Spatial distribution of ectomycorrhizal Basidiomycete Russula subsect. Foetentinae populations in a primary dipterocarp rainforest

The spatial distribution of basidiocarps of the ectomycorrhizal Basidiomycete Russula subsect. Foetentinae was assessed in a primary forest in the Western Ghats (India) dominated by the ectomycorrhizal tree species Vateria indica and Dipterocarpus indicus. Over a 7,700-m² sampling area, both trees and basidiocarps of Russula subsect. Foetentinae were mapped during the first month of the 2002 rainy season. First-order spatial analysis revealed that the distribution of the 45 collected carpophores was highly aggregated, with 60% of all basidiocarps located at a distance lower than 1 m from the nearest one. The genetic structure of the Russula subsect. Foetentinae population was studied by inter-simple sequence repeat polymorphism analysis using three primers. Eighteen of the 45 genotypes were represented by single basidiocarps. Twenty-seven basidiocarps were identified as belonging to 11 genets or separated ramets. Five genets were small, with diameters ranging from 0.5 to 5 m. The six others were large, with a diameter ranging from 31 m to a maximum measured distance of 70 m. In spite of the lack of data concerning the reproductive biology of this species, the presence of large genets suggests that mature stands may shelter well-spread underground mycelium, crucial for durable interaction with plant partner.     

Species richness and seasonal abundance of ectomycorrhizal fungi in plantations of<Emphasis Type="Italic"> Eucalyptus dunnii</Emphasis> and<Emphasis Type="Italic"> Pinus taeda</Emphasis> in southern Brazil

The abundance and diversity of ectomycorrhizal fungi (EMF) was assessed based on the collection of basidiocarps during 12 months comprising the spring of 1995, and the summer, autumn, and winter of 1996, in three stands of young, middle-aged, and rotation age plantations of Pinus taeda and Eucalyptus dunnii, in the state of Santa Catarina, southern Brazil. A total of 3,085 collections yielded 34 presumed EMF taxa in ten genera, including mushroom-like and sequestrate species. Fruiting patterns of EMF differed with host and season, and host specificity was apparent in some. The overall relative importance (RI) and the Shannon diversity index (H) suggested that stands of E. dunnii had a more diverse aboveground EMF community than those of P. taeda. Overall, species of Scleroderma and Laccaria were not only the most abundant but also had the highest biomass values. The results show that a small number of species of abundant biomass and a larger number of species of less-abundant biomass characterize each forest class.     

Spatial distribution of the basidiocarps of aphyllophoraceous fungi in a tropical rainforest on Borneo Island, Malaysia

The spatial distribution of basidiocarps provides much information on the dispersal abilities, habitat preferences, and inter- and intraspecific interactions of aphyllophoraceous fungi. To reveal the spatial distribution and resource utilization patterns of aphyllophoraceous fungi in Malaysia, we conducted field observations in a primary forest in 2006 and analyzed the relationships between the abundance of eight dominant fungal species and various environmental factors. The topographical characteristics were significantly patchily distributed at the 100-m scale, whereas woody debris and most fungal species were distributed randomly. Although the dominant fungal species differed among the decay classes and diameters of the woody debris, the abundance of a few dominant species was significantly correlated with environmental factors. Although the latter factors might affect the spatial distribution of these fungi, the effects appear to be so small that they would not create an aggregated distribution at a few 100-m scales.     

The feeding preference of mycophagous Collembola varies with the ectomycorrhizal symbiont

The interactions of the collembolan insect Proisotoma minuta with ectomycorrhizal and/or pathogenic fungi was examined in three experiments: (1) in vitro analysis of feeding patterns, (2) in vitro food preference test, and (3) in situ analysis of ectomycorrhizal colonization in relation to population density. The ectomycorrhizal fungi Laccaria laccata, Pisolithus tinctorius, Suillus luteus, Thelephora terrestris and the pathogenic fungi Rhizoctonia solani were employed in all experiments. In vitro and in situ experiments revealed that Pr. minuta consumed all the ectomycorrhizal fungi tested but the feeding pattern and consumption varied with each isolate. In a comparative in vitro feeding preference test, where Pr. minuta was given a choice, R. solani was grazed more heavily than the ectomycorrhizal fungi. Among the ectomycorrhizal fungi examined, Pi. tinctorius was consumed significantly less than L. laccata, S. luteus or T. terrestris in the presence of R. solani. A 10-week in situ analysis of loblolly pine (Pinus taeda L.) seedling root systems inoculated with Pr. minuta revealed that ectomycorrhizal colonization was significantly less than that of control plants (without Pr. minuta). Collectively, these data suggest that mycophagous Collembola may play a major role in the distribution and biomass of ectomycorrhizal fungi in the rhizosphere of tree seedlings.     

Interactions between fire,mycophagous mammals,and dispersal of ectromycorrhizal fungi in Eucalyptus forests

Several species of marsupials in Eucalyptus forests in Australia feed predominantly on the sporocarps of hypogeous fungi. This feeding is apparently beneficial to the fungi as it results in dispersal of spores. As these fungi are in almost all cases ectomycorrhiza-forming species, mycophagy by mammals may play an important role in the maintenance of mycorrhizal symbiosis in Eucalyptus forests. Fire is frequent and a dominant ecological factor in these forests, and this study tested the hypothesis that fire triggers both increased sporocarp production by some hypogeous ectomycorrhizal fungi associated with eucalypts, and increased mycophagy by mammals. Three experimental burns were set in E. tenuiramus forest in southeastern Tasmania. Digging activity (which reflects feeding on hypogeous fungi) by a mycophagous marsupial, the Tasmanian bettong Bettongia gaimardi, increased up to ten-fold after fire, with a peak about 1 month post-fire. This was associated with a similar pattern of increase in sporocarp production, which was due to species in the family Mesophelliaceae (especially Castoreum tasmanicum and Mesophellia spp.). This family appears to have radiated in association with eucalypts and has an exclusively Australasian distribution, unlike many of the other ectomycorrhizal fungi collected in this study which are cosmopolitan and have broad host ranges. No B. gaimardi were killed by fire, and there was no increase in mortality following fire. Population density increased after fire as a result of immigration of adult males. However, body condition and fecundity of individual B. gaimardi were maintained at pre-fire levels. This suggests that the availability of energy to B. gaimardi increased as a result of fire, and the fact that the contribution of fungus to the diet of B. gaimardi was high on burnt relative to control sites suggests further that this increase in energy availability was provided by hypogeous fungi. Effects of fire on hypogeous fungi and B. gaimardi were short-lived; all measured variables returned to control values about 4 months after fire. The capacity of B. gaimardi to survive fire and to harvest the increased sporocarp production triggered by fire provides a mechanism for the rapid dispersal of spores after fire. This should result in the establishment of ectomycorrhizae very early in post-fire succession. Because only some species of ectomycorrhizal fungi fruited in response to burning, fire probably has a strong influence on community structure among ectomycorrhizal fungi.     

Partial restoration of fungal and plant species diversity by removal of litter and humus layers in stands of Scots pine in the Netherlands

A field experiment was set up in five mature Scots pine (Pinus sylvestris) stands in the Netherlands in order to study the effects of removal of litter and humus on ectomycorrhizal fungi and vegetation of higher plants, bryophytes, and lichens. Lime was also applied as a countermeasure to the removal of surplus cations. Application of lime did not have significant effects on mycorrhizal fungi. Removal of ectorganic material increased species richness of ectomycorrhizal fungi. The number of fruit bodies was also higher in the sod-cut plots, but the difference compared with the controls was not significant in all years. A major effect of removal of the ectorganic layer was a reversion of ectomycorrhizal succession to earlier stages. Liming increased the number and cover of ruderal, nitrophilous plant species. Sod-cutting caused a reversion of the green vegetation to earlier successional stages.     

Mean reproductive traits of fungal assemblages are correlated with resource availability

Organisms have evolved a fascinating variety of strategies and organs for successful reproduction. Fruit bodies are the reproductive organ of fungi and vary considerably in size and shape among species. Our understanding of the mechanisms underlying the differences in fruit body size among species is still limited. Fruit bodies of saprotrophic fungi are smaller than those of mutualistic ectomycorrhizal fungi. If differences in fruit body size are determined by carbon acquisition, then mean reproductive traits of saprotrophic and ectomycorrhizal fungi assemblages should vary differently along gradients of resource availability as carbon acquisition seems more unpredictable and costly for saprotrophs than for ectomycorrhizal fungi. Here, we used 48 local inventories of fungal fruit bodies (plot size: 0.02 ha each) sampled along a gradient of resource availability (growing stock) across 3 years in the Bavarian Forest National Park in Germany to investigate regional and local factors that might influence the distribution of species with different reproductive traits, particularly fruit body size. As predicted, mean fruit body size of local assemblages of saprotrophic fungi was smaller than expected from the distribution of traits of the regional species pool across central and northern Europe, whereas that of ectomycorrhizal fungi did not differ from random expectation. Furthermore and also as expected, mean fruit body size of assemblages of saprotrophic fungi was significantly smaller than for assemblages of ectomycorrhizal species. However, mean fruit body sizes of not only saprotrophic species but also ectomycorrhizal species increased with resource availability, and the mean number of fruit bodies of both assemblages decreased. Our results indicate that the differences in carbon acquisition between saprotrophs and ectomycorrhizal species lead to differences in basic reproductive strategies, with implications for the breadth of their distribution. However, the differences in resource acquisition cannot explain detailed species distribution patterns at a finer, local scale based on their reproductive traits.     

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。     

Spatial Segregation and Aggregation of Ectomycorrhizal and Root-Endophytic Fungi in the Seedlings of Two Quercus Species

Diverse clades of mycorrhizal and endophytic fungi are potentially involved in competitive or facilitative interactions within host-plant roots. We investigated the potential consequences of these ecological interactions on the assembly process of root-associated fungi by examining the co-occurrence of pairs of fungi in host-plant individuals. Based on massively-parallel pyrosequencing, we analyzed the root-associated fungal community composition for each of the 249 Quercus serrata and 188 Quercus glauca seedlings sampled in a warm-temperate secondary forest in Japan. Pairs of fungi that co-occurred more or less often than expected by chance were identified based on randomization tests. The pyrosequencing analysis revealed that not only ectomycorrhizal fungi but also endophytic fungi were common in the root-associated fungal community. Intriguingly, specific pairs of these ectomycorrhizal and endophytic fungi showed spatially aggregated patterns, suggesting the existence of facilitative interactions between fungi in different functional groups. Due to the large number of fungal pairs examined, many of the observed aggregated/segregated patterns with very low P values (e.g., < 0.005) turned non-significant after the application of a multiple comparison method. However, our overall results imply that the community structures of ectomycorrhizal and endophytic fungi could influence each other through interspecific competitive/facilitative interactions in root. To test the potential of host-plants'' control of fungus–fungus ecological interactions in roots, we further examined whether the aggregated/segregated patterns could vary depending on the identity of host plant species. Potentially due to the physiological properties shared between the congeneric host plant species, the sign of hosts'' control was not detected in the present study. The pyrosequencing-based randomization analyses shown in this study provide a platform of the high-throughput investigation of fungus–fungus interactions in plant root systems.     

Invasion biology of Australian ectomycorrhizal fungi introduced with eucalypt plantations into the Iberian Peninsula

In the last two centuries, several species of Australian eucalypts (e.g. Eucalyptus camaldulensis and E.␣globulus) were introduced into the Iberian Peninsula for the production of paper pulp. The effects of the introduction of exotic root-symbitotic fungi together with the eucalypts have received little attention. During the past years, we have investigated the biology of ectomycorrhizal fungi in eucalypt plantations in the Iberian Peninsula. In the plantations studied, we found fruit bodies of several Australian ectomycorrhizal fungi and identified their ectomycorrhizas with DNA molecular markers. The most frequent species were Hydnangium carneum, Hymenogaster albus, Hysterangium inflatum, Labyrinthomyces donkii, Laccaria fraterna, Pisolithus albus, P. microcarpus, Rhulandiella berolinensis, Setchelliogaster rheophyllus, and Tricholoma eucalypticum. These fungi were likely brought from Australia together with the eucalypts, and they seem to have facilitated the establishment of eucalypt plantations and their naturalization. The dispersion of Australian fungal propagules may be facilitating the spread of eucalypts along watercourses in semiarid regions increasing the water lost. Because ectomycorrhizal fungi are obligate symbionts, their capacity to persist after eradication of eucalypt stands, and/or to extend beyond forest plantations, would rely on the possibility to find compatible native host trees, and to outcompete the native ectomycorrhizal fungi. Here we illustrate the case of the Australasian species Laccaria fraterna, which fruits in Mediterranean shrublands of ectomycorrhizal species of Cistus (rockroses). We need to know which other Australasian fungi extend to the native ecosystems, if we are to predict environmental␣risks associated with the introduction of Australasian ectomycorrhizal fungi into the Iberian Peninsula. This revised version was published online in July 2006 with corrections to the Cover Date.     

Fine-level mycorrhizal specificity in the Monotropoideae (Ericaceae): specificity for fungal species groups

The Monotropoideae (Ericaceae) are non-photosynthetic angiosperms that obtain fixed carbon from basidiomycete ectomycorrhizal fungi. In previous work, we showed that each plant species is associated with a single genus or a set of closely related genera of ectomycorrhizal fungi. Here we show that the level of specificity is much higher. We used a molecular phylogenetic approach to contrast specificity patterns among eight plant lineages and three fungal genera. We relied on fungal nuclear internal transcribed spacer (nrITS) sequence data obtained from 161 basidiocarps and 85 monotropoid roots representing 286 sampled plants screened using restriction length polymorphisms. From the phylogenetic placement of fungal symbionts in fungal phylograms, we found that three basal (Sarcodes, Pterospora, Pleuricospora) and one derived lineage (Allotropa) of plants target narrow clades of closely related species groups of fungi, and four derived lineages (Monotropa hypopithys species group, Pityopus) target more distant species groups. Within most plant lineages, geography and photobiont association constrain specificity. Specificity extended further in Pterospora andromedea, in which sequence haplotypes at the plastid trn L-F region of 73 plants were significantly associated with different fungal species groups even in sympatry. These results indicate that both the macro- and microevolution of the Monotropoideae are tightly coupled to their mycorrhizal symbionts.     

Ectomycorrhizal responses to organic and inorganic nitrogen sources when associating with two host species

While it is established that increasing atmospheric inorganic nitrogen (N) deposition reduces ectomycorrhizal fungal biomass and shifts the relative abundances of fungal species, little is known about effects of organic N deposition. The effects of organic and inorganic N deposition on ectomycorrhizal fungi may differ because responses to inorganic N deposition may reflect C-limitation. To compare the effects of organic and inorganic N additions on ectomycorrhizal fungi, and to assess whether host species may influence the response of ectomycorrhizal fungi to N additions, we conducted an N addition experiment at a field site in the New Jersey pine barrens. Seedlings of two host species, Quercus velutina (black oak) and Pinus rigida (pitch pine), were planted at the base of randomly-selected mature pitch pine trees. Nitrogen was added as glutamic acid, ammonium, or nitrate at a rate equivalent to 227.5 kg ha⁻¹ y⁻¹ for eight weeks, to achieve a total application of 35 kg ha⁻¹ during the 10-week study period. Organic and inorganic N additions differed in their effects on total ectomycorrhizal root tip abundance across hosts, and these effects differed for individual morphotypes between oak and pine seedlings. Mycorrhizal root tip abundance across hosts was 90 % higher on seedlings receiving organic N compared to seedlings in the control treatment, while abundances were similar among seedlings receiving the inorganic N treatments and seedlings in the control. On oak, 33–83 % of the most-common morphotypes exhibited increased root tip abundances in response to the three forms of N, relative to the control. On pine, 33–66 % of the most-common morphotypes exhibited decreased root tip abundance in response to inorganic N, while responses to organic N were mixed. Plant chemistry and regression analyses suggested that, on oak seedlings, mycorrhizal colonization increased in response to N limitation. In contrast, pine root and shoot N and C contents did not vary in response to any form of N added, and mycorrhizal root tip abundance was not associated with seedling N or C status, indicating that pine received sufficient N. These results suggest that in situ organic and inorganic N additions differentially affect ectomycorrhizal root tip abundance and that ectomycorrhizal fungal responses to N addition may be mediated by host tree species.     

Discrimination of <Emphasis Type="Italic">Tricholoma</Emphasis> species by species-specific ITS primers

The ITS region of ectomycorrhizal fungi was analyzed, and species-specific PCR primers were designed for 8 ectomycorrhizal Tricholoma species. Although a high degree of intraspecific homology was observed, interspecific variation was sufficient to design species-specific primers based on sequence of the ITS region. PCR amplification with the specific primers generated fragments of the expected sizes from DNA extracted from the strains of each species but gave no amplified products from the strains of the other 16 species in eight genera. These results suggest that sequence of the ITS region is appropriate to be used for species-level identification of ectomycorrhizal fungi.     

Spatial pattern of downed logs and wood‐decaying fungi in an old‐growth Picea abies forest

Abstract. Since many wood‐living forest species are influenced by the dynamics of coarse woody debris (CWD), information about the spatial pattern of CWD under natural conditions is essential to understand species distributions. In this study we examined the spatial pattern of downed logs and wood‐decaying fungi in an old‐growth boreal Picea abies forest in northwestern Sweden that is governed by gap‐phase dynamics. The spatial pattern of wood‐decaying fungi was studied to draw conclusions about species dispersal abilities. A total of 684 logs with a diameter > 10 cm were mapped and analysed with Ripley's K‐function. The distribution of all logs taken together displayed a significant aggregated pattern up to 45 m. The different decay stages also deviated from random expectations. Fairly fresh logs and logs in the middle decay stage were clumped up to about 25 and 35 m respectively, and late decayed logs aggregated up to 95 m. Logs with diameters from 10–29 cm were aggregated up to 25 m, whereas logs ≥30 cm diameter were randomly distributed. The result suggests that gap‐dynamics do have an impact on the spatial pattern of the CWD, creating fine‐scale clumping. The random distribution of large logs may result from the slightly regular spacing of large living trees. The spatial patterns of 16 species (n > 20) of wood‐decaying fungi were analysed with Ripley's K‐function. Three patterns were aggregated, for Gloeophyllum sepiarium, Coniophora olivacea and Vesiculomyces citrinus. These results indicate that the distribution of most species at the stand level is generally not influenced by dispersal limitations.     

Host plants and edaphic factors influence the distribution and diversity of ectomycorrhizal fungal fruiting bodies within rainforests from Tshopo,Democratic Republic of the Congo

Ectomycorrhizal fungi constitute an important component of forest ecosystems that enhances plant nutrition and resistance against stresses. Diversity of ectomycorrhizal (EcM) fungi is, however, affected by host plant diversity and soil heterogeneity. This study provides information about the influence of host plants and soil resources on the diversity of ectomycorrhizal fungal fruiting bodies from rainforests of the Democratic Republic of the Congo. Based on the presence of fungal fruiting bodies, significant differences in the number of ectomycorrhizal fungi species existed between forest stand types (p < 0.001). The most ectomycorrhizal species‐rich forest was the Gilbertiodendron dewevrei‐dominated forest (61 species). Of all 93 species of ectomycorrhizal fungi, 19 demonstrated a significant indicator value for particular forest stand types. Of all analysed edaphic factors, the percentage of silt particles was the most important parameter influencing EcM fungi host plant tree distribution. Both host trees and edaphic factors strongly affected the distribution and diversity of EcM fungi. EcM fungi may have developed differently their ability to successfully colonise root systems in relation to the availability of nutrients.     

Ectomycorrhizal fungi associated with ponderosa pine and Douglas-fir: a comparison of species richness in native western North American forests and Patagonian plantations from Argentina

The putative ectomycorrhizal fungal species registered from sporocarps associated with ponderosa pine and Douglas-fir forests in their natural range distribution (i.e., western Canada, USA, and Mexico) and from plantations in south Argentina and other parts of the world are listed. One hundred and fifty seven taxa are reported for native ponderosa pine forests and 514 taxa for native Douglas-fir forests based on available literature and databases. A small group of genera comprises a high proportion of the species richness for native Douglas-fir (i.e., Cortinarius, Inocybe, and Russula), whereas in native ponderosa pine, the species richness is more evenly distributed among several genera. The comparison between ectomycorrhizal species richness associated with both trees in native forests and in Patagonia (Argentina) shows far fewer species in the latter, with 18 taxa for the ponderosa pine and 15 for the Douglas-fir. Epigeous species richness is clearly dominant in native Douglas-fir, whereas a more balanced relation epigeous/hypogeous richness is observed for native ponderosa pine; a similar trend was observed for Patagonian plantations. Most fungi in Patagonian Douglas-fir plantations have not been recorded in plantations elsewhere, except Suillus lakei and Thelephora terrestris, and only 56% of the fungal taxa recorded in Douglas-fir plantations around the world are known from native forests, the other taxa being new associations for this host, suggesting that new tree + ectomycorrhizal fungal taxa associations are favored in artificial situations as plantations.     

Effects of isolates of ectomycorrhizal fungi and endophytic Mycelium radicis atrovirens that were dominant in soil from disturbed sites on growth of Betula platyphylla var. japonica seedlings

Effects of ectomycorrhizal fungi and endophytic Mycelium radicis atrovirens Melin (MRA) on growth of Betula platyphylla var. japonica seedlings were investigated under aseptic culture conditions. Three isolates of ectomycorrhizal fungi and two isolates of MRA were used. One MRA isolate was Phialocephala fortinii. Previous field work revealed that these isolates were dominant on the roots of B. platyphylla var. japonica seedlings grown in a mineral subsoil that had been exposed by the removal of surface soil. After a 100-day incubation, the growth of the seedlings was significantly enhanced by the colonization of these ectomycorrhizal fungal isolates as compared with uninoculated seedlings. In contrast, the growth of seedlings was retarded by the colonization of the MRA isolates. The growth of seedlings that were co-inoculated with ectomycorrhizal fungi and MRA was similar to that of uninoculated seedlings in most cases. These results suggest that ectomycorrhizal fungi have a beneficial effect on the growth of B. platyphylla var. japonica seedlings and that they suppress the deleterious effect of MRA. Thus, these ectomycorrhizal fungi probably have an important role in establishing B. platyphylla var. japonica seedlings during the initial stage of re-vegetation following site disturbance by the removal of surface soil.     

Recovery of mycorrhizas of a fungus, <Emphasis Type="Italic">Cenococcum geophilum</Emphasis>, after urea treatment in warm temperate forests in Japan

We studied recovery of the ectomycorrhizal species Cenococcum geophilum (Cg) after urea treatment in two types of vegetation. The recovery was as quick as 6 months after the treatment and overlapped the fruiting period of ectomycorrhizal ammonia fungi. Ectomycorrhizas investigated as Cg belonged to a single species irrespective of treatment and vegetation type. Cg ectomycorrhizas were significantly more abundant in density in nontreated soil than in treated soil. Between vegetation types, Cg ectomycorrhizas were significantly more in density in broad-leaved deciduous forest than in broad-leaved evergreen forest. Moreover, Cg was dominant in the nontreated soils of the former type of forest.     

Inoculation and field testing of Sitka spruce and Douglas fir with ectomycorrhizal fungi in the United Kingdom

Picea sitchensis and Pseudotsuga menziesii seedlings were grown in containers, inoculated with ectomycorrhizal fungi, and planted in British forestry sites. Root samples taken during the year after planting were assessed for mycorrhiza formation. Survival and shoot height were assessed at the end of each year. Observations were made each autumn on the occurrence of sporophores of ectomycorrhizal fungi. Pot experiments were used to assess the colonization potential of soils from the experimental locations. Assessment of mycorrhiza formation by the inoculant fungi both before planting and the following year showed much variation among the fungi used. Similar variation was found among field sites. Inoculation with Laccaria isolates was most successful. Height measurements are reported for the first 2 years after planting, at which time there were few significant effects on growth of Picea sitchensis or Pseudotsuga menziesii seedlings. Experimental assessment of colonization potential was of little value in this work for predicting events in the forest.     

内蒙古地区白桦外生菌根形态类型及分子鉴定

以内蒙古不同地区白桦外生菌根为材料,采用形态解剖学方法和分子生物学手段对与白桦共生的外生菌根真菌多样性进行全面的调查,并经对所测序列与GenBank和Database比对。结果显示:在内蒙古地区与白桦共生的外生菌根真菌共13种,其中担子菌7种,子囊菌4种,分别来自于丝膜菌属、丝盖伞属、蜡壳耳属、毛革菌属、滑菇属和空团菌属、块菌属、地怀菌属。其中,菌根类型T₈和T₁₁未能提出其总DNA,根据其外生菌根形态类型并参照Agerer体视显微镜菌根图谱和Haug菌根图谱进行比较,分类鉴定为荷顿氏疣柄牛肝菌和白桦外生菌根真菌一种。结果表明,内蒙古地区白桦外生菌根真菌多样性相对较高,且与利用地上子实体鉴定的外生菌根真菌种类有一定的区别。