接种丛枝菌根对玉米生长与抗旱性的影响

采用盆栽试验,研究了水分胁迫下接种丛枝菌根真菌对玉米生长及其抗旱性的影响。结果表明:玉米与丛枝菌根可形成良好的共生关系,接种丛枝菌根显著提高了玉米生物量、株高、地径。与未接菌相比,接菌提高了植株水分利用效率,水分胁迫和正常供水条件下,较对照分别提高117%和24.6%。接菌后玉米叶片SPAD值和可溶性蛋白含量增加,叶片过氧化氢酶活性增强。同时,接种菌根显著降低了植株叶片脯氨酸、丙二醛含量,干旱胁迫和正常供水条件下,较未接菌处理分别降低了14.1%、18.9%和59%、69%。由此可见,接种丛枝菌根真菌能够促进玉米的生长,缓解干旱胁迫对玉米生长造成的不利影响,提高了玉米的抗旱性。     

大田条件下丛枝菌根真菌对西瓜生长和枯萎病的影响

 在大田条件下研究丛枝菌根(AM)真菌对西瓜(Citrullus lanatus)生长和枯萎病的影响。接种AM真菌能显著降低西瓜枯萎病的发病率、病情指数、根内和根围土壤中镰刀菌繁殖体的数量,促进植株对N、P、B和Zn等矿物质的吸收,提高西瓜叶片中叶绿素的含量、叶片净光合速率、气孔导度和水分利用效率,促进植株生长,增加西瓜产量。     

不同形态磷肥对棉花生长和AM真菌接种效应的影响

通过两室根箱栽培棉花新陆早13号实验,研究了磷酸二氢钾、植酸钠(Na-phytate)2种磷源形态对AM真菌Glomus mosseae接种效应的影响及棉花生长的影响。结果表明:在不施磷肥的条件下,接种Glomus mosseae真菌时,棉花的生长势没有显著差异,棉株地上部磷含量显著高于没有接种Glomus mosseae真菌的处理。施磷酸二氢钾时,接种Glomus mosseae真菌对棉花生长势起到显著的促进作用,棉株地上部磷含量也显著提高;施用植酸钠时,接种Glomus mosseae真菌对棉花生长势与棉珠地上部磷含量都没有显著影响。对Glomus mosseae真菌接种处理而言,不同形态磷素处理,植物室土壤有效磷的含量大小顺序为磷酸二氢钾>植酸钠>对照。磷素形态对Glomusmosseae真菌的侵染率没有显著影响。不施磷肥Glomus mosseae真菌的侵染率要显著高于施用磷酸二氢钾、植酸钠磷肥的处理,这说明,Glomus mosseae真菌在土壤磷较低时有利于侵染棉花根系。     

生防荧光假单胞菌CPF-10对西瓜根围土壤真菌群落的影响

探讨了生防菌荧光假单胞菌Pseudomonas fluorescens CPF-10对西瓜根围土壤真菌群落结构的影响。采用传统分离培养法,结合变性梯度凝胶电泳(DGGE)分析,研究了施用CPF-10后不同生育期西瓜根围土壤真菌群落结构的变化。结果表明:施入生防菌CPF-10后2周,其对土壤真菌有一定的促进作用;第3～7周时,CPF-10对土壤真菌尤其是部分病原菌有较强的抑制作用;CPF-10对丛枝菌根真菌(AMF)有一定的促进作用,可维持3周左右;收获期后则检测不到CPF-10对土壤真菌群落的影响。生防菌CPF-10对西瓜根围土壤真菌群落产生的短暂影响不会对土壤生态系统构成长期威胁。对比土著真菌及丛枝菌根真菌的DGGE图谱和切胶条带测序结果,发现DGGE技术更适用于分析小范围特定菌属如丛枝菌根真菌的变化。     

禾草内生真菌与丛枝菌根互作对多年生黑麦草生长及叶斑病的影响

为明确禾草内生真菌和丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)互作对多年生黑麦草Lolium perenne生长发育及叶斑病的影响,设置禾草内生真菌处理(由带有和不带禾草内生真菌种子建立)、AMF(幼套球囊霉Claroideoglomus etunicatum和根内球囊霉Rhizophagus intraradices)单独接种和混合接种处理及不接菌处理(对照),并在植物生长6周后接种或不接种多年生黑麦草叶斑病病原菌根腐离蠕孢Bipolaris sorokiniana,测定各处理多年生黑麦草的发病率、叶绿素含量、净光合速率、水分利用效率、AMF侵染率、P含量和生物量。结果表明:接种病原菌2周后,多年生黑麦草叶斑病的发病率为25.00%～38.75%,禾草内生真菌和幼套球囊霉均在一定程度上降低了多年生黑麦草的发病率,二者共同作用时发病率显著降低了35.48%。禾草内生真菌与AMF互作能在一定程度上提高植物叶绿素含量,促进光合作用,并促进P吸收和植物生长,二者的互作效应因禾草内生真菌与AMF组合而异,但均优于二者单独使用时的效应,其中禾草内生真菌与幼套球囊霉互作对多年生黑麦草生长及叶斑病防治的效果最好。     

两种内生真菌联合使用对烟草抗青枯病的影响

为探究内生真菌联合使用对烟草抗青枯病的影响,在云烟87上分别接种印度梨形孢（CP）、丛枝菌根真菌（PC）,以及联合接种印度梨形孢和丛枝菌根真菌两种真菌（PP）,分析在青枯病胁迫下烟草生理生化指标及抗病相关基因的表达情况。结果表明,在青枯病胁迫下,CP、PC和PP组烟草叶片中SOD、PPO、PAL活性均高于无菌水对照组,其中SOD活性分别提高37.71%、61.88%和88.03%,PPO活性分别提高54.28%、33.64%和112.08%,PAL活性分别提高73.35%、88.74%和152.13%。qRT-PCR结果表明,在青枯病胁迫下,病程相关蛋白基因PR-1b和PR2的相对表达量均呈先上调后下调的趋势。与对照组相比,CP、PC和PP组烟草的PR-1b基因表达量分别提高91.32%、103.40%和187.75%,PR2基因表达量分别提高142.09%、151.49%和227.41%。通过研究发现印度梨形孢和丛枝菌根真菌联合使用可以增强烟草对青枯病的抗性,为复合生物菌剂的开发及烟草青枯病的绿色防控提供了理论依据。     

AM真菌和镰刀菌对西瓜根系膜脂过氧化作用和膜透性的影响

 在温室盆栽条件下研究了丛枝菌根(arbuscular mycorrhiza,AM)真菌Glomus versiforme (Karsten) Berch和西瓜枯萎镰刀菌(Fusarium oxysporum f. sp. niveum)对西瓜根系中膜脂过氧化产物丙二醛(MDA)含量和细胞膜透性的影响。结果表明,接种AM真菌的西瓜根系中MDA含量、组织自动氧化速率和膜透性均低于对照,先接种G. versiforme,后接种F. oxysporum f. sp. niveum处理的MDA含量、组织自动氧化速率和细胞膜透性均低于只接种F. oxysporum f. sp. niveum的处理。接种G. versiforme感枯萎病西瓜品种"郑杂5号"MDA含量、组织自动氧化速率和膜透性降低幅度大于抗病品种"京欣1号"的接种处理,说明G. versiforme可降低感病西瓜品种的膜透性和MDA的产生,从而有效地保护细胞膜系统,减轻F. oxysporum f. sp. niveum对西瓜的为害程度。     

丛枝菌根真菌与小麦孢囊线虫的相互作用

 近年来, 小麦孢囊线虫(cereal cyst nematodes, CCN:主要病原为燕麦孢囊线虫Heterodera avenae)对小麦(Triticum aestivum)的危害日益严重, 亟待探索新的生防途径。丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)作为环境功能生物, 对寄主植物具有生物药肥双重作用, 不仅能促进植物吸收利用养分, 而且能拮抗土传病原物、提高植物抗病性。本研究以AMF与CCN相互作用为切入点, 试图明确AMF与CCN相互作用关系, 并科学评价不同AMF抑制CCN、降低病害的效应。试验于温室盆栽条件下进行, 设接种AMF Gigaspora margarita(Gi.m)、Glomus mosseae(G.m)、Glomus intraradices(G.i)、Glomus versiforme(G.v)、Gi.m +G.m+G.i+G.v、CCN、CCN+Gi.m、CCN+G.m、CCN+G.i、CCN+G.v、CCN+Gi.m+G.m+ G.i+G.v和不接种对照(CK)共12个处理。结果表明, 接种AMF各处理均能降低小麦孢囊线虫侵染率、土壤中孢囊数和根内J2数量, 其中Gi.m处理抑制效果最大;CCN不同程度减少AMF侵入点数和产孢数量。Gi.m 和CCN+Gi.m处理的根内丛枝着生数量最多, 而后者根内的超氧化物歧化酶、苯丙氨酸解氨酶和过氧化氢酶活性显著高于其他处理、丙二醛含量则显著低于其他CCN+AM真菌处理。Gi.m和G.i处理的小麦株高、地上部干重高于其他处理;Gi.m 和CCN+Gi.m的处理的单穗重和单株产量均高于其他处理。表明AMF能不同程度拮抗CCN、促进小麦生长和提高产量, 其中, Gi.m是高效菌种。结论认为, AMF与CCN之间存在一定相互抑制作用, AMF能通过诱导植株防御反应拮抗CCN。     

丛枝菌根菌丝桥传递作用对烟草抗病性相关酶活性的影响

为明确供体与受体植株间菌丝桥传递抗病信号对受体植株生长以及抗病性相关酶活性的影响,利用丛枝菌根真菌在供体与受体烟苗植株间建立菌根菌丝桥,对供体植株接种青枯菌的方法进行研究。结果表明:在供体烟苗接种丛枝菌根真菌条件下,再接种青枯菌,比只有菌丝连接的受体烟苗叶片内的过氧化物酶(peroxidase,POD)、多酚氧化酶(polyphenol oxidase,PPO)、苯丙氨酸解氨酶(phenylalanine ammonialyas,PAL)的活性分别提高了21%、29%和14%,地上部干重和植株磷含量也有相同的趋势;而在不接种丛枝菌根真菌条件下,供体烟苗接种青枯菌与否对酶的活性、植株干重及氮、磷含量均无显著影响。表明供体烟苗产生的抗病信号可以通过菌丝桥传递给受体烟苗,增强受体烟苗的抗病性。     

Arbuscular mycorrhizal fungi ameliorate the chemical properties and enzyme activities of rhizosphere soil in reclaimed mining subsidence in northwestern China

In semi-arid region of northwestern China, underground mining subsidence often results in decreased vegetation coverage, impoverishment of soil fertility and water stress. In addition, the physical-chemical and biological properties of soil also change, resulting in more susceptible to degradation. In particular, subsidence causes disturbance of the symbioses of plant and microbe that can play a beneficial role in the establishment of vegetation communities in degraded ecosystems. The objective of this study was to evaluate the effects of revegetation with exotic arbuscular mycorrhizal fungi(AMF) inoculum on the chemical and biological properties of soil over time in mining subsidence areas. Soils were sampled at a depth up to 30 cm in the adjacent rhizosphere of Amorpha fruticose Linn. from five reclaimed vegetation communities in northwestern China. In August 2015, a field trial was set up with five historical revegetation experiments established in 2008(7-year), 2011(4-year), 2012(3-year), 2013(2-year) and 2014(1-year), respectively. Each reclamation experiment included two treatments, i.e., revegetation with exotic AMF inoculum(AMF) and non-AMF inoculum(the control). Root mycorrhizal colonization, glomalin-related soil protein(GRSP), soil organic carbon(SOC), soil nutrients, and enzyme activities were also assessed. The results showed that mycorrhizal colonization of inoculated plants increased by 33.3%–163.0% compared to that of non-inoculated plants(P<0.05). Revegetation with exotic AMF inoculum also significantly improved total GRSR(T-GRSP) and easily extracted GRSP(EE-GRSP) concentrations compared to control, besides the T-GRSP in 1-year experiment and the EE-GRSP in 2-year experiment. A significant increase in SOC content was only observed in 7-year AMF reclaimed soils compared to non-AMF reclaimed soils. Soil total N(TN), Olsen phosphorus(P) and available potassium(K) were significantly higher in inoculated soil after 1–7 years of reclamation(except for individual cases), and increased with reclamation time(besides soil Olsen P). The exotic AMF inoculum markedly increased the average soil invertase, catalase, urease and alkaline phosphatase by 23.8%, 21.3%, 18.8% and 8.6%, respectively(P<0.01), compared with the control. Root mycorrhizal colonization was positively correlated with soil parameters(SOC, TN and soil available K) and soil enzyme activities(soil invertase, catalase, urease and alkaline phosphatase) in both AMF and non-AMF reclaimed soils(P<0.05), excluding availableK in non-AMF reclaimed soils. T-GRSP(P<0.01) and EE-GRSP(P<0.05) were significantly correlated with the majority of edaphic factors, except for soil Olsen P. The positive correlation between root mycorrhizal colonization and available K was observed in AMF reclaimed soils, indicating that the AMF reclaimed soil with a high root mycorrhizal colonization could potentially accumulate available K in soils. Our findings concluded that revegetation with exotic AMF inoculum influenced soil nutrient availability and enzyme activities in the semi-arid ecosystem, suggesting that inoculating AMF can be an effective method to improve soil fertility and support restoration of vegetation communities under poor conditions like soil nutrient deficiency and drought.     

Dynamics of arbuscular mycorrhizal fungi associated with desert ephemeral plants in Gurbantunggut Desert

Previous studies documented that most desert plants can be colonized by arbuscular mycorrhizal (AM) fungi,however,little is known about how the dynamics of AM fungi are related to ephemerals in desert ecosystems.The dynamics of AM fungi with desert ephemerals were examined to determine the effects of host plant life stages on the development of AM fungi.Mean colonization of ephemeral annual plants was 45% lower than that of ephemeral perennial plants.The colonizations were much higher in the early part of the growing season than in later parts,peaking at flowering times.The phenology of AM fungi in root systems varied among different ephemerals.The density of AM fungal spores increased with the development of ephemeral annual plants,reached its maximum at flowering times,and then plateaued about 20 days after the aboveground senescence.A significant positive correlation was found between AM fungi spore density and biomass of ephemeral annual plants.The life cycles of AM fungi associated with desert ephemerals were very short,being about 60-70 days.Soil temperature and water content had no direct influence on the development of AM fungal spores.We concluded that the development of AM fungi was in response to desert ephemeral phenology and life history strategy.     

AM真菌对加拿大一枝黄花与菌根植物和非菌根植物种间作用的影响

为明确丛枝菌根(arbuscular mycorrhizal,AM)真菌对加拿大一枝黄花Solidago canadensis与本地菌根植物和非菌根植物种间竞争格局的调控作用,采用温室盆栽试验,通过接种摩西球囊霉Glomus mosseae(GM)、根内球囊霉G. intraradices(GI)及其混合菌种(GM+GI)3种处理,分析AM真菌对加拿大一枝黄花与本地菌根植物玉米Zea mays和非菌根植物油菜Brassica campestris种间作用的影响。结果表明:与对照相比,接种AM真菌均显著提高了加拿大一枝黄花和玉米的菌根侵染率,菌根侵染率为13.720%～50.015%,且前者的菌根侵染率明显高于后者。单独种植时,与对照相比,接种AM真菌尤其是接种混合菌种显著提高了加拿大一枝黄花的株高、叶片数和总干重。在加拿大一枝黄花与玉米混合种植时,与单独种植相比,加拿大一枝黄花的株高、叶片数、根长和总干重均较低;同时,与对照相比,接种AM真菌显著提高了玉米的相对竞争强度而对加拿大一枝黄花的相对竞争强度没有显著影响。在加拿大一枝黄花和油菜混合种植时,与对照相比,接种AM真菌则显著提高了加拿大一枝黄花的株高、叶片数、净光合速率和总干重;同时,接种AM真菌促进了入侵种的竞争优势而抑制了非菌根植物油菜的生长。说明加拿大一枝黄花与本地种的竞争格局受到与之混生物种的菌根依赖性强度以及AM真菌的种类差异影响。     

Sand mining disturbances and their effects on the diversity of arbuscular mycorrhizal fungi in a riparian forest of Iran

The major objective of this study was to evaluate the effects of sand mining disturbances on the diversity of arbuscular mycorrhizal fungi(AMF). In addition, the proportional changes in the diversity of AMF to the distances from riverbanks were assessed. For this purpose, the riparian forest of the Maroon River, Iran was divided into three locations with a 200-meter wide zone in between. Thus, the locations studied were named Distance I(riverbank), Distance II(intermediate), and Distance III(farthest from riverbank). In each of these distances, 10 Tamarix arceuthoides and Populus euphratica of each species were randomly selected. At the same time, soil and root samples were collected from the rhizosphere of the tree species studied. Results indicated that totally 13 AMF species were observed in T. arceuthoides and 19 AMF species were recorded in P. euphratica rhizosphere belonging to 6 genera and 6 families. In these AMF species, Glomus segmentatum, G. geosporum, G. rubiforme, G. nanolumen, G. spinuliferum, Claroideoglomus drummondii, Gigaspora gigantea and Acaulospora paulinae appeared only in P. euphratica rhizosphere, while G. multiforum and Claroideoglomus claroideum were observed only in T. arceuthoides rhizosphere. Moreover, Distance II had the least AMF species both in T. arceuthoides and in P. euphratica rhizospheres, and also the least spore density and root colonization rate. Our results are important in that they provide a list of resistant AMF species that could be used in the conservation of biodiversity.     

Isolation and identification of desert habituated arbuscular mycorrhizal fungi newly reported from the Arabian Peninsula

Arbuscular mycorrhizal fungi（AMF） are known to facilitate the growth and vigour of many plants, particularly in arid ecosystems. In a survey of AMF in a date palm plantation and two natural sites of a desert in Oman, we generated many single spore-derived cultures of AMF. We identified a number of these isolates based on spore morphotyping and molecular phylogenetic analysis using the sequence of the LSU-rDNA. Here, we presented the characteristics of four species of AMF recovered, namely Claroideoglomus drummondii, Diversispora aurantia, Diversispora spurca and Funneliformis africanum. The four species have been described previously, but for the Arabian Peninsula they are reported here for the first time. Our endeavor of isolation and characterization of some AMF habituated to arid sites of Arabia represents a first step towards application for environmental conservation and sustainable agriculture in this region.     

Effect of native and allochthonous arbuscular mycorrhizal fungi on Casuarina equisetifolia growth and its root bacterial community

Exotic trees are often planted to recover degraded lands. Inoculation with mycorrhizal fungi can improve their survival. Plant growth is partly dependent on the strain used, but little attention has been paid to the selection of mycorrhizal fungi. The aim of this study was to determine whether the growth of Casuarina equisetifolia L. (Johnson) is affected by two different mycorrhizal inocula generated using fungal spores retrieved from an Australian site (allochthonous soil) and a Senegalese site (native soil) under C. equisetifolia trees. Comparative experiments were conducted with plants in a Senegalese soil, previously sterilized or not, and grown in a greenhouse. At harvest, parameters related to plant growth and mycorrhization were evaluated and soil bacterial communities were compared. Tree growth was significantly influenced by both types of inoculants. In unsterilized soil, plants inoculated with the native inoculant were taller than plants inoculated with the allochthonous inoculant and control plants. The frequency of mycorrhization with both inoculants was higher in unsterilized soil. The strongest effects of the mycorhizosphere on the soil microbiome were obtained with the allochthonous inoculum, and analysis of the taxonomic composition revealed mycorrhizal communities specific to each inoculum. These results suggest that the development of C. equisetifolia and its root bacterial community are dependent on the composition of the mycorrhizal inoculum. The functional consequences of this rhizosphere effect in terms of soil fertility should be further studied to better guide reforestation operations.     

抗黄瓜枯萎病丛枝菌根真菌与根围促生细菌组合菌剂的筛选

 丛枝菌根真菌(AMF)和植物根围促生细菌(PGPR)同时接种具有促生防病的作用。本试验旨在评价AMF与PGPR组合菌剂防治黄瓜枯萎病(Fusarium oxysporum f. sp. cucumerinum )的效果,以获得高效生防菌剂。于温室盆栽条件下将AMF Funneliformis mosseae(Fm)、Glomus intraradices(Gi)和 Glomus versiforme(Gv)与PGPR菌株(PR2-1、PS1-3、PS1-5、PS2-6和PS3-2)不同组合菌剂处理黄瓜(Cucumis sativus, 品种:香翠16号),测定各处理对黄瓜植株生长量、枯萎病防治效果和黄瓜产量的影响。供试AMF+PGPR各组合菌剂处理能不同程度的增加黄瓜根系AMF侵染率和根围细菌的定殖数量、促进黄瓜生长发育和降低枯萎病危害程度。其中,以Fm+PS3-2和 Gv+PS2-6组合菌剂促生和增产效果最好, 以Fm+PS1-5、Fm+PS3-2和Gv+PS2-6组合菌剂防治枯萎病效果最好。综合评价筛选获得高效组合为Fm+PS3-2和Gv+PS2-6。这两个处理可使黄瓜枯萎病病情指数分别下降50.0%和58.4%,防效达到54.5%和63.7%,具有一定的田间应用潜力。     

AMF+PGPR组合提高黄瓜抗枯萎病的作用机制

对黄瓜(Cucumis sativus)品种香翠16接种尖孢镰刀菌黄瓜专化型(Fusarium oxysporum f.sp.cucumerinum,Foc)、丛枝菌根真菌(AMF)Funneliformis mosseae(Fm)+Foc、丛枝菌根真菌Glomus versiforme(Gv)+Foc、根围促生细菌(PGPR)PS2-6+Foc、PS3-2+Foc、Fm+PS3-2+Foc以及Gv+PS2-6+Foc,以不接种处理作为对照。结果表明,接种Foc条件下,Fm+PS3-2和Gv+PS2-6组合处理的抗病效果显著优于单接种AMF或PGPR处理;镜检观测到靠近AMF菌丝的Foc菌丝纤细,生长不良。AMF菌丝能缠绕Foc菌丝,并阻挡其侵入根系;AMF侵染率与其防效均呈正相关(P0.05);Fm+PS3-2+Foc和Gv+PS2-6+Foc处理的根系活力是单接种Foc的4.6倍;与不接种对照相比,Fm+PS3-2+Foc和Gv+PS2-6+Foc处理的黄瓜叶片中吲哚乙酸(IAA)含量分别提高了205%和166%,赤霉素(GA3)提高了33%和22%,玉米素核甘(ZR)提高了100%和80%,JA平均提高了65%,ABA降低23%和17%;而与单接种Foc处理相比,IAA提高了667%和568%,GA3提高了223%和196%,ZR提高了254%和219%,茉莉酸(JA)含量平均提高了215%,而脱落酸(ABA)含量只有单接种Foc处理的53%;Fm+PS3-2+Foc和Gv+PS2-6+Foc处理显著提高了黄瓜叶内苯丙氨酸解氨酶(PAL)防御酶活性和PAL基因表达量。综上推断AMF+PGPR组合是通过拮抗病原物、促进合成抗病信号物质、上调防御基因表达、提高防御酶活性和降低植株体内有毒物质等机制降低病害和改善植物抗病性。