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1.
为探讨马尾松不同类型林地地上部微生物区系及优势种群及其季节性变化,对三峡库区云阳县马尾松近熟龄天然林、中龄天然林和人工林林地空气、叶面和树皮表面等地上部的可培养细菌和真菌进行了分析。结果表明,空气、叶面和树皮表面的真菌、细菌两大类微生物数量四季变化趋势基本一致,夏季和秋季的数量多于冬季和春季,中龄天然林的两大类微生物数量最大且四季变化亦最大;优势种群的种类和数量随季节和林地类型不同而有所变化。人工林空气中可培养真菌种类秋、冬、春、夏分别有4、3、4、3种,近熟龄天然林和中龄天然林四季中均为3种;优势种群多  相似文献   

2.
为探讨马尾松不同类型林地土壤微生物区系及其季节变化,对三峡库区云阳县马尾松近熟龄天然林、中龄天然林和人工林林地土壤可培养细菌、芽孢杆菌(Bacillus spp.)和真菌进行了分析。结果表明,林地土壤微生物优势种群种类和数量因不同森林类型林地和季节有所差异。中龄天然林的细菌数量显著高于近熟龄天然林和人工林,其四季变化也最大,而近熟龄天然林和人工林则相对平缓。林地土壤细菌优势种群主要是芽孢杆菌(Bacillus spp.)和假单胞菌(Pseudomonas spp.),尤以蜡状芽孢杆菌(Bacillus cereus)居多,在四季中冬季细菌的优势种群数量所占比例最高(近熟龄天然林＞人工林＞中龄天然林),优势种群近熟龄天然林为芽孢杆菌,占39.74%;人工林为假单胞菌,占37.26%;中龄天然林为蜡状芽孢杆菌,占24.91%。三种林地类型土壤的芽孢杆菌在不同季节都以蜡状芽孢杆菌(占20% - 49%)和芽孢杆菌科(Bacillaceae)一种(种名未定)为优势种群。三种林地类型土壤真菌优势种群在秋季所占比例最高,且人工林＞近熟龄天然林＞中龄天然林;优势种群数量及所占比例人工林为核盘菌(Sclerotinia sclerotiorum),33.08%,近熟龄天然林为核盘菌, 31.7%,中龄天然林为瓦克青霉(Penicillium waksmanii), 25.15%。  相似文献   

3.
A total of 3611 fungal isolates were recovered from 4200 leaf segments incubated from 7 medicinal herbs during monsoon, winter and summer seasons. These fungal isolates belonged to teleomorphic Asco-mycota （23.5%）, anamorphic Ascomycota producing conidiomata （17.4%）, anamorphic Ascomycota without conidiomata （46.9%）, Zygo-mycota （1.42%） and sterile forms （10.6%）. Chaetomium globosum, As-pergillus niger, Aureobasidium pullulans, Curvularia lunata, Fusarium spp., Penicillium spp., Pestalotiopsis spp., Trichoderma viridae, Cladosporium cladosporioides, were frequently isolated from more than one host plant. The number of endophytic isolates was higher in winter than in monsoon and summer seasons.  相似文献   

4.
Elevational changes in patterns of diversity are important to understanding of the influence of global changes, yet few studies have addressed the distribution of microorganisms, e.g. soil micro-fungi. We studied the diversity of the forest soil micro-fungi in four vegetation belts along an elevation gradient on the north slope of Changbai Mountain in Changbai National Nature Reserve.The four belts were characterized as coniferous–deciduous mixed forest, coniferous forest, Erman's birch forest, and alpine tundra. We estimated the quantity and distribution of the fungal species in each belt and calculated three indices,viz. Shannon–Wiener diversity(H'), Pielou's evenness(J'),and Margalef's abundance(E), to depict fungal species diversity. A total of 932 strains were recorded and identified, representing 53 genera, and 108 species. Among these, Penicillium, Aspergillus, Trichoderma, Mucor, Rhizopus and Fusarium were the dominant genera. With increasing elevation, the quantity of fungi and values of H',E, and J' gradually declined.  相似文献   

5.
A total of 4,009 endophytic fungal isolates were recovered from healthy leaves, bark and xylem of Citrus sinensis in different seasons and age‐classes. Corresponding to those factors, the majorities of fungal isolates were recovered from leaves, 2‐yr‐old trees and winter, respectively. Fungal isolates were initially categorized based on cultural and morphological characters, and representatives of each morphotype were subjected to molecular identifications based on ITS‐rDNA and β‐tubulin sequences. All isolates obtained in this study belonged to the phyla Ascomycota and Basidiomycota assigned to 30 fungal taxa. The most abundant fungal species were Alternaria spp. Species diversity indices of Margalef richness and Shannon–Wiener revealed a high diversity of fungal taxa recovered from leaf and during winter. Frequency (%) of fungal endophytes was highest in winter followed by summer, autumn, and spring significantly, whereas the corresponding sequence was winter, autumn, summer and spring for the diversity of endophytic fungi. Overall, the results of this study based on the community and diversity of endophytic fungal species in C. sinensis showed that the type of plant tissue, season of sampling and age of tree play a driving role on their abundance while their diversity was mainly dependent on the type of plant tissue, season of sampling than on the age of tree.  相似文献   

6.
对广西现代林业科技园优良树种展示区的灰木莲8年生(G1)和灰木莲45年生(G2)的0～20cm土层一年四季的微生物数量及土壤酶活性进行分析。结果表明:灰木莲幼林(G1)与成熟林(G2)的林地土壤微生物和土壤酶有明显的差异。微生物总量和细菌数量的季节变化,G1均为夏>冬>秋>春,而G2是秋>冬>夏>春。真菌数量上无论是G1或G2均是秋季最多而冬季最少。放线菌数量的季节变化是,G1:春季>冬季>秋季>夏季,G2:冬季>春季>秋季>夏季。对两种林地不同季节的微生物而言,春秋冬季的细菌>放线菌>真菌,夏季则是细菌>真菌>放线菌。土壤蛋白酶活性表现为:G1,春>夏>秋>冬;G2,秋>春>夏>冬,而G1和G2的过氧化氢酶活性均是冬>夏>秋>春。  相似文献   

7.
紫金山两种主要林型有机物层中丝状真菌多样性   总被引：5，自引：0，他引：5  
本文对紫金山两种主要林型,栓皮栎林(Quercus variabilis)和马尾松-枫香(Pinus massoniana-Liguidam barformasana)混交林的有机物层(L, F, H层及土壤淋溶A层)可培养丝状真菌多样性进行了研究。通过分离鉴定,共得到真菌67种,其中接合菌3种、子囊菌5种、半知菌类56种和未确定种3种,半知菌类最为丰富。两种林型分解真菌优势种群为链格孢(Alternaria sp.)、曲霉(Aspergillus spp.)、枝孢(Cladosporium sp.)、毛霉(Mucor sp.)、青霉(Penicillium sp.)、木霉(Trichoderma spp.)、根霉(Rhizopus sp.)、粘帚霉(Gliocladium sp.)。混交林型中真菌的种类和数量明显高于栓皮栎林。两个林型均以F层真菌种类最多,但F层之间和L层之间真菌多样性差异较大。在混交林型中从马尾松针叶上分离的真菌种类和数量比从枫香上分离得到的少; 从马尾松针叶上分离的真菌丰富度随着有机物层深度增加而增加,枫香则反之。比较两个林型以及混交林的两种落叶上真菌种类发现,随着有机物层深度的增加,真菌的种类差异性却随之减少,即同时出现在两个林型或两种针叶上的真菌种类增多。真菌种类随着分解过程的进行具有明显的演替现象。混交林型中同一层内不同落叶上分解真菌多样性的差异,表明凋落物基质的差异是决定真菌种类和数量的重要因素  相似文献   

8.
This work quantified the total carbon and 12 other sediment characteristics at 10 soil depths, in planted and or natural mangrove forests in comparison with non-vegetated soil for four seasons of the year 2009-2010 in the Vellar-Coleroon estuarine complex, India. The sedi- ment characteristics varied significantly between mangrove-vegetated and non-vegetated habitats or seasons of analysis, but not between soil depths. The mangrove sediments were rich in total carbon and total or- ganic carbon as compared to non-mangrove sediments （p 〈0.01）. Total carbon was 98.2% higher in mature mangroves and 41.8% in planted mangroves than that in non-mangrove soil. Total organic carbon was as much as 2.5 times greater in mature mangroves and 2 times greater in planted mangroves than that in unvegetated soil. Carbon contents also varied many fold by season. Total carbon content was 8.6 times greater during pre-monsoon, 4.1 times greater during post-monsoon and 2.5 times greater during monsoon than during summer （P〈0.01 in all cases）. Similarly, total organic carbon was 5.9 times greater during pre-monsoon, 3.1 times greater during post-monsoon and 69% greater during monsoon than during summer. In general, higher levels of sediment carbon were recorded during pre and post-monsoon seasons than during other seasons. Total carbon concentration was correlated negatively to temperature, sand and phosphorus （P 〈0.01）; positively correlated with redox potential, silt, clay, C/N ratio, potassium （P 〈0.01） and nitrogen （P〈0.05）; but not correlated with soil depth, pH or salinity. This work revealed that the carbon burial was rapid at the annual rate of 2.8% for total carbon, and 6.7% for total organic carbon in mangrove-planted sediment. Cleating of mangroves can result in significantly and rapidly reduced carbon stores.Our study highlights the importance of natural and plantation mangrove stands for conserving sediment carbon in the tropical coastal domain.  相似文献   

9.
We used a litterbag method to investigate litter decomposition and related soil degradative enzyme activities across four seasons in a broad-leaved forest and a coniferous forest on Zijin Mountain in s...  相似文献   

10.
Microbial population and activity can be influenced by changes in the physical and chemical conditions of the soil. The objective of this study was to compare fungal diversity under different agricultural management systems and associated differences in soil properties. This research was carried out in three areas, representing the Atlantic Forest, AFS and cassava (Manihot esculenta Crantz) monoculture system. Five composite samples were collected during the rainy and dry seasons from each area. Using the composite soil samples, fungal isolation was carried out using a serial dilution technique. Physical, chemical and DGGE analyses of the filamentous fungi community were performed. The fungal isolation data were used to calculate ecological indices of diversity, species richness, equitability, dominance, similarity and density. In general, Atlantic Forest soil presented the highest ecological indices followed by the AFS. The DGGE technique revealed that the structure of the soil mycobiota of the Atlantic Forest and AFS are more than 50% similar. The data indicate that the similarity of the structure and composition of soil mycobiota between AFS and Atlantic Forest is mainly due to the conservation of above-ground plant diversity, and the conservation of soil characteristics can be attributed to the absence of pesticides and fertilizers.  相似文献   

11.
We investigated soil physical properties in three forest types in tropical lowland monsoon forests in central Cambodia under the same climatic conditions, i.e., Kanhaplic Haplustults in dry evergreen forest (KH-E), Arenic Haplustults in dry deciduous forest (AH-D), and Arenic Ultic Alorthods in mixed evergreen–deciduous forest (AA-M), to clarify the relationship between forest types and soil physical properties. The clay content was correlated with water content at ψ = −9.8 and −1500 kPa (WC10 and WC1500), available water capacity (AWC), and the van Genuchten (vG) parameter N (P < 0.01). vG parameter N was in the order AH-D > AA-M > KH-E whereas vG parameter α had a high value in KH-E soil at 0–100 cm in depth. The cumulative AWC (AWCcl, mm) at a soil depth of 0–200 cm was higher in the AH-D than in the KH-E, and was not considered a major factor affecting the distribution of different forest types under the same climatic conditions. The unsaturated hydraulic conductivity (K) at 0–100 cm in depth, estimated by use of models, was higher in AH-D than in KH-E mostly at matric potential ψ > −10 kPa. The low K in KH-E at ψ > −10 kPa was considered favorable for evergreen trees to retain the soil water for the transpiration in the dry season, and the matric potential in KH-E showed more gentle decreases in the early dry seasons than AH-D. Thus the differences in K among generally sandy soil types could possibly affect the establishment of different forest types in the study area with the same climate.  相似文献   

12.
A large-scale ectomycorrhizal (ECM) fungus inoculation program was conducted in plantation forest tree nurseries in Australia and China over a period of 2 years. These experiments used a wide diversity of fungi (90 isolates belonging to 23 genera), most of which were obtained from Australian eucalyptus plantations or forests. These trials compared the effectiveness of mycelial slurries (homogenised liquid fungal cultures) and spore suspensions (ground dried fruit bodies) as inoculum forms in nurseries with widely differing management regimes. The success rate of inoculation was moderate, regardless of nursery management regime (38% overall). However, there were substantial differences in overall performance between fungal genera, with agaricoid genera, such as Descolea and Laccaria, and hypogeous (truffle-like) fungi performing better than sequestrate genera, such as Pisolithus and Scleroderma. Comparison of congeneric fungal isolates from different climatic regions did not show significant differences in the performance of fungi from regions where climatic conditions were most similar to nursery conditions relative to those from disparate climatic regions (tropical, temperate, or mediterranean). There was a higher overall success rate for inoculation with spore suspensions (49%) than for mycelial slurries obtained from liquid cultures (35%). Spore-based inoculum was also easier to use and much less expensive to produce than mycelial slurries. It is recommended that future studies investigate the use of mixtures of fungi and attempt to optimise spore germination to increase the reliability of eucalypt seedling nursery inoculation.  相似文献   

13.
We attempted to introduce ectomycorrhizal (ECM) fungi onto seedlings of Dipterocarpus alatus (Dipterocarpaceae) by soil inocula collected from tree stands of D. alatus. Top soils collected from beneath the trees of D. alatus in a dry evergreen forest and a 15-year-old plantation were inoculated onto germinating seeds of D. alatus. After 7 months of seedling cultivation, ECM fungal communities in the seedlings were investigated based on the sequences of ITS rDNA. The ECM fungi detected were divided into 19 phylotypes by molecular analysis. Most of the phylotypes were identified as ECM fungal taxa, i.e., Clavulina, Laccaria, Lactarius, Tomentella, Pyronemataceae, and Tricholomataceae. Accordingly, we can confirm that soil inoculation is a simple method to induce ECM formation with diverse fungi in pot cultured seedlings, which would be useful for introducing diverse ECM fungi to dipterocarp plantations.  相似文献   

14.
Fungal abundance and diversity were assessed in two differently managed forest soils. In soil 1, chipped woody debris had been spread on the top soil and mixed with the soil by standard deep ploughing to 50 cm. In soil 2, woody debris was removed and there was no ground preparation. Ten years later, the different methods of management resulted in unexpectedly distinctive habitat heterogeneity with a high variation in structure of the mycobiota communities. Incorporation of woody debris into soil resulted in lower abundance of fungi but greater fungal diversity (which may enhance ecosystem stability) and was beneficial for the growth of Scots pines. Removal of post‐harvest woody debris from the surface of the clear‐cut site with no subsequent ground preparation, compared with incorporating chipped debris and deep ploughing, resulted in the soil of the subsequent 10‐year‐old Scots pine plantation having: (a) 159‐fold greater abundance of fungi, (b) lower fungal diversity, (c) different fungal community composition, (d) higher proportion of mycorrhizal fungi, (e) no root rot pathogens, (f) less tree biomass. The study showed that removal of post‐harvest woody debris and no ground preparation is potentially beneficial for the health of young coniferous trees.  相似文献   

15.
【目的】揭示呼伦贝尔沙区4种生境土壤真菌群落结构与多样性及其影响因素,探究不同生境对土壤真菌的影响。【方法】选择裸沙地、草地、樟子松人工林和樟子松天然林4种生境土壤真菌为研究对象,采用野外调查、ITS高通量测序结合RDA分析,比较分析不同生境土壤真菌种群特征。【结果】呼伦贝尔沙区土壤共检测到真菌5门22纲73目28科257属。其中,裸沙地和草地土壤优势真菌门为子囊菌门,樟子松人工林和天然林中优势真菌门为担子菌门。优势属共31属,裸沙地、樟子松人工林的优势属分别是被孢霉属和丝膜菌属,草地和天然林土壤中的优势属分别为被孢霉属和Archaeorhizomyces、红菇属和Geminibasidium。其中裸沙地和草地、樟子松人工林和天然林的土壤真菌进化分支更为接近。草地土壤真菌物种丰富度和个体数最高,分布最为均匀;裸沙地其次;樟子松天然林和人工林物种丰富度、个体数和多样性指数较低,分布也较为集中。土壤真菌群落分布的主要影响因子是土壤含水量,优势真菌属分布受多种环境因子影响,土壤孔隙度、含水量、有机质分别是被孢霉属、Archaeorhizomyces、丝膜属的主导影响因子,全磷则是红菇属和Geminibasidium的主导影响因子。【结论】呼伦贝尔沙区4种生境土壤真菌主要由子囊菌门和担子菌门组成,其中裸沙地和草地、樟子松人工林和天然林土壤真菌群落结构相似度较高。多类型草本植物使真菌种类增多且分布更为均匀,樟子松在一定程度上降低真菌数量和种类,并使其分布更为集中。不同生境的不同植被可以改变土壤性质,而土壤水分、营养元素及孔隙结构等土壤环境因素会直接影响4种生境土壤优势真菌属的代谢过程和功能特征,因此4种不同生境真菌群落结构及多样性呈显著差异。  相似文献   

16.
The main objective of this study was to obtain more comprehensive knowledge about the effect of water stress on endophytic fungal communities in asymptomatic and declining cork oak trees. Six asymptomatic and six declining cork oak trees were randomly selected in a natural cork oak forest located in Sardinia, Italy. In February 2003, the soil around three asymptomatic and three declining trees was covered with a circular plastic film to reduce rain water supply with the intention to induce water stress. The remaining six trees served as controls. Predawn xylematic water potential (PWP) was used as water status indicator and measured seasonally. Between July 2003 and June 2004, fungal endophytes were isolated every 2–4 months from twigs, branches and woody tissues. Significant differences in PWP between covered and control trees were detected mainly in autumn. Gas exchange was greatest in asymptomatic control plants. All tissues were colonized by endophytic fungi. Nineteen fungal species were isolated from 1620 plant fragments. Biscogniauxia mediterranea was the most frequently isolated fungus. Its isolation frequency was significantly higher in declining covered trees than in control trees (p < 0.05). Presence of this fungus in asymptomatic control trees was significantly higher in winter than in summer. Water stress seems to reduce species diversity of the endophytic mycobiota in cork oak and to promote proliferation of some potentially pathogenic endophytes.  相似文献   

17.
We used standard isolation protocols to explore the endophytic fungal communities in three tissue types of two dominant orchids (Bulbophyllum neilgherrense and Vanda testacea) of the Kaiga forest ofthe Western Ghats. We surface sterilized and assessed 90 segments ofeach orchid for the occurrence and diversity of endophytic fungal taxa.The 118 fungal isolates were obtained from root, bulb and leaves of B.neilgherrense, consisting of 17 anamorphic taxa (range, 10 15 taxa) with 1.3 fungal taxa per segment (range, 1.2 1.4 taxa). Four taxa (Aspergillus flavus, A. niger, Penicillium sp. and morpho sp. 1) belonged to the coregroup (11.1% 32.2%). The relative abundance of A. flavus and morpho sp.1 was more than 10%. A total of 130 fungal isolates from roots, stems and leaves of V. testacea yielded 20 anamorphic taxa (range, 11 15 taxa)with 1.4 fungal taxa per segment (range, 1.4 1.5 taxa). Aspergillus flavus,A. niger, A. ochraceus, Gliocladium viride, Penicillium sp. and morphosp. 1 belonged to the core group. Relative abundance exceeded 10% for A. flavus, A. niger, and morpho sp. 1. The Simpson and Shannon diversity indices were higher in leaf than root or bulb/stem of both orchids.Jaccard’s similarity coefficient was higher between root and leaf in both orchids (56.3% 60%) than between other pairs. Our study revealed thatthe endophytic fungal assemblage and diversity of B. neilgherrense and V.testacea of Kaiga forest of the Western Ghats were relatively similar between orchids and their tissues.  相似文献   

18.
We aimed to study tree effects on the chemical properties of forest soils. We compared soil features of three types of forest ecosystems, each with four stands (replicates): beech forests (Fagus sylvatica), oak forests (dominated by Quercus pyrenaica) and pine plantations (Pinus sylvestris). Five samples from the top 10 cm of soil were taken per stand, from which pH, organic matter content (O.M.), total nitrogen (N) and available calcium (Ca2+), magnesium (Mg2+), potassium (K+) and sodium (Na+) were determined. Litter layer depth was measured at each soil sampling point. We also measured tree density and crown diameters at each stand. Our results indicated that soil samples from the four pine plantation stands were more similar while oak and beech stands were characterised by great variability in terms of soil properties and leaf litter depth. Although the identity of the dominant tree species significantly influenced several topsoil chemical properties (increase in pH and available cations in oak forests and higher organic matter and total nitrogen in beech and pine ecosystems), there were other important factors affecting soil features that may be taken under consideration. Differences between soil properties of the three types of forest ecosystems were mainly related to the characteristics of the litter layer and less related to the tree layer structure. Finally, the establishment of pine plantations in naturally deciduous tree areas made the topsoil features more homogeneous.  相似文献   

19.
The relative diversity and abundance of different functional groups of macrofungi were investigated in the northern jarrah forest, a mediterranean climate sclerophyllous forest dominated by eucalyptus trees in Western Australia. We sampled paired sites that were either severely affected by dieback, a disease caused by Phytophthora cinnamomi which causes selective plant mortality, or unaffected by this type of forest decline. Macrofungi were sampled 3 times during the growing season along six 100 m × 2 m transects in these sites. Dieback-unaffected sites were found to have significantly different macrofungal floras than unaffected sites. Macrofungal abundance and diversity were approximately 1.5 times and 1.8 times greater respectively in dieback-unaffected sites than in severely affected sites. Dieback-affected sites had a similar diversity of saprotrophic and ectomycorrhizal fungi, whereas more fungal taxa on dieback-unaffected sites were mycorrhizal (>60%). Dung fungi were the most common saprophytes, especially in dieback-affected sites, but abundance data greatly overestimated the importance of these relatively small fungi. We concluded that vegetation changes linked to dieback had a negative effect on fungal community structure and biodiversity in the northern jarrah forest, in a similar manner to other forms of severe disturbance. Conversely, high tree mortality increased the abundance of wood decay fungi, at least in the short term. We expect that reductions in macrofungal species richness were indirectly linked to impacts on mycorrhizal host plants and saprotrophic substrates. Our data show that changes in vegetation composition had the greatest effect on ectomycorrhizal fungi, presumably due to their obligate symbiotic associations.  相似文献   

20.
Estimating large herbivore density has been a major area of research in recent decades. Previous studies monitoring ungulate density, however, focused mostly on determining animal abundance, and did not interpret animal distribution in relation to habitat parameters. We surveyed large ungulates in the Biodiversity Exploratory Schorfheide-Chorin using faecal pellet group counts. This allowed us to explore the link between relative ungulate abundance, habitat use, and browsing damage on trees in a region with several types of forest, including unharvested and age-class beech forests, as well as age-class pine forests. Our results demonstrate that roe deer and fallow deer relative abundance is negatively correlated with large tree cover, and positively correlated with the cover of small shrubs (Rubus spec., Vaccinium spec.), and winter food supply. Habitat use of roe deer and fallow deer, as estimated by counting faecal pellet groups, revealed a preference for mature pine forests, and avoidance of deciduous forests. This differential habitat use is explained by different distributions of high quality food resources during winter. The response of deer to understory cover differed between roe deer and fallow deer at high cover percentages. The amount of browsing damage we observed on coniferous trees was not consistent with the relative deer abundance. Browsing damage was consistently higher on most deciduous trees, except for beech saplings which sustained less damage when roe deer density was low. Because roe deer is a highly selective feeder, it was reported to affect tree diversity by feeding only on trees with high nutritional value. Consequently, we propose that managing the number of all deer species by hunting is necessary to allow successful forest regeneration. Such an adjustment to deer numbers would need to account for both current tree diversity and alternative food resources. Our findings may be applicable to other forest landscapes in northeastern Germany including mature pine stands and differently harvested deciduous forests.  相似文献   

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