Morphological Characterization of Arbuscular Mycorrhizal Fungi Associated with the Rhizosphere According to the Age of Xanthosoma sagittifolium L. Schott Plants in the Field

The objective of this work was to carry out a morphological characterization of arbuscular mycorrhizal fungi in the rhizosphere of Xanthosoma sagittifolium L. Schott plants. The plant material used was the white and red cultivars of X. sagittifolium, belonging to age intervals of 3 - 6, 6 - 9, and 9 - 12 months. Three harvest sites were chosen in the Central Region of Cameroon. In each site, soil from the rhizosphere and plant roots was collected in a randomized manner. In the field, the agronomic parameters were evaluated. The physicochemical characteristics of the soils, the mycorrhization index, and the morphological characterization of the mycorrhizal types of each site were carried out. The results obtained show that the agronomic growth parameters varied significantly using the Student Newman and Keuls Test depending on the harvest sites. The soils’ pH in all sites was acidic and ranged between 4.6 and 5.8. The Nkometou site has a loamy texture while the Olembe and Soa sites have loam-clay-sandy and loam-clay textures respectively. The highest mycorrhization frequencies appeared at the Nkometou site, with 75 and 87.33% of the white and red cultivars plant roots at 6 - 9 and 3 - 6 months. The relative abundance of AMF arbuscular mycorrhizal fungal spores in the rhizosphere of X. sagittifolium plants varied with age and cultivar. There were 673 spores between 9 - 12 months in Nkometou in the red cultivar. Six AMF genera were identified in all the different soils collected: Acaulospora sp., Funneliformis sp., Gigaspora sp., Glomus sp., Scutellospora sp., and Septoglomus sp. The genus Glomus sp. was the most present at all age intervals in both cultivars.

Diversity of Arbuscular Mycorrhizal Fungi Associated with Six Rice Cultivars in Italian Agricultural Ecosystem Managed with Alternate Wetting and Drying

Alternate wetting and drying(AWD)system,in which water has been reduced by approximately 35%with an increased occurrence of beneficial arbuscular mycorrhizal(AM)symbiosis and no negative impact on rice yield,was proposed to utilize water and nutrients more sustainable.In this study,we selected six rice cultivars(Centauro,Loto,Selenio,Vialone nano,JSendra and Puntal)grown under AWD conditions,and investigated their responsiveness to AM colonization and how they select diverse AM taxa.In order to investigate root-associated AM fungus communities,molecular cloning-Sanger sequencing on small subunit rDNA data were obtained from five out of the six rice cultivars and compared with Next Generation Sequencing(NGS)data,which were previously obtained in Vialone nano.The results showed that all the cultivars were responsive to AM colonization with the development of AM symbiotic structures,even if with differences in the colonization and arbuscule abundance in the root systems.We identified 16 virtual taxa(VT)in the soil compartment and 7 VT in the root apparatus.We emphasized that the NGS analysis gives additional value to the results thanks to a more in-depth reading of the less represented AM fungus taxa.

Review of Research Methods on Biodiversity of Arbuscular Mycorrhizal Fungi

Arbuscular mycorrhizal fungi （AMF） are essential functional microbiology in natural ecosystems. It is very important to research community composition and di- versity of AMF for achieving sustainable development of ecosystems. The paper described several methods of researching the diversity of AMF, especially for molecular techniques, reviewed the application status of these methods in AMF research, and pointed out that the effective combination of morphological and molecular methods could better reveal the biodiversity and ecological functions of AMF in natural ecosystems.

Species Diversity of Arbuscular Mycorrhizal Fungi in the Rhizosphere of Hevea brasiliensis in Hainan Island,China

Hevea brasiliensis is one of the important economic trees with a great economic value for natural rubber production.Symbiosis between roots of H.brasiliensis and arbuscular mycorrhizal fungi(AMF)is widely recognized,and can provide a range of benefits for both of them.Hainan Island harbors is one of the largest plantations of H.brasiliensis in China,whereas the information regarding the diversity of AMF in the rhizosphere of H.brasiliensis on this island is scarce.The diversity of AMF species in the rhizosphere of rubber tree plantations in Hainan was investigated in this study.A total of 72 soil samples from the rhizosphere of H.brasiliensis RY7-33-97 were collected.These included 48 samples from plantations in 11 cities or counties that had been planted for 15–25 years,and 24 samples from a demonstrating plantation site of the China National Rubber Tree Germplasm Repository representing plantations with tree plantation ages from one to 40 year-old.Collectively,a total of 68 morphotypes of AMF,belonging to the genera of Archaeospora(1),Glomus(43),Acaulospora(18),Entrophospora(3),Scutellospora(2),and Gigaspora(1)were isolated and identified,as per morphological characteristics of spores presented in the collected soil samples.Glomus(Frequency,F=100%)and Acaulospora(F=100%)were the predominant genera,and A.mellea(F=63.9%)and A.scrobiculata(F=63.9%)were the predominant species.AMF species differed significantly among collected sites in spore density(SD,290.7–2,186.7 spores per 100 g dry soil),species richness(SR,4.3–12.3),and Shannon-Weiner index of diversity(H,1.24–2.24).SD was negatively correlated with available phosphorus level in the soil;SR was positively correlated with soil total phosphorus content;and H was positively correlated with levels of soil organic matter and total phosphorus.Similarly,SD,SR,and H were also correlated with H.brasiliensis plantation age,and an increasing trend was observed up to 40 years.These results suggest that the AMF community was complex and ubiquitous in the island plantation ecosystems of H.brasiliensis,with high species abundance and diversity.Soil factors and plantation age dramatically affected AMF diversity at species level.

Diversity of Arbuscular Mycorrhizal Fungi Species Associated with Soybean (Glycine max L. Merill) in Benin

Arbuscular Mycorrhizal Fungi (AMFs) could be used to sustainably improve crop yields. The present study evaluated the diversity of AMF species associated with soybean (Glycine max L. Merill) in main soybean-producing areas in Benin. Composite soil samples from 13 production areas at a rate of 04 villages per production areas were collected. A spore trapping device was set up to reveal the diversity of spores. The physical and chemical properties of the soils, the frequency and intensity of mycorrhization of roots, and the diversity of AMF spores were determined in the soil samples following trapping. As result, eight morphotypes belonging to four genera: Glomus, Acaulospora Gigaspora and Disversispora and three families: Diversisporales, Glomérales and Paraglomérales were observed. An important variability of spore densities was observed from one production areas to another with a higher abundance in the production areas of Copargo estimated at 3584 spores/100g soil. The biological diversity indexes as Shannon (0.0311), Simpson (0.0204) and Hill (0.0235), varied significantly (p < 0.05) from one production areas to another. There was significant correlation between the parameters studied, particularly between the physico-chemical parameters of the soils and between the physico-chemical parameters and the biological diversity indexes. For the mycorrhization parameters, the mycorhization frequencies did not vary from one production areas to another, unlike the intensities, which significantly varied from one production areas to another (2.31% to 24.62%). Finally, this study revealed that the physico-chemical parameters of the soils had an influence on the other parameters studied. Moreover, there were an abundance and a significant diversification of AMFs associated with soybean in the different production areas, which are influenced by certain physico-chemical soil parameters.

神东矿区接种AMF对植物−土壤生态化学计量及养分回收的影响

矿区采煤沉陷地植被恢复和微生物复垦是打造绿色矿山的关键点。丛枝菌根真菌(Arbuscular Mycorrhizal Fungi,AMF)和恢复植被类型对植物−枯落叶−土壤连续体的生态化学计量学特征及养分回收的影响尚不明朗,但对阐明西北干旱采煤沉陷区生态修复后养分循环和可持续发展具有重要意义。选择复垦10 a后接种AMF与对照的紫穗槐、沙棘、文冠果、欧李、野樱桃5种恢复植被及对应植被的0~10 cm土壤进行研究,旨在探明接菌和恢复植被类型对植物−枯落叶−土壤连续体碳(C)、氮(N)、磷(P)含量和生态化学计量比,养分回收率、养分限制的影响。结果表明:5种恢复植被各器官平均养分含量与全国水平相比呈现出高C、P低N的特点,土壤N的缺乏限制了枯落物分解和植物生长。冗余分析表明影响植物生态化学计量的主要土壤因子是土壤有机碳、P、土壤易提取球囊霉素并且土壤养分与叶养分回收在菌根介导下呈正相关。AMF接种提高了植物、土壤养分含量、N、P回收率和土壤碳氮比,降低了植被的氮磷比,进而缓解植物N限制,增加植物生长速率支持恢复植被重建,促进连续体养分循环。在不同人工重建植被中接菌的固氮植被紫穗槐和沙棘养分含量、稳定性及生长速率高。植物−枯落叶−土壤连续体生态化学计量及养分回收特征预测土壤氮限制沉陷区可持续生态恢复,接种AMF则促进沉陷区持续生态恢复的潜力。

The Effects of Arbuscular Mycorrhizal Fungi on Reactive Oxyradical Scavenging System of Tomato Under Salt Tolerance

The effects of arbuscular mycorrhizal fungi （AMF）, Glomus mosseae, on oxygen radical scavenging system of tomato under salt stress were studied in potted culture experiments. The response of tomato （Lycopersieon eseulentum L.） cultivar Zhongza 9 seedlings with AMF inoculation and control to salt stress （0, 0.5 and 1.0% NaCl solution, respectively） was investigated. The results showed that the salt stress significantly reduced the dry matter content of roots, stems and leaves, and also the leaf area as compared with the control treatment. However, arbuscular mycorrhizal-inoculated （AM） significantly improved the dry matter and the leaf area in the salt-stressed plants. The effect of AMF on dry matter was more pronounced in aerial bromass than in root biomass which might be due to AM colonization. The activities of SOD, POD, ASA-POD, and CAT in leaves and roots of mycorrhizal and non-mycorrhizal treatment of tomato plants were increased and had different rules under different NaCl concentrations （solution of 0, 0.5 and 1% NaCl）, but all enzymes had a rise in the beginning of treatment under salt stress conditions. The AMF did not change the rule of tomato itself under salt stress, but AMF increased these enzyme activities in different levels. The AMF treatment significantly increased SOD, POD and ASA-POD activities in leaves and roots, whereas it had little effects on CAT in root. O2- production rate and MDA content in leaves increased continuously, which showed a positive line correlation with salt stress concentration. O2- production rate and MDA content in tomato plants significantly decreased by AM treatment compared with nonmycorrhizal treatment. In conclusion, AM could alleviate the growth limitations imposed by saline conditions, and thereby play a very important role in promoting plant growth under salt stress in tomato.

Arbuscular mycorrhizal fungal diversity in some commonly occurring medicinal plants of Western Ghats,Goa region

Thirty-six medicinal plant species belonging to 25 families were surveyed to study Arbuscular mycorrhizal （AM） fungal diversity from different localities of North and South Goa of Western Ghats, Goa region, India. A total of 30 medicinal plant species were found to be mycorrhizal and six plant species showed absence of AM fungal colonization. Forty two AM fungal species belonging to five genera viz., Glomus, Acaulospora, Scutellospora, Gigaspora and Ambispora were recovered from the rhizosphere soil. Glomus was found to be the most dominant genera in the study sites, and Glomus fasciculatum the most dominant AM fungal species. Negative significant correlation was observed between percent colonization and spore density. Simpson＇s and Shannon Weiner diversity index studies carried out in North and South Goa exhibited less variation in both the sites, indicating a stable and a diverse plant community.

Effects of microplastic polystyrene,simulated acid rain and arbuscular mycorrhizal fungi on Trifolium repens growth and soil microbial community composition

Microplastic pollution is a global and ubiquitous environmental problem in the oceans as well as in the terrestrial environment.We examined the fate of microplastic polystyrene(MPS)beads in experimental soil in the presence and absence of symbiotic arbuscular mycorrhizal fungi(AMF)and simulated acid rain(SAR)to determine whether the combinations of these three factors altered the growth of white clover Trifolium repens.We found that MPS,SAR,or AMF added singly to soil did not alter T.repens growth or yields.In contrast,MPS and AMF together significantly reduced shoot biomass,while SAR and MPS together significantly reduced soil available phosphorus independent of AMF presence.Microplastic polystyrene,AMF,and SAR together significantly reduced soil NO_(3)^(-)-N.Arbuscular mycorrhizal fungi added singly also enriched the beneficial soil bacteria(genus Solirubrobacter),while MPS combined with AMF significantly enriched the potential plant pathogenic fungus Spiromastix.Arbuscular mycorrhizal fungi inoculation with MPS increased the abundance of soil hydrocarbon degraders independent of the presence of SAR.In addition,the abundance of soil nitrate reducers was increased by MPS,especially in the presence of AMF and SAR.Moreover,SAR alone increased the abundance of soil pathogens within the fungal community including antibiotic producers.These findings indicate that the coexistence of MPS,SAR,and AMF may exacerbate the adverse effects of MPS on soil and plant health.

Effect of Inoculation with Arbuscular Mycorrhizal Fungus on Nitrogen and Phosphorus Utilization in Upland Rice-Mungbean Intercropping System

The effect of arbuscular mycorrhiza fungi （AMF） on plant growth and nutrition utilization in upland rice and mungbean intercropping system was studied. A pot experiment was conducted in the greenhouse and AMF colonization rates of rice and mungbean roots, plant nutrient contents, the ability of nitrogen fixation, and nutrient contents changed in the soil were analyzed. The results were obtained as follows： the rates of AMF colonization of rice and mungbean roots were reached to 14.47 and 92.2% in intercopping system, and increased by 4.11 and 11.95% compared with that of in monocropping; the nirtrogen contents of mungbean and rice were increased by 83.72 and 64.83% in shoots, and 53.76 and 41.29% in roots, respectively, while the contents of iron in shoot and root of mungbean were increased by 223.08 and 60.19%, respectively. In the intercropping system with inoculation of AMF, the biomass of mungbean increased by 288.8%. However, the biomass of rice was not significantly changed among all treatments with or without inoculation of AMF recorded. The number and dry weight of nodules were significantly increased either when mungbean was intercropped with rice or inoculated with AMF. When compared with that of monocropping without AMF inoculation, the contents of nitrogen, phosphorus and iron in nodules of intercropping mungbean with inoculation increased by 80.14, 69.54 and 39.62%, respectively. Additionally, intercropping with AMF inoculation significantly increased soil nitrogen content, but reduced soil phosphorus content. We concluded that upland rice-mungbean intercropping system and inoculation with AMF improved the nutrient uptake, the ability of nitrogen fixation and the growth of mungbean.

油茶炭疽病发生与丛枝菌根真菌(AMF)关系研究

为应用丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)防控油茶炭疽病,探究土壤AMF与油茶炭疽病发生程度之间的关系。采用湿筛沉淀法和AMF定殖染色法探究油茶炭疽病发生样点土壤的AMF孢子密度、丰富度、多样性指数和菌根定殖率及病健植株发病率与病情指数间的关系。结果表明,病健油茶根部AMF孢子密度、定殖率具有显著差别,感病油茶土壤中AMF孢子的丰富度与多样性指数有下降趋势(P<0.05);AMF孢子密度、丰富度、定殖率与油茶炭疽病发病率和病情指数呈极显著负相关关系(P<0.01),多样性指数与油茶炭疽病发病率和病情指数呈显著负相关关系(P<0.05)。研究发现AMF孢子密度、菌根定殖率、丰富度和多样性指数越大,油茶炭疽病越轻,显示AMF对防治油茶炭疽病具有潜在应用价值。

横断山脉亚高山带几种高山栎林下丛枝菌根菌(AMF)调查

[目的]明确横断山脉亚高山带高山栎林下AMF孢子分类地位。[方法]自横断山脉亚高山带不同地段选择6个高山栎根围土壤和根系样本,对其土壤中AMF孢子利用湿筛沉淀法进行选取。利用AMF特异引物对其ITS区段18S rRNA基因进行扩增,结合形态学与分子生物学手段对其进行鉴定,构建系统发育演化树并推测其亲缘关系。[结果]四川、西藏高山栎林下土壤AMF孢子与根系克隆为类球囊霉属(Paraglomus),云南香格里拉高山栎林下土壤AMF孢子与根系克隆为球囊霉属(Glomus)。克隆结果表明:AMF能够广泛存在于高山栎组植物根系。根系苯胺蓝染色结果可见明显类似丛枝和泡囊的结构。综合高山栎土壤AMF孢子与根际AMF鉴定结果认为,高山栎林下存在大量AMF,且目前不同采样地高山栎林下根围土和根系分别仅发现一种AMF存在,提示各高山栎同时仅能与一种AMF发生共生关系。此外,高山栎林下AMF孢子在演化过程中发生分化并介于Paraglomus与Glomus的分类地位之间,且西藏、四川地区AMF与云南香格里拉地区AMF存在差异。[结论]本研究发现,自然条件下横断山脉亚高山地区高山栎林下菌塘普遍存在AMF,且云南香格里拉地区高山栎根系AM与Glomus属更接近,说明AM在长期演化过程中随地域迁移出现分化。为了解横断山脉亚高山带高山栎林下AMF的形成与演化提供理论参考。

From Monoculture to Norfolk System: How the Number of Crops in Rotation Can Influence the Biodiversity of Arbuscular Mycorrhiza Assemblages in the Soil

Given the attention drawn since several decades by arbuscular mycorrhizal fungi (AMF) as potential biological alternatives to chemicals in a low-input agriculture, much effort has been spent in the investigation of mechanisms influencing the dynamics inside AMF communities. In the present study we evaluated the influence of different crop rotations on the AMF soil community, after a 50 y long-term field experiment established at Martonvásár, Hungary. Four types of crop rotation were chosen for sampling: corn monocropping, corn-alfalfa, corn-wheat, and corn-spring barley-peas-wheat. Community composition of AMF in soil was analyzed with a molecular approach amplifying a portion of 28S rDNA. The crop rotation practice didn’t show an influence on identity of the species composing AMF assemblages, but on the other hand seemed to affect positively the true diversity, defined as number of MOTUs present in the communities.

盐胁迫下外源褪黑素和丛枝菌根真菌对月季幼苗生长生理特性的影响

【目的】盐胁迫易导致月季生长发育不良、观赏品质下降,严重影响其在高盐环境或沿海地区室外绿化应用,探究施用外源褪黑素(MT)和接种丛枝菌根真菌(AMF)对其幼苗生长、叶绿素荧光参数以及激素代谢的调控作用,解析它们促进月季适应盐胁迫的生理生化机制,对于增强月季抗盐性,扩大月季应用范围具有重要意义。【方法】以月季品种‘月月红’幼苗为试验材料,采用室内盆栽试验,设置对照(CK)、100 mol/L NaCl胁迫、根际施用MT、根际接种AMF幼套近明球囊霉(Claroideoglomus etunicatum)及其组合等8个处理,考察各处理对月季幼苗生长、叶绿素荧光参数、激素代谢及抗氧化系统的影响。【结果】(1)施用MT可以促进AMF对月季幼苗根系的侵染,提高侵染率、丛枝着生率、泡囊数和侵入点数;(2)月季幼苗株高、茎粗以及生物量等在盐胁迫下显著下降,在MT或AMF处理下均不同程度增加,而AMF+MT处理下株高、茎粗无显著变化,地上部干重、地下部干重分别显著增加24.1%和37.0%;(3)月季幼苗叶绿素含量在盐胁迫下显著下降,叶绿素荧光参数也降低,MT或AMF处理能提高盐胁迫月季幼苗叶绿素含量以及叶绿素荧光参数,AMF+MT处理则使叶绿素总量、叶绿素a/b分别增加46.2%和67.2%,PSⅡ最大光化学效率(F_(v)/F_(m))、潜在活性(F_(v)/F_(o))、实际光化学效率(ΦPSⅡ)、有效光化学量子效率(Fv'/Fm')、光化学淬灭系数(qP)分别增加4.9%、51.0%、175.0%、168.7%和92.5%,而NPQ下降42.7%;(4)在盐胁迫下,月季叶片中玉米素(ZT)、赤霉素(GA)、生长素(IAA)含量下降,而脱落酸(ABA)含量增加,MT或AMF处理有利于盐胁迫下ZT、GA、IAA含量的提高以及ABA含量的下降,AMF+MT处理后ZT、GA、IAA分别增加146.9%、116.9%、35.7%,ABA下降21.1%;(5)在盐胁迫下,抗氧化酶SOD、CAT活性增强,超氧阴离子(O_(2)^(-·))产生速率和H_(2)O_(2)累积大量增加,MT或AMF处理有助于增加抗氧化酶活性并减少O_(2)^(-·)产生速率和H_(2)O_(2)含量,而AMF+MT处理能够进一步激活SOD、CAT活性,降低O_(2)^(-·)产生速率和H_(2)O_(2)累积。【结论】接种AMF、添加MT或者AMF+MT处理均可以提高盐胁迫下月季幼苗叶绿素含量,保护叶绿素荧光系统,维持植物内源激素的平衡,激活SOD、CAT等抗氧化酶活性以及降低脂质过氧化和H_(2)O_(2)累积,以减轻盐胁迫对月季幼苗的伤害,促进月季生长,并以AMF+MT处理增强月季幼苗抗盐性的效果更佳。

人工混播草地土壤丛枝菌根真菌对轮牧的响应

为探究轮牧对人工混播草地生态系统中植被群落及土壤丛枝菌根(arbuscular mycorrhiza,AM)真菌群落的影响机制,以宁夏盐池县人工混播草地为试验对象,采用单因素随机区组设计,设置T1(无芒雀麦+新麦草+紫羊茅+苜蓿+菊苣)、T2(垂穗披碱草+新麦草+早熟禾+苜蓿+鹰嘴紫云英)、T3(扁穗冰草+新麦草+蒙古冰草+苜蓿)3种混播组合模式,并通过Illumina高通量测序和生物信息学分析,开展轮牧影响下3种人工混播草地土壤AM真菌群落差异性研究,分析人工混播草地生态系统中植被-土壤-AM真菌群落的相互作用关系。结果表明:连续2年轮牧对植被群落生物量产生了显著影响,与轮牧第1年相比,豆科植被群落的相对重要值降低,但禾本科植被群落的相对重要值分别增加了51.16%、81.25%和33.33%。土壤AM真菌中球囊霉属和类球囊霉属为优势属;与轮牧第1年相比,连续轮牧2年后,T1处理的土壤AM真菌群落Chao 1指数较第1年显著降低了12.35%,T3处理的土壤AM真菌群落Chao 1指数、香农-维纳指数、均匀度指数和物种数较第1年分别提升了20.73%、12.80%、7.69%和31.16%(P<0.05),说明T3处理的土壤AM真菌群落对轮牧的响应更加敏感。随轮牧年限增加,T1与T2处理的土壤AM真菌群落组成相似性增加,T1与T3处理的土壤AM真菌群落组成相似性差异较大。连续轮牧2年后,土壤养分对AM真菌群落丰富度的作用强度减弱,但植被群落多样性和植被群落生物量对AM真菌群落丰富度及其组成的作用强度增强;驱动AM真菌群落变化的环境因子由土壤有效磷(p=0.006)和碱解氮(p=0.016)转变为植被群落生物量(p=0.036)。综上所述,不同类型人工混播草地植被群落和土壤AM真菌群落对轮牧表现出不同的响应特征,其中以T3混播组合处理的效果较好。

天然林改造为单一茶园前后不同生境土壤丛枝菌根真菌物种多样性的差异

在贵州省遵义市正安县和湄潭县,选择地理位置相邻的3种生境类型样地——天然林、由天然林改造而来的人工林、不同种植年限茶园(茶园依据种植年限(t)不同划分为5组:t<10 a、10 a≤t<20 a、20 a≤t<30 a、30 a≤t<40 a、t≥40 a);采用分层随机抽样法设计3种生境的土壤样品采集,共选取37个采样点(茶园17个、天然林10个、人工林10个),统一采集深为5~40 cm的根际土壤,每个样点采集3~5份混合土壤作为重复,共采集128份土壤样品;参照相关标准和规范测定土壤理化性质(pH、有机质质量分数、全氮质量分数、全磷质量分数、全钾质量分数、解氮质量分数、有效磷质量分数、速效钾质量分数、土壤粒径、质地类型),采用湿筛倾注-蔗糖离心法进行土壤丛枝菌根(AM)真菌孢子分离和形态鉴定,采用孢子密度、物种丰富度、分离频度、相对多度、重要值、香农-威纳多样性指数(Shannon-Wiener Index)、辛普森多样性指数(Simpson Index)、皮卢均匀度指数(Pielou’s Evenness Index)评估丛枝菌根真菌群落结构;采用聚类分析法、冗余分析(RDA)法、方差分析法,分析3种生境土壤丛枝菌根真菌物种多样性的差异。结果表明:3种生境中共检出7科11属48种丛枝菌根真菌。孢子密度、物种丰富度、香农-威纳多样性指数、辛普森多样性指数,在天然林土壤中最高、茶园土壤中次之、人工林土壤中最低。种植年限小于20 a的茶园土壤中丛枝菌根真菌物种组成与人工林相似,主要受土壤因子的影响;而种植年限大于20 a的茶园土壤中丛枝菌根真菌物种组成丰富,接近天然林,受土壤因子和宿主植物的双重影响。说明人为因素引起的生境变化会影响丛枝菌根真菌物种组成,扰动后的丛枝菌根真菌生态平衡重建需要一定年限。

干旱胁迫下AMF对云南蓝果树幼苗生长和光合特征的影响

采用盆栽试验与称重控水法,将土壤相对含水量分别控制在田间最大持水量的100%、91.68%、82.85%、60.00%、41.86%和21.28%,并在这6个不同的土壤相对含水量条件下,分别设添加苯菌灵(杀真菌剂)(低AMF)和不添加苯菌灵(高AMF)处理,研究干旱胁迫下AMF对极小种群野生植物云南蓝果树幼苗生长和光合特征的影响,揭示云南蓝果树濒危的微生物学机制,为云南蓝果树保护措施的制定与实施奠定基础。结果表明,添加苯菌灵处理显著降低了不同水分条件下的AMF侵染率,说明试验中AMF处理的实生苗在生长和光合特征上的差异是苯菌灵处理下侵染率下降导致的;随着干旱胁迫的加剧,云南蓝果树幼苗的根部AMF侵染率显著降低、叶面积等生长指标和净光合速率(Pn)等光合参数都发生显著变化;高AMF处理可以显著增加水分充足和轻度干旱胁迫条件下云南蓝果树幼苗的大部分生长指标和光合参数,而对重度胁迫下的云南蓝果树幼苗没有显著影响,说明重度干旱胁迫对其影响大于AMF的影响;另外,整合了可塑性指数分析和隶属函数分析两种方法对其抗旱性进行评价,云南蓝果树幼苗基本上无法通过调节形态和光合能力来适应水分环境的变化,但是高AMF处理可使云南蓝果树幼苗具有较强的可塑性和更强的抗旱性。实验结果为云南蓝果树的科学保育及种苗繁育提供了理论依据。

当归根际丛枝菌根真菌群落及其影响因子分析

分析丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)菌群在当归生长过程中的变化,以期为AMF在当归提质增效中的应用提供一定的研究基础。基于Illumina Miseq高通量测序技术,测定当归叶丛期、根膨大期和成药期根际土壤的AMF多样性和菌群组成。同时测定根际土壤理化特性和重金属镉和砷含量,并分析AMF菌群对土壤因子的响应。结果显示:随着当归的生长,当归根际土壤AMF菌群的α多样性增加,β多样性存在差异;当归根际AMF的优势菌属为球囊霉属Glomus_f_Glomeraceae和多孢囊霉属Diversispora;在当归的生长阶段,多孢囊霉属的丰度逐渐降低,而球囊霉属的丰度逐渐增加成为绝对优势菌,仅Unclassified_o_Diversisporales属在当归不同生长期的差异显著(p<0.05);土壤pH值、电导率及重金属镉和砷共同影响当归根际AMF的多样性和菌群组成。以上结果表明AMF多样性和菌群组成在当归的不同生长期具有明显的变化,土壤因子是AMF多样性和菌群组成变化的重要驱动因素,这些发现将有助于揭示当归生长与AMF的相互关系和机制,为当归的生态种植和提质增效提供理论参考依据。

藏南谷地湿地植物丛枝菌根真菌群落结构随海拔变化的驱动因素初探

丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)在维持高原湿地生态系统功能和促进其稳定性等方面发挥着重要作用,但AMF群落多样性及其构建过程对海拔的响应尚不清楚。本研究在藏南谷地沿4200~5100 m的海拔梯度进行了湿地植物调查、水体因子测定和土壤样品采集并分析。结果显示,藏南谷地湿地生态系统的AMF群落结构随海拔变异较大,其中以Glomus为优势属,且其相对丰度随海拔的上升呈显著下降的趋势。所有采样点中,AMF群落组成的差异以物种替换过程为主。变差分解结果表明,底泥和水体是解释AMF多样性海拔格局的主要环境因子。

接种丛枝菌根真菌(AMF)对施磷石膏云烟87的生长以及砷污染的影响

【目的】丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)能够促进作物养分的吸收及生长,且对土壤砷污染有一定的抗性。磷石膏(phosphogypsum,PG)因含有丰富的磷、硫等养分可以为作物生长提供必要的养分,同时也可能带来砷污染的风险。【方法】为了探讨接种AMF对云烟87生长的影响以及磷石膏农用可能引起的砷污染风险,通过盆栽模拟试验研究了不同PG添加量(0和40 g/kg以PG0、PG40表示)和接种不同AMF[不接种None mycorrhizal(NM)、接种G.mosseae丛枝菌根真菌(GM)、接种G.aggregatum丛枝菌根真菌(GA)]对云烟87苗期生长及其磷、硫、砷吸收的影响。【结果】试验结果表明:无论接种与否,PG40处理的云烟87植株磷含量、吸收量及吸收效率均显著增加,其地上部硫含量及吸收量也显著增加;除NM处理外,添加PG均显著增加了云烟87根系的硫含量、硫吸收量及吸收效率,并显著增加了其植株的生物量。相同PG添加水平下,与NM处理相比,接种GM显著增加了云烟87根系的磷、硫吸收效率和植株的磷、硫含量及吸收量,另外,GM处理显著降低了其地上部砷含量及吸收量但显著增加了其植株的磷砷吸收比。在PG0处理下,接种GA显著增加了云烟87植株的磷含量及吸收量,并显著增加了其地上部硫含量及吸收量。在PG40处理下,接种GA显著增加了云烟87根系的硫含量和吸收量以及植株的生物量。无论是否添加PG,接种GA不同程度地降低了云烟87地上部砷含量和吸收量从而增加了其地上部的磷砷吸收比。【结论】在所有复合处理中,以添加磷石膏40 g/kg和接种GM对云烟87生长的促进效果较好,对施用磷石膏造成的砷污染有一定程度的抵御作用。