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1.
Studies on the diversity of arbuscular mycorrhizal fungi and the efficacy of two native isolates in a highly alkaline anthropogenic sediment 总被引:7,自引:0,他引:7
A field survey of the arbuscular mycorrhizal status of herbaceous plant species was conducted in a highly alkaline anthropogenic sediment resulting from the disposal of waste from an acetylene and polyvinyl chloride factory. Most plant species found at the site were mycorrhizal and the dominant mycotrophic plant species was Conyza bilbaoana. Fungal species richness was assessed by identification of spores extracted from the sediment and from continuously propagated trap pot cultures. All of the six species of arbuscular mycorrhizal fungi (AMF) found were from the genus Glomus. Glomus intraradices and G. mosseae were found in field-collected sediment samples and also occurred most frequently in trap cultures. To test the symbiotic effectiveness of these two fungi, seedlings of C. bilbaoana were inoculated with either native G. intraradices BEG163 or G. mosseae BEG198 and non-native G. intraradices BEG75 or G. mosseae BEG25 isolates in sterile and non-sterile sediment collected from the study site. All four isolates were able to colonise C. bilbaoana. However, AMF native to the target sediments were generally more effective than the non-native fungi in promoting plant establishment and growth under highly alkaline conditions. The non-native G. intraradices was, however, more effective than the non-native G. mosseae. The results of this study suggest the use of adapted AMF as inoculants for phytorestoration of alkaline anthropogenic-stressed sediments. 相似文献
2.
The form and localisation of Cu accumulation in the extraradical mycelium (ERM) of three arbuscular mycorrhizal fungi (AMF), isolated from the same polluted soil contaminated with the Cu and Arsenate, was studied. There were differences in the capacity of the ERM of the three AMF to sorb and accumulate Cu. Glomus caledonium BEG133 had a significantly lower Cu-sorption capacity than Glomus mosseae BEG132 and Glomus claroideum BEG134 isolated from the polluted soil as well as an isolate of G. mosseae BEG25 from a non-polluted soil. This was directly related to the cation exchange capacity (CEC) of the ERM of these fungi. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) linked to an energy dispersive X-ray spectrometer (EDAX) gave more detailed information, showing that the ERM of AMF from the polluted soil was able to accumulate Cu in the mucilaginous outer hyphal wall zone, cell wall and inside the hyphal cytoplasm. The EDAX spectra showed that the accumulated Cu was mainly associated with Fe in the mucilaginous outer hyphal wall zone and in the cell wall. Cu was associated with traces of arsenate inside the cytoplasm of the ERM of Glomus mosseae BEG132 but this was not visible inside the ERM of Glomus caledonium BEG133 or Glomus claroideum BEG134. This work suggests that the ERM of AMF is able to sorb and accumulate Cu, but different tolerance mechanisms exist between the three AMF isolated from the same polluted soil providing further evidence for functional diversity within populations of AMF in soils. 相似文献
3.
Detection of arbuscular mycorrhizal fungi (Glomales) in roots by nested PCR and SSCP (Single Stranded Conformation Polymorphism) 总被引:10,自引:1,他引:9
PCR amplification of a region of the large subunit ribosomal DNA sequence with Glomus specific primers was used to detect arbuscular mycorrhizal fungi in root tissue of four plant species. The primers were specific
to Glomus mosseae, Glomus caledonium, Glomus geosporum, Glomus coronatum, Glomus fragilistratum and Glomus constrictum, and did not recognise sequences from Glomus claroideum. Sequence differences between isolates were detected by Single Stranded Conformation Polymorphisms (SSCPs) in polyacrylamide
gels under non-denaturing conditions. Isolates of G. mosseae, G. caledonium and G. coronatum could be separated by their SSCP patterns, while three isolates of G. geosporumshowed no variation. Specific SSCP patterns from isolates of G. mosseae and G. caledonium allowed detection of both fungi in the same root segment. Sequence differences leading to variations in SSCP patterns were
confirmed by direct sequencing.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
4.
The aim of this field study was to examine how the development of arbuscular mycorrhizal fungi (AMF) on coal mine spoil banks
is affected by the presence of plants with different mycorrhizal status. A 3-year trial was conducted on the freshly created
spoil bank Vršany, North-Bohemian coal basin, the Czech Republic. Three plant species – non-mycotrophic annual Atriplex sagittata, highly mycotrophic annual Tripleurospermum inodorum (both dominants of early stages of succession) and facultatively mycotrophic Arrhenatherum elatius (a perennial grass species of the later stage of succession) – were planted on 1 m2 plots over 3 years in different sequences that simulated the progress of succession on spoil banks. The development of AMF
populations was monitored by evaluation of mycorrhizal colonization of plant roots and by measurement of the mycorrhizal inoculation
potential (MIP) of soil. These two parameters were compared between plots inoculated with the mixture of three AMF isolates
– Glomus mosseae BEG95, G. claroideum BEG96 and G. intraradices BEG140 – (“inoculated plots”) and plots exposed only to natural dispersal of AMF propagules (“uninoculated plots”). Highly
colonized roots of plants together with a high MIP of soil in uninoculated plots were already found at the end of the first
season, indicating rapid natural dispersal of AMF propagules. Root colonization of facultatively mycotrophic and non-mycotrophic
plants in later years was affected by the mycorrhizal status of the previous plant species. The MIP of soil continuously increased
throughout the experiment; in uninoculated plots, the MIP was temporarily decreased if plant species of higher mycotrophy
were replaced by species of lower mycotrophy. The results lead to the conclusion that AMF colonize freshly formed sites very
quickly and reproduce or accumulate in the soil, which leads to increasing MIP values. However, this infective potential can
be decreased if non-mycotrophic plants predominate on the site. 相似文献
5.
Two pot experiments were conducted to examine three-level interactions between host plants, mycorrhizal fungi and parasitic
plants. In a greenhouse experiment, Poa annua plants were grown in the presence or absence of an AM fungus (either Glomus lamellosum V43a or G. mosseae BEG29) and in the presence or absence of a root hemiparasitic plant (Odontites vulgaris). In a laboratory experiment, mycorrhizal infection (Glomus claroideum BEG31) of Trifolium pratense host plants (mycorrhizal versus non-mycorrhizal) was combined with hemiparasite infection (Rhinanthus serotinus) of the host (parasitized versus non-parasitized). Infection with the two species of Glomus had no significant effect on the growth of P. annua, while hemiparasite infection caused a significant reduction in host biomass. Mycorrhizal status of P. annua hosts (i.e. presence/absence of AM fungus) affected neither the biomass nor the number of flowers produced by the attached O. vulgaris plants. Infection with G. claroideum BEG31 greatly increased the biomass of T. pratense, but hemiparasite infection had no effect. The hemiparasitic R. serotinus plants attached to mycorrhizal hosts had higher biomass and produced more flowers than plants growing with non-mycorrhizal
hosts. Roots of T. pratense were colonized by the AM fungus to an extent independent of the presence or absence of the hemiparasite. Our results confirm
earlier findings that the mycorrhizal status of a host plant can affect the performance of an attached root hemiparasite.
However, improvement of the performance of the parasitic plant following attachment to a mycorrhizal host depends on the extent
to which the AM fungi is able to enhance the growth of the host.
Accepted: 23 February 2001 相似文献
6.
Plant can be infected by different arbuscular mycorrhizal fungi, but little is known about the interaction between them within
root tissues mainly because different species cannot be distinguished on the basis of fungal structure. Accurate species identification
of Arbuscular mycorrhizal fungi (AMF) colonized in plant roots is the comerstone of mycorrhizal study, yet this fundamental
step is impossible through its morphological character alone. For accurate, rapid and inexpensive detection of partial mycorrhizal
fungal community in plant roots, a nested multiplex polymerase chain reaction (PCR) was developed in this study. Five discriminating
primers designed based on the variable region of the 5′ end of the large ribosomal subunit were used in the experiment for
testing their specificity and the sensitivity in nested PCR by using spores from Glomus mosseae (BEG12), Glomus intraradices (BEG141), Scutellospora castaneae (BEG1) and two unidentified Glomus sp. HAUO3 and HAUO4. The feasibility assay of nested multiplex PCR was conducted by use
of spore mixture, Astragalus sinicum roots co-inoculated with 4 species of arbuscular mycorrhizal fungi from pot cultures and 15 different field-growing plant
roots respectively after analyses of the compatibility of primers. The result indicated that the sensitivity was in the same
range as that of the corresponding single PCR reaction. Overall accuracy was 95%. The efficiency and sensitivity of this multiplex
PCR procedure provided a rapid and easy way to simultaneously detect several of arbuscular mycorrhizal fungal species in a
same plant root system. 相似文献
7.
Plant can be infected by different arbuscular mycorrhizal fungi, but little is known about the interaction between them within
root tissues mainly because different species cannot be distinguished on the basis of fungal structure. Accurate species identification
of Arbuscular mycorrhizal fungi (AMF) colonized in plant roots is the comerstone of mycorrhizal study, yet this fundamental
step is impossible through its morphological character alone. For accurate, rapid and inexpensive detection of partial mycorrhizal
fungal community in plant roots, a nested multiplex polymerase chain reaction (PCR) was developed in this study. Five discriminating
primers designed based on the variable region of the 5′ end of the large ribosomal subunit were used in the experiment for
testing their specificity and the sensitivity in nested PCR by using spores from Glomus mosseae (BEG12), Glomus intraradices (BEG141), Scutellospora castaneae (BEG1) and two unidentified Glomus sp. HAUO3 and HAUO4. The feasibility assay of nested multiplex PCR was conducted by use
of spore mixture, Astragalus sinicum roots co-inoculated with 4 species of arbuscular mycorrhizal fungi from pot cultures and 15 different field-growing plant
roots respectively after analyses of the compatibility of primers. The result indicated that the sensitivity was in the same
range as that of the corresponding single PCR reaction. Overall accuracy was 95%. The efficiency and sensitivity of this multiplex
PCR procedure provided a rapid and easy way to simultaneously detect several of arbuscular mycorrhizal fungal species in a
same plant root system. 相似文献
8.
Phosphorus Acquisition Strategies within Arbuscular Mycorrhizal Fungal Community of a Single Field Site 总被引:2,自引:1,他引:1
Diversity in phosphorus (P) acquisition strategies was assessed among eight isolates of arbuscular mycorrhizal fungi (AMF)
belonging to three Glomus species, all obtained from the same field site. Maize (Zea mays L. cv. Corso) was used as a test plant. Compartmented cultivation containers coupled with 33P radioisotope labeling of soil P were employed to estimate (1) the distance from the roots that AMF were able to acquire
soil P from, (2) the rate of soil colonization, (3) the efficiency of uptake of soil P by AMF, (4) benefits provided to maize
in terms of P acquisition and growth. Glomus mosseae and G. intraradices took up P 10 cm from roots, whereas G. claroideum only up to 6 cm from the roots. G. mosseae most rapidly colonized the available soil volume and transported significant amounts of P to maize from a distance, but provided
no net P uptake benefit to the plants. On the other hand, both G. intraradices and three out of four G. claroideum isolates significantly improved net P uptake by maize. These effects seem to be related to variability between and to a limited
extent also within AMF species, in mycelium development, efficiency of hyphal P uptake and effects on plant P acquisition
via the root pathway. In spite of absence of maize growth responses to inoculation with any of the AMF isolates, this study
indicates remarkable functional diversity in the underground component of the studied field site. 相似文献
9.
S. C. K. Carlsen A. Understrup I. S. Fomsgaard A. G. Mortensen S. Ravnskov 《Plant and Soil》2008,302(1-2):33-43
The effects of two arbuscular mycorrhizal fungi (AMF) (Glomus mosseae and G. claroideum) and a pathogenic fungus (Pythium ultimum) on the production of eight flavonoids in roots of two white clover (Trifolium repens L.) cultivars were evaluated. Quantification of AM and pathogenic fungi in the roots showed that the AM symbiosis significantly
reduced P. ultimum biomass and in some cases prevented infection. The flavonoid productions in clover roots varied depending on the presence
of beneficial and/or pathogenic fungi, fungal isolate or plant cultivar. Only plants colonized with G. claroideum showed detectable concentrations of either coumestrol or kaempferol (cultivar-dependant). In addition, inoculation with G. claroideum resulted in significantly higher concentrations of coumestrol in cv. Sonja and medicarpin in cv. Milo. A low production of
coumestrol and kaempferol in mycorrhizal plants may be G. mosseae-specific. Only the concentrations of formononetin and daidzein increased in clover roots in response to infection with P. ultimum. These flavonoids are supposedly stress metabolites, synthesized or produced from glycosides in response to pathogen infection.
However, the presence of one or both AMF significantly lowered the formononetin and daidzein concentrations, and overruled
the inductive effect of P. ultimum. Therefore the antagonistic action of AM against the pathogen must take place through another mechanism. 相似文献
10.
Hypericum perforatum L. (St. John’s-wort, Hypericaceae) is a valuable medicinal plant species cultivated for pharmaceutical purposes. Although
the chemical composition and pharmacological activities of H. perforatum have been well studied, no data are available concerning the influence of arbuscular mycorrhizal fungi (AMF) on this important
herb. A laboratory experiment was therefore conducted in order to test three AMF inocula on H. perforatum with a view to show whether AMF could influence plant vitality (biomass and photosynthetic activity) and the production of
the most valuable secondary metabolites, namely anthraquinone derivatives (hypericin and pseudohypericin) as well as the prenylated
phloroglucinol—hyperforin. The following treatments were prepared: (1) control—sterile soil without AMF inoculation, (2) Rhizophagus intraradices (syn. Glomus intraradices), (3) Funneliformis mosseae (syn. Glomus mosseae), and (4) an AMF Mix which contained: Funneliformis constrictum (syn. Glomus constrictum), Funneliformis geosporum (syn. Glomus geosporum), F. mosseae, and R. intraradices. The application of R. intraradices inoculum resulted in the highest mycorrhizal colonization, whereas the lowest values of mycorrhizal parameters were detected
in the AMF Mix. There were no statistically significant differences in H. perforatum shoot mass in any of the treatments. However, we found AMF species specificity in the stimulation of H. perforatum photosynthetic activity and the production of secondary metabolites. Inoculation with the AMF Mix resulted in higher photosynthetic
performance index (PItotal) values in comparison to all the other treatments. The plants inoculated with R. intraradices and the AMF Mix were characterized by a higher concentration of hypericin and pseudohypericin in the shoots. However, no
differences in the content of these metabolites were detected after the application of F. mosseae. In the case of hyperforin, no significant differences were found between the control plants and those inoculated with any
of the AMF applied. The enhanced content of anthraquinone derivatives and, at the same time, better plant vitality suggest
that the improved production of these metabolites was a result of the positive effect of the applied AMF strains on H. perforatum. This could be due to improved mineral nutrition or to AMF-induced changes in the phytohormonal balance. Our results are
promising from the biotechnological point of view, i.e. the future inoculation of H. perforatum with AMF in order to improve the quality of medicinal plant raw material obtained from cultivation. 相似文献
11.
Two glasshouse experiments were performed to assess the development and metabolic activity of mycorrhizas formed by isolates
of arbuscular mycorrhizal fungi (AMF) from three different genera, Acaulospora, Gigaspora and Glomus on Desmodium ovalifolium L. plants. In the first experiment the effect of disturbance of a pre-established extra-radical mycelium (ERM) was studied.
In the second experiment the effect of phosphate addition as either organic matter (OM) or fertiliser was studied. Disturbance
of a pre-established ERM reduced the formation of mycorrhizas by Gigaspora rosea (BEG111) and increased that by Glomus manihotis (BEG112) on D. ovalifolium plants. Acaulospora tuberculata (BEG41) failed to form mycorrhizas in the experiment. Either Gi. rosea (BEG111) or G. manihotis (BEG112) appeared to be the major component of the colonisation resulting from treatments with combinations of two or three
of the AMF and determined the sensitivity of these treatments to disturbance of a pre-established ERM. The addition of phosphate
fertiliser (10 mg P kg-1) reduced mycorrhiza formation by each species of AMF compared with the addition of OM (10 mg P kg-1). This work indicates that AMF from different genera respond differently to management by agricultural practices when in
association with a tropical legume. Clearly, there is potential to alter the formation of mycorrhizas of AMF from different
genera, through the use of agricultural practices. The significance of the development and metabolic activity of mycorrhizas
formed by AMF from different genera for plant growth is discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
Two grass species — Calamagrostis villosa (Chaix) J.F. Gmelin and Deschampsia flexuosa (L.) Trin. — are expanding in mountain Norway spruce (Picea abies L. Karst.) forests of Central Europe damaged by anthropogenic pollution constituted particularly of acid rain. This invasion
of grasses may be caused by the higher irradiance reaching the forest floor after the pollution-induced tree defoliation.
The relative abundance of the two grass species is changing during the process of forest decline. Our study investigated the
effects of arbuscular mycorrhizal fungi (AMF) on the growth and coexistence of both species under simulated acid rain (SAR)
and two levels of irradiance. Three microcosm experiments were conducted to investigate how both grasses are influenced by
the AMF when grown separately or together interacting via extraradical mycelium (ERM). A positive growth response to inoculation
with Glomus mosseae BEG 25 was found for both grass species when cultivated separately and the mycorrhizal dependence and the growth benefit
for D. flexuosa was greater than for C. villosa. However, when both grass species were grown together in the rhizoboxes with separated root and hyphal compartments, the
growth effect of the AMF was the opposite, i.e. C. villosa benefited more. The plants did not benefit from the AMF inoculation under the SAR treatment compared with dH2O treatment.
The SAR also negatively influenced root length colonised by AMF, length of the ERM, alkaline phosphatase and NADH diaphorase
activities of the ERM. The role of the ERM in transporting phosphorus between these grasses was verified by applying the radioisotope
32P. There was a greater transport of isotopic 32P between inoculated plants C. villosa and D. flexuosa grown in separated root compartments, as compared to non-inoculated plants. The amount of transported 32P was low: a maximum of 3% of applied 32P was detected in the shoots of receiver plants. Mechanical disturbance of the ERM significantly decreased the 32 P transport between plants. The 32P transport between mycorrhizal plants was higher in the D. flexuosa to C. villosa direction than in the opposite one. Neither the SAR nor the low level of irradiance influenced the amount of transported
32P. We discuss the role of ERM links between root systems in the coexistence of both grass species.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
13.
Martina Janoušková Pascale Seddas Libor Mrnka Diederik van Tuinen Anna Dvořáčková Marie Tollot Vivienne Gianinazzi-Pearson Miroslav Vosátka Armelle Gollotte 《Mycorrhiza》2009,19(6):393-402
The co-existence of two arbuscular mycorrhizal fungal (AMF) species, Glomus intraradices and Glomus claroideum, in the root systems of plants was investigated in a greenhouse experiment aimed at reconstructing interactions during an
early stage of primary succession on a coal-mine spoil bank in Central Europe. Two plant species, Tripleurospermum inodorum and Calamagrostis epigejos, were inoculated either with one or both AMF species. Fungal development, determined by trypan blue and alkaline phosphatase
staining as well as by PCR amplification of rRNA genes with species-specific primers, and the expression of five genes with
different metabolic functions in the intraradical structures of G. intraradices were followed after 6 and 9 weeks of cultivation. The two AMF closely co-existed in the root systems of both plants possibly
through similar colonisation rates and competitivity. Inoculation with the two fungi, however, did not bring any additional
benefit to the host plants in comparison with single inoculation; moreover, plant growth depression observed after inoculation
with G. claroideum persisted also in mixed inoculation. The expression of all the assayed G. intraradices genes was affected either by host plant or by co-inoculation with G. claroideum. The effects of both factors depended on the time of sampling, which underlines the importance of addressing this topic in
time-course studies. 相似文献
14.
Impact of two fluorescent pseudomonads and an arbuscular mycorrhizal fungus on tomato plant growth,root architecture and P acquisition 总被引:5,自引:0,他引:5
The ability of fluorescent pseudomonads and arbuscular mycorrhizal fungi (AMF) to promote plant growth is well documented but knowledge of the impact of pseudomonad-mycorrhiza mixed inocula on root architecture is scanty. In the present work, growth and root architecture of tomato plants (Lycopersicon esculentum Mill. cv. Guadalete), inoculated or not with Pseudomonas fluorescens 92rk and P190r and/or the AMF Glomus mosseae BEG12, were evaluated by measuring shoot and root fresh weight and by analysing morphometric parameters of the root system. The influence of the microorganisms on phosphorus (P) acquisition was assayed as total P accumulated in leaves of plants inoculated or not with the three microorganisms. The two bacterial strains and the AMF, alone or in combination, promoted plant growth. P. fluorescens 92rk and G. mosseae BEG12 when co-inoculated had a synergistic effect on root fresh weight. Moreover, co-inoculation of the three microorganisms synergistically increased plant growth compared with singly inoculated plants. Both the fluorescent pseudomonads and the myco-symbiont, depending on the inoculum combination, strongly affected root architecture. P. fluorescens 92rk increased mycorrhizal colonization, suggesting that this strain is a mycorrhization helper bacterium. Finally, the bacterial strains and the AMF, alone or in combination, improved plant mineral nutrition by increasing leaf P content. These results support the potential use of fluorescent pseudomonads and AMF as mixed inoculants for tomato and suggest that improved tomato growth could be related to the increase in P acquisition. 相似文献
15.
Diversity and infectivity of arbuscular mycorrhizal fungi in agricultural soils of the Sichuan Province of mainland China 总被引:1,自引:0,他引:1
Knowledge about the presence and diversity of arbuscular mycorrhizal fungi (AMF) in a specific area is an essential first
step for utilizing these fungi in any application. The community composition of AMF in intensively managed agricultural soil
in the Sichuan Province of southwest China currently is unknown. In one set of samples, AMF were trapped in pot cultures from
40 fields growing legumes in the Panxi region, southeast Sichuan. In a second set of samples, the MPN method with four-fold
dilutions and maize as host was used to estimate infective propagules in soil from another 50 agricultural sites throughout
the province. Soil types were heterogeneous and were classified as purple, yellow, paddy and red. Crops at each site were
either maize, wheat or sweet orange. From this set of soil, AMF spores were also extracted and identified. Including all ninety
soils, thirty glomeromycotan species in Glomus (20 species), Acaulospora (four species), Scutellospora (three species), Ambispora (one species), Archaeospora (one species) and Paraglomus (one species) were identified. Yellow, red and purple soils yielded similar numbers of AMF species, while AMF species diversity
was clearly lower in paddy soil. In trap culture soils, the most frequent species were Glomus aggregatum or Glomus intraradices, Glomus claroideum and Glomus etunicatum. The species Acaulospora capsicula, Acaulospora delicata, G. aggregatum (or intraradices), G. claroideum, Glomus epigaeum, G. etunicatum, Glomus luteum, Glomus monosporum, Glomus mosseae and Glomus proliferum were successfully cultured as single-species pot cultures in Plantago lanceolata. The three most frequent species in field soils were G. mosseae, Glomus caledonium and Glomus constrictum. MPN values varied between 17 and 3334 propagules 100 g soil−1 among the fifty field sites sampled. Regression analysis, including host&soil, log(P) and pH as explanatory variables explained
59% of the variation in log(MPN). The highest MPN estimates were found in purple soil cropped with maize and citrus, 324 and
278 propagules 100 g soil−1, respectively. The lowest MPN value, 54 propagules 100 g soil−1, was measured in wheat in purple and yellow soil. Despite intensive agricultural management that can include often repeated
tillage, our examination of 90 agricultural sites revealed that soils of the Sichuan region have moderate to high numbers
of infective AMF propagules as well as a high AMF species diversity. This opens possibilities for further studies and utilization
of AMF in agriculture and horticulture in the Sichuan province, People’s Republic of China. 相似文献
16.
Positive Feedback between Mycorrhizal Fungi and Plants Influences Plant Invasion Success and Resistance to Invasion 总被引:1,自引:0,他引:1
Negative or positive feedback between arbuscular mycorrhizal fungi (AMF) and host plants can contribute to plant species interactions, but how this feedback affects plant invasion or resistance to invasion is not well known. Here we tested how alterations in AMF community induced by an invasive plant species generate feedback to the invasive plant itself and affect subsequent interactions between the invasive species and its native neighbors. We first examined the effects of the invasive forb Solidago canadensis L. on AMF communities comprising five different AMF species. We then examined the effects of the altered AMF community on mutualisms formed with the native legume forb species Kummerowia striata (Thunb.) Schindl. and on the interaction between the invasive and native plants. The host preferences of the five AMF were also assessed to test whether the AMF form preferred mutualistic relations with the invasive and/or the native species. We found that S. canadensis altered AMF spore composition by increasing one AMF species (Glomus geosporum) while reducing Glomus mosseae, which is the dominant species in the field. The host preference test showed that S. canadensis had promoted the abundance of AMF species (G. geosporum) that most promoted its own growth. As a consequence, the altered AMF community enhanced the competitiveness of invasive S. canadensis at the expense of K. striata. Our results demonstrate that the invasive S. canadensis alters soil AMF community composition because of fungal-host preference. This change in the composition of the AMF community generates positive feedback to the invasive S. canadensis itself and decreases AM associations with native K. striata, thereby making the native K. striata less dominant. 相似文献
17.
Inoculation of grass and tree seedlings used for reclaiming eroded areas in Iceland with mycorrhizal fungi 总被引:1,自引:0,他引:1
The objective of this study was to investigate the response of plant species used for reclamation of eroded areas in Iceland
to inoculation with mycorrhizal fungi. In a greenhouse trial,Leymus arenarius andDeschampsia beringensis were grown in pots with volcanic ash collected from a site near the Mt. Hekla volcano in Iceland and were inoculated with
arbuscular mycorrhizal fungi (AMF) isolatesGlomus mosseae BEG25 orGlomus intraradices BEG75. In two field experiments conducted on volcanic tephra fields near Mt. Hekla, a native soil inoculum or commercial
inocula TerraVital-D and Terra Vital-G Ecto Mix were compared for efficacy onL. arenarius andBetula pubescens. After four months of growth, the presence of AMF in the pot experiment significantly increased the capacity of grass root
systems to bind soil particles. In the field, inoculation significantly increased the number ofL. arenarius plants, which emerged from seed and their subsequent survival and growth. Seedlings ofB. pubescens grew best following inoculation with ectomycorrhizal fungal (ECMF) inoculum and a subsequent application of inorganic NP-fertilizer.
The addition of native soil inoculum had almost no effect on growth of either grass or trees. Our results indicate that reclamation
of eroded areas in Iceland could benefit from the use of a ppropriate mycorrhizal fungi, which might improve plant establishment
and growth and increase soil aggregation and stability. 相似文献
18.
Bacterial effects on arbuscular mycorrhizal fungi and mycorrhiza development as influenced by the bacteria, fungi, and host plant 总被引:1,自引:0,他引:1
Pivato B Offre P Marchelli S Barbonaglia B Mougel C Lemanceau P Berta G 《Mycorrhiza》2009,19(2):81-90
Bacterial strains from mycorrhizal roots (three belonging to Comamonadaceae and one to Oxalobacteraceae) and from non-mycorrhizal roots (two belonging to Comamonadaceae) of Medicago truncatula and two reference strains (Collimonas fungivorans Ter331 and Pseudomonas fluorescens C7R12) were tested for their effect on the in vitro saprophytic growth of Glomus mosseae BEG12 and on its colonization of M. truncatula roots. Only the Oxalobacteraceae strain, isolated from barrel medic mycorrhizal roots, and the reference strain P. fluorescens C7R12 promoted both the saprophytic growth and root colonization of G. mosseae BEG12, indicating that they acted as mycorrhiza helper bacteria. Greatest effects were achieved by P. fluorescens C7R12 and its influence on the saprophytic growth of G. mosseae was compared to that on Gigaspora rosea BEG9 to determine if the bacterial stimulation was fungal specific. This fungal specificity, together with plant specificity,
was finally evaluated by comparing bacterial effects on arbuscular mycorrhizal symbiosis when each of the fungal species was
inoculated to two different plant species (M. truncatula and Lycopersicon esculentum). The results obtained showed that promotion of saprophytic growth by P. fluorescens C7R12 was expressed in vitro towards G. mosseae but not towards G. rosea. Bacterial promotion of mycorhization was also expressed towards G. mosseae, but not G. rosea, in roots of M. truncatula and L. esculentum. Taken together, results indicated that enhancement of arbuscular mycorrhiza development was only induced by a limited number
of bacteria, promotion by the most efficient bacterial strain being fungal and not plant specific. 相似文献
19.
A method for assessing arbuscular mycorrhizal fungi group distribution in tree roots by intergenic transcribed sequence variation 总被引:1,自引:0,他引:1
Mervyn Shepherd Linh Nguyen Megan E. Jones J. Doland Nichols F. Lynn Carpenter 《Plant and Soil》2007,290(1-2):259-268
We identified five taxonomic groups of arbuscular mycorrhizal fungi (AMF) inside roots of young trees of six species of legumes
and six species of non-legumes from a field site in southern Costa Rica using an AMF group-specific PCR assay of the intergenic
transcribed sequence and 18S rRNA gene fragment. Assay specificity was verified by cloning and sequencing representatives
from four of the five AMF groups. We found no difference in overall AMF diversity levels between legumes and non-legumes or
between plant species. Some groups of AMF may associate more frequently with legumes than others, as Glomus Group A (Glomus mosseae/intradices group) representatives were detected more frequently in legumes than non-legumes relative to Glomus Group B (Glomus etunicatum/claroideum) representatives. 相似文献
20.
The arbuscular mycorrhizal status of fifteen mangroves and one mangrove associate was investigated from 27 sites of three
inundation types namely, diurnal, usual springtide and summer springtide. Roots and rhizospheric soil samples were analysed
for spore density, frequency of mycorrhizal colonization and some chemical characteristics of soil. Relative abundance, frequency
and spore richness of AMF were assessed at each inundation type. All the plant species except Avicennia alba exhibited mycorrhizal colonization. The study demonstrated that mycorrhizal colonization and spore density were more influenced
by host plant species than tidal inundation. Forty four AMF species belonging to six genera, namely Acaulospora, Entrophospora, Gigaspora, Glomus, Sclerocystis and Scutellospora, were recorded. Glomus mosseae exhibited highest frequency at all the inundation types; Glomus fistulosum, Sclerocystis coremioides and Glomus mosseae showed highest relative abundance at sites inundated by usual springtides, summer springtides and diurnal tides, respectively.
Spore richness of AMF was of the order usual springtide > diurnal > summer springtide inundated sites. The mean spore richness
was 3.27. Diurnally inundated sites had the lowest concentrations of salinity, available phosphorus, exchangeable potassium,
sodium and magnesium. Statistical analyses indicated that mycorrhizal frequency and AMF spore richness were significantly
negatively correlated to soil salinity. Spore richness was also significantly negatively correlated to available phosphorus.
The soil parameters of the usual springtide inundated sites appeared to be favourable for the existence of maximum number
of AMF. Glomus mosseae was the predominant species in terms of frequency in the soils of the Sundarbans. 相似文献