连续三年夜间增温和施氮对云杉外生菌根及菌根真菌多样性的影响

以西南亚高山针叶林建群种粗枝云杉(Picea asperata)为研究对象,采用红外加热模拟增温结合外施氮肥(NH₄NO₃ 25 g N m^-2 a^-1)的方法,研究连续3a夜间增温和施肥对云杉幼苗外生菌根侵染率、土壤外生菌根真菌生物量及其群落多样性的影响。结果表明:夜间增温对云杉外生菌根侵染率的影响具有季节性及根级差异。夜间增温对春季(2011年5月)云杉1级根,夏季(2011年7月)和秋季(2010年10月)云杉2级根侵染率影响显著。除2011年7月1级根外,施氮对云杉1、2级根侵染率无显著影响。夜间增温对土壤中外生菌根真菌的生物量和群落多样性无显著影响,施氮及增温与施氮联合处理使土壤中外生菌根真菌生物量显著降低,但却提高了外生菌根真菌群落的多样性。这说明云杉幼苗外生菌根侵染率对温度较敏感,土壤外生菌根真菌生物量及其群落多样性对施氮较敏感。这为进一步研究该区域亚高山针叶林地下过程对全球气候变化的响应机制提供了科学依据。     

菌根接种对长苞铁杉幼苗生长的影响

采用天然长苞铁杉林富含菌根真菌的根际土壤,对长苞铁杉种子进行盆栽接种育苗试验,比较接种处理和未接种的长苞铁杉种子萌发率、菌根侵染率、幼苗生长、生物量分配及氮磷钾含量的差异。结果表明,外生菌根对长苞铁杉种子的萌发没有影响,对幼苗生长和氮磷钾养分的吸收有明显的促进作用,接种幼苗菌根感染率超过75%,其株高、根生物量、叶生物量和氮磷钾含量等均比对照显著增加,但对生物量在器官中的分配没有显著影响。     

华北山地6个外生菌根树种的根属性及其与菌根侵染率的关系

该研究以共存于同一暖温带森林的6个外生菌根(ECM)树种为研究对象,测定分析不同根序(1～5级)和功能根系(吸收细根和运输细根)的主要形态和构型属性及ECM侵染率,探究不同外生菌根树种的根属性变异模式及其与菌根真菌侵染程度的关系。结果表明:(1)随着根序的增加,不同树种根直径和单根长度均增加,而比根长和根分支强度均降低;根属性在同一根序下均存在显著的种间差异,尤其是2个裸子植物(落叶松和油松)的根直径较其他4个被子植物大。(2)同一树种的所有根属性在吸收细根和运输细根之间均有显著差异;吸收细根和运输细根的根直径、比根长和根组织密度在树种间均存在显著差异,而其单根长度和根分支强度在树种间无显著差异。(3)ECM侵染率以落叶松最高,千金榆和白桦最低,且与根尖直径呈显著正相关关系,与根尖比根长呈显著负相关关系。研究发现,基于根序或者功能根系,根属性在种间的变异模式不完全一致,单根长度和根分支强度在两个功能根系中均没有表现出显著的种间差异;吸收细根的比根长和根分支强度的变异系数较大,对环境变化有较敏感的响应;古老树种的根直径相对较粗,对菌根真菌的依赖性更高。     

甘肃盐碱土植物VA菌根真菌侵染研究

对甘肃盐碱土中植物的VA菌根真菌共生状况进行研究,结果表明：在10科17种植物中,除碱蓬（Suaeda glauca Beg.）外均被菌根真菌侵染,占94.1%;盐碱土中孢子密度较高,表明甘肃盐碱土生态系统中植物对菌根真菌具有较高的依赖性,菌根真菌在盐碱土中产孢能力较强;所调查植物的VA菌根结构类型Arum型占68.75%,Pris型占31.25%;菌根结构类型与宿主植物类型有关,禾本科（Poaceae）和鸢尾科（Iridaceae）植物为P型菌根,百合科（Liliaceae）、胡颓子科（Elaeagnaceae）等其它科植物均为A型菌根;土壤类型影响了宿主植物的菌根侵染率和根际土的孢子密度,相同宿主植物在不同类型土壤中的菌根侵染率和孢子密度具有很大的差异.     

亚热带典型树种根毛特征及其与共生真菌的关系

根毛和共生真菌增加了吸收面积,提高了植物获取磷等土壤资源的能力。由于野外原位观测根表微观结构较为困难,吸收细根、根毛、共生真菌如何相互作用并适应土壤资源供应,缺乏相应的数据和理论。该研究以受磷限制的亚热带森林为对象,选取了21种典型树种,定量了根毛存在情况、属性变异,分析了根毛形态特征与共生真菌侵染率、吸收细根功能属性之间的关系,探讨了根表结构对低磷土壤的响应和适应格局。结果表明:1)在亚热带森林根毛不是普遍存在的, 21个树种中仅发现7个树种存有根毛, 4个为丛枝菌根(AM)树种, 3个为外生菌根(ECM)树种。其中,马尾松(Pinus massoniana)根毛出现率最高,为86%;2)菌根类型是理解根-根毛-共生真菌关系的关键,AM树种根毛密度与共生真菌侵染率正相关,但ECM树种根毛直径与共生真菌侵染率负相关; 3) AM树种根毛长度和根毛直径、ECM树种根毛出现率与土壤有效磷含量呈负相关关系。该研究揭示了不同菌根类型树种根毛-共生真菌-根属性的格局及相互作用,为精细理解养分获取策略奠定了基础。     

川西亚高山岷江冷杉外生菌根形态随海拔梯度的分化

外生菌根真菌是一类有助于植物生长及应对环境变化的重要共生真菌类群。深入认识外生菌根特征有助于理解植物对环境变化的响应规律。本研究在四川省卧龙自然保护区巴郎山脉设置海拔2850、3000、3194、3413和3593 m 5个样地,利用中心象限法进行土块样品(10 cm×10 cm×10 cm)采集,通过分析各海拔每土块中岷江冷杉外生菌根形态个数、形态多样性及养分获取类型等指标,研究岷江冷杉外生菌根形态特性随海拔的变异特征及土壤环境因子的作用。结果表明: 1) 菌根形态为橘黄色或橘色、单轴羽状分支或不分支、菌套表面光滑、无或少见外延物、根尖直筒型或膨大的菌根类型是卧龙自然保护区岷江冷杉外生菌根的主要形态类型。该形态类型在研究区内的侵染率最高,为12.4%;2) 随着海拔的升高,岷江冷杉外生菌根形态多样性下降,每土块内的形态个数减少;3) 单因素方差分析结果表明,不同海拔上无外延菌丝或极少外延菌丝的紧密接触类型(CE)和短距离养分获取类型(SDE)外生菌根侵染率有显著差异,CE类型外生菌根侵染率随着海拔的升高而增加;4) 土壤环境因子对岷江冷杉外生菌根形态在海拔上的变异有一定的影响,冗余分析(RDA)表明,土壤全氮含量、全磷含量、土壤温度、土壤含水率、pH值及酸性磷酸酶活性对岷江冷杉外生菌根形态在海拔上的变异有显著影响,其中土壤全氮含量和土壤温度的影响最大,分别解释了岷江冷杉形态特征变异的5.4%和4.9%。本研究揭示了岷江冷杉外生菌根形态形成在海拔上的差异,为进一步研究亚高山针叶树种菌根策略对环境变化的响应机制提供了科学依据。     

山西历山珍稀药用植物AM真菌资源与土壤因子的关系

以山西历山自然保护区暴马丁香、连香树、南方红豆杉和领春木4种珍稀药用植物为材料,研究其根际土壤中丛枝菌根真菌(AMF)的菌根结构类型和种属分布,同时分析土壤因子与其侵染率和孢子密度的关系。结果表明:(1)暴马丁香菌根类型为中间型(I-型),连香树和领春木为重楼型(P-型),南方红豆杉为疆南星型(A-型);4种植物根际共鉴定AMF 27种,分别隶属于球囊霉属(Glomus)、无梗囊霉属(Acaulospora)、盾巨孢囊霉属(Scutellos-pora)、多孢囊霉属(Diversispora)和原囊霉属(Archaeospora)5属,其中Glomus为优势属。(2)pH与暴马丁香和领春木的侵染率和孢子密度呈正相关,但与连香树和南方红豆杉呈负相关;速效磷与暴马丁香、南方红豆杉和领春木的侵染率和孢子密度呈正相关,但与连香树呈负相关;碱解氮、有机质与暴马丁香、连香树和领春木的侵染率和孢子密度呈正相关,但与南方红豆杉呈负相关。(3)4种药用植物的菌根侵染率主要受其根际土壤碱解氮的影响,而根际AMF孢子密度主要受根际土壤pH制约。可见,历山自然保护区内AMF资源丰富,多样性程度也较高;宿主植物不同,土壤因子对其侵染率和孢子密度的影响也不同。     

秦岭辛家山林区落叶松外生菌根真菌多样性

【目的】以秦岭辛家山林区落叶松为研究对象,观察鉴定与其共生的外生菌根真菌。【方法】通过野外调查结合形态学和分子生物学鉴定方法。【结果】鉴定出31种外生菌根真菌,分属2门4目11科11属,分别有毛革菌属(Tomentella)、丝盖伞属(Inocybe)、红菇属(Russula)、Amphinema、蜡蘑属(Laccaria)、蜡壳耳属(Sebacina)、鹅膏菌属(Amanita)、牛肝菌属(Boletus)、丝膜菌属(Cortinarius)、乳菇属(Lactarius)和硬皮马勃属(Scleroderma),丝盖伞属是优势类群。阳坡外生菌根真菌多样性高于阴坡。对菌根根际土与非根际土化学性质分析表明,pH值显著低于非根际,速效磷、速效钾含量显著高于非根际。对根际土化学性质与外生菌根侵染率相关性分析表明,落叶松外生菌根侵染率与土壤pH值呈显著正相关;与速效钾呈极显著正相关;与全氮、速效磷呈显著负相关。【结论】落叶松外生菌根真菌多样性丰富,且受坡向影响。外生菌根真菌可降低根际pH,提高根际有机质、全氮、速效磷、速效钾、水溶性钙和水溶性镁的含量。外生菌根侵染率受土壤pH值、全氮、速效磷、速效钾的影响。     

内蒙古中西部草原主要植物的丛枝菌根及其结构类型研究

2002年6-9月,对内蒙古中西部草原建群植物及优势植物的丛枝菌根共生状况进行了调查。在观察的28科125种植物中,被丛枝菌根真菌侵染的植物有104种(占83．2％);在过去认为不能侵染的莎草科植物中发现卯穗苔草(Carex duriuscula)和黄囊苔草( C. korshinskyi)有侵染现象。在所调查的植物中,多年生草本和灌木类植物被丛枝菌根真菌侵染的比例较高,占被调查该类植物总数的90．4％;而一年生和二年生草本植物被侵染的比例仅为47．6％。本地区野生植物的丛枝菌根结构类型多数为Arum类型,占65．38％,尤其在百合科(Liliaceae)、菊科(Compositae)、豆科(Leguminosae)和蔷薇科(Rosaceae)植物中比例较高;而Paris类型仅有19．23％,多见于禾本科(Gramineae!)、唇形科(Labiatae)、桔梗科(Campanulaceae)和百合科。丛枝菌根的结构类型与植物的根系类型、生活型和菌根侵染率无关,而与植物所属的科属关系比较密切。     

菌根菌剂对科尔沁沙地3种常见造林绿化树种幼苗生长的影响

如何在沙地成功造林并使其快速生长是沙地生态环境建设面临的一个重大挑战。菌根菌剂具有改善造林树种生存环境、调节植物生长的作用，但菌根菌剂对不同植物的影响有何差异，以及如何依据不同生境条件和目标施用合适的菌根菌剂尚缺乏清晰认知。本研究以科尔沁沙地3种常见造林绿化树种樟子松(Pinus sylvestris var.mongolica)、紫穗槐(Amorpha fruticosa)和水蜡(Ligustrum obtusifolium)为对象，采用穴施方法按0、100、200和300 g·m^-2剂量，对紫穗槐和水蜡接种内生菌根菌剂(根内根孢囊霉，Rhizophagus intraradices),对樟子松接种外生菌根菌剂(彩色豆马勃，Pisolithus tinctorius)。在幼苗生长1年后，测定菌根侵染率及生长指标。结果表明：樟子松菌根侵染率随菌剂用量增加而显著增加，在300 g·m^-2处理下侵染率最高(17.8%);紫穗槐菌根侵染率随菌剂用量变化不显著；水蜡菌根侵染率随菌剂用量增加而显著减少，在100 g·m^-2处理下侵...     

菌根及其在荒漠化土地恢复中的应用

对菌根的作用及其荒漠化对其影响,以及菌根在荒漠化土地恢复中的应用进行了探讨,指出菌根不仅能够促进植物个体养分的吸收,提高植物光合作用,增强植物抗旱、抗盐性,而且能够调节群落内植物间的关系、群落的演替轨道及其生物多样性、耕作、灌溉、过度放牧和开矿等诱发土地荒漠化过程的人类活动直接影响菌根的建立和生存,采用外来菌引入及原来残存菌培育,在恢复区建立丛状菌根植物,菌木化菌根造林及开矿土地管理中表土的存贮等方式都会有力地促进恢复地菌根的建立,并可缩短恢复周期。     

Mycorrhiza-plant colonization patterns on a subalpine glacier forefront as a model system of primary succession

Lyman glacier in the North Cascades Mountains of Washington has a subalpine forefront characterized by a well-developed terminal moraine, inconspicuous successional moraines, fluting, and outwash. These deposits were depleted of symbiotic fungi when first exposed but colonized by them over time after exposure. Four major groups of plant species in this system are (1) mycorrhiza-independent or facultative mycotrophic, (2) dependent on arbuscular mycorrhizae (AM) (3) dependent on ericoid mycorrhiza (ERM) or ectomycorrhizae (EM), and (4) colonized by dark-septate (DS) endophytes. We hypothesized that availability of mycorrhizal propagules was related to the success of mycorrhiza-dependent plants in colonizing new substrates in naturally evolved ecosystems. To test this hypothesis roots samples of 66 plant species were examined for mycorrhizal colonization. The plants were sampled from communities at increasing distances from the glacier terminus to compare the newest communities with successively older ones. Long established, secondary successional dry meadow communities adjacent to the glacier forefront, and nearby high alpine communities were sampled for comparison. DS were common on most plant species on the forefront. Nonmycorrhizal plants predominated in the earlier successional sites, whereas the proportion of mycorrhizal plants generally increased with age of community. AM were present, mostly at low levels, and nearly absent in two sites of the forefront. ERM were present in all species of Ericaceae sampled, and EM in all species of Pinaceae and Salicaceae. Roots of plants in the long established meadow and heath communities adjacent to the forefront and the high alpine community all had one or another of the colonization types, with DS and AM predominating.     

Mycorrhizal relationships in bottomland hardwood forests of the southern United States

Mycorrhizae are important in the functioning of forest ecosystems worldwide, and play a critical role in water uptake, nutrient acquisition, and prevention of feeder root disease. The majority of mycorrhizal research has been conducted on upland sites, especially in coniferous ecosystems and in commercial agricultural production. However, the maintenance and restoration of bottomland hardwood (BLH) forest ecosystems in the southern United States is of increasing concern. Both ectomycorrhizae and endomycorrhizae are present in BLH forests, although the dominance of one or the other type depends primarily on both the tree species and the hydrologic regime. Ectomycorrhizae tend to be more sensitive to flooding, while endomycorrhizal infection can be present even in permanently flooded soils. The mycorrhizae of sweetgum (Liquidambar styraciflua), green ash (Fraxinus pennsylvanica), and the oaks (Quercus spp.) have been studied most due to their economic importance.Considerable work is still needed to better understand mycorrhizal relationships in BLH ecosystems and associated trees, both with respect to infectivity and nutrient cycling. Such information may be necessary for restoration of BLH forests on old agricultural fields, or to maintain the productivity of BLH forests after harvest. This paper summarizes studies on mycorrhizae relationships in BLH forests and suggests future work necessary for understanding the role mycorrhizae can have in managing these ecosystems.     

Interspecific nutrient transfer in a tallgrass prairie plant community

Interplant nutrient transfer may be an important ecological process in grasslands, and may significantly influence plant neighborhood interactions. We investigated the potential for phosphorus transfer between the dominant grass Andropogon gerardii and several neighboring plant species in tallgrass prairie via a field ³²PO₄ labelling experiment. The mean amount of ³²P received from donor shoots differed significantly among neighboring species and decreased with increasing distance from the donor. In general, forbs and cool-season C₃ grasses received more labelled ³²P than warm-season C₄ grasses. Phosphorus transfer occurred over distances up to 0.5 m. The effects of species and distance on movement of phosphorus changed with increasing time after labelling. The relative mass of receiver and donor shoots did not affect amounts of ³²P transfer. A benomyl fungicide treatment, applied to suppress mycorrhizal activity, likely did not affect existing vegetative hyphae and did not affect the amount of ³²P transferred. These studies demonstrate that: (1) phosphorus is transferred among neighboring species in tallgrass prairie plant communities, (2) phosphorus may be transferred over significantly greater distances than reported in other grasslands, and (3) there is differential transfer among co-occurring species. Hypothesized mechanisms accounting for these patterns in tallgrass prairie include mycorrhizal hyphal interconnections and/or extensive and differential root and rhizosphere overlap among neighboring species.     

Adaptation of plant‐mycorrhizal interactions to moisture availability in prairie restoration

The strength and direction of plant response to inoculation with arbuscular mycorrhizal fungi (AM fungi) is dependent on both abiotic and biotic contexts, often generating patterns of AM fungal mediation of plant adaptation. However, knowledge of plant‐community level effects of these interactions in grassland restoration is limited. We conducted a field inoculation experiment by inoculating five plant species native to a drier prairie and five plant species native to a moister prairie with mycorrhizal fungal communities from each prairie type. Species were paired by genus or family to account for phylogenetic effects. The inoculated plants were transplanted to study plots seeded with a restoration seed mix. Plots were manipulated to create either moister or drier conditions similar to environments of the plant species and mycorrhizal communities. In both transplanted and seeded plant species, we found that only drier prairie‐range species benefited from moisture‐regime matched AM fungal inoculum. Other seeded prairie plant species demonstrated a negative response to inoculation, likely due to the earlier successional stage of these species. Additionally, nonseeded plants benefited from inoculation in different ways: native nonseeded plants had highest cover with drier prairie inoculum in drier conditions, while nonnative plants had highest cover with moister prairie‐origin inoculum. These results suggest that use of local AM fungi may be particularly important in restorations at drier sites, even at relatively small differences in moisture availability. Further, specific knowledge of relative responsiveness of seeded plant species and nonseeded plant species to AM fungal inoculation will be useful in planning restorations.     

Performance of vesicular-arbuscular mycorrhizae in saline-alkali soil in relation to various amendments

The present study shows that vesicular-arbuscular mycorrhizal colonization in plants grown in saline-alkali soil is host dependent and it is significantly affected by various amendments given to reclaim such soils. Maximum reduction in vesicular-arbuscular mycorrhizal colonization was observed in the plants raised in saline-alkali soil amended with gypsum and maximum colonization was observed after plant-growth promoting rhizobacterium or farm yard manure amendments. Plants possessing high level of vesicular-arbuscular mycorrhizal colonization (50–70%) included Acacia nilotica, Albizia lebbeck and Dalbergia sissoo. Casuarina equisetifolia possessed moderate level of vesicular-arbuscular mycorrhizae colonization (30–50%) and Azadirachta indica possessed low level of colonization (20–40%).     

不同pH水平下两种菌根真菌对紫云英生长的影响及其相互作用

设计在不同pH水平（4.3、5.1、5.8、6.8）下两种VA菌根真菌Glomus mosseae和Gigaspora margarita对紫云英Astragalus sinicus进行单接种、混合接种及无接种对照的盆栽实验。对紫云英地上和地下部分生物量、根部侵染率、SDH和ALP酶活进行了检测。实验结果表明：紫云英的生长效应与VA菌根真菌的侵染率及两种酶活成明显相关性。土壤pH升高,单接种Glomus mosseae和混合接种的侵染率也随之升高,而单接种Gigaspora margarita的侵染率呈现     

The effect of aluminium and media on the growth of mycorrhizal and nonmycorrhizal highbush blueberry plantlets

A factorial experiment was conducted to determine the effect of aluminium (0 and 600M) and media (sand, and 1:1 sand:soil) on mycorrhizal (M) and non-mycorrhizal (NM) highbush blueberry plantlets. There were no differences in nutrient uptake and total plant dry weight between M and NM plantlets. However, more root growth, as determined by dry weight, was observed in M than NM plantlets. The plantlets growing in sand had more dry weight than did those in the soil medium. Although the root growth and shoot growth were reduced by the 600M Al treatment, the direct effect of Al on plantlet growth was not clear due to Al and P interactions. Plant nutrient uptake was reduced by high concentrations of Al, suggesting that high Al concentration limited the ability of roots to acquire most of the nutrients. Mycorrhizal cortical cell infection levels of 15–20% wene maintained in the roots in soil medium but decreased to about 5% over the 6 weeks of the experiment in the sand medium. Although M plantlets accumulated more Al in their roots, Al was readily transported to the leaf tissues of M and NM plantlets.     

不同pH水平下两种菌根真菌对紫云英生长的影响及其相互作用

设计在不同pH水平(4.3、5.1、5.8、6.8)下两种VA菌根真菌Glomus mosseae和Gigaspora margarita对紫云英Astragalus sinicus进行单接种、混合接种及无接种对照的盆栽实验.对紫云英地上和地下部分生物量、根部侵染率、SDH和ALP酶活进行了检测.实验结果表明:紫云英的生长效应与VA菌根真菌的侵染率及两种酶活成明显相关性.土壤pH升高,单接种Glomus mosseae和混合接种的侵染率也随之升高,而单接种Gigaspora margarita的侵染率呈现出先上升后下降的趋势.本实验设计了特异性扩增Glomus mosseae和Gigaspora margarita的引物gml和gigl,在混合接种实验中,nested PCR扩增结果显示:在低pH水平下(4.3-5.1)大多数根段为Gigaspora margarita所侵染,在高pH水平下(5.8-6.8)Glomusmosseae表现出较强的竞争力,但并没有检测到两种VA真菌存在于同一条侵染根段;对比单接种实验,在低pH水平下,Glomus mosseae显著抑制了Gigaspora margarita的侵染,而在高pH水平下Gigasporamargarita明显促进Glomus mosseae的侵染.