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1.
Differential benefits of arbuscular mycorrhizal and ectomycorrhizal infection of Salix repens 总被引:6,自引:0,他引:6
E. W. van der Heijden 《Mycorrhiza》2001,10(4):185-193
The functional significance of arbuscular mycorrhiza (AM) and ectomycorrhiza (EcM) for Salix repens, a dual mycorrhizal plant, was investigated over three harvest periods (12, 20 and 30 weeks). Cuttings of S. repens were collected in December (low shoot P) and March (high shoot P). Glomus mosseae (an arbuscular mycorrhizal fungus, AMF) resulted in low AM colonization (<5%), but showed large short-term (<12 weeks) effects
on shoot growth and root length. Hebeloma leucosarx (an ectomycorrhizal fungus, EcMF) resulted in high EcM colonization (70%), but benefits occurred over a longer term (>12 weeks).
Furthermore, G. mosseae colonization resulted in higher shoot P uptake, shoot growth, root growth and response duration for S. repens collected in December than for those collected in March, whereas with H. leucosarx and the non-mycorrhizal treatment there were no differences between cuttings collected on different dates. Low AMF colonization
was effective in the short term for cuttings at both collecting dates. Low AMF colonization of S. repens occurred irrespective of the amount of AMF inoculum used. The intensities and relative amounts of AMF structures in S. repens and Trifolium repens were compared over three harvest periods (12, 20 and 30 weeks) to assess plant species effects on AM colonization patterns.
Accepted: 13 October 2000 相似文献
2.
The objective of this study was to determine patterns of ectomycorrhizas (ECM) and arbuscular mycorrhizas (AM) colonization associated with Alnus acuminata (Andean alder), in relation to soil parameters (electrical conductivity, field H2O holding capacity, pH, available P, organic matter, and total N) at two different seasons (autumn and spring). The study was conducted in natural forests of A. acuminata situated in Calilegua National Park (Jujuy, Argentina). Nine ECM morphotypes were found on A. acuminata roots. The ECM colonization was affected by seasonality and associated positively with field H2O holding capacity, pH, and total N and negatively associated with organic matter. Two morphotypes (Russula alnijorullensis and Tomentella sp. 3) showed significant differences between seasons. Positive and negative correlations were found between five morphotypes (Alnirhiza silkacea, Lactarius omphaliformis, Tomentella sp. 1, Tomentella sp. 3, and Lactarius sp.) and soil parameters (total N, pH, and P). A significant negative correlation was found between field H2O holding capacity and organic matter with AM colonization. Results of this study provide evidence that ECM and AM colonization of A. acuminata can be affected by some soil chemical edaphic parameters and indicate that some ECM morphotypes are sensitive to changes in seasonality and soil parameters. 相似文献
3.
We investigated the accumulation of reactive oxygen species (ROS) in arbuscular mycorrhizal (AM) roots from Medicago truncatula, Zea mays and Nicotiana tabacum using three independent staining techniques. Colonized root cortical cells and the symbiotic fungal partner were observed to be involved in the production of ROS. Extraradical hyphae and spores from Glomus intraradices accumulated small levels of ROS within their cell wall and produced ROS within the cytoplasm in response to stress. Within AM roots, we observed a certain correlation of arbuscular senescence and H2O2 accumulation after staining by diaminobenzidine (DAB) and a more general accumulation of ROS close to fungal structures when using dihydrorhodamine 123 (DHR 123) for staining. According to electron microscopical analysis of AM roots from Z. mays after staining by CeCl3, intracellular accumulation of H2O2 was observed in the plant cytoplasm close to intact and collapsing fungal structures, whereas intercellular H2O2 was located on the surface of fungal hyphae. These characteristics of ROS accumulation in AM roots suggest similarities to ROS accumulation during the senescence of legume root nodules. 相似文献
4.
Environmental and genetic effects on the formation of ectomycorrhizal and arbuscular mycorrhizal associations in cottonwoods 总被引:1,自引:0,他引:1
Although both environment and genetics have been shown to affect the mycorrhizal colonization of host plants, the impacts of these factors on hosts that can be dually colonized by both ectomycorrhizal (EM) and arbuscular mycorrhizal (AM) fungi are less understood. We examined the influence of environment and host crosstype on the EM and AM colonization of cottonwoods (Populus angustifolia and natural hybrids) by comparing levels of colonization of trees growing in common gardens that differed in elevation and soil type. We also conducted a supplemental watering experiment to determine the influence of soil moisture on AM and EM colonization. Three patterns emerged. First, garden location had a significant impact on mycorrhizal colonization, such that EM colonization was 30% higher and AM colonization was 85% lower in the higher elevation garden than the lower elevation garden. Second, crosstype affected total (EM + AM) colonization, but did not affect EM or AM colonization. Similarly, a significant garden × crosstype interaction was found for total colonization, but not for EM or AM colonization. Third, experimental watering resulted in 33% higher EM colonization and 45% lower AM colonization, demonstrating that soil moisture was a major driver of the mycorrhizal differences observed between the gardens. We conclude that environment, particularly soil moisture, has a larger influence on colonization by AM versus EM fungi than host genetics, and suggest that environmental stress may be a major determinant of mycorrhizal colonization in dually colonized host plants. 相似文献
5.
Mycorrhizal plants often have greater tolerance to drought than nonmycorrhizal plants. This study was conducted to determine the effects of arbuscular mycorrhizal (AM) fungi inoculation on growth, grain yield and mineral acquisition of two winter wheat (Triticum aestivum L.) cultivars grown in the field under well-watered and water-stressed conditions. Wheat seeds were planted in furrows after treatment with or without the AM fungi Glomus mosseae or G. etunicatum. Roots were sampled at four growth stages (leaf, tillering, heading and grain-filling) to quantify AM fungi. There was negligible AM fungi colonization during winter months following seeding (leaf sampling in February), when soil temperature was low. During the spring, AM fungi colonization increased gradually. Mycorrhizal colonization was higher in well-watered plants colonized with AM fungi isolates than water-stressed plants. Plants inoculated with G. etunicatum generally had higher colonization than plants colonized with G. mosseae under both soil moisture conditions. Biomass and grain yields were higher in mycorrhizal than nonmycorrhizal plots irrespective of soil moisture, and G. etunicatum inoculated plants generally had higher biomass and grain yields than those colonized by G. mosseae under either soil moisture condition. The mycorrhizal plants had higher shoot P and Fe concentrations than nonmycorrhizal plants at all samplings regardless of soil moisture conditions. The improved growth, yield and nutrient uptake in wheat plants reported here demonstrate the potential of mycorrhizal inoculation to reduce the effects of drought stress on wheat grown under field conditions in semiarid areas of the world. 相似文献
6.
Growth and arsenic uptake by Chinese brake fern inoculated with an arbuscular mycorrhizal fungus 总被引:2,自引:0,他引:2
Yu Liu Peter Christie Junling Zhang Xiaolin Li 《Environmental and Experimental Botany》2009,66(3):435-441
A split-root experiment investigated the effects of inoculation with the arbuscular mycorrhizal fungus Glomus mosseae and arsenic (As) addition on As uptake by Pteris vittata L. Either part or all of the root system was inoculated with G. mosseae or exposed to As addition (50 ml 1000 μmol L−1 As 1 week before harvest). Mycorrhizal colonization substantially increased frond and root dry weight and P and As contents irrespective of As addition. Frond As contents in mycorrhizal plants were highest when the whole root system was exposed to As. Frond As concentrations and contents were higher when inoculation and As addition were in the same parts of the root system than when spatially separate. There were positive effects of arbuscular mycorrhiza inoculation on plant growth and As uptake, and inoculation of part of the roots seemed to be as effective as inoculation of the whole root system. 相似文献
7.
Akiko Sasaki Masaaki Fujiyoshi Sohsuke Shidara Takayuki Nakatsubo 《Ecological Research》2001,16(1):165-172
A field survey and a pot culture experiment were conducted to examine the effects of nutrients (N and P) and arbuscular mycorrhizal (AM) fungi on the growth of Salix gracilistyla, a pioneer plant in riparian habitats. The plants growing in the field were colonized by AM and/or ectomycorrhizal fungi. However, the direct effect of AM colonization on seedling growth was not detected in the pot culture experiment. In contrast, N application significantly promoted plant growth, suggesting that the growth of S. gracilistyla seedlings is largely limited by the availability of N in the field. 相似文献
8.
Effects of arbuscular mycorrhizal colonization and phosphorus application on nuclear ploidy in Allium porrum plants 总被引:1,自引:0,他引:1
Arbuscular mycorrhizal (AM) colonization can strongly affect the plant cell nucleus, causing displacement from the periphery to the center of the cell, hypertrophy and polyploidization. The hypertrophy response has been shown in a variety of AM plants whilst polyploidization has been reported only in Lycopersicon esculentum, a multiploid species with a small genome. In order to determine whether polyploidization is a general plant response to AM colonization, analyses were performed on Allium porrum, a plant with a large genome, which is much less subject to polyploidization than L. esculentum. The ploidy status of leaves, complete root systems and four zones of the adventitious roots was investigated in relation to phosphorus content, AM colonization and root differentiation in A. porrum plants grown under two different regimes of phosphate nutrition in order to distinguish direct effects of the fungus from those of improved nutrition. Results showed the presence of two nuclear populations (2C and 4C) in all treatments and samples. Linear regression analyses suggested a general negative correlation between phosphorus content and the proportion of 2C nuclei. The percentage of 2C nuclei (and consequently that of 4C nuclei), was also influenced by AM colonization, differentiation and ageing of the root cells, which resulted in earlier occurrence, in time and space, of polyploid nuclei. 相似文献
9.
Effect of arbuscular mycorrhiza on inter- and intraspecific competition of two grassland species 总被引:4,自引:0,他引:4
We were interested in the role of arbuscular mycorrhiza (AM) in the competition between plants of different sizes. A pot experiment of factorial design was established, in which AM root colonization and competition were used as treatments. Five-week-old Prunella vulgaris seedlings were chosen as target plants (i.e. plants whose response to competition was studied) and the following (13 replicates of each) were used as neighbours: (1) a large, 10-week-old P. vulgaris, (2) two P. vulgaris seedlings, and (3) a large, 10-week-old Fragaria vesca. In the experiment where small neighbours were grown together with small target plants, competition did not reduce target plant weight significantly, compared to the other two treatments. The competitive effects of large neighbours were significant, regardless of species (both older neighbours reduced the weights of target plants similarly), but there was a clear difference between intra- and interspecific competition when plants were mycorrhizal. In intraspecific competition with a large neighbour, the target plant shoot weight was reduced 24% when inoculated with AM. Thus, AM amplified rather than balanced intraspecific competition. In interspecific competition with old F. vesca, the shoot weights of target plants were 22% greater when inoculated with AM than when non-mycorrhizal. The results showed that, for given soil condition, AM might increase species diversity by increasing competitive intraspecific suppression and decreasing the interspecific suppression of small plants by larger neighbours. 相似文献
10.
Vierheilig H 《Journal of plant physiology》2004,161(3):339-341
An established arbuscular mycorrhizal symbiosis suppresses further mycorrhization. It is not clear whether the observed suppressional effect is linked with the level of root colonization or not. In the present work we studied the effect of the degree of root colonization by the arbuscular mycorrhizal fungus Glomus mosseae on further root colonization by G. mosseae. At different time points barley plants grown in split-root compartments were pre-inoculated on one half of the split-root system with G. mosseae. Sequential inoculation resulted in different colonization levels. Thereafter, the second half of the split root system was inoculated. The results indicate an enhanced suppression of root colonization on the second side of the split-root system when colonization levels increased on the first side. 相似文献
11.
Two challenges frequently encountered in the production of ornamental plants in organic horticulture are: (1) the rate of
mineralization of phosphorus (P) and nitrogen (N) from organic fertilizers can be too slow to meet the high nutrient demand
of young plants, and (2) the exclusive use of peat as a substrate for pot-based plant culture is discouraged in organic production
systems. In this situation, the use of beneficial soil microorganisms in combination with high quality compost substrates
can contribute to adequate plant growth and flower development. In this study, we examined possible alternatives to highly
soluble fertilizers and pure peat substrates using pelargonium (Pelargonium peltatum L’Her.) as a test plant. Plants were grown on a peat-based substrate with two rates of compost addition and with and without
arbuscular mycorrhizal (AM) fungi. Inoculation with three different commercial AM inocula resulted in colonization rates of
up to 36% of the total root length, whereas non-inoculated plants remained free of root colonization. Increasing the rate
of compost addition increased shoot dry weight and shoot nutrient concentrations, but the supply of compost did not always
completely meet plant nutrient demand. Mycorrhizal colonization increased the number of buds and flowers, as well as shoot
P and potassium (K) concentrations, but did not significantly affect shoot dry matter or shoot N concentration. We conclude
that addition of compost in combination with mycorrhizal inoculation can improve nutrient status and flower development of
plants grown on peat-based substrates. 相似文献
12.
Labidi S Calonne M Ben Jeddi F Debiane D Rezgui S Laruelle F Tisserant B Grandmougin-Ferjani A Sahraoui AL 《Phytochemistry》2011,72(18):2335-2341
The present work underlined the negative effects of increasing CaCO3 concentrations (5, 10 and 20 mM) both on the chicory root growth and the arbuscular mycorrhizal fungus (AMF) Glomus irregulare development in monoxenic system. CaCO3 was found to reduce drastically the main stages of G. irregulare life cycle (spore germination, germinative hyphae elongation, root colonization, extraradical hyphae development and sporulation) but not to inhibit it completely. The root colonization drop was confirmed by the decrease in the arbuscular mycorrhizal fungal marker C16:1ω5 amounts in the mycorrhizal chicory roots grown in the presence of CaCO3. Oxidative damage evaluated by lipid peroxidation increase measured by (i) malondialdehyde (MDA) production and (ii) the antioxidant enzyme peroxidase (POD) activities, was highlighted in chicory roots grown in the presence of CaCO3. However, MDA formation was significantly higher in non-mycorrhizal roots as compared to mycorrhizal ones. This study pointed out the ability of arbuscular mycorrhizal symbiosis to enhance plant tolerance to high levels of CaCO3 by preventing lipid peroxidation and so less cell membrane damage. 相似文献
13.
The invasive plant species Centaurea maculosa alters arbuscular mycorrhizal fungal communities in the field 总被引:2,自引:0,他引:2
While several recent studies have described changes in microbial communities associated with exotic plant invasion, how arbuscular mycorrhizal fungi (AMF) communities respond to exotic plant invasion is not well known, despite the salient role of this group in plant interactions. Here, we use molecular methods (terminal restriction fragment length polymorphism analyses based on the large subunit of the rRNA gene) to examine AMF community structure in sites dominated by the invasive mycorrhizal forb, Centaurea maculosa Lam. (spotted knapweed), and in adjacent native grassland sites. Our results indicate that significant AMF community alteration occurs following C. maculosa invasion. Moreover, a significant reduction in the number of restriction fragment sizes was found for samples collected in C. maculosa-dominated areas, suggesting reduced AMF diversity. Extraradical hyphal lengths exhibited a significant, on average 24%, reduction in C. maculosa-versus native grass-dominated sites. As both AMF community composition and abundance were altered by C.maculosa invasion, these data are strongly suggestive of potential impacts on AMF-mediated ecosystem processes. Given that the composition of AMF communities has the potential to differentially influence different plant species, our results may have important implications for site restoration after weed invasion. 相似文献
14.
Arbuscular mycorrhizal (AM) fungi naturally colonize grapevines in California vineyards. Weed control and cover cropping may affect AM fungi directly, through destruction of extraradical hyphae by soil disruption, or indirectly, through effects on populations of mycorrhizal weeds and cover crops. We examined the effects of weed control (cultivation, post-emergence herbicides, pre-emergence herbicides) and cover crops (Secale cereale cv. Merced rye, × Triticosecale cv.Trios 102) on AM fungi in a Central Coast vineyard. Seasonal changes in grapevine mycorrhizal colonization differed among weed control treatments, but did not correspond with seasonal changes in total weed frequency. Differences in grapevine colonization among weed control treatments may be due to differences in mycorrhizal status and/or AM fungal species composition among dominant weed species. Cover crops had no effect on grapevine mycorrhizal colonization, despite higher spring spore populations in cover cropped middles compared to bare middles. Cover crops were mycorrhizal and shared four AM fungal species (Glomus aggregatum, G. etunicatum, G. mosseae, G. scintillans) in common with grapevines. Lack of contact between grapevine roots and cover crop roots may have prevented grapevines from accessing higher spore populations in the middles. 相似文献
15.
A technique has been developed to efficiently extract purified, restrictable genomic DNA from spores of different arbuscular mycorrhizal fungi in order to begin detailed investigations of the genome of the Glomales. The protocol yielded variable amounts of DNA depending on the fungal species; for Scutellospora castanea and Gigaspora rosea it reached values of 1.5–2 ng/spore. EcoRI digests of DNA from S. castanea were cloned into pUC18 and about 1000 recombinant DNA clones were obtained. Of those screened, 50 contained inserts of 500–7000 bp. Selected inserts detected DNA sequences from S. castanea spores or roots infected by this fungus, but not from nonmycorrhizal roots. This is the first report of a partial genomic library from an arbuscular mycorrhizal fungus. 相似文献
16.
Renato Peretto Paola Bonfante Vittorio Bettini Francesco Favaron Paolo Alghisi 《Mycorrhiza》1995,5(3):157-163
Polygalacturonase activity and location were analysed in leek roots (Allium porrum L.) colonized by Glomus versiforme (Karst.) Berch, an arbuscular mycorrhizal (AM) fungus. Polygalacturonase activity in mycorrhizal roots did not differ quantitatively from that found in nonmycorrhizal roots on all of the four harvesting dates. Fractionation of mycorrhizal root extracts by ion-exchange chromatography showed that expression of polygalacturonase was specific to the mutualistic association. Immunofluorescence and immunogold experiments were carried out to locate the polygalacturonase in mycorrhizal roots using a polyclonal antibody raised against a Fusarium moniliforme endopolygalacturonase. Immunolabelling was observed all over the arbuscules (intracellular fungal structures) but particularly at the interface between the arbuscule and the plant membrane. Since pectins are located in this area, we suggest that polygalacturonase produced during the symbiosis could play a role in plant pectin degradation. 相似文献
17.
Influence of two legume species on hyphal production and activity of two arbuscular mycorrhizal fungi 总被引:5,自引:0,他引:5
Two arbuscular mycorrhizal (AM) fungi (Glomus
mosseae and G. intraradices) were compared for abundance of intraradical and soil-borne hyphae in association with Astragalus sinicum, a small-seeded, and Glycine
max, a large-seeded legume. A. sinicum was more responsive than G. max to mycorrhizal formation, especially at early growth stages. Biomass allocation was greater in roots than shoots for mycorrhizal
A. sinicum, while the opposite was true for G. max. Hyphal development in root and soil compartments was estimated by trypan blue staining and after staining for succinate
dehydrogenase (SDH) or alkaline phosphatase (ALP) activity. Total fungal abundance increased steadily in roots and soil with
time to a maximum 8 weeks after planting. SDH- and ALP-active AM hyphae increased in roots during plant growth but decreased
in soil at later harvests. Mycorrhizal root mass in A. sinicum and G. max increased about 14-fold and 2.5-fold, respectively, but total length of soil hyphae produced per plant differed little, so
that the pattern of AM soil to root abundance of the two fungi varied considerably with the host plant.
Accepted: 23 July 1997 相似文献
18.
In arbuscular mycorrhizal symbioses, solutes such as phosphate are transferred to the plant in return for photoassimilates.
The uptake mechanism is probably facilitated by a proton gradient generated by proton H+-ATPases. We investigated expression of Lycopersicon esculentum Mill. H+-ATPases in mycorrhizal and non-mycorrhizal plants to determine if any are specifically regulated in response to colonization.
Tissue expression and cellular localization of H+-ATPases were determined by RNA gel blot analysis and in situ hybridization of mycorrhizal and non-mycorrhizal roots. LHA1, LHA2, and LHA4 had high levels of expression in roots and were expressed predominantly in epidermal cells. LHA1 and LHA4 were also expressed in cortical cells containing arbuscules. The presence of arbuscules in root sections was correlated with
lower levels of expression of these two isoforms in the epidermis. These results suggest that LHA1 and LHA4 expression is decreased in epidermal cells located in regions of the root that contain arbuscules. This provides evidence
of differential regulation between molecular mechanisms involved in proton-coupled nutrient transfer either from the soil
or fungus to the plant. 相似文献
19.
Influence of temperature on colonization of spring barleys by vesicular arbuscular mycorrhizal fungi
William E. Gpey 《Plant and Soil》1991,137(2):181-190
The effects of three soil temperatures on growth of spring barleys (Hordeum vulgare L.) and on their root colonization by vesicular arbuscular mycorrhizal (VAM) fungi from agricultural soils in Montana (USA) or Syria at different inoculum concentrations were tested in soil incubators in the greenhouse. The number of mycorrhizal plants as well as the proportion and intensity of roots colonized increased with higher soil temperatures. VAM fungi from Montana, primarily Glomus macrocarpum, were cold tolerant at 11°C while those from Syria, primarily G. hoi, were heat tolerant at 26°C. Inoculum potential of Montana VAM fungi was higher than Syrian VAM fungi in cool soils. Harmal, selected from Syrian barley land races, had the highest colonization by mycorrhizal fungi of the cultivars tested.Journal Series Paper: J-2532 Montana Agricultural Experiment Station. 相似文献
20.
Differences in the effects of three arbuscular mycorrhizal fungal strains on P and Pb accumulation by maize plants 总被引:2,自引:0,他引:2
The effect of arbuscular mycorrhizal (AM) fungi on the accumulation and transport of lead was studied in a pot experiment
on maize plants grown in anthropogenically-polluted substrate. The plants remained uninoculated or were inoculated with different
Glomus intraradices isolates, either indigenous to the polluted substrate used or reference from non-polluted soil. A considerably lower tolerance
to the conditions of polluted substrate was observed for the reference isolate that showed significantly lower frequency of
root colonisation as well as arbuscule and vesicule abundance. Plants inoculated with the reference isolate also had significantly
lower shoot P concentrations than plants inoculated with the isolate from polluted substrate. Nevertheless, inoculation with
either indigenous or reference G. intraradices isolate resulted in higher shoot and root biomass and inoculated plants showed lower Pb concentrations in their shoots than
uninoculated plants, regardless of differences in root colonisation. Root biomass of maize plants was divided according to
AM-induced colouration into brightly yellow segments intensively colonised by AM fungus and non-colonised or only slightly
colonised whitish ones. Intensively colonised segments of the isolate from polluted substrate contained significantly higher
concentrations of phosphorus and lead than non-colonised ones, which suggest significant participation of fungal structures
in element accumulation.
Responsible Editor: Peter Christie. 相似文献