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1.
Diversity of mycorrhizal fungi of terrestrial orchids: compatibility webs, brief encounters, lasting relationships and alien invasions 总被引:1,自引:1,他引:0
Yumiko Bonnardeaux Mark Brundrett Andrew Batty Kingsley Dixon John Koch K. Sivasithamparam 《Mycological Research》2007,111(1):51-61
The diversity of mycorrhizal fungi associated with an introduced weed-like South African orchid (Disa bracteata) and a disturbance-intolerant, widespread, native West Australian orchid (Pyrorchis nigricans) were compared by molecular identification of the fungi isolated from single pelotons. Molecular identification revealed both orchids were associated with fungi from diverse groups in the Rhizoctonia complex with worldwide distribution. Symbiotic germination assays confirmed the majority of fungi isolated from pelotons were mycorrhizal and a factorial experiment uncovered complex webs of compatibility between six terrestrial orchids and 12 fungi from Australia and South Africa. Two weed-like (disturbance-tolerant rapidly spreading) orchids — D. bracteata and the indigenous Australian Microtis media, had the broadest webs of mycorrhizal fungi. In contrast, other native orchids had relatively small webs of fungi (Diuris magnifica and Thelymitra crinita), or germinated exclusively with their own fungus (Caladenia falcata and Pterostylis sanguinea). Orchids, such as D. bracteata and M. media, which form relationships with diverse webs of fungi, had apparent specificity that decreased with time, as some fungi had brief encounters with orchids that supported protocorm formation but not subsequent seedling growth. The interactions between orchid mycorrhizal fungi and their hosts are discussed. 相似文献
2.
《Journal of Plant Interactions》2013,8(1):305-314
Diversity and heat-adaptation of endophytic fungi (EF) and rhizospheric fungi associated with plants growing in geothermal ecosystems, Southwest China, as well as their benefit in improving host plant thermotolerances were investigated. A total of 1589 culturable fungi belonging to 38 taxa were isolated, in which Curvularia, Acrophialophora, Penicillium, and Aspergillus were the dominant genera. The Shannon indices of EF and rhizospheric fungi ranged from 1.80 to 2.56 and 0.73 to 2.11, respectively. Phylogenetic analysis indicated that the EF have a close relationship with rhizospheric fungi. However, some fungi exhibited apparently species-specific habitat distribution patterns. Growth temperature tests indicated that 60.22% of the tested isolates were thermotolerant fungi and only 39.78% were mesophiles, and the number of heat-adapted fungi increased with increasing environmental temperatures. The strain G1-29, which was isolated from the roots of Hedyotis diffusa and identified as Curvularia crepinii, significantly improved host plant thermotolerance under laboratory conditions: the death rate of endophyte-infected plants was significantly lower than that of endophyte-free plants (t-test, p?=?.0158, df?=?4). Our results suggested that the EF and rhizospheric fungi associated with plants growing in geothermal ecosystems are diverse, and many of them have adapted to the high environmental temperatures. Some fungi have come to be the dominant endemic inhabitants of specific niches, and some played an important role in improving host plant thermotolerances. 相似文献
3.
Aims: The present study was conducted to evaluate the possibility of using cyanobacterial bloom materials as a medium for white rot fungi and the capability of white rot fungi, Trichaptum abietinum 1302BG and Lopharia spadicea to biodegrade dried cyanobacterial bloom material taken from Taihu Lake. Methods and Results: The results showed T. abietinum 1302BG and L. spadicea could use the cyanobacterial bloom materials taken from Taihu Lake for growth to measure the mycelial plaque and dry‐weight mycelial pellicles of fungi. The removal rate of dried cyanobacterial bloom materials incubated with white rot fungi is approximately 100%. Conclusions: The cyanobacterial bloom material can be used as a glucose substitute in white rot fungi medium. The white rot fungi, T. abietinum 1302BG and L. spadicea, can also directly decrease the biomass of cyanobacterial bloom material taken from Taihu Lake. Significance and Impact of the Study: Cyanobacterial bloom thrives in eutrophic fresh waters all over the world. Micro‐organisms, particularly fungi, have attracted attention as possible agents for the degradation of phytoplankton species. Dealing with cyanobacterial bloom material as a medium for fungi instead of directly discharging them as organic fertilizers is a new, safe and environmentally friendly approach. 相似文献
4.
Niranjan Kumar R. K. Singh K. P. Singh 《Archives Of Phytopathology And Plant Protection》2013,46(12):1182-1195
Seventeen species of nematophagous fungi were recorded, three species were endoparasitic and fourteen species were predacious fungi. Among the predacious fungi Arthrobotrys oligospora, Dactylaria brochopaga and Monacrosporium eudermatum were very frequent, whereas others were recorded at lower frequency. Twelve species of nematophagous fungi from compost as well as cow dung manure, 15 species from leaf litter and only eight species from agricultural soils were recorded. In general, substrate colonization by nematophagous fungi was higher in leaf litter, compost and cow dung manure. The agricultural soil amended with FYM (farm yard manure) recorded nine species of nematophagous fungi while unamended soil recorded only seven species. Thirteen species of nematophagous fungi were recorded from soils under banyan tree. Of all these fungi unidentified net-forming fungus, M. eudermatum, A. cladodes, D. brochopaga, S. hadra, A. oligospora and A. dactyloides had higher percentage of soil colonization. In soil collected under pipal tree only eight species were recorded, of which A. oligospora, A. cladode and an unidentified fungus were more predominant as their percentage colonized in soil samples was higher. Few studies have examined root galls as a substratum for colonization of nematophagous fungi. Of all the root gall samples, okra root galls recorded maximum colonization by predacious fungi. Maximum percentage of root gall colonization was recorded for M. eudermatum followed by A. oligospora and M. ellipsosporum. M. eudermatum was also most predominant colonizer of balsam, brinjal and rice root galls. 相似文献
5.
为充分开发黄花倒水莲(Polygala fallax)的内生真菌资源,获得具有抗植物病原真菌、抗氧化活性的内生真菌,该文以黄花倒水莲内生真菌为研究对象,使用平板对峙法检测内生真菌对6种植物病原真菌的抑菌活性,测定内生真菌发酵液的DPPH清除自由基能力和总还原能力,评价内生真菌的抗氧化活性,并对具有强抑菌活性和抗氧化活性的菌株进行形态和ITS鉴定。结果表明:(1)黄花倒水莲内生真菌中有2株内生真菌对香蕉专化尖孢镰刀菌、柑橘树脂病菌、叶点霉菌、香蕉具条叶斑病菌、茄病镰刀菌、三七根腐病菌具有明显的抑菌活性,抑菌率在50.3%~91.4%之间,其中HNLF-5对柑橘树脂病菌的抑菌率为73.2%,HNLF-44对香蕉专化尖孢镰刀菌抑菌率为91.4%。(2)内生真菌发酵液具有良好的抗氧化活性,DPPH清除率均在80%以上,总还原能力吸光值范围为0.279 2~0.748 8。(3)HNLF-44菌株为链格孢属真菌。该研究表明,药用植物黄花倒水莲内生真菌具有较好的生物活性,为后续从黄花倒水莲内生真菌中挖掘潜在新型抑菌活性和抗氧化活性物质奠定了基础。 相似文献
6.
为研究云南马铃薯(Solanum tuberosum)内生真菌的多样性,该文以采自云南省德宏芒市、大理喜洲和临沧双江3个地区的马铃薯植株为研究对象,采用组织块分离法、尖端菌丝挑取法对马铃薯根、茎及块茎中的内生真菌进行分离纯化,并采用形态学鉴定方法和ITS序列分析法对分离得到的内生真菌进行鉴定,对内生真菌的定殖率、分离率及多样性指数进行计算和分析。结果表明:(1)共分离得到内生真菌98株,其中从德宏芒市的样品中获得40株,从大理喜洲的样品中获得27株,从临沧双江的样品中获得31株。(2)经鉴定,分离得到的马铃薯内生真菌共涵盖10目10科13属,大多为子囊菌门和担子菌门,优势菌为镰刀菌属(Fusarium)和青霉属(Penicillium),褶皱裸孢壳(Emericella rugulosa)、接骨木镰刀菌(Fusarium sambucinum)、毛韧革菌(Stereum hirsutum)、Psathyrella sulcatotuberculosa和Epicoccum catenisporum 5种真菌均为首次从马铃薯植株中分离得到。(3)马铃薯块茎内生真菌的定殖率最高,根部内生真菌定殖率最低; 内生真菌的分离率以马铃薯根部为最高,而茎部最低; 不同组织中内生真菌的多样性指数趋势均为根>块茎>茎。从综合来看,云南马铃薯植株中的内生真菌具有较高的多样性,不同地区的马铃薯样品中内生真菌优势菌不同,马铃薯根部具有最丰富的内生真菌种群和最高的分离率,是最适合进行内生真菌分离的材料。该研究结果为后期探究马铃薯内生真菌对病原菌的拮抗作用奠定了基础,也为马铃薯内生真菌多样性研究提供了参考数据。 相似文献
7.
Endophytic fungi are rich in orchids and have great impacts on their host plants. 53 endophytes (30 isolates from Dendrobium devonianum and 23 endophytic fungi from D. thyrsiflorum) were isolated, respectively, from roots and stems of Dendrobium species. All the fungi were identified by way of morphological and/or molecular biological methods. 30 endophytic fungi in
D. devonianum were categorized into 11 taxa and 23 fungal endophytes in D. thyrsiflorum were grouped into 11 genera, respectively. Fusarium was the dominant species of the two Dendrobium species in common. Antimicrobial activity of ethanol extract of fermentation broth of these fungi was explored using agar
diffusion test. 10 endophytic fungi in D. devonianum and 11 in D. thyrsiflorum exhibited antimicrobial activity against at least one pathogenic bacterium or fungus among 6 pathogenic microbes (Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus). Out of the fungal endophytes isolated from D. devonianum and D. thyrsiflorum, Phoma displayed strong inhibitory activity (inhibition zones in diameter >20 mm) against pathogens. Epicoccum nigrum from D. thyrsiflorum exhibited antibacterial activity even stronger than ampicillin sodium. Fusarium isolated from the two Dendrobium species was effective against the pathogenic bacterial as well as fungal pathogens. The study reinforced the assumption that
endophytic fungi isolated from different Dendrobium species could be of potential antibacterial or antifungal resource. 相似文献
8.
Zakaria A.M. Baka 《Archives Of Phytopathology And Plant Protection》2013,46(8):736-743
Six medicinal plants such as Amaranthus spinosus, Barbeya oleoides, Clutia lanceolata, Lavandula pubescens, Maerua oblongifolia and Withania somnifera collected from different locations in the southwestern part of Saudi Arabia were tested for antifungal activities against five plant pathogenic fungi causing serious diseases of vegetable crops. These fungi were Alternaria brassicae, Alternaria solani, Botrytis fabae, Fusarium solani and Phytophthora infestans. Aqueous plant extracts reduced mycelial growth and inhibited spore germination of all fungi tested. It is clear that the aqueous extract of Lavandula pubescens leaves was the best for controlling all phytopathogenic fungi under study. These results suggested that medicinal plant extracts play an important role in controlling the phytopathogenic fungi. 相似文献
9.
对我国古老特有植物青檀叶片进行内生和附生真菌的研究,以了解青檀叶片内生和附生真菌的组成特点和探讨内生和附生真菌菌群之间的可能联系,为研究真菌资源多样性、植物附生和内生真菌的相互演化关系及真菌与宿主植物协同进化等提供有益参考资料。研究结果表明,从健康的青檀叶片获得可培养内生真菌839株,附生真菌1857株,共计2696株,鉴定其分属于4目,5科,43属。在目的分类水平上,内生和附生真菌均以丛梗孢目Moniliales为优势菌群,分别占90.23%和92.51%;在科的水平上,内生真菌以暗梗孢科Dematiaceae和丛梗孢科Moniliaceae为优势菌群,分别占47.56%和42.67%,附生真菌以丛梗孢科Moniliaceae和暗梗孢科Dematiaceae为优势菌群,分别占67.04%和25.47%;在属的水平上,内生真菌以黑团孢属Periconia和青霉属Penicillium为优势菌群,分别占31.47%和10.73%,附生真菌以小球霉属Glomerularia、膝葡孢属Gonatobotrys和青霉属Penicillium为优势菌群,分别占20.03%、13.95%和12.22%。青檀叶片内生真菌和附生真菌均存在的菌群数量达到23个属,占53.49%。内生真菌特有的属有6个,共分离19株,占0.70%,附生真菌特有的属有14个,共分离120株,占4.45%。内生真菌的Shannon-Wiener index(H')多样性指数(2.44)和Margalef index(R)丰富度指数(2.88)分别小于附生真菌ShannonWiener index(H')多样性指数(2.57)和Margalef index(R)丰富度指数(3.32),但两者的Evenness index(E)均匀度指数几乎相等。青檀叶片内生和附生真菌菌群组成具有较高的相似性,相似性系数达0.70。通过Fisher's exact test分析表明青檀叶片内生和附生真菌菌群组成无明显差异(P=0.072)。 相似文献
10.
The aim of this study is to assess the mycorrhizal status of Eucalyptus plantations in south China and to determine the need for inoculation. In four provinces in south China, 155 plantations were
sampled for sporocarps of ectomycorrhizal (ECM) fungi, spores of arbuscular mycorrhizal (AM) fungi, and mycorrhizas over 2 years.
This study revealed a low above-ground diversity of ECM fungi consisting of 15 taxa fruiting beneath Eucalyptus plantations. The most common ECM genera were Scleroderma and Pisolithus, but they were infrequent. A total of 21 AM fungi, mostly Glomus species, were recognized from spores collected from eucalypt plantations. Four Glomus species were frequently present in soils, but spore density and relative abundance of AM fungi were generally low. Eucalypt
roots from all plantation sites were poorly colonized by either ECM fungi or AM fungi. A bioassay with E. urophylla as a bait host, using soils collected from 11 eucalypt plantations, confirmed low levels of inoculum of both ECM and AM fungi
in field soil. This is the first integrated study on the mycorrhizal status of eucalypt plantations in China. Findings from
this research can be used to encourage adoption of mycorrhizal technology by eucalypt nurseries in the region. The potential
of using spores of compatible ECM fungi or collections for forest nurseries is discussed. 相似文献
11.
Mycorrhizal fungi were isolated from the nonphotosynthetic orchid Chamaegastrodia sikokiana and identified as members of Ceratobasidiaceae by phylogenetic analysis of the internal transcribed spacer (ITS) region of
ribosomal deoxyribonucleic acid. The ITS sequences were similar among geographically separated samples obtained from Mt. Kiyosumi
in Chiba Prefecture and Mt. Yokokura in Kochi Prefecture. One of the isolated fungi, KI1-2, formed ectomycorrhiza on seedlings
of Abies firma in pot culture, suggesting that tripartite symbiosis exists among C. sikokiana, mycorrhizal fungi, and A. firma in nature, and carbon compounds are supplied from A. firma to C. sikokiana through the hyphae of the mycorrhizal fungi. To our knowledge, this is the second study to suggest the involvement of Ceratobasidiaceae
fungi in tripartite symbiosis with achlorophyllous orchids and photosynthetic host plants. 相似文献
12.
红树林叶片感染真菌后可能会向非健康状态变化,为了比较三种红树林植物海漆、秋茄和桐花树健康与非健康叶片真菌类群,明确其中真菌类群的差异,该研究从广西茅尾海红树林自然保护区采集海漆、秋茄和桐花树健康与非健康叶片,对叶片中真菌分离纯化并进行形态学鉴定,提取真菌的DNA,采用RAPD多样性、ITS序列对真菌进行分子鉴定。经过初步分析,从海漆、秋茄和桐花树中共分离到157株真菌,经过形态学和RAPD分析,可能为19种不同的真菌。采用真菌ITS序列对19种真菌代表性菌株进行分析,结果表明:19种真菌都属于子囊菌门,有15株与已有的真菌ITS序列相似性在97%以上;有4株相似性低于95%,可能为新种。海漆健康和非健康叶片分别分离到真菌7种和5种,健康叶片含了非健康叶片中所有真菌;秋茄健康和非健康叶片分离到真菌1种和9种,且健康叶片中分离到的内生真菌Dothiorella aegiceri也包含于非健康叶片分离的真菌中;桐花树健康和非健康叶片分离到真菌1种和3种,且桐花树分离的内生真菌也是Dothiorella aegiceri,其包含于非健康叶片中分离到的真菌。该研究证明,海漆内生真菌同时也可能是植物病原菌,内生真菌与植物病原菌没有明显界限;另一方面,该研究发现秋茄和桐花树叶片的病变是由外部的病原真菌感染引起,感染的原因可能是昆虫叮咬红树林植物后留下了创口,这些创口有利于真菌的感染。 相似文献
13.
14.
Guadalupe Medina-de la Rosa Moisés Graciano Carcaño-Montiel Jesús Francisco López-Olguín Miguel Ángel Hernández-Espinosa José Antonio Rivera-Tapia 《Archives Of Phytopathology And Plant Protection》2016,49(11-12):310-321
The chitinase enzyme was identified in isolated bacteria of maize rhizosphere as well as its potential for the biological control of fungi associated at seeds of the same plant. The production of chitinase enzyme was found in the genera identified as Acinetobacter, Bacterium, Burkholderia, Paenibacillus, Pseudomonas, Rhizobium, Shewanella, Sphingomonas and Stenotrophomonas. Bacterial isolates with ability to degrade fungal mycelium from maize fungi as Fusarium and Alternaria among others, were detected. Bacterial chitinase activity and the presence of the chiA gene were determined. The inoculation of chitinolytic bacteria showed a positive effect in the control of fungi in maize seeds. The results support the potential use of chitinase enzyme producing bacteria on the control of phytopathogenic fungi. 相似文献
15.
Lyssa L. Martin Cynthia M. Ross Friedman Lori A. Phillips 《American journal of botany》2012,99(12):2027-2034
• Premise of the study: Endophytic fungi likely occur in all plants, yet little is known about those of parasitic plants, despite their potential to influence parasite success. Arceuthobium americanum is a parasitic angiosperm that greatly compromises the North American timber industry. We hypothesized that (1) A. americanum hosts fungal endophytes, and (2) these endophytes help A. americanum resist infection by fungal pathogens. • Methods: Healthy A. americanum stem and fruit tissues were differentially stained for cellulose and chitin and visualized using fluorescence microscopy. Stem sections (sterilized vs. unsterilized) and seeds were incubated on agar plates to cultivate fungi, both to extract DNA for ITS rDNA sequencing and to observe interactions with native fungi from unsterilized specimens. • Key results: Aside from xylem vessel elements, fungal structures were observed in all tissues, including those of the embryo. The ITS sequences of fungi cultured from internal tissues closely matched those of the known endophytes Phoma, Sydowia, and Phacidiopycnis, while those of surface organisms closely matched Cladosporium spp. Cultured fungi from internal tissues (putative endophytes) inhibited the growth of the surface organisms without affecting the other endophytes. • Conclusion: Fungal communities are established in A. americanum stems as well as in fruits and seeds, suggesting vertical transmission. These internally derived fungi act antagonistically toward fungi with pathogenic tendencies. As such, native mistletoe endophytes might protect A. americanum against fungal pathogens in nature. In the future, manipulation of endophytes might be a component of mistletoe control programs. 相似文献
16.
Xiao‐Yu Yang Jun‐Xian Zhang Qiu‐Yan Ding Zi‐Cong He Chun‐Yan Zhu Ke‐Qin Zhang Xue‐Mei Niu 《化学与生物多样性》2020,17(5)
Thermomyces lanuginosus and Scytalidium thermophilum are among the most ubiquitous thermophilic fungi in compost and soil. Chemical study on these two prevalent strains collected from Yunnan led to isolation of 23 metabolites, including one new metabolite, therlanubutanolide, and 15 known compounds, isolated from the YGP culture broth of Thermomyces lanuginosus and 7 known compounds isolated from Scytalidium thermophilum, respectively. Therlanubutanolide shared the quite similar features of the same carbon skeleton and saturation as natural hexadecanoic acids. This was the first reported discovery of such a lactone as natural occurring metabolite. All the compounds were reported for the first time from thermophilic fungi. Among them, N‐[(2S,3R,4E,8E)‐1,3‐dihydroxy‐9‐methyloctadeca‐4,8‐dien‐2‐yl]acetamide was for the first time reported to be a naturally occurring metabolite and its NMR data was first provided in this study. A type of PKS‐derived metabolites, three 3,4‐dihydronaphthalen‐1(2H)‐ones, which were widely found in plant pathogenic fungi as phytotoxins and reported to have antimicrobial activity, were obtained from both dominant thermophilic fungi. The frequent occurrence of such PKS phytotoxins in these two thermophilic fungi might suggest particular ecological interest. 相似文献
17.
Plants harbor diverse communities of fungi and other microorganisms. Fungi are known to occur both on plant surfaces (epiphytes)
and inside plant tissues (endophytes), but the two communities have rarely been compared. We compared epiphytic and endophytic
fungal communities associated with leaves of coffee (Coffea arabica) in Puerto Rico. We asked whether the dominant fungi are the same in both communities, whether endophyte and epiphyte communities
are equally diverse, and whether epiphytes and endophytes exhibit similar patterns of spatial heterogeneity among sites. Leaves
of naturalized coffee plants were collected from six sites in Puerto Rico. Epiphytic and endophytic fungi were isolated by
placing leaf pieces on potato dextrose agar without and with surface sterilization, respectively. A total of 821 colonies
were isolated and grouped into 131 morphospecies. The taxonomic affinities of the four most common nonsporulating fungi were
determined by sequencing the nuclear ribosomal internal transcribed spacer (ITS) region: two grouped with Xylaria and one each with Botryosphaeria and Guignardia. Of the most common genera, Pestalotia and Botryosphaeria were significantly more common as epiphytes; Colletotrichum, Xylaria, and Guignardia were significantly more common as endophytes. Suprisingly, more morphospecies occurred as endophytes than as epiphytes. Differences
among sites in number of fungi per plant were significant. Thus epiphytic and endophytic communities differed greatly on a
single leaf, despite living only millimeters apart, and both communities differed from site to site. Significant correlations
between occurrence of fungal morphospecies suggested that fungi may have positive or negative effects on their neighbors.
This is the first quantitative comparison of epiphytic and endophytic fungal floras in any plant, and the first to examine
endophytic fungi or epiphytic fungi in leaves of coffee, one of the world’s most valuable crops. 相似文献
18.
California exports tree nuts to countries where they face stringent standards for aflatoxin contamination. Trade concerns
have stimulated efforts to eliminate aflatoxins and Aspergillus flavus from almonds, pistachios and walnuts. Incidence of fungi on tree nuts and associations among fungi on tree nuts were studied.
Eleven hundred pistachios, almonds, walnuts and brazil nuts without visible insect damage were plated on salt agar and observed
for growth of fungi. Samples came both from California nut orchards and from supermarkets. To distinguish internal fungal
colonization of nuts from superficial colonization, half the nuts were surface-sterilized before plating. The most common
genera found were Aspergillus , Rhizopus and Penicillium . Each species of nut had a distinct mycoflora. Populations of most fungi were reduced by surface sterilization in all except
brazil nuts, suggesting that they were present as superficial inoculum on (rather than in) the nuts. In general, strongly
positive associations were observed among species of Aspergillus ; nuts infected by one species were likely to be colonized by other species as well. Presence of Penicillium was negatively associated with A. niger and Rhizopus in some cases. Results suggest that harvest or postharvest handling has a major influence on nut mycoflora, and that nuts
with fungi are usually colonized by several fungi rather than by single species.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
19.
Five early-phase ammonia fungi (EP fungi) – Amblyosporium botrytis, Ascobolus denudatus, Peziza moravecii, Pseudombrophila petrakii, Coprinopsis phlyctidospora, and Tephrocybe tesquorum, and one late-phase ammonia fungus (LP fungus), Hebeloma vinosophyllum – were co-cultured on malt extract-yeast extract agar media at pH 5.5, 7.0, 8.0, and 9.0. The co-cultures among the early-stage
EP fungi Amblyosporium botrytis, Ascobolus denudatus, Peziza moravecii, and Pseudombrophila petrakii, generally did not inhibit or accelerate the reproductive structure formation of the opposed fungi. Among the EP fungi, Am. botrytis, As. denudatus, and Pe. moravecii intermingled with each other. The late-stage EP fungus T. tesquorum inhibited the growth of other EP fungi. Another late-stage EP fungus, C. phlyctidospora, showed ability to invade other EP fungi, but it did not deeply invade into the territories of early-stage EP fungi. The
LP fungus H. vinosophyllum tended to accelerate basidioma formation of C. phlyctidospora at pH 5.5 and 9.0. H. vinosophyllum formed the highest numbers of basidomata at pH 5.5. These results show that successive occurrence of ammonia fungi is caused
by the interspecific interactions among ammonia fungi as well as by the physiological characteristic of each fungus associated
with conditions of its inhabiting soils, such as pH and nitrogen concentration. 相似文献
20.
Soil samples from an agricultural field contaminated with 10 ppm14C-benz(a)anthracene in glass tubes were brought into contact with cultures of wood-rotting fungi, precultivated on wheat straw substrate.
Forty-five strains of white-rot fungi and four brown-rot fungi were tested for their ability to colonize the soil and to mineralize14C-benz(a)anthracene to14CO2 within a 20-week incubation time. Twenty-two white-rot fungi and all brown-rot fungi were unable to colonize the soil. Twenty-three
strains of white-rot fungi, all belonging to the genusPleurotus, colonized the soil. During the experiment the noncolonizing fungi and their substrate disintegrated more and more to a nonstructured
pulp from which water diffused into the soil. The same phenomenon was observed in the control which contained only straw without
fungus and contaminated soil. In samples with colonizing fungi the substrate as well as the mycelia in the soil remained visibly
unchanged during the entire experiment. Surprisingly, most samples with fungi not colonizing the soil and the control without
fungus liberated between 40 and 58 % of the applied radioactivity as14CO2 whereas the samples with the colonizing fungi respired only 15–25 % as14CO2. This was 3–5 times more14CO2 than that liberated from the control (4.9 %) which contained only contaminated soil without straw and fungus. A similar result
was obtained with selected colonizing and noncolonizing fungi and soil contaminated with 10 ppm14C-pyrene. However, in pure culture studies in which14C-pyrene was added to the straw substrate,Pleurotus sp. (P2), as a representative of the colonizing fungi, mineralized 40.3 % of the added radioactivity to14CO2. The noncolonizing fungiDichomitus squalens andFlammulina velutipes liberated only 17.2 or 1.7 %, respectively, as14CO2. These results lead to the hypothesis that the native soil microflora stimulated by the formed products of straw lysis is
responsible for high degradation rates found with noncolonizing fungi. 相似文献