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E. S. Dias E. F. Araújo W. V. Guimarães R. M. C. Muchovej 《World journal of microbiology & biotechnology》1996,12(6):625-628
Experiments were performed with the mycorrhizal fungus Suillus granulatus to define the parameters for production and regeneration of protoplasts. Protoplasts were released at frequencies between 1 and 3×107/ml from mycelium 3 to 7 days old. The best osmotic stabilizer for protoplast release was MgSO4 (0.7 m). To optimize protoplast release and regeneration an enzyme (Novozym 234) concentration 1.7 mg/ml was chosen, with a digestion time of 1 to 2 h. Regenerated colonies formed mycorrhizae within 60 days after inoculation in Pinus caribaea var. hondurensis seedlings. 相似文献
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Suillus grevillei , and found that one, SG-5, is species-specific to S. grevillei and polymorphic. Using the SG-5 marker, we analyzed for the first time the horizontal and vertical distribution of the subterranean
parts of several S. grevillei genets. The spatial distribution of S. grevillei genets in the soil demonstrated that the development of S. grevillei sporocarps is correlated with that of extra-radical mycelia and ectomycorrhizae of the same genet, which are distributed
in a narrow area. However, sporocarps are not always centered over the subterranean parts and the amount of subterranean mycelia
and mycorrhizae is not always correlated to the number of sporocarps formed on them. No S. grevillei mycelia and mycorrhizae were detected beneath the positions where S. grevillei sporocarps emerged in the previous year. The observation indicates the rapid alteration of the subterranean parts of S. grevillei genets, and suggests that S. grevillei genets change location rather than merely extend their habitat year after year.
Received 13 October 2000/ Accepted in revised form 15 March 2001 相似文献
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Summary Mycorrhization of Picea abies has been achieved, for the first time, with six strains of Suillus grevillei by a new culture method, using activated charcoal paper and liquid medium as a substrate. Mycorrhization of P. abies and Larix decidua was compared, and the process was found to be significantly different in the two tree species. S. grevillei is not incompatible with P. abies, but it forms mycorrhizae more readily with L. decidua. Hyphal growth was clearly stimulated on the surface of roots of Larix but retarded on Picea. A well organized Hartig net was formed with both tree species, but wall protuberances were frequently observed on the outer cell walls of Picea cortex cells when the Hartig net was not fully developed. No conspicuous cell wall reactions occurred in Larix roots. Cell wall protuberances may be comparable to those in transfer cells and are interpreted as an alternative to Hartig net development. Anatomical differences between roots of Larix and Picea, and physiologically active substances such as recognition factors on the root surfaces, are discussed with respect to their responsibility for the different reactions of S. grevillei. 相似文献
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Tillmann Bauer Sabine Blechschmidt-Schneider Walter Eschrich 《Trees - Structure and Function》1991,5(1):36-43
Summary Seedlings of Pinus sylvestris L. were grown on defined nutrient solutions on carbon filters, either sterile or infected with the basidiomycete Suillus variegatus O. Kuntze. After mycorrhizas were established, the shoot of the seedling was subjected to 14CO2 photosynthesis. 14C-labelled photoassimilates were translocated to both mycorrhizas and non-infected root tips. Microautoradiographs of mycorrhizas indicated that omission of external sugars did not affect the formation of mycorrhizas; 14C-photoassimilates were supplied to cortex, Hartig net and the mantle of hyphae surrounding the rootlet. Nutrient solution containing sugars (malt extract, glucose) enhanced the growth of the fungus. As a consequence, 14C-photoassimilates from the seedling were accumulated in the mantle, but defence mechanisms of the host cannot be excluded. When soluble nitrogen was omitted from the nutrient solution and replaced by chitin precipitated on the filter-bearing mycorrhizas, the fungus appeared strongly labelled in the mantle, where the fungal chitinase provided soluble nitrogen compounds, necessary for the growth of the seedling. 相似文献
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Since ericoid mycorrhizae become dominant in heathland plant communities on acid soils, we assessed the effect of pH on the hydroxamate siderophore production by a typical ericoid mycorrhizal fungus under pure culture conditions. In addition, we determined whether the supplementation of the nutrient medium with L-ornithine or L-proline as precursors for hydroxamate siderophores would enhance their biosynthesis. The results indicate that the hydroxamate siderophore production by Hymenoscyphus ericae has its optimum at pH 4.5 (between 3.5 and 5.5). L-ornithine rather than L-proline appears to favour the biosynthesis of hydroxamate siderophores. 相似文献
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Suillus grevillei in two Larix kaempferi stands was determined over two years by inter-simple sequence repeat (ISSR) polymorphism analysis using primers, (GTG)5, (GCC)5 and (GACA)4. Thirty-five genets were identified from 67 sporocarps at the older stand (stand A in which the distribution of S. grevillei genet in 1997 was analyzed previously) in 1998, and 14 genets from 52 sporocarps at the younger stand (stand B) in 1997 and 1998. The characteristics of S. grevillei genets in stand A in 1998 were similar to those in 1997. A single genet was represented by 1.8 and 3.7 sporocarps on average in stands A and B, respectively. In stand A, 42 out of 61 genets, i.e., about 70% were represented by individual sporocarps compared to five out of 14 genets, i.e., about 35% in stand B. The largest and the average genet sizes was 6.8 m and less than 1 m in stand A, and 11 m and 2.3 m in stand B, respectively. A t-test showed the genet size in stand A to be significantly smaller than that in stand B. The above results indicate that the smaller genets of the S. grevillei population in stand A might be due to environmental conditions not genetic traits specific to this species. Observations over two years showed that although some genets formed sporocarps in both 1997 and 1998, many formed sporocarps only in one of the two years. Emerging positions of sporocarps in 1997 and 1998, which belonged to the same genet, were similar but not identical, about 2 m apart, suggesting mobility in the subterranean parts of ECM fungal genets. Received 10 April 2000/ Accepted in revised form 31 August 2000 相似文献
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Genetic structure of a natural population of the ectomycorrhizal fungus Suillus pungens 总被引:3,自引:5,他引:3
Sequence-based markers were developed to study the genetic structure and reproductive biology of the ectomycorrhizal fungus Suillus pungens Thiers & Smith in a Bishop pine ( Pinus muricata D. Don) forest. Six different basidiome genotypes were found in a 1200 m2 area. Five of the six genotypes were represented by single basidiomes. The remaining genotype comprised 13 basidiomes and covered an area of at least 300 m2 , with maximum measured dimensions of 40 m and 14 m. This is the largest genet of an ectomycorrhizal fungus described to date, and is likely the result of vegetative growth, because analysis of single spore isolates eliminates the possibility of genetic identity resulting from either apomixis or fortuitously indistinguishable recombinant genotypes. Genetic analysis also shows that although out-crossing appears to predominate in the population, at least a low percentage (1·4%) of spores are secondarily homothallic.
The combination of extensive vegetative growth and abundant fruiting suggests S. pungens utilizes more carbon than might be expected for a species which accounts for <3% of the total ectomycorrhizal abundance at the site. Additional carbon might come from either more efficient host–fungus transfer, pooling of carbon from the roots of different host plants, or saprophytism. 相似文献
The combination of extensive vegetative growth and abundant fruiting suggests S. pungens utilizes more carbon than might be expected for a species which accounts for <3% of the total ectomycorrhizal abundance at the site. Additional carbon might come from either more efficient host–fungus transfer, pooling of carbon from the roots of different host plants, or saprophytism. 相似文献
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Thomas G. M. Gerlitz 《Plant and Soil》1996,178(1):133-140
Aluminium toxicity may be an important factor in the decline in vitality of many forest trees and the associated ectomycorrhizal fungal flora. In this study, comparative in vivo 31P NMR investigations on Al-adapted and non-Aladapted fungus of Suillus bovinus in pure culture have produced interesting new data. With respect to intracellular compartments, 31P NMR spectroscopy showed the spectra to differ in a peak-6 ppm appearing in the spectra of the A1-adapted fungus indicating terminal phosphate groups of mobile polyphosphate. Thus, in the Al-adapted fungus the average chain length of mobile polyphosphate is considerably shorter than in the non-Al-adapted fungus. A special method of cyclic phosphate supply followed by block averaging of the NMR spectra was used to determine the kinetic behaviour of phosphate uptake, storage and incorporation into polyphosphate at a constant external pH 3.5. While the Al-adapted fungus showed resistance to Al, an irreversible break-down in phosphate metabolism of the non-Al-adapted fungus by exposure to Al was caused. In comparison with the non-Al-adapted fungus supplied by nutrient solutions omitting Al, the Al-adapted fungus showed higher levels in both phosphate uptake and mobile polyphosphate concentration. As a consequence of these results a de-toxification of freely mobile Al-ions into a stable and insoluble complex in the Al-adapted fungus is considered to be due to a capture of intracellular Al by mobile polyphosphate of shorter chain length. 相似文献
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The purpose of this study was to explore further the relation between the rates of oxygen consumption and ammonium (NH4+) production in the kidney during chronic metabolic acidosis. The experimental model was the dog with chronic metabolic acidosis because of the extensive background literature in this species. Chronic metabolic acidosis was produced by the ingestion of 10 mmol NH4Cl/kg body weight for 5 days. There was a significant increase in the rate of oxygen extraction when hypernatremia was present. Despite this rise in the rate of oxygen consumption, there was no increase in the rate of NH4+ production nor in the rate of glutamine extraction. These data suggest that hypernatremia might prevent a further augmentation in glutamine extraction when the rate of oxygen consumption rises. In addition, a larger proportion of the NH4+ produced was excreted in the urine during hypernatremia. This increase was associated with a rise in the urine flow rate, but not with a fall in urine pH. 相似文献
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Comparative in vivo
31P-NMR studies of the fungus Suillus bovinus (L.: Fr.) O. Kuntze in pure culture have produced interesting new data. To investigate the response of phosphate metabolism to a change in external monovalent cations, samples were exposed to a Hoagland solution containing different monovalent cations Li+, Na+, K+, or Rb+ at 10 mM concentration. A method of nutrient cycling during analysis where the cation was changed and the phosphate kept constant allowed us to determine the kinetics of phosphate accumulation, storage and incorporation into polyphosphate following exposure to the range of test cations. Different external monovalent cations had different effects upon changes in the content of both phosphate and polyphosphate. Treatment with Li+, Na+, or Rb+ resulted in a change in phosphate accumulation to 60, 73, and 107% and in content of the intracellular mobile polyphosphate (polyP) to 119, 112, and 94%, respectively, compared with the control taken as 100%. The effect of each cation is related to its position in the periodic table. Reversing this process, i.e., exchanging with K+, returned phosphate metabolism to normal. Although, the increase in depolarization of the cell membrane should affect the internal pH, fungal metabolism using energy requiring mechanisms appeared necessary to maintain the intracellular pH. Thus, increasing contents of mobile polyP were the consequence of an increasing energy demand. On the other hand, the increasing depolarization of the cell membrane following the sequence Rb+ < K+ < Na+ < Li+ inhibited the net Pi accumulation. Furthermore, it is postulated that the Pi accumulation was also regulated by the intracellular content in polyP. 相似文献
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In this work, we report the occurrence of chemotropism in the arbuscular mycorrhizal (AM) fungus Glomus mosseae. Fungal hyphae were able to respond to host-derived signals by reorienting their growth towards roots and to perceive chemotropic signals at a distance of at least 910 microm from roots. In order to reach the source of chemotropic signals, hyphal tips crossed interposed membranes emerging within 1 mm from roots, eventually establishing mycorrhizal symbiosis. The specificity of chemotropic growth was evidenced by hyphal growth reorientation and membrane penetration occurring only in experimental systems set up with host plants. Since pre-symbiotic growth is a critical stage in the life cycle of obligate AM fungal symbionts, chemotropic guidance may represent an important mechanism functional to host root location, appressorium formation and symbiosis establishment. 相似文献