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1.
Arbuscular mycorrhizal and dark septate endophytic fungal colonization in a grassland in Kunming, southwest China, was investigated monthly over one year. All plant roots surveyed were co-colonized by arbuscular mycorrhizal and dark septate endophytic fungi in this grassland. Both arbuscular mycorrhizal and dark septate endophytic fungal colonization fluctuated significantly throughout the year, and their seasonal patterns were different in each plant species. The relationships between environmental (climatic and edaphic) factors and fungal colonization were also studied. Correlation analysis demonstrated that arbuscular mycorrhizal colonization was significantly correlative with environmental factors (rainfall, sunlight hours, soil P, etc.), but dark septate endophytic fungal colonization was only correlative with relative humidity and sunlight hours. 相似文献
2.
Molecular and cell biology of arbuscular mycorrhizal symbiosis 总被引:15,自引:0,他引:15
The roots of most extant plants are able to become engaged in an interaction with a small group of fungi of the fungal order Glomales (Glomeromycota). This interaction—arbuscular mycorrhizal (AM) symbiosis—is the evolutionary precursor of most other mutualistic root-microbe associations. The molecular analysis of this interaction can elucidate basic principles regarding such associations. This review summarizes our present knowledge about cellular and molecular aspects of AM. Emphasis is placed on morphological changes in colonized cells, transfer of nutrients between both interacting partners, and plant defence responses. Similarities to and differences from other associations of plant and microorganisms are highlighted regarding defence reactions and signal perception. 相似文献
3.
Temporal temperature gradient gel electrophoresis (TTGE) as a tool for the characterization of arbuscular mycorrhizal fungi 总被引:3,自引:0,他引:3
The aim of this study was to assess the feasibility of using temporal temperature gradient electrophoresis (TTGE) of PCR-amplified 18S rDNA fragments of different Glomus species for their detection and characterization. Screening of Glomus clarum, Glomus constrictum, Glomus coronatum, Glomus intraradices, Glomus mosseae and Glomus viscosum by PCR-TGGE revealed that the NS31-AM1 region of the 18S rRNA gene contained insufficient variation to discriminate between them. In contrast, TTGE analysis of the NS31-Glo1 region, which was obtained by nested PCR of the NS31-AM1 amplicon, showed that each species was characterized by a specific TTGE fingerprint. However, isolates of the same species could not be distinguished. The nested PCR-TTGE approach developed allowed identification of the Glomus species colonising the roots of different plant species. 相似文献
4.
The arbuscular mycorrhizal (AM) status of two plant communities on a calamine spoil mound (rich in cadmium, lead and zinc)
in southern Poland was surveyed: an undisturbed grassland community and an early succession community that developed after
complete removal of the surface layer of the calamine substrate about 10 years earlier. The undisturbed site harbored 40 herbaceous
species making up 87% of the absolute cover. AM colonization was recorded in 25 species accounting for 77% of the relative
cover. Species with 51–75% AM root colonization such as Festuca ovina and Leontodon hispidus dominated the undisturbed turf, contributing 45% to the relative cover. Carex ssp. were the most abundant nonmycorrhizal plants and accounted for 9% of the relative cover. Spores of Glomus aggregatum, G. constrictum, G. fasciculatum, G. pansihalos, Glomus sp. and Entrophospora sp. averaged 25 per 100 g dry substrate at the undisturbed site. The disturbed site was colonized by 25 species accounting
for 17% of the absolute cover. Among the AM plants, most abundant were the species with up to 20% AM root colonization, such
as Agrostis stolonifera and Thymus pulegioides, wich accounted for 24% of the relative cover. Nonmycorrhizal species, such as Biscutella laevigata,
Cardaminopsis arenosa, Gypsophila fastigiata and Silene vulgaris, dominated the early succession community and contributed 64% to the relative cover. Spores of G. fasciculatum and Entrophospora sp. averaged 20 per 100 g dry substrate at the disturbed site.
Accepted: 29 November 1996 相似文献
5.
Complex relationships occur among plants, mycorrhizal fungi, and herbivores. By altering plant nutrient status, mycorrhizas may alter herbivory or plant tolerance to herbivory via compensatory regrowth. We examined these interactions by assessing grasshopper preference and plant growth and fungal colonization responses to herbivory under mycorrhizal and non‐mycorrhizal conditions within tallgrass prairie microcosms. Mycorrhizal symbiosis increased plant regrowth following defoliation, and some strongly mycotrophic plant species showed overcompensation in response to herbivory when they were mycorrhizal. Although grasshoppers spent more time on mycorrhizal plants, herbivory intensity did not differ between mycorrhizal and non‐mycorrhizal plants. Aboveground herbivory by grasshoppers significantly increased mycorrhizal fungal colonization of plant roots. Thus mycorrhizas may greatly benefit plants subjected to herbivory by stimulating compensatory growth, and herbivores, in turn, may increase the development of the symbiosis. Our results also indicate strong interspecific differences among tallgrass prairie plant species in their responses to the interaction of aboveground herbivores and mycorrhizal symbionts. 相似文献
6.
N. A. Sajedi M. R. Ardakani F. Rejali F. Mohabbati Mohammad Miransari 《Physiology and Molecular Biology of Plants》2010,16(4):343-351
With respect to the significance of improving hybrid corn performance under stress, this experiment was conducted at the Islamic Azad University, Arak Branch, Iran. A complete randomized block design with three levels of irrigations (at 100%, 75% and 50% crop water requirement), two levels of arbuscular mycorrhizal (AM) fungi (Glumus intraradisis) (including control), and three levels of zinc (Zn) sulfate (0, 25 and 45 kg ha−1), was performed. Results of the 2-year experiments indicated that irrigation treatment significantly affected corn yield and its components at P = 1%. AM fungi and increasing Zn levels also resulted in similar effects on corn growth and production. Although AM fungi did not significantly affect corn growth at the non-stressed irrigation treatment, at moderate drought stress AM fungi significantly enhanced corn quality and yield relative to the control treatment. The combined effects of AM fungi and Zn sulfate at 45 kg ha−1 application significantly affected corn growth and production. In addition, the tripartite treatments significantly enhanced corn yield at P = 1%. Effects of Zn and AM fungi on plant growth under drought stress is affected by the stress level. 相似文献
7.
Interacting influence of mycorrhizal symbiosis and competition on plant diversity in tallgrass prairie 总被引:13,自引:0,他引:13
In tallgrass prairie, plant species interactions regulated by their associated mycorrhizal fungi may be important forces that
influence species coexistence and community structure; however, the mechanisms and magnitude of these interactions remain
unknown. The objective of this study was to determine how interspecific competition, mycorrhizal symbiosis, and their interactions
influence plant community structure. We conducted a factorial experiment, which incorporated manipulations of abundance of
dominant competitors, Andropogon gerardii and Sorghastrum nutans, and suppression of mycorrhizal symbiosis using the fungicide benomyl under two fire regimes (annual and 4-year burn intervals).
Removal of the two dominant C4 grass species altered the community structure, increased plant species richness, diversity, and evenness, and increased abundance
of subdominant graminoid and forb species. Suppression of mycorrhizal fungi resulted in smaller shifts in community structure,
although plant species richness and diversity increased. Responses of individual plant species were associated with their
degree of mycorrhizal responsiveness: highly mycorrhizal responsive species decreased in abundance and less mycorrhizal responsive
species increased in abundance. The combination of dominant-grass removal and mycorrhizal suppression treatments interacted
to increase synergistically the abundance of several species, indicating that both processes influence species interactions
and community organization in tallgrass prairie. These results provide evidence that mycorrhizal fungi affect plant communities
indirectly by influencing the pattern and strength of plant competitive interactions. Burning strongly influenced the outcome
of these interactions, which suggests that plant species diversity in tallgrass prairie is influenced by a complex array of
interacting processes, including both competition and mycorrhizal symbiosis.
Received: 7 April 1999 / Accepted: 30 July 1999 相似文献
8.
The occurrence of arbuscular mycorrhiza (AM) was surveyed in ten endemic plant species of the Koniambo Massif (New Caledonia) and associated metal-enriched ultramafic soils along a topographic sequence ranging from a plateau at 900 m altitude to a valley at 700 m. In the four different plant formations (Araucaria group on the plateau, ligno-herbaceous maquis, Tristaniopsis maquis and Nothofagus forest in the valley), all plants were consistently colonised by AM fungi, even the sedges Costularia arundinacea, C. nervosa and Lepidosperma perteres and the nickel-hyperaccumulating plant Phyllanthus favieri. Dual (AM and ectomycorrhiza EM) colonisation was observed in the two plant formations dominated by the ectomycorrhizal plants Nothofagus balansae for the forest (site 4) and Tristaniopsis guillainii and T. calobuxus for the Tristaniopsis maquis (site 3). In the soils, there are strong positive correlations between microbial activity, black AM spore abundance and concentrations of available metals indicating the role of the biotic component in the release of metals. These results suggest that these symbioses are important in the adaptation of the endemic plants to these soils, and may be relevant to ecological restoration of the ancient nickel mines. 相似文献
9.
《Microbiological research》2014,169(1):49-58
Egyptian soils are generally characterized by slightly alkaline to alkaline pH values (7.5–8.7) which are mainly due to its dry environment. In arid and semi-arid regions, salts are less concentrated and sodium dominates in carbonate and bicarbonate forms, which enhance the formation of alkaline soils. Alkaline soils have fertility problems due to poor physical properties which adversely affect the growth and the yield of crops. Therefore, this study was devoted to investigating the synergistic interaction of Rhizobium and arbuscular mycorrhizal fungi for improving growth of faba bean grown in alkaline soil. A total of 20 rhizobial isolates and 4 species of arbuscular mycorrhizal fungi (AMF) were isolated. The rhizobial isolates were investigated for their ability to grow under alkaline stress. Out of 20 isolates 3 isolates were selected as tolerant isolates. These 3 rhizobial isolates were identified on the bases of the sequences of the gene encoding 16S rRNA and designated as Rhizobium sp. Egypt 16 (HM622137), Rhizobium sp. Egypt 27 (HM622138) and Rhizobium leguminosarum bv. viciae STDF-Egypt 19 (HM587713). The best alkaline tolerant was R. leguminosarum bv. viciae STDF-Egypt 19 (HM587713). The effect of R. leguminosarum bv. viciae STDF-Egypt 19 and mixture of AMF (Acaulospora laevis, Glomus geosporum, Glomus mosseae and Scutellospora armeniaca) both individually and in combination on nodulation, nitrogen fixation and growth of Vicia faba under alkalinity stress were assessed. A significant increase over control in number and mass of nodules, nitrogenase activity, leghaemoglobin content of nodule, mycorrhizal colonization, dry mass of root and shoot was recorded in dual inoculated plants than plants with individual inoculation. The enhancement of nitrogen fixation of faba bean could be attributed to AMF facilitating the mobilization of certain elements such as P, Fe, K and other minerals that involve in synthesis of nitrogenase and leghaemoglobin. Thus it is clear that the dual inoculation with Rhizobium and AMF biofertilizer is more effective for promoting growth of faba bean grown in alkaline soils than the individual treatment, reflecting the existence of synergistic relationships among the inoculants. 相似文献
10.
《Journal of plant physiology》2014,171(18):1774-1781
Medicago sativa L. (alfalfa) can exhibit photosynthetic down-regulation when grown in greenhouse conditions under elevated atmospheric CO2. This forage legume can establish a double symbiosis with nitrogen fixing bacteria and arbuscular mycorrhizal fungi (AMF), which may increase the carbon sink effect of roots. Our aim was to assess whether the association of alfalfa with AMF can avoid, diminish or delay the photosynthetic acclimation observed in previous studies performed with nodulated plants. The results, however, showed that mycorrhizal (M) alfalfa at the end of their vegetative period had lower carbon (C) discrimination than non-mycorrhizal (NM) controls, indicating photosynthetic acclimation under ECO2 in plants associated with AMF. Decreased C discrimination was due to the acclimation of conductance, since the amount of Rubisco and the expression of genes codifying both large and small subunits of Rubisco were similar or slightly higher in M than in NM plants. Moreover, M alfalfa accumulated a greater amount of soluble sugars in leaves than NM plants, thus favoring a down-regulation effect on photosynthetic rates. The enhanced contents of sugars in leaves coincided with a reduced percentage of arbuscules in roots, suggesting decreased sink of carbohydrates from shoots to roots in M plants. The shorter life cycle of alfalfa associated with AMF in comparison with the NM controls may also be related to the accelerated photosynthetic acclimation in M plants. Further research is needed to clarify to what extent this behavior could be extrapolated to alfalfa cultivated in the field and subjected to periodic cutting of shoots under climatic change scenarios. 相似文献
11.
《Saudi Journal of Biological Sciences》2017,24(1):170-179
Salinity is one of the serious abiotic stresses adversely affecting the majority of arable lands worldwide, limiting the crop productivity of most of the economically important crops. Sweet basil (Osmium basilicum) plants were grown in a non-saline soil (EC = 0.64 dS m−1), in low saline soil (EC = 5 dS m−1), and in a high saline soil (EC = 10 dS m−1). There were differences between arbuscular mycorrhizal (Glomus deserticola) colonized plants (+AMF) and non-colonized plants (−AMF). Mycorrhiza mitigated the reduction of K, P and Ca uptake due to salinity. The balance between K/Na and between Ca/Na was improved in +AMF plants. Growth enhancement by mycorrhiza was independent from plant phosphorus content under high salinity levels. Different growth parameters, salt stress tolerance and accumulation of proline content were investigated, these results showed that the use of mycorrhizal inoculum (AMF) was able to enhance the productivity of sweet basil plants under salinity conditions. Mycorrhizal inoculation significantly increased chlorophyll content and water use efficiency under salinity stress. The sweet basil plants appeared to have high dependency on AMF which improved plant growth, photosynthetic efficiency, gas exchange and water use efficiency under salinity stress. In this study, there was evidence that colonization with AMF can alleviate the detrimental salinity stress influence on the growth and productivity of sweet basil plants. 相似文献
12.
The genera Cryptococcus and Dioszegia contain basidiomycetous yeasts found in a wide range of habitats. Primers to amplify the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA (nrDNA) of arbuscular mycorrhizal fungi (AMF) also allow detecting members of this yeast group. Here we report the results of a sequence analysis using maximum parsimony on a set of 50 ITS sequences of yeasts associated with AMF structures (roots of 26 plant species, AM spores) from six field sites in Central Germany. Among 10 separated taxa, respectively five in the Tremellales and two in the Filobasidiales had unknown sequences. Therefore it was not possible to assign these sequences to any known species. The study indicates that exploring the diversity of Cryptococcus and Dioszegia in soil habitats with molecular methods might enlarge the actually estimated biodiversity of the group. 相似文献
13.
Arbuscular mycorrhizal fungi in non-grazed,restored and over-grazed grassland in the Inner Mongolia steppe 总被引:3,自引:0,他引:3
Arbuscular mycorrhizal (AM) fungal diversity was investigated in non-grazed, restored and over-grazed (fenced) plots of a
grassland in the Inner Mongolia steppe. Plant cover and variety differ between the plots, being highest in the non-grazed
to lowest in the over-grazed plots. A total of 19 AM fungal taxa belonging to six genera were found based on spores isolated
from field samples and trap cultures. One belonged to Acaulospora, one to Archaeospora, one to Entrophospora, one to Gigaspora, 12 to Glomus and three to Scutellospora. Glomus was the dominant genus in all plots, and Glomus geosporum was the dominant species, whilst G. albidum and G. etunicatum were dominant in the restored plot. Scutellospora was the second dominant genus in the non-grazed plot with Scutellospora calospora being the dominant species. The mean spore density and mean species richness of AM fungi were significantly decreased by
long-term over-grazing. The Sorenson’s similarity coefficients of AM fungal community composition ranged from 0.5 to 0.64
among the three types of plot management. The results suggest that the AM fungal diversity is greatly affected by long-term
over-grazing and that fencing of degraded areas partly restores plant cover and AM fungal diversity in grassland ecosystems. 相似文献
14.
Domenico Zocco Joel Fontaine Evgenia Lozanova Laurent Renard Cline Bivort Roger Durand Anne Grandmougin-Ferjani Stphane Declerck 《Mycological Research》2008,112(5):592-601
The effects of different concentrations (0.2, 2, 20, 200 mg l−1) of two sterol biosynthesis inhibitor (SBI) fungicides, i.e. fenpropimorph and fenhexamid, were evaluated on the spore germination, germ tube elongation, sporulation, and root colonization of Glomus intraradices grown monoxenically in association with transformed carrot roots. The percentage of germinated spores incubated on the SBI fungicides and the length of the germ tubes decreased with increasing concentrations of both fungicides. However, for spore germination this impact was fungistatic rather than fungicidal. Extraradical mycelium architecture and spore production in contact with the SBI fungicides were also strongly impacted at high concentration (20 mg l−1). Conversely, the colonization of roots developing in the fungicide-free compartment, but interconnected with the extraradical mycelium developing on the SBI fungicides, appeared unaffected. Our results demonstrated that the monoxenic culture system could be used as a standardized, reproducible technique to compare the impacts of different molecules on arbuscular mycorrhizal fungi, and for the initial screening of new candidate molecules before registration. 相似文献
15.
Arbuscular mycorrhizal status of wild plants in saline-alkaline soils of the Yellow River Delta 总被引:8,自引:0,他引:8
A survey was made of the arbuscular mycorrhizal (AM) status of five dominant wild plants Tamarix chinensis, Phragmites communis, Suaeda glauca, Aeluropus littoralis var. sinensis and Cirsium setosum in saline-alkaline soils of the Yellow River Delta that show low plant diversity. All of the species were colonized and showed typical AM structures (arbuscules, vesicles). The colonization percentage ranged from 0.2% to 9.5%, where C. setosum was the highest. The species richness of AMF at the different sites ranged from 2.00 to 2.40 per 50 ml soil, with an average of 2.16. Species diversity ranged from 1.99 to 2.22 per 50 ml soil, with an average of 2.13. Spore density ranged from 3 to 30 per 50 ml soil, with an average of 12. Glomus was the dominant genus, with a frequency and relative abundance of 88.1% and 68.4%, respectively. G. caledonium, with a frequency and relative abundance of 15.0% and 4.6%, respectively, was the dominant species. Differences were also observed in the distribution of AMF in different soil layers. Although there were still AM fungal spores in the layer 40 cm below the surface, most spores were found at a depth of 0–40 cm. 相似文献
16.
《Fungal Ecology》2014
Aerial dispersal of fungal spores is common, but the role of wind and air movement in dispersal of spores of arbuscular mycorrhizal (AM) fungi is largely unknown. Several studies have examined the possibility of AM fungal spores being moved by wind vectors without observing spores taken from the air environment. For the first time this study observed the presence of AM fungal spores in the air. The frequency of AM fungal spores in the air was determined in six North American biomes composed of 18 ecoregions. Multiple samples were taken from both the air and the soil at each location. AM fungal spores were found in high abundance in the soil (hundreds of spores per gram of soil), however, they were rarely found in the air (most samples contained no AM fungal spores). Furthermore, only the Glomus morphotype was found in the air, whereas spores in the soil were taxomomically more diverse (Glomus, Acaulospora, Gigaspora, Scutellospora morphotypes were observed). The proportion of Glomus spores in the air relative to Glomus spores in the soil was highest in more arid systems, indicating that AM fungi may be more likely to be dispersed in the air in such systems. Nonetheless, the results indicate that the air is not likely a dominant mode of dispersal for AM fungi. 相似文献
17.
The arbuscular mycorrhizal (AM) fungi colonizing the sporophytes of the eusporangiate rattlesnake fern (Botrychium virginianum, Ophioglossaceae) in its Hungarian population were investigated in the present study. Different regions of the nrRNA gene
complex were analyzed using two different primer sets. These produced similar results for the detected AM fungi phylotypes.
Several AM fungal lineages were associated with sporophytes of B. virginianum. Phylogenetic analyses of different partial small subunit datasets grouped one lineage into the Gigasporaceae, showing similarities
with Scutellospora sequences. In addition to unidentified Scutellospora phylotypes, it is possible that S. gregaria also colonized the fern. Several AM fungal phylotypes colonizing the sporophytes grouped into Glomus group A. They did not form distinct clades but grouped with sequences of AM fungi with different geographic and host origins.
One main lineage clustered into the widespread G. fasciculatum/G. intraradices group and one into the subgroup GlGrAc, while others had no affinity to the subgroups of Glomus group A. As AM fungal phylotypes associated with B. virginianum seem to belong to widespread AM fungal taxa and show no specificity to this fern, we suppose that the previously described
special anatomy of AM of B. virginianum is determined by the plant. 相似文献
18.
This study investigated the effect of arbuscular mycorrhizal (AM) fungal consortia on growth, photosynthetic pigments, solutes concentration (e.g., sugars and proline), and antioxidant responses at different levels of Na2SO4 stress (0–0.5%, w:w) in potted culture of Jatropha. Results showed that increasing salt levels caused a significant reduction in survival (%), growth parameters, leaf relative water content (LRWC) (%), and chlorophyll content with an increase in electrolyte leakage (%) and lipid peroxidation of membranes of Jatropha. AM inoculation improved biomass yields as well as other physiological parameters (LRWC (%), chlorophyll, proline, and soluble sugar) of salt-stressed Jatropha over noninoculated plants. Tolerance index of Jatropha was higher with AM fungi than without at all salt levels; however, a decline in its value was recorded with increased salinity levels. AM inoculation also enhanced the activities of antioxidant enzymes (e.g., superoxide dismutase, peroxidase, ascorbate peroxidase, and glutathione reductase) and decreased oxidative damage to lipids. In conclusion, results indicate that AM inoculation was capable of alleviating the damage caused by salinity stress on Jatropha plants by reducing lipid peroxidation of membrane and membrane permeability and increasing the accumulation of solutes and antioxidant enzyme activity. 相似文献
19.
Responses of soil microbial catabolic diversity to arbuscular mycorrhizal inoculation and soil disinfection 总被引:1,自引:0,他引:1
Dabire AP Hien V Kisa M Bilgo A Sangare KS Plenchette C Galiana A Prin Y Duponnois R 《Mycorrhiza》2007,17(6):537-545
Although it is usually admitted that arbuscular mycorrhizal (AM) fungi are key components in soil bio-functioning, little
is known on the response of microbial functional diversity to AM inoculation. The aims of the present study were to determine
the influence of Glomus intraradices inoculum densities on plant growth and soil microflora functional diversity in autoclaved soil or non-disinfected soil. Microbial
diversity of soil treatments was assessed by measuring the patterns of in situ catabolic potential of microbial communities.
The soil disinfection increased sorghum growth, but lowered catabolic evenness (4.8) compared to that recorded in the non-disinfected
soil (6.5). G. intraradices inoculation induced a higher plant growth in the autoclaved soil than in the non-disinfected soil. This AM effect was positively
related to inoculum density. Catabolic evenness and richness were positively correlated with the number of inoculated AM propagules
in the autoclaved soil, but negatively correlated in the non-disinfected soil. In addition, after soil disinfection and AM
inoculation, these microbial functionality indicators had higher values than in the autoclaved or in the non-disinfected soil
without AM inoculation. These results are discussed in relation to the ecological influence of AM inoculation, with selected
fungal strains and their associated microflora on native soil microbial activity. 相似文献
20.
We investigated the spore density, species composition, and diversity of arbuscular mycorrhizal fungi (AMF) in a cultivated
land (CL), an old field (OF), and a never-cultivated field (NCF), which are located adjacently in a slope in the hot and arid
ecosystem of southwest China. AMF spores in the rhizosphere soils of representative plants in the three habitats were extracted
by wet-sieving and decanting. A total of 47 taxa of AMF including 31 taxa from the genus Glomus, 8 from Acaulospora, 6 from Scutellospora, 1 from Entrophospora, and 1 from Gigaspora were extracted and identified morphologically. The highest spore density occurred in NCF, slightly lower in OF and lowest
in CL, and the Shannon–Wiener index of species diversity was reversed. The dominant species of AMF were different in the three
habitats. OF resembled NCF more than CL in AMF spore density, species richness, and community composition, which means that
AMF community in the OF has been developing from cultivated land to natural habitat. Cluster analysis based on the similarity
in AMF community composition indicated that the distribution of AMF was not random over space and that AMF community composition
associated with a given plant species was greatly habitat-convergence. Following the cluster analysis, we hypothesized that
the effect of habitats on AMF communities were greater than that of the host preference to AMF.
L-F. Li and T. Li contributed equally to this work. 相似文献