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1.
The aim of a 3-year study was to investigate whether inoculation of Pinus sylvestris L. and Picea abies (L.) Karst. seedlings with mycorrhizas of Cenococcum geophilum Fr., Piceirhiza bicolorata, and Hebeloma crustuliniforme (Bull.) Quel. has any impact on: 1) survival and growth of outplanted seedlings on abandoned agricultural land, and 2) subsequent
mycorrhizal community development. For inoculation, the root system of each plant was wrapped in a filter paper containing
mycelium, overlaid with damp peat–sand mixture and wrapped in a paper towel. In total, 8,000 pine and 8,000 spruce seedlings
were planted on 4-ha of poor sandy soil in randomized blocks. Already after the first year natural mycorrhizal infections
prevailed in the inoculated root systems, and introduced mycorrhizas were seldom found. Yet, the seedlings that had been pre-inoculated
with C. geophilum and the P. bicolorata during the whole 3-year period showed significantly higher survival and growth as compared to controls. Moreover, the independent
colonization of roots by C. geophilum and the P. bicolorata from natural sources was also observed. A diverse mycorrhizal community was detected over two growing seasons in all treatments,
showing low impact of inoculation on subsequent fungal community development. A total of 19 additional ectomycorrhizal morphotypes
was observed, which clustered into two well-separated groups, according to host tree species (pine and spruce). In conclusion,
the results showed limited ability to increase tree survival and growth, and to manipulate the mycorrhizal community even
by extensive pre-inoculations, indicating that fungal community formation in root systems is governed mainly by environmental
factors. 相似文献
2.
To examine the mechanisms of earlier reported alleviation of fluoride injury in ectomycorrhizal plants by NaCl, jack pine
(Pinus banksiana) and white spruce (Picea glauca) seedlings were subjected to 1 mM and 5 mM KF in the presence of either 60 mM NaCl or 10% polyethylene glycol 3350 (PEG)
for 2 weeks. Before the treatments, seedlings had either been inoculated with the ectomycorrhizal fungus Suillus tomentosus or remained non-inoculated. The inoculation with S. tomentosus reduced Na uptake by shoots and roots of jack pine seedling and by roots of white spruce that were treated with 60 mM NaCl.
Mycorrhizal associations also drastically decreased fluoride uptake by jack pine seedlings, but did not affect shoot fluoride
concentrations in white spruce. When NaCl was replaced by PEG in the 5 mM KF treatment solution, shoot fluoride concentrations
were reduced by more than twofold without corresponding reductions in transpiration rates in mycorrhizal and non-mycorrhizal
white spruce seedlings. When fluoride was present in the treatment solution, Na concentrations were lower in shoots and roots
of both jack pine and white spruce mycorrhizal and non-mycorrhizal seedlings. The results suggest that Suillus tomentosus may help alleviate the effects of soil fluoride and salinity in jack pine and that fluoride uptake in white spruce is sensitive
to osmotic stress. 相似文献
3.
Summary Restoration of scrub and woodland in deforested upland sites is an important conservation activity. However, little is known about the mycorrhizal colonisation potential of upland soils or the factors that influence the distribution of mycorrhizal inoculum. We investigated the effect of existing vegetation on mycorrhizal colonisation potential for a sub-arctic willow (Salix lapponum) by planting uninoculated cuttings into plotsrepresenting two upland habitats with either grassand herbs (‘grass’) or Vaccinium myrtillus (‘vaccinium’) and assessing mycorrhizal colonisation after 14 months using morphological and molecular techniques. From 40 willow cuttings (20 in each habitat), DNA sequences of rive ectomycorrhizal (EcM) fungal taxa were recovered: Laccaria proxima, Thelephora terrestris, Hebeloma sp., ‘Thelephoraceae sp.’ and ‘Pezizales sp.’. Cuttings in the ‘grass’ habitat were dominated by Laccaria proxima and ‘Pezizales sp.’ and in the ‘vaccinium’ habitat by Thelephora terrestris which was absent from the ‘grass’ habitat. There were no significant differences between habitats in frequency of EcM inoculum (overall percentage of cuttings colonised = 70%) or colonisation potential (overall mean percentage of root tips colonised per cutting = 20 %). These data suggest that the mycorrhizal colonisation potential and diversity of fungi available to willow in these upland soils are low and planted willow may benefit from inoculum enhancement. 相似文献
4.
Demography and fungal diversity of the belowground ectomycorrhizal community in a chronosequence of Sitka spruce [Picea sitchensis (Bong.) Carr.] in Northumberland, Northern England, were analysed; mycorrhizal root samples were taken from 6-, 12-, 30-
and 40-year-old stands, and fungal fruiting bodies were collected in autumn to complement the survey. Naturally germinated
seedlings less than 1 year of age (taken from the 30-year-old stand) were also examined. A total of 118,000 mycorrhizal root
tips were extracted from 40 soil cores (ten per age class) and from the complete root systems of 25 seedlings and separated
into active and senescent root tips according to their morphology and anatomy. Active tips were distinguished according to
their mycobionts which were characterised and identified microscopically. Although almost 100% of all fine roots were mycorrhizal,
EM fungal diversity throughout the chronosequence was low, consisting of a total of 16 species of which three were only found
as fruiting bodies. Of the six mycobionts found most regularly below ground, Tylospora fibrillosa was the most common, colonising about 70% of all root tips and more than 90% of those of seedlings and young trees. Root
density and mycorrhizal diversity increased, but percentage of vital root tips decreased with increasing tree age, levelling
off in the 30- and 40-year-old stand. Among the five subdominant fungal species, Dermocybe crocea was found to have its peak of distribution in the 12-year-old stand and Russula emetica, Lactarius rufus, Hymenoscyphus ericae agg. and the unidentified Piceirhiza sulfo-incrustata in the 30- and 40-year-old stands. The possible correlations between the mycorrhizal community structure and biotic and abiotic
factors are discussed. 相似文献
5.
Plamboeck AH Dawson TE Egerton-Warburton LM North M Bruns TD Querejeta JI 《Mycorrhiza》2007,17(5):439-447
Little is known about water transfer via mycorrhizal hyphae to plants, despite its potential importance in seedling establishment
and plant community development, especially in arid environments. Therefore, this process was investigated in the study reported
in this paper in laboratory-based tripartite mesocosms containing the shrub Arctostaphylos viscida (manzanita) and young seedlings of sugar pine (Pinus lambertiana) and Douglas-fir (Pseudotsuga menziesii). The objectives were to determine whether water could be transported through mycorrhizal symbionts shared by establishing
conifers and A. viscida and to compare the results obtained using two tracers: the stable isotope deuterium and the dye lucifer yellow carbohydrazide.
Water containing the tracers was added to the central compartment containing single manzanita shrubs. The fungal hyphae were
then collected as well as plant roots from coniferous seedlings in the other two compartments to determine whether water was
transferred via fungal hyphae. In addition, the length of the hyphae and degree of mycorrhizal colonisation were determined.
Internal transcribed spacer–restriction fragment length polymorphism (ITS-RFLP) analysis was used to identify the fungal species
involved in dye (water) transfer. Results of the stable isotope analysis showed that water is transferred via mycorrhizal
hyphae, but isotopically labelled water was only detected in Douglas-fir roots, not in sugar pine roots. In contrast, the
fluorescent dye was transported via mycorrhizal hyphae to both Douglas-fir and sugar pine seedlings. Only 1 of 15 fungal morphotypes
(identified as Atheliaceae) growing in the mesocosms transferred the dye. Differences were detected in the water transfer patterns indicated by the
deuterium and fluorescent dye tracers, suggesting that the two labels are transported by different mechanisms in the same
hyphae and/or that different fungal taxa transfer them via different routes to host plants. We conclude that both tracers
can provide information on resource transfer between fungi and plants, but we cannot be sure that the dye transfer data provide
accurate indications of water transfer rates and patterns. The isotopic tracer provides more direct indications of water movement
and is therefore more suitable than the dye for studying water relations of plants and their associated mycorrhizal fungi. 相似文献
6.
The ectomycorrhizal (ECM) colonisation of seedling Sitka spruce (Picea sitchensis) was examined in an uneven-aged plantation forest in southern Scotland. The extent of ECM colonisation of individual seedlings
was 43.8–97.2%, with an overall mean of 80.3 ± 1.1%. A total of 13 ECM morphotypes were differentiated, with 1–4 ECM types
colonising an individual seedling. ECM colonisation was dominated by a single species, Tylospora
fibrillosa, which accounted for 72.4–97.7% of the ECM colonisation recorded, on a plot mean basis. Other ECM types appeared to be distributed
very patchily, only two types (Lactarius sp. and Mycelium radicis atrovirens Melin) exceeding a mean of 10% colonisation in any one plot. No significant correlations were recorded between ECM colonisation
and seedling growth, or between ECM colonisation and soil pH, loss-on-ignition, or water content.
Accepted: 16 October 1997 相似文献
7.
Growth and Mycorrhizal Community Structure of Pinus sylvestris Seedlings following the Addition of Forest Litter
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Algis Au
ina Maria Rudawska Tomasz Leski Audrius Skridaila Edvardas Riepas Michal Iwanski 《Applied microbiology》2007,73(15):4867-4873
We report the effects of pine and oak litter on species composition and diversity of mycorrhizal fungi colonizing 2-year-old Pinus sylvestris L. seedlings grown in a bare-root nursery in Lithuania. A layer of pine or oak litter was placed on the surface of the nursery bed soil to mimic natural litter cover. Oak litter amendment appeared to be most favorable for seedling survival, with a 73% survival rate, in contrast to the untreated mineral bed soil (44%). The concentrations of total N, P, K, Ca, and Mg were higher in oak growth medium than in pine growth medium. Relative to the control (pH 6.1), the pH was lower in pine growth medium (5.8) and higher in oak growth medium (6.3). There were also twofold and threefold increases in the C content of growth medium with the addition of pine and oak litter, respectively. Among seven mycorrhizal morphotypes, eight different mycorrhizal taxa were identified: Suillus luteus, Suillus variegatus, Wilcoxina mikolae, a Tuber sp., a Tomentella sp., Cenococcum geophilum, Amphinema byssoides, and one unidentified ectomycorrhizal symbiont. Forest litter addition affected the relative abundance of mycorrhizal symbionts more than their overall representation. This was more pronounced for pine litter than for oak litter, with 40% and 25% increases in the abundance of suilloid mycorrhizae, respectively. Our findings provide preliminary evidence that changes in the supply of organic matter through litter manipulation may have far-reaching effects on the chemistry of soil, thus influencing the growth and survival of Scots pine seedlings and their mycorrhizal communities. 相似文献
8.
Effect of Plant Growth Promoting Bacillus Strains on Pine and Spruce Seedling Growth and Mycorrhizal Infection 总被引:4,自引:0,他引:4
Rifamycin-resistant derivatives of plant growth promotingBacilluspolymyxa strains L6, Pw-2, and S20 were used to evaluate theinteraction of bacterialmycorrhizal co-inoculation onpine and spruce seedling growth. We were particularly interestedin determining if the mechanism by which bacteria stimulatedseedling growth depended on the presence of ectomycorrhizae.Mycorrhizal inoculum was introduced by adding 2ml of one ofsix forest floor soil types originating from different spruceand pine stands to seedling containers. Mycorrhizal roots developedin 34% of pine and 27% of spruce seedlings treated with forestsoil, but no differences between forest soils were detected.Most mycorrhizae were formed byWilcoxinasp. (E-strain) (98%for spruce and 67% for pine); small numbers ofAmphinema-like,Myceliumradicis atrovirens, Suillus-like,Thelephora-like, andTuber-likemycorrhizae were also found on pine (27% in total).Thelephora-likefungi comprised 2% of spruce mycorrhize. In the absence of bacterialinoculum, spruce seedling biomass was positively correlatedwith the number of mycorrhizal root tips, but this trend wasnot detected in spruce inoculated with bacteria or in pine.Bacterial inoculation did not influence the mycorrhizal statusof seedlings, but all threeBacillusstrains stimulated growthof both conifer species. Root biomass, in particular, was significantlyenhanced by up to 18% compared with uninoculated controls. Mycorrhizalfungi improved the growth of spruce seedlings, but plant growthpromotion byBacilluswas similar for mycorrizal and non-mycorrhizalseedlings of both species. Our results suggest thatBacillusstrainsL6-16R, Pw-2R, and S20-R enhance conifer seedling growth througha mechanism unrelated to mycorrhizal fungi. Hybrid spruce; Picea glaucaxengelmannii ; lodgepole pine; Pinus contortavar.latifoliaEngelm.; inoculation; Bacillus polymyxa; seedling growth promotion; mycorrhizae 相似文献
9.
Two study plots, burned and control, were established in autumn 1998 in a Quercus ilex forest located in northern Spain, part of which had been affected by a low intensity fire in 1994. Soil samples for ectomycorrhizae (ECM) were taken over a 3-year period in each study plot in spring, summer, autumn and winter. ECM morphotypes were identified and the relative abundance of each morphotype in each soil sample calculated, along with species richness, Shannon diversity index and percentage of mycorrhization in each soil sample. The relative abundance of certain ECM morphotypes differed between burned and control plots, and the percentage of mycorrhizal tips was significantly lower in the burned than in the control plot. Nevertheless, there were no significant differences in the diversity, species richness or species composition of the ECM community in the burned and control plots. The dominant ECM morphotypes in both stands were Cenococcum geophilum and several thelephoroid fungi. Sphaerosporella brunnea and Pisolithus tinctorius thrived especially in the burned plot, whereas three ectomycorrhizal morphotypes assigned to the genus Hebeloma were especially abundant in the control plot. There was no significant variation in the relative abundance of the ECM morphotypes between seasons, but ECM community species richness was highest in autumn and lowest in summer. The percentage of mycorrhizal tips reached a maximum in winter, with its minimum in autumn. Collection of samples over the 3-year period also enabled us to detect a significant increase in percentage of ECM colonisation in the burned stand over time. 相似文献
10.
Meghan L. Avolio Amy R. Tuininga J.D. Lewis Michael Marchese 《Mycological Research》2009,113(8):897-907
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. 相似文献
11.
Lu-Min Vaario Taina Pennanen Tytti Sarjala Eira-Maija Savonen Jussi Heinonsalo 《Mycorrhiza》2010,20(7):511-518
This study aimed to test the ability of Tricholoma matsutake isolates to form mycorrhizas with aseptic seedlings of Pinus sylvestris L. and Picea abies (L.) Karst. Germinated seedlings of Scots pine and Norway spruce were separately inoculated with either isolates originating from Finland
or Japan. Eight months after inoculation, the Finnish isolate had formed a sheath and Hartig net on both host species. Ectomycorrhizal
Scots pine seedlings inoculated with the Finnish isolate showed the same shoot height and dry mass as the controls. Ectomycorrhizal
Norway spruce seedlings inoculated with the Finnish isolate had similar shoot height but slightly less dry mass than the control
seedlings. For both tree species, inoculation with the Finnish isolate resulted in reduced total nitrogen content per seedling,
but carbon content was unaffected. Inoculation with the Japanese isolate resulted in an initial Hartig net-like structure
in pine but not in spruce. No typical Hartig net was observed on either tree species. Furthermore, seedlings of both species
inoculated with the Japanese isolate showed significantly reduced growth, dry mass, nitrogen, and carbon content per seedling
and shoot height (in spruce) compared to the controls. This study documents and describes the in vitro ectomycorrhization
between T. matsutake and Scots pine or Norway spruce and the variable mycorrhizal structures that matsutake isolates can form. 相似文献
12.
The aims of this study were to investigate patterns of ectomycorrhizal (ECM) colonisation and community structure on nursery grown seedlings of Pinus sylvestris, spatial distribution of ECMs in the nursery plot and genetic diversity of commonly isolated ECM basidiomycete Hebeloma cavipes. One hundred seedlings were sampled in 225?m2 area using a systematic grid design. For each seedling, 20 individual root tips were randomly collected, morphotyped, and surface sterilised for fungal isolation in pure culture. Results showed that ECM community was comprised of nine distinct morphotypes among which Thelephora terrestris (39.7%), Hebeloma sp. (17.8%) and Suillus luteus (6.1%) were the most abundant. Spatial distribution of ECMs in the nursery plot was determined by their relative abundance: even in common ECMs and random in rare ones. Fungal isolation yielded 606 pure cultures, representing 71 distinct taxa. The most commonly isolated fungi were the ascomycetes Neonectria macrodidyma (20.3%), Phialocephala fortinii (13.5%), Neonectria radicicola (6.3%) and the ECM basidiomycete H. cavipes (4.5%). Intraspecific genetic diversity within 27 H. cavipes isolates was studied using two methods: restriction digestion of the amplified intergenic spacer of nuclear ribosomal DNA and genealogical concordance of five genetic markers. Five and eight genotypes were revealed by each respective method, but both of those were largely consistent, in particular, in determining the largest genotype (A) composed of 18 isolates. Mapping positions for each H. cavipes isolate and genotype in the field showed that isolates of the A genotype covered a large part of the nursery plot. This suggests that H. cavipes is largely disseminated by vegetative means of local genotypes and that nursery cultivation practices are likely to contribute to the dissemination of this species in the forest nursery soils. 相似文献
13.
Tenna Toftegaard Glenn R. Iason Ian J. Alexander Søren Rosendahl Andy F. S. Taylor 《Biodiversity and Conservation》2010,19(14):3963-3971
The plant intermediate wintergreen (Pyrola media, Ericaceae) is in need of conservation action in Scotland. Although widespread, it is locally distributed in dwarf shrub
heath and more commonly in Scots pine (Pinus sylvestris) woodlands. A recent study on the mycorrhizal status of Pyrola suggested that they associate with a restricted range of ectomycorrhizal (ECM) fungi. Here, we examined the hypothesis that
specialisation by P. media for fungi usually associated with Scots pine is a factor in promoting its occurrence in this habitat. The fungal community
associated with the roots of P. media growing in a Scots pine forest was determined by morphotyping, polymerase chain reaction, cloning and sequencing. Molecular
identification found 49 taxa representing ecto- and ericoid mycorrhizal fungi, dark septate endophytes, saprotrophs, and fungi
of unknown trophic status. The majority of the taxa (67.4%) were Basidiomycota, with 24.4% known to be ECM fungi specific
to Pinus sp. or conifers. However, a wide range of other mycorrhizal fungi with varying degrees of host specificity were also found,
including taxa usually associated with deciduous hosts. In conclusion, the broad range of mycorrhizal fungi recovered from
the roots of P. media suggests that specialization is not a major factor in determining its distribution. 相似文献
14.
Marie-Béatrice Bogeat-Triboulot François Bartoli Jean Garbaye Roland Marmeisse Denis Tagu 《Plant and Soil》2004,267(1-2):213-223
Pinus pinaster seedlings were grown in a sandy dune soil either inoculated withHebeloma cylindrosporum or let to natural colonisation. Six months later, half of the seedlings of both treatments were subjected to a 3-week moderate
drought. Root colonisation analysis showed that root tips were colonised to almost 100% independent of the inoculation. DNA
determination of the ectomycorrhizal morphotypes showed that inoculated seedlings were extensively mycorrhized byH. cylindrosporum (more than 75%) whereas non-inoculated seedlings were mycorrhized by the exotic speciesThelephora terrestris (50%) andLaccaria bicolor (30%) and to a lesser extent byH. cylindrosporum (20%). Drought did not affect these frequencies. Total plant biomass was not affected by the mycorrhizal status or by drought
but the root/shoot biomass ratio as well as the root/leaf surface area ratio were much lower in seedlings extensively colonised
byH. cylindrosporum. Root hydraulic conductivity was higher in plants mainly mycorrhized byH. cylindrosporum, showing that this fungus improved the water uptake capacity of the root system as compared toT. terrestris and/orL. bicolor. This positive effect was also found under drought but to a lesser extent.H. cylindrosporum also increased the amount of root-adhering soil as compared to the other fungal symbionts, illustrating the performance of
this association in aggregating sandy soil particles and developing the rhizosheath. The origin of the reduced root hydraulic
resistance byH. cylindrosporum mycorrhization is discussed for the whole path including soil, soil-root interface and root cortex. 相似文献
15.
Tomasz Leski Algis Aučina Audrius Skridaila Marcin Pietras Edvardas Riepšas Maria Rudawska 《Mycorrhiza》2010,20(7):473-481
In this paper, we report the effect of Scots pine genotypes on ectomycorrhizal (ECM) community and growth, survival, and foliar
nutrient composition of 2-year-old seedlings grown in forest bare-root nursery conditions in Lithuania. The Scots pine seeds
originated from five stands from Latvia (P1), Lithuania (P2 and P3), Belarus (P4), and Poland (P5). Based on molecular identification,
seven ECM fungal taxa were identified: Suillus luteus and Suillus variegatus (within the Suilloid type), Wilcoxina mikolae, Tuber sp., Thelephora terrestris, Cenococcum geophilum, and Russuloid type. The fungal species richness varied between five and seven morphotypes, depending on seed origin. The
average species richness and relative abundance of most ECM morphotypes differed significantly depending on pine origin. The
most essential finding of our study is the shift in dominance from an ascomycetous fungus like W. mikolae in P2 and P4 seedlings to basidiomycetous Suilloid species like S. luteus and S. variegatus in P1 and P5 seedlings. Significant differences between Scots pine origin were also found in seedling height, root dry weight,
survival, and concentration of C, K, Ca, and Mg in the needles. The Spearman rank correlation coefficient revealed that survival
and nutritional status of pine seedlings were positively correlated with abundance of Suilloid mycorrhizas and negatively
linked with W. mikolae abundance. However, stepwise multiple regression analysis showed that only survival and magnesium content in pine needles
were significantly correlated with abundance of ECM fungi, and Suilloid mycorrhizas were a main significant predictor. Our
results may have implications for understanding the physiological and genetic relationship between the host tree and fungi
and should be considered in management decisions in forestry and ECM fungus inoculation programs. 相似文献
16.
The co-occurrence of ectomycorrhizal,arbuscular mycorrhizal,and dark septate fungi in seedlings of four members of the Pinaceae 总被引:1,自引:0,他引:1
Although roots of species in the Pinaceae are usually colonized by ectomycorrhizal (EM) fungi, there are increasing reports
of the presence of arbuscular mycorrhizal (AM) and dark septate endophytic (DSE) fungi in these species. The objective of
this study was to determine the colonization patterns in seedlings of three Pinus (pine) species (Pinus banksiana, Pinus strobus, Pinus contorta) and Picea glauca x Picea engelmannii (hybrid spruce) grown in soil collected from a disturbed forest site. Seedlings of all three pine species and hybrid spruce
became colonized by EM, AM, and DSE fungi. The dominant EM morphotype belonged to the E-strain category; limited colonization
by a Tuber sp. was found on roots of Pinus strobus and an unknown morphotype (cf. Suillus–Rhizopogon group) with thick, cottony white mycelium was present on short roots of all species. The three fungal categories tended to
occupy different niches in a single root system. No correlation was found between the percent root colonized by EM and percent
colonization by either AM or DSE, although there was a positive correlation between percent root length colonized by AM and
DSE. Hyphae and vesicles were the only AM intracellular structures found in roots of all species; arbuscules were not observed
in any roots. 相似文献
17.
Six-week-old, mycorrhiza-free, bareroot jack pine and black spruce seedlings were outplanted in ten reforestation sites, situated
between 45–48° latitude N and 69–74° longitude W, within the province of Quebec, representing diverse operational forestry
disturbances and ecological conditions.
Two months after outplanting, root systems of black spruce seedlings had fewer mycorrhizae than those of jack pine seedlings.
Ectomycorrhizal colonization on black spruce seedlings did not vary significantly with the reforestation site. Percent mycorrhizal
colonization for these seedlings was positively correlated with seedling dry weight while with the jack pine seedlings, mycorrhizal
colonization varied significantly with the outplanting site and there was no correlation between mycorrhizal formation and
seedling dry weight.
Multiple linear regressions showed pH to be a determinant soil factor for mycorrhizal colonization for the two species. Drainage
was the other influential factor affecting colonization of black spruce while organic matter accumulation was more important
for jack pine.
Inoculation with selected ectomycorrhizal fungi could be more important for black spruce than for jack pine seedlings. 相似文献
18.
We report the effect of ectomycorrhizal fungi (Suillus variegatus, Paxillus involutus) and defoliation on polyamine concentrations in pine (Pinus silvestris) and birch (Betula pendula) foliage and roots. Symbiotic root tips showed consistently higher concentrations of putrescine than non-symbiotic roots.
Partial defoliation had no effect on the polyamine levels in mycorrhizal pine or birch roots. The foliage of mycorrhizal pine
seedlings had lower putrescine concentrations and higher spermidine than foliage of non-mycorrhizal plants, and defoliation
reversed this pattern. The response to partial defoliation differed in birch foliage: mycorrhizal status had no effect and
all new growth after defoliation had higher spermidine levels than in non-defoliated birch. The potential role of polyamines
in mycorrhizal symbiosis is discussed.
Accepted: 26 February 1997 相似文献
19.
Little information is known on what the magnitude of nitrogen (N) processed by ectomycorrhizal (ECM) fungal species in the
field. In a common garden experiment performed in a northern California oak woodland, we investigated transfer of nitrogen
applied as 15NH4 or 15NO3 from leaves to ectomycorrhizal roots of three oak species, Quercus agrifolia, Q. douglasii, and Q. garryana. Oak seedlings formed five common ectomycorrhizal morphotypes on root tips. Mycorrhizal tips were more enriched in 15N than fine roots. N transfer was greater to the less common morphotypes than to the more common types. 15N transfer from leaves to roots was greater when , not , was supplied. 15N transfer to roots was greater in seedlings of Q. agrifolia than in Q. douglasii and Q. garryana. Differential N transfer to ectomycorrhizal root tips suggests that ectomycorrhizal morphotypes can influence flows of N
from leaves to roots and that mycorrhizal diversity may influence the total N requirement of plants. 相似文献
20.
Commercial nursery practices usually fail to promote mycorrhization of interior Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco] seedlings in British Columbia, which may account for their poor performance following planting in the field.
We tested the effects of four nursery cultivation factors (nitrogen fertilization, phosphorus fertilization, watering, and
soil aeration) and field soil addition on mycorrhization, survival, growth, and biomass allocation of interior Douglas-fir
seedlings in a series of greenhouse experiments. Where field soil was added to the growing medium, mycorrhization and root/shoot
ratios were maximized at lower levels of mineral nutrient application and aeration. Where field soil was not added, mycorrhization
was negligible across all fertilization and aeration treatments, but root/shoot ratio was maximized at lower levels of mineral
nutrients and the highest level of aeration. Regardless of whether field soil was added, intermediate levels of soil water
resulted in the best mycorrhizal colonization and root/shoot ratios. However, field soil addition reduced seedling mortality
at the two lowest water levels. A cluster analysis placed ectomycorrhizal morphotypes into three groups (Mycelium radicis-atrovirens Melin, Wilcoxina, and mixed) based on their treatment response, with all but two morphotypes in the mixed group whose abundance was maximized
under conditions common to advanced seedling establishment. For maximal mycorrhization and root development of interior Douglas-fir
seedlings, nurseries should minimize addition of nitrogen and phosphorus nutrients, maximize aeration, provide water at moderate
rates, and, where possible, add small amounts of field soil to the growing medium. 相似文献