Studies on the distribution of alkalophilic and alkali-tolerant soil fungi I

Soil fungi were isolated from two different soil types using alkaline and slightly acidic media (alkaline cornmeal agar (AC-MA), pH 9.7; cornmeal agar (CMA), pH 6.0) to study their distribution. Different species were obtained on each isolation medium. The number of species ofAcremonium andFusarium increased on ACMA, though many species growing well in acidic conditions were not detected on ACMA. Most of the fungi isolated on ACMA, especially from the alkaline soils, were alkalophiles or alkali-tolerants that can grow at pH 10.Acremonium alternatum, A. furcatum, Acremonium sp. 6,Gliocladium cibotii (YBLF 575),Phialophora geniculata, Stachylidium bicolor andStilbella annulata were alkalophilic, of whichAcremonium sp. 6 was the most pronounced alkalophile. Ability to grow under alkaline conditions, as well as under acidic conditions, was common in manyAcremonium species. The use of alkaline medium facilitates the isolation of alkalophilic soil fungi.     

生物炭对岩溶区石灰土性质及作物生长的影响

以玉米(迪卡008)和大豆(开鲜9号)为供试材料,通过野外盆栽实验,设置5个处理,每个处理蔗渣生物炭材料分别以土壤质量百分比0(CK)、0.5%(T1)、1%(T2)、2%(T3)、5%(T4)添加,研究蔗渣生物炭对岩溶区石灰土性质及农作物生长的影响。结果表明:生物炭对石灰土p H和碱解氮均无显著影响,土壤容重显著降低,提高了土壤有机碳、全氮、速效磷和速效钾的含量;与对照相比,玉米组和大豆组T2、T3、T4处理的土壤有机碳含量分别显著增加了53.01%、96.77%、237.03%和32.66%、107.84%、256.46%,速效磷分别显著增加了32.26%、34.78%、85.37%和34.85%、35.60%、81.71%,速效钾分别显著增加了41.93%、82.49%、155.15%和69.77%、116.58%、206.91%;T3、T4处理土壤全氮分别显著增加了5.68%、25.57%和9.04%、19.77%,T3、T4处理玉米棒干重分别显著增加了11.51%、16.41%;T1、T2、T3、T4处理大豆豆荚干重分别显著增加了11.07%、11.24%、35.14%、24.89%。可见,蔗渣生物炭作为土壤改良剂,在一定程度上改善了石灰土的养分状况,促进了玉米和大豆生长。     

Ecology of nematophagous fungi: Effect of the soil nutrients N,P and K,and seven major metals on distribution

The effects of the major soil nutrients and seven common metals on the distribution of nematophagous fungi were evaluated by comparing the concentration of the elements in soils with and without nematophagous fungi. Mineral nutrients, which were all positively correlated with nematode density, were the most important elements determining the presence of such fungi. Endoparasites producing adhesive conidia were independent of all the elements tested, while those species forming ingested conidia were isolated from soils high in nutrients, indicating a strong dependence on nematode density. Knob forming predators which rely on their ability to spontaneously produce traps to obtain nutrients were isolated from soils with low concentrations of mineral nutrients, while species with constricting rings were isolated from richer soils containing a greater density of nematodes. Net-forming species were largely independent of soil fertility, although generally they were isolated from soils with limited nutrientsd, especially K. Like other fungi, nematophagous fungi are generally not found in soils containing elevated concentrations of heavy metals. The results indicate that even concentrations of heavy metals which naturally occur in Irish soils can restrict the distribution of this fungal group. However the endoparasiteMeria coniospora is tolerant to all metals and to Cu in particular.     

荒漠沙柳根围AM真菌的空间分布

为探明荒漠植物沙柳(Salix psammophila)根围AM真菌空间分布和土壤因子生态作用,2009年5月在内蒙古黑城子、正蓝旗、元上都3个样地分别从0—10、10—20、20—30、30—40、40—50cm 5个土层采集沙柳根围土壤样品,系统研究了AM真菌空间分布及与土壤因子的相关性。结果表明,沙柳根围AM真菌平均孢子密度为108个?100g-1 土,平均定殖率61.7%;沙柳与AM真菌可形成良好的I型丛枝菌根。不同样地和采样深度对AM真菌孢子密度和定殖率有显著影响,最大孢子密度和最高定殖率均出现在0—10cm土层,并随土层深度增加而下降。黑城子样地孢子密度显著高于其它样地。沙柳根围土壤总球囊霉素(TEG)和易提取球囊霉素(EEG)含量在3个样地均随土层加深而降低,平均值分别为0.24mg?g-1和 0.16mg?g-1,占土壤有机C 23.6%—24.6% 和14.9%—17.3%。相关分析表明,土壤速效P、碱解N与孢子密度显著负相关;土壤有机C与菌丝定殖率显著正相关,与泡囊定殖率显著负相关;土壤磷酸酶与孢子密度和侵染强度极显著正相关;土壤脲酶与孢子密度和定殖率极显著正相关;土壤总球囊霉素和易提取球囊霉素与土壤有机C极显著正相关。主成分分析表明,土壤有机C、磷酸酶和碱解N是影响荒漠土壤AM真菌分布和活动的主要因子。上述结果对进一步探明宿主植物、菌根和土壤三者之间的内在联系,充分利用AM真菌资源,促进荒漠植被恢复和生态重建具有重要意义。     

中国盐碱土壤中AM菌的生态分布

对我国盐碱土壤中丛枝菌根（Ａｒｂｕｓｃｕｌａｒ Ｍｙｃｏｒｒｈｉｚａ,ＡＭ） 菌的种属构成、生态分布状况进行了研究．结果表明,不同地区ＡＭ 菌种属构成不同,其种属组成、分布与土壤类型、碱化度和土壤有机质含量有关．盐渍化砂土、壤土和粘土中,Ｇｌｏｍｕｓ 属的真菌数量最多,Ａｃａｕｌｏｓｐｏｒａ 属次之,而Ｇｌｏｍｕｓ 属中的Ｇ．ｍｏｓｓｅａｅ 则是分布最为广泛的菌种．随土壤碱化度的增加,Ｇｌｏｍｕｓ ｍｏｓｓｅａｅ 出现频率随之相对增加．在一定范围内有机质含量越高,土壤中ＡＭ 菌种和属的种类就越多．ＡＭ 菌的种属组成因不同寄主植物而异,其中豆科植物根围中ＡＭ 菌分布的种属数量最多．     

Materials for the rust flora of Japan VI

Ten rust species are reported with new information on range of distribution and host relations. Among these,Puccinia fagopyricola andUromyces junci were new to Japan, andAecidium araliae was newly found in northern Honshu. Additional collections were made ofBlastospora smilacis, Puccinia malvacearum andP. orbicula in northern Honshu. New hosts were added toColeosporium solidaginis, C. tussilaginis, Phragmidium miyakeanum andPuccinia caricis, and a new Japanese host toPuccinia malvacearum.V: Trans. Mycol. Soc. Japan29: 471–478, 1988.     

Materials for the fungus flora of Japan (55)

From recent isolates of microfungi on soil materials collected at several localities in Japan, three onygenalean species are described and photographed as new to Japan:Aphanoascus durus, Kuehniella racovitzae, andShanorella spirotricha. (54) Yokoyama, T. and Nasu, H., Mycoscience41: 91–93, 2000.     

桂西北喀斯特地区石灰土养分空间变异特征

从区域尺度出发,将整个桂西北喀斯特地区作为研究区域,以大面积野外调查采样和室内分析数据为基础,采用经典统计学和地统计学方法,探索喀斯特区域内石灰土养分的空间异质性和分布格局。结果表明:桂西北喀斯特地区石灰土pH为弱变异,其他养分变异系数为30%—75%,变异程度中等。石灰土各养分的空间变异特征不同,土壤有机质(SOM)、速效磷(AP)和速效钾(AK)的最佳拟合模型依次为球状模型、高斯模型和线性模型,pH、碱解氮(AN)、全氮(TN)、全磷(TP)和全钾(TK)的最佳拟合模型均为指数模型。SOM、AP、TN和TP表现为中等空间相关性,空间差异是由随机因素和结构性因素共同作用引起的;pH、AN、AK和TK呈弱空间相关性,空间变异主要受随机因素的控制;SOM和TN的空间变异尺度较大,pH、AN和TK的空间变异尺度最小。SOM、TN、TP和AP养分含量呈自西向东逐渐减少的趋势,pH、AN、AK和TK在区域尺度上的分布没有呈现一定的规律性。相关分析结果表明,在区域大尺度下,地形因子(如海拔、坡度和岩石裸露率等)和植被类型是影响桂西北喀斯特石灰土空间变异特征的重要因素。     

Influence of resource unit distribution and quality on the activity of soil fungi in a particulate medium

Experiments were set up to assess the relative impacts of grass lamina fragment density, size and quality on the activity and growth of four fungi in a particulate soil-like matrix. The fungi studied were Cladosporium cladosporioides , Fusarium lateritium , Phoma exigua and Trichoderma viride , all of which are common inhabitants of UK upland grassland soils. Resource quality was varied by using three contrasting grasses as sources of lamina fragments: Lolium perenne , Agrostis capillaris and Nardus stricta . All the fungi were able to forage effectively through the soil-like matrix (at a rate of 1–2 ml matrix d⁻¹) and colonize and partially decompose available lamina fragments (up to 40% d. wt loss). Foraging rates (ml matrix d⁻¹) were affected by lamina fragment species but not by fragment density or size. In general, F. lateritium and T. viride foraged at a faster rate than the other species. Mycelial activity in the soil-like matrix was directly proportional to total lamina fragment availability and was unaffected by fragment size. Biomass production on solid media was also directly related to substrate (carbohydrate) availability. The results indicate that these fungi can adjust their growth patterns in response to fragment density so as to maximize foraging efficiency (energy acquired per unit exploratory biomass production). Differences in lamina fragment species were responsible for up to 50% reduction in mycelial activity.     

铁皮石斛内生真菌分布

本研究从铁皮石斛(Dendrobium officinale)根、茎和叶中分离得到内生真菌67株,经形态学和分子生物学鉴定分别归属于16个属,Fusarium和Alternaria为铁皮石斛内生真菌的优势种群。研究发现,铁皮石斛根、茎、叶中内生真菌分布存在较大差别,具有一定的组织差异性,不同石斛植物中内生真菌的存在情况差别较大,具有一定的宿主差异性。本研究丰富了真菌资源,为石斛属药用植物内生真菌资源的开发利用提供了基础理论依据。     

皖北石灰岩山地植被对地表节肢动物组成及多样性的影响

调查皖北石灰岩山地退化生态系统不同植被恢复类型地表节肢动物群落组成、类群多样性以及功能群组成,揭示退化生态系统植被恢复进程中土壤地表节肢动物群多样性变化规律及其影响因素,为石灰岩山地植被恢复成效评价提供科学依据。采用陷阱法对皖北石灰岩山地侧柏+构树混交林、酸枣+牡荆灌丛和荩草+牡荆草灌丛样地地表节肢动物群落组成、多样性以及功能群进行调查。共采节肢动物个体数11601,隶属8纲14目44科。酸枣+牡荆灌丛样地采集到节肢动物37科,占所有类群的84.1%,荩草+牡荆草灌丛和侧柏+构树混交林采集到土壤节肢动物类群为35和26科,分别占总科数的79.6%和59.1%。在目的分类单元下,直翅目、等足目和鞘翅目类群相对多度较高,而科的分类单元下,潮虫科、金龟甲科、蚁科和蟋蟀科为皖北石灰岩山地优势地表节肢动物类群。酸枣+牡荆灌丛节肢动物类群丰富度和荩草+牡荆草灌丛多样性指数最高,侧柏+构树混交林两者均最低。3个样地地表节肢动物营养功能群均以植食性为主。不同植被恢复类型间群落相似性也有变化,酸枣+牡荆灌丛和荩草+牡荆草灌丛间相似性较高,而侧柏+构树混交林与其他2种类型之间相似度均较低。研究结果表明石灰岩山地生境不同植被群落组成、数量和结构及其驱动形成的土壤理化特性、表层的凋落物数量、质量和微生境条件的变异,引起地表节肢动物群落组成、结构和多样性和营养功能群的不同。     

澜沧江两条支流捕食线虫真菌水陆分布差异及关联性

为探究微生物在流域中的水、陆分布差异和相互关系,对澜沧江两条支流捕食线虫真菌多样性水陆分布进行了调查研究。在枯水期,以澜沧江一级支流沘江和黑惠江为研究区域,系统布设12个采样点(水流交汇点),每个采样点采集水、陆对称样品各5份,共采集土样120份。结合传统分离纯化、形态学及分子生物学方法筛选和鉴定菌株,按照《Nematode-Trapping Fungi》进行分类,共获得2属13种88株捕食线虫真菌;其中,陆地样品中共分离到2属11种45株,水体底泥中分离出1属10种43株,检出率分别为41.67%和53.33%。结果表明,澜沧江两条支流捕食线虫真菌在物种、属、群落结构3个层面上均存在水陆差异,也相互联系;陆地土壤可能是流域内捕食线虫真菌多样性的源,水流是其重要的传播因子。在流域生态系统内,水陆间的扩散限制和水流的连通性都是维持微生物物种多样性的重要机制。     

Inoculation with arbuscular mycorrhizal fungi: the status quo in Japan and the future prospects

Inoculation of arbuscular mycorrhizal (AM) fungi has potential benefits in not only sustainable crop production but also environmental conservation. However, the difficulty of inoculum production due to the obligate biotrophic nature of AM fungi has been the biggest obstacle to putting inoculation into practice. Nevertheless, several companies have sought to produce inoculum of AM fungi. Firstly in this review, the present status of inoculum production and its use in Japan is described. Secondly, although the effectiveness of inoculation is primarily limited by environmental and biological factors, some possible ways to improve inoculation performance are discussed. Approaches include use of chemicals to increase spore germination and colonization and soil application of charcoal to provide a microhabitat for AM fungi to colonize and survive.     

Factors affecting the distribution of lignicolous marine fungi in Hong Kong

An investigation into the effect of environmental factors on the general distribution and occurrence of lignicolous marine fungi using submerged blocks of pine (Pinus massoniana Lamb.) and teak (Tectona grandis L.) was carried out for 18 months in the coastal waters of Hong Kong. Five test sites, with environmental conditions varying from estuarine to oceanic, and from polluted to non-polluted, were selected. During each collection, salinity, temperature, pH, dissolved oxygen, biochemical oxygen demand, nitrate-nitrogen, inorganic phosphate-phosphorus and light transmission were measured. A total of 51 species of fungi were recorded among which only 28 were either obligate or facultative marine forms. Neither the general distribution pattern nor the distribution of the more frequent fungi could be solely accounted for by differences in salinity at the test sites and it is suggested that other ecological factors such as heavy sediments in the waters, low pH, and the presence of an abundant source of inocula may be important.     

大兴安岭林区多孔菌的区系组成与种群结构

本文在过去10 a野外调查和室内鉴定及分析研究的基础上,对大兴安岭林区多孔菌的区系组成和种群结构进行了分析,发现大兴安岭林区的多孔菌具有较高的多样性,共有5目11科56属129种,占中国多孔菌区系的21.36%,优势科是多孔菌科。种的区系地理成分分为7类,以北温带成分和世界广布成分为主,具有明显的北温带成分的区系特征。大兴安岭的多孔菌常见种较多,种群结构中共生菌3种,寄生菌27种,腐生菌占大多数,有99种。在能够引起木材腐朽的126种真菌中,白腐菌93种,占多数,褐腐菌33种,占少数,但该地区褐腐菌所占比例明显高于全国范围内褐腐菌在多孔菌中的比例。通过对大兴安岭主要树种上的种群结构进行比较,表明阔叶树上的木材腐朽菌绝大部分是白色腐朽菌,而针叶树上的白腐菌与褐腐菌数量相差不大,褐腐菌对于针叶林特别是落叶松的更新具有非常重要的作用。     

盐渍化土壤根际微生物群落及土壤因子对AM真菌的影响

为探明盐渍化土壤影响下AM真菌与根际土壤间的关系,试验选取宁夏碱化龟裂土、草甸盐土、盐化灌淤土3种类型4个样地上典型植被群落,测定了植物根际土壤养分含量、微生物群落结构、AM真菌侵染率以及孢子密度。结果显示:盐渍化土壤根际微生物碳源利用类型显著不同,对芳香类化合物的代谢能力整体较弱;红寺堡草甸盐土上微生物优势群落为氨基酸代谢类群,惠农盐化灌淤土为多聚化合物代谢群,西大滩碱化龟裂土为碳水化合物代谢群。AM真菌孢子密度与微生物碳源代谢群间的关系比较复杂。其中,惠农样点根际土壤孢子密度与多聚化合物微生物代谢群呈显著正相关,西大滩地区孢子密度与碳水化合物微生物代谢群呈显著正相关。土壤有机质、全盐、全氮、碱解氮等土壤肥力因子及土壤中的HCO-3、Na+、Cl-等盐基离子含量能解释AM真菌孢子密度与土壤环境因子之间相互关系的大部分信息。较高的HCO-3浓度促进了AM真菌侵染率的提高,但高盐浓度下Na+和Cl-降低了菌根侵染率。土壤对AM真菌孢子密度、侵染率的影响因土壤盐分组成类型的不同而异。研究结果为深入了解AM真菌多样性,促进宁夏盐碱地的合理开发与利用提供了理论依据。     

Ecology of nematophagous fungi: vertical distribution in a deciduous woodland

Summary The distribution of nematophagous fungi in soil collected from a deciduous woodland is compared to various biotic and abiotic soil factors. The microfungi are isolated at all depths down to a maximum of 35 cm. Predators forming constricting rings, adhesive branches and adhesive knobs are restricted to the upper litter and humus layers. The net forming predators and endoparasites are isolated at all depths, although they are significantly more abundant in the lower mineral rich soils. A much greater species diversity of nematophagous fungi is recorded in the upper organic zones.Preliminary soil analysis indicates thatCephalosporium balanoides is independent of all soil variables, while predators able to form traps spontaneously are restricted to the organic soils which are rich in nematodes. Non-spontaneous trap forming predators, which are excellent saprophytes, are isolated from the deeper soils which are low in nutrients. The ecological significance of these results is discussed.     

Isolation of fungi from soil using the keratin-baiting technique

Of 236 soil samples baited with wool, some 71.2% (168) produced fungal growth. Gliocladium (25.0%), Paecilomyces (14.8%), Trichophyton (11.9%) species were the most prevalent in soil moistened with sterile distilled water (SDW) containing antibiotics. On the other hand, in soil moistened with SDW only, Trichophyton (32.6%), Paecilomyces (27.5%), Diheterospora (16.5%), Gliocladium (13.6%) and Fusarium (13.1%) species were more common. Of the known potential pathogens, the Paecilomyces and Fusarium species were frequently isolated from soil collected in parks, cleared areas, paddocks, rivers and roadsides. All five sites are areas of human and animal activity. The keratinolytic species were Microsporum cookei, M. gypseum complex, Trichophyton ajelloi and T. terrestre, which are regarded as nonpathogens with the exception of M. cookei and M. gypseum complex.     

Specificity and localised distribution of mycorrhizal fungi in the soil may contribute to co-existence of orchid species

Co-occurring orchid species tend to occupy different areas and associate with different mycorrhizal fungi, suggesting that orchid mycorrhizal (OrM) fungi may be unevenly distributed within the soil and, therefore, impact the aboveground spatial distribution of orchids. To test this hypothesis, we investigated spatial variations in the community of potential OrM associates within the roots of three co-habitating orchid species (Anacamptis morio, Gymnadenia conopsea, and Orchis mascula) and the surrounding soil in an orchid-rich calcareous grassland in Southern Belgium using 454 amplicon pyrosequencing. Putative OrM fungi were broadly distributed in the soil, although variations in community composition were strongly related to the proximal host plant. The diversity and frequency of sequences corresponding to OrM fungi in the soil declined with increasing distance from orchid plants, suggesting that the clustered distribution of orchid species may to some extent be explained by the localised distribution of species-specific mycorrhizal associates.     

Interaction of soil microbes with mycorrhizal fungi in tomato

In this study, the interaction of soil microbes with mycorrhizal fungi (MF) was performed to understand the effect on tomato. A pot and a field experiment were employed to investigate the impact of soil microbes i.e. Fusarium oxysporum f. sp. lycopersici, Trichoderma harzianum, Aspergillus niger and Rhizobium leguminosarum, on AM fungi in pots and field studies. The soils without microbes which treated controls with or without mycorrhizal inoculation were also included. Plant growth and root colonisation were measured 36, 75 and 120?days post inoculation (dpi) in the both pot experiment and field study. Soil microbes’ effects on the growth behaviour of the tomato plant were determined via the shoot and root weight. R. leguminosarum and A. niger did not affect the colonisation ability much, but F. oxysporum f. sp. lycopersici and T. harzianum resulted in the inhibition of AM fungal colonisation in both pot and field studies. Our study provides evidence for the effects of soil microbes on the diversity of AM fungi and their effect on the tomato plants. The higher concentrations of phosphorus and of proteins in the root tissues, previously colonised with AM fungi, point out their effect as biofertilizers, according to the concept of sustainable agriculture.