bacillus subtilis,BS)双接种对小麦生长和磷肥利用率的影响。结果表明:(1)与对照相比,接菌组小麦的菌根侵染率、产量、速效磷含量均显著提高,而土壤pH值显著下降,小麦产量和速效磷含量在接菌处理下分别提高了7.31%~27.00%和19.03%~60.35%。(2)GI+AP处理的产量最高,添加RI接菌组的速效磷含量、碱性磷酸酶活性均高于添加GI的接菌组,其中以RI+BS处理的最高;RI+BS和RI+BA处理的磷肥吸收利用率最高,分别为30.86%和27.94%。(3)相关性分析结果表明,小麦磷肥吸收利用率与菌根侵染率、籽粒重、籽粒磷含量、速效磷含量、碱性磷酸酶活性呈极显著正相关,与叶片磷含量呈显著正相关,与土壤pH值呈极显著负相关。综上,双接种丛枝菌根真菌和解磷细菌有利于增强土壤碱性磷酸酶活性、增加土壤速效磷含量、降低土壤pH值,从而提高小麦产量和磷素积累量,其中RI+BS处理对小麦磷肥利用率的提高作用最为显著。

细菌群落主导沙漠公路防护林营造后的土壤功能变化

防护林作为沙漠公路的安全保护屏障,其生长和应对胁迫所需的养分供给依赖于土壤微生物。以塔里木沙漠公路防护林和自然沙漠为研究系统,探究土壤细菌和真菌群落、两种生境共有和特有微生物物种变化对土壤物质循环功能的驱动作用。结果显示,土壤细菌和真菌物种丰富度(P<0.01,P<0.01)及群落组成(P<0.05,P<0.01)均受防护林营造的显著影响,细菌物种丰富度的响应增幅为77.5%,高于真菌22.1%。细菌群落是导致土壤酶活性升高的显著驱动因素,而非真菌群落或环境因子;细菌物种丰富度(rho=0.46,P<0.01)和群落组成(rho=0.68,P<0.01)与土壤酶之间呈显著偏Mantel相关。共有细菌相对丰度(rho=0.47,P<0.01)和特有细菌物种丰富度(rho=0.36,P<0.01)是驱动土壤酶活性改善的关键因素,与土壤酶之间呈显著偏Mantel相关。研究表明,沙漠公路防护林土壤细菌而非真菌主导微生物群落的响应,细菌群落通过改变本地物种丰度和新物种数量来调控土壤功能。

乡土草草地建植对辽西北连作农田土壤的改良效果研究

长期的耕作导致了辽西北农田土壤的严重退化。本研究以辽西北连作农田为研究对象,通过分析实验组与周边自然生境土壤理化性质和微生物群落结构差异,探讨乡土草种植对连作农田土壤的改良效果。结果表明:野古草(Arundinella anomala)草地和鹅观草(Elymus kamoji)草地的土壤pH值显著高于农田和撂荒地,养分含量显著低于农田。披碱草(Elymus dahuricus)草地和野古草草地土壤细菌的观测物种数与Chao1指数显著低于农田。土壤细菌α多样性与土壤硝态氮含量呈显著正相关关系,真菌α多样性与土壤硝态氮含量和全磷含量呈显著正相关关系。野古草、鹅观草和披碱草草地土壤细菌根瘤菌目和弗兰克氏菌目的相对丰度高于农田,芽单胞菌目的相对丰度低于农田,真菌寡囊盘菌目相对丰度高于农田和撂荒地。综上,乡土草草地建植可缓解农田土壤酸化,改善微生物群落结构,促进土壤的可持续发展。