Soil Physico-Chemical Properties and Different Altitudes Affect Arbuscular Mycorrhizal Fungi Abundance and Colonization in Cacao Plantations of Cameroon

This study aims to investigate the abundance of AMF according to soil properties and altitudes in different cacao plantations of Cameroon. Physico-chemical analyses were made on soil samples collected from three agro-ecological zones. Soil samples were also used to evaluate directly the AMF abundance following the various altitudes and after trapping by sorghum plant. The results showed that soil properties, AMF spore abundances and colonization fluctuated significantly at different altitudes. The most represented texture was sandy loam. The bimodal zone presented a homogeneous texture (sandy loam) in all its localities. Cacao soil chemical characteristics showed that, the highest nitrogen rate (0.47%;p 0.05, Scott-Knott test) was recorded at Melong in a monomodal zone while Tonga in the Western highlands displayed the lowest rate (0.13%). Soil P concentration was significantly high in monomodal zones (Mbanga and Melong). Soil pH level indicated that the soil from Tonga in the Western highlands was neutral (pH = 6.67), and soils of other localities under study were acidic with the lowest (4.75) pH level recorded at Melong in a monomodal zone. In soil samples, the highest spore density (1.03 spores/g soil) was observed at Ntui in Bimodal zone, while the lowest spore density (0.26 spores/g soil) was observed at Bafang in the Western highlands. Root colonization showed that the sample from Bokito in a bimodal zone displayed the best frequency of mycorrhization (86.11%) while the sample from Bafang in the Western highlands recorded the lowest (27.11%). The PCA analysis highlighted that available phosphorus, pH and altitude all strongly correlated with AMF root colonization ability and can be used as a predictor of AMF colonization ability in cacao rhizosphere.

Arbuscular mycorrhizal fungi ameliorate the chemical properties and enzyme activities of rhizosphere soil in reclaimed mining subsidence in northwestern China

In semi-arid region of northwestern China, underground mining subsidence often results in decreased vegetation coverage, impoverishment of soil fertility and water stress. In addition, the physical-chemical and biological properties of soil also change, resulting in more susceptible to degradation. In particular, subsidence causes disturbance of the symbioses of plant and microbe that can play a beneficial role in the establishment of vegetation communities in degraded ecosystems. The objective of this study was to evaluate the effects of revegetation with exotic arbuscular mycorrhizal fungi(AMF) inoculum on the chemical and biological properties of soil over time in mining subsidence areas. Soils were sampled at a depth up to 30 cm in the adjacent rhizosphere of Amorpha fruticose Linn. from five reclaimed vegetation communities in northwestern China. In August 2015, a field trial was set up with five historical revegetation experiments established in 2008(7-year), 2011(4-year), 2012(3-year), 2013(2-year) and 2014(1-year), respectively. Each reclamation experiment included two treatments, i.e., revegetation with exotic AMF inoculum(AMF) and non-AMF inoculum(the control). Root mycorrhizal colonization, glomalin-related soil protein(GRSP), soil organic carbon(SOC), soil nutrients, and enzyme activities were also assessed. The results showed that mycorrhizal colonization of inoculated plants increased by 33.3%–163.0% compared to that of non-inoculated plants(P<0.05). Revegetation with exotic AMF inoculum also significantly improved total GRSR(T-GRSP) and easily extracted GRSP(EE-GRSP) concentrations compared to control, besides the T-GRSP in 1-year experiment and the EE-GRSP in 2-year experiment. A significant increase in SOC content was only observed in 7-year AMF reclaimed soils compared to non-AMF reclaimed soils. Soil total N(TN), Olsen phosphorus(P) and available potassium(K) were significantly higher in inoculated soil after 1–7 years of reclamation(except for individual cases), and increased with reclamation time(besides soil Olsen P). The exotic AMF inoculum markedly increased the average soil invertase, catalase, urease and alkaline phosphatase by 23.8%, 21.3%, 18.8% and 8.6%, respectively(P<0.01), compared with the control. Root mycorrhizal colonization was positively correlated with soil parameters(SOC, TN and soil available K) and soil enzyme activities(soil invertase, catalase, urease and alkaline phosphatase) in both AMF and non-AMF reclaimed soils(P<0.05), excluding availableK in non-AMF reclaimed soils. T-GRSP(P<0.01) and EE-GRSP(P<0.05) were significantly correlated with the majority of edaphic factors, except for soil Olsen P. The positive correlation between root mycorrhizal colonization and available K was observed in AMF reclaimed soils, indicating that the AMF reclaimed soil with a high root mycorrhizal colonization could potentially accumulate available K in soils. Our findings concluded that revegetation with exotic AMF inoculum influenced soil nutrient availability and enzyme activities in the semi-arid ecosystem, suggesting that inoculating AMF can be an effective method to improve soil fertility and support restoration of vegetation communities under poor conditions like soil nutrient deficiency and drought.

Indigenous arbuscular mycorrhizal fungi play a role in phosphorus depletion in organic manure amended high fertility soil

The species richness and propagule number of arbuscular mycorrhizal fungi(AMF)are high in intensively-managed agricultural soils.Past research has shown that AMF improve crop phosphorus(P)uptake under low soil P conditions,however it is unclear if AMF play a role in high Olsen-P soils.In this study,we investigated whether native fungal benefits exist under high P input field conditions in-situ and contribute to P utilization.We installed in-grow tubes which were sealed with different membrane pore sizes(30 or 0.45μm)to allow or prevent AMF hyphae access to the hyphal compartment and prevent cotton roots from penetrating the chamber.We used the depletion of soil available P(Olsen-P)in the hyphae accessed compartment to indicate P uptake by the native AMF community.Our results showed that the native AMF mediated P depletion and microbial biomass P(MBP)turnover and caused the largest Olsen-P depletion ratio and MBP turnover ratio in the high P treatments(Olsen-P:78.29 mg kg^(-1)).The cotton roots in each fertilization regime were colonized by a unique AMF community and Glomus and Paraglomus were the dominant genera,implying the longterm fertilization regimes domesticated the AMF community.We conclude that native AMF caused the P depletion and P turnover even under high soil Olsen-P conditions.

Study of cellulolytic soil fungi and two nova species and new medium

This study is aimed at identifying and determining the percentage of occurrence frequency of cellulose decomposing soil fungi. The soil samples were inoculated into culture plates prepared in Sabouraud medium under sterilized conditions and incubated at 30 ℃ for 4 to 7 d. The identified fungal species were incubated in self-designed cellulose medium for testing their cellulolytic ability. Forty-two species, including2 nova species, representing sixteen genera showed growth and sporulation in the cellulose medium. Most of the isolated species were from genus Aspergillus and Penicillium. Aspergillus niger and Mucor hiemalis showed highest occurrence frequency （45% and 36% respectively）, as these species were collected from about 80% of soil samples. Being agar free and cheaper, the new fungal medium designed showed results equivalent to Sabouraud medium.

Diversity and Classification of Soil Fungi in Main Peanut Producing Areas of China

In the study, 1 255 fungal strains were isolated from 105 peanut soil samples collected from 15 counties in 10 provinces of China. These fungi were identified to 21 genera, using the method of microscopical observation according to morphology. And 2 genera were members of oomycetes, 3 genera of ascomycota and 16 genera of mitosporic fungi. In these soil samples, the dominant species were Penicillium, Trichoderma and Fusarium, accounting for 28.89%, 14.16% and 8.64%, respectively.

Synergistic combination of arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria modulates morpho-physiological characteristics and soil structure in Nitraria tangutorum bobr.Under saline soil conditions

Nitraria tangutorum Bobr.,a typical xero-halophyte,can be used for vegetation restoration and reconstruction in arid and semiarid regions affected by salinity.However,global climate change and unreasonable human activity have exacerbated salinization in arid and semi-arid regions,which in turn has led to the growth inhibition of halophytes,including N.tangutorum.Arbuscular mycorrhizal fungi(AMF)and plant growth-promoting rhizobacteria(PGPR)have the potential to improve the salt tolerance of plants and their adaptation to saline soil environments.In this study,the effects of single and combined inoculations of AMF(Glomus mosseae)and PGPR(Bacillus amyloliquefaciens FZB42)on N.tangutorum were evaluated in severe saline soil conditions.The results indicate that AMF and PGPR alone may not adapt well to the real soil environment,and cannot ensure the effect of either growth promotion or salt-tolerance induction on N.tangutorum seedlings.However,the combination of AMF and PGPR significantly promoted mycorrhizal colonization,increased biomass accumulation,improved morphological development,enhanced photosynthetic performance,stomatal adjustment ability,and the exchange of water and gas.Co-inoculation also significantly counteracted the adverse effect of salinity on the soil structure of N.tangutorum seedlings.It is concluded that the effectiveness of microbial inoculation on the salt tolerance of N.tangutorum seedlings depends on the functional compatibility between plants and microorganisms as well as the specific combinations of AMF and PGPR.

Effectivity of arbuscular mycorrhizal fungi collected from reclaimed mine soil and tallgrass prairie

We examined suitability of arbuscular mycorrhizal fungi (AMF) associated with cool-season nonnative forages on reclaimed surface-mined land in southeast Ohio for establishment of native warm-season grasses. The goal of establishing these grasses is to diversify a post-reclamation landscape that is incapable of supporting native forest species. A 16-week glasshouse study compared AMF from a 30-year reclaimed mine soil (WL) with AMF from native Ohio tallgrass prairie soil (CL). Four native grasses were examined from seedling through 16 weeks of growth. Comparisons were made between CL and WL AMF on colonized (+AMF) and non-colonized plants (–AMF) at three levels of soil phosphorus (P). Leaves were counted at 4 week intervals. Shoot and root biomass and percent AMF root colonization were measured at termination. We found no difference between WL and CL AMF. Added soil P did not reduce AMF colonization, but did reduce AMF efficacy. Big bluestem (Andropogon gerardii Vitman), Indiangrass (Sorghastrum nutans (L.) Nash), and tall dropseed (Sporobolus asper (Michx.) Kunth) benefited from AMF only at low soil P while slender wheatgrass (Elymus trachycaulus (Link) Gould ex Shinners) exhibited no benefit. Establishment of tallgrass prairie dominants big blue-stem and Indiangrass would be supported by the mine soil AMF. It appears that the non-native forage species have supported AMF equally functional as AMF from a regionally native tallgrass prairie. Tall dropseed and slender wheatgrass were found to be less dependent on AMF than big bluestem or Indiangrass and thus would be useful in areas with little or no AMF inoculum.

The effect of soil moisture on the response by fungi and bacteria to nitrogen additions for N_(2)O production

In addition to bacteria,the contribution of fungi to nitrous oxide(N_(2)O)production has been recognized but the responses of these two broad and unrelated groups of microorganisms to global environmental changes,atmospheric nitrogen(N)deposition,and precipitation in terms of N_(2)O production are unclear.We studied how these two microbial-mediated N_(2)O production pathways responded to soil moisture conditions and to N addition in an N-limited temperate forest.Soils from a long-term N addition experiment in Changbai Mountain,northeastern China were incubated.Varied concentrations of cycloheximide and streptomycin,both inhibitors of fungal and bacterial activity,were used to determine the contributions of both to N_(2)O production in 66%,98%and 130%water-filled pore spaces(WFPS).The results showed that N_(2)O production decreased significantly with increasing cycloheximide concentration whereas streptomycin was only inhibiting N_(2)O emissions at 98%and 130%WFPS.The bacterial pathway of N_(2)O production in N-addition(Nadd)soil was significantly more dominant than that in untreated(Namb)soil.The difference in the fungal pathway of N_(2)O production between the soil with nitrogen addition and the untreated soil was not significant.Net N_(2)O emissions increased with increasing soil moisture,especially at 130%WFPS,a completely flooded condition.Bacteria dominated carbon dioxide(CO_(2))and N_(2)O emissions in Nadd soil and at 130%WFPS regardless of N status,while fungi dominated CO_(2)and N_(2)O emissions in soil without N addition at 66%and 98%WFPS.The results suggest that flooded soil is an important source of N_(2)O emissions and that bacteria might be better adapted to compete in fertile soils under anoxic conditions.

Shifting cultivation effects on soil fungi and bacterial population in Chittagong Hill Tracts, Bangladesh

A study was conducted at two pair sites of Chittagong Hill Tracts in Bangladesh to find out the effects of shifting cultivation on soil fungi and bacterial population. The first pair of sites with shifting culti-vation and village common forest-managed by indigenous community was at Madhya Para in Rangamati district and the second pair of sites with the shifting cultivated land and village common forest at Ampu Para in Bandarban district of Chittagong Hill Tracts. At both the locations with two different land uses, soil textures in surface （0？10 cm） and sub-surface （10？20 cm） soils varied from sandy loam to sandy clay loam. Soil pH and moisture content were lower in shifting cultivated land com-pared to village common forest. The results also showed that both fungal and bacterial population in surface and subsurface soils was significantly （p ≤ 0.05） lower, in most cases, in shifting cultivated land compared to village common forest at both Madhya Para and Ampu Para. At Ranga-mati and Bandarban in shifting cultivated lands, Colletrotrichum and Fusarium fungi were absent and all the bacterial genus viz. Coccus, Bacillus and Streptococcus common in two different locations with dif-ferent land uses. Common identified fungi at both the land uses and locations were Aspergillus, Rhizopus, Trichoderma and Penicillium. Further study can be done on the other soil biota to understand the extent of environmental deterioration due to shifting cultivation.

Effects of Biochar,Arbuscular Mycorrhizal Fungi and Nitrogen Application on Crop(Cichorium intybus L.)Growth and Soil Properties in Cadmium Contaminated Soil

The effects of biochar(BC),arbuscular mycorrhizal fungi(AM),nitrogen(N)and their composite treatments(BC+N,AM+N,BC+AM and BC+AM+N)application on Cichorium intybus L.(C.intybus L.)nutrient uptake,soil properties and cadmium(Cd)accumulation were investigated in Cd contaminated soil(0.11 mg·kg^(-1)).The results showed that the addition of BC increased the rate of mycorrhizal infection.However,the addition of N slightly inhibited mycorrhizal colonization,and the shoot and root bioaccumulation of chicory was positively influenced by BC and N when inoculated with AM fungi.Compared with the single component treatment(AM,BC or N)or two-component treatment(BC+N,AM+N or BC+AM),the three-component composite treatment(BC+AM+N)had the highest shoot bioaccumulation,whereas BC+AM treatment was considered the best for root biomass bioaccumulation.Compared with the control treatment,the single component treatment(AM,BC or N)and the composite treatment resulted in an overall improvement of the chicory shoot,root related nutrient uptake(N,P,K,Mg,Ca,Mn and Fe)and some soil physicochemical properties;in addition,these treatments showed better results than BC+AM+N and BC+AM treatments.Among the Cd-related indexes,Cd concentrations in the shoot,root and soil of C.intybus L.were reduced through treatment with AM and BC.However,a lower bioconcentration coefficient(BCF)and a higher transfer coefficient(TF)were observed in both treatments,and the most desirable effect was observed following the combination treatment(BC+AM).Compared with other single management,the shoot and root Cd concentrations of C.intybus L.after the management of N alone were higher,and the value of BCF(2.63%)was higher,but the value of TF(1.05%)was lower.Indexes related to Cd improved concurrently following the application of N in combination with BC or AM.Therefore,in Cd contaminated soils,single or combined application of BC,AM and N could promote chicory growth and nutrient uptake and improve some soil physicochemical properties.However,N should not be applied alone and needed to be combined with AM and BC;furthermore,it was evident that the treatment with the three composites(BC+AM+N)was optimal from an application point of view.

Diversity of soil fungi in dry deciduous forest of Bhadra Wildlife Sanctuary,Western Ghats of southern India

Abstract： We assessed soil fungal diversity in the dry deciduous forest ofa Bhadra Wildlife Sanctuary of the Western Ghats （210.31 m a.s.1.; N 13044＇ and E75°37′）. Soil samples were collected by random mixed sampling during winter （November, 2008）, summer （March, 2009） and monsoon （August, 2009） seasons, and physico-chemical parameters were recorded. During winter, summer, and monsoon seasons, 49, 45 and 49 of fungal species belongs to 20, 18 and 19 of genera were isolated, respectively. Isolated soil fungi were mainly of the Mitosporic fungi, followed by Zygomycotina, Ascomycotina, Oomycotina and Coelomycetes. Indices of diversity, dominance and fisher alpha during winter, summer and monsoon seasons were 3.756, 3.638 and 3.738 （H）, 0.9737, 0.9694 and 0.9726 （I-D） and 18.84, 29.83 and 19.46 （a）, respectively. Spear- man＇s （r） correlation coefficient of fungal population with physicochemical parameters of soils showed significantly positive and negative correlations （p〈0.01） during winter, summer and monsoon seasons. Physico-chemical soil parameters played an important role in the occurrence, diversity, distribution, and relative abundance of fungal species in the tropical dry deciduous forest soil.

Optimization of ITS rDNA Amplification for Fungi from Black Soil in North China

In order to optimize polymerase chain reaction（PCR） amplification of the internal transcribed spacer（ITS） rDNA region from fungi found in black soil in North China,an orthogonal experimental design [L16（45）] was used to evaluate five factors（template,Mg2＋,dNTP,Taq DNA polymerase,and primer） from four levels.Subsequently,the optimal annealing temperature,annealing time,extension time and cycle numbers were evaluated.The results showed that the optimized PCR solution for amplification of ITS region comprised 5 μL 10× buffer,30 ng soil DNA template,3.0 mmol·L-1 Mg2＋,0.2 mmol·L-1 dNTPs,0.1 μmol·L-1 each forward and reverse primer,and 2.0 U Taq enzyme in 50 μL reaction volume.The optimal thermal cycling protocol consisted of initial melting at 94℃ for 5 min,followed by 35 cycles at 94℃ for 30 s,56℃ for 30 s,72℃ for 90 s,and a final extension of 72℃ for 10 min.

The occurrence of keratinophilic fungi in selected soils of Ladakh (India)

138 soil samples were collected from various loca-tions in Ladakh, a cold desert in the Himalayan region, India and the samples were screened for the presence of keratinophilic fungi using the hair baiting techniques. 58 isolates were recovered and identified. The cultures were identified based on their macro- and micro-morphological features. A total of six genera and fourteen species were isolated namely Amauroascus kuehnii (0.72%), Aphanoascus keratinophilus (4.34%), Aphanoascus terreus (2.17%), Auxarthron alboluteum (0.72%), Auxarthron conjugatum (0.72%), Chrysosporium articulatum (0.72%), Chrysosporium mephiticum (0.72%), Chrysosporium minutisporosum (2.17%), Chrysosporium siglerae (0.72%), Chrysosporium sp. (1.44%), Chrysosporium tropicum (15.94 %), Chrysosporium submersum (3.62%), Chrysosporium state of Ctenomyces serratus (6.52%) and Geomyces pannorum (1.45%). The present study shows that keratinophilic fungi exist in the cold desert of Ladakh.

有机肥配施生物炭对碱化土壤真菌群落结构的影响研究

为探究有机肥配施生物炭对干旱区碱化土壤真菌群落结构的重塑效果,通过田间试验,采用高通量测序技术研究不同用量有机肥(0、7.5 t/hm^(2))和生物炭(0、2%和4%)配施对土壤真菌群落结构及作物产量的影响。结果表明:相较于对照,7.5 t/hm^(2)有机肥与2%、4%生物炭复配处理显著降低了门分类水平上子囊菌门的相对丰度,而担子菌门和球囊菌门等有益菌群的相对丰度显著提高;土壤真菌的Observed指数和Shannon指数明显增加,Simpson指数明显减少,复配处理明显改善了土壤真菌的丰富度和多样性,改变了土壤真菌群落结构。同时,复配处理有利于油葵生长及产量增加,其中7.5 t/hm^(2)有机肥配施4%生物炭的产量最高,为2521.5 kg/hm^(2),较对照增加1589.1 kg/hm^(2)。因此,相较于单一材料,有机肥配施生物炭可以进一步优化土壤真菌群落结构及多样性,提高作物产量。

Dynamic of Soil Microorganisms from Root Region of Ginseng with Different Growing Years

Objective To see the dynamic of fungi, bacilli and actinomyces communities from root region of ginseng with different growing years.Method With ginseng root region soils from several sampling sites of Jilin Province as materials, concentrations of fungi, bacilli and antinomyces were evaluated by spread-plate method. Result Though there are differences on statistic data among soil samples, commonly with the increasing of growing years, concentration of fungi in ginseng root region increased, which were on the contrary for bacilli and antinomyces, and bacilli changed even more significant than antinomyces. Conclusion Concentrations of soil microorganisms can be influenced by soil type, planting mode and growing years simultaneously, but growing years influenced even more significantly.

Studies on Chemical Constituents of the Fermentation Liquor of Soil Fungus 07-11

Two compounds were isolated from ethyl acetate extract of the fermentation of fungus 07-11, which obtained from the soil of Yunnan Province. They were identified as N-(4-hydroxy-2-methoxyphenyl) acetamide (1) and ergosta-7,22-diene-3,6-dione (2) respectively on the basis of spectral analyses and physical and chemical identifications. Compound 1 was a new natural product. Compound 2 was firstly isolated from its genus. Spectral data of 1 and complete 1H NMR data of 2 were reported for the first time.

A Review of Methods for Studying Microbial Diversity in Soils

Soil microorganisms play a central role in decomposing organic matter, in determining the release of mineral nutrients, and in nutrient cycling. Recently, extensive studies have focused on soil microbial diversity. However, understanding the diversity of this complex microbial community in the soil environment is a challenging task. Thus, it is important to master and comprehend appropriate methods for studying soil microbial diversity. Concepts of soil microbial diversity and major methods of study are briefly introduced in this paper. Then, the application of biochemical-based and molecular-based techniques in this area, and their advantages and disadvantages are evaluated. Based on recent related research, perspectives for studying microbial diversity in soils are presented.

Effects of arbuscular mycorrhizal fungi inoculation on arsenic accumulation by tobacco (Nicotiana tabacum L.)

A pot experiment was conducted to study the effects of arbuscular mycorrhizal （AM） fungi （from contaminated or uncontaminated soils） on arsenic （As） uptake of tobacco （Nicotiana tabacurn L.） in As-contaminated soil. Mycorrhizal colonization rate, dry weight, As and P uptake by plants, concentrations of water-extractable As and As fractions were determined. A low mycorrhizal colonization rate （〈 25%） was detected. Our research indicated that AM fungi isolated from polluted soils were no more effective than those from unpolluted soils when grown in symbiosis with tobacco. No significant differences were observed in roots and stalks dry weights among all treatments. Leaves and total plant dry weights were much higher in Glomus versiforme treatment than that in control treatment. As contents in roots and stalks from mycorrhizal treatments were much lower than that from control treatment. Total plant As content exhibited the same trend. P concentrations in tobacco were not affected by colonization, nor were stalks, leaves and total plant P contents. Roots P contents were remarkably lower in HN treatments than in other treatments. Meanwhile, decreased soil pH and lower water-extractable As concentrations and higher levels of As fraction bound to well-crystallized hydrous oxides of Fe and AI were found in mycorrhizal treatments than in controls. The protective effect of mycorrhiza against plant As uptake may be associated with changes in As solubility mediated by changing soil pH. These results indicated that under As stress, proper mechanisms employed by AM fungi can protect tobacco against As uptake. Results confirmed that AM fungi can play an important role in food quality and safety.

Microscopy Observations of Habitable Space in Biochar for Colonization by Fungal Hyphae From Soil

Biochar is a potential micro-environment for soil microorganisms but evidence to support this suggestion is limited. We explored imaging techniques to visualize and quantify fungal colonization of habitable spaces in a biochar made from a woody feedstock. In addition to characterization of the biochar, it was necessary to optimize preparation and observation methodologies for examining fungal colonization of the biochar. Biochar surfaces and pores were investigated using several microscopy techniques. Biochar particles were compared in soilless media and after deposition in soil. Scanning electron microscopy （SEM） observations and characterization of the biochar demonstrated structural heterogeneity within and among biochar particles. Fungal colonization in and on biochar particles was observed using light, fluorescence and electron microscopy. Fluorescent brightener RR 2200 was more effective than Calcofluor White as a hyphal stain. Biochar retrieved from soil and observed using fluorescence microscopy exhibited distinct hyphal networks on external biochar surfaces. The extent of hyphal colonization of biochar incubated in soil was much less than for biochar artificially inoculated with fungi in a soilless medium. The location of fungal hyphae was more clearly visible using SEM than with fluorescence microscopy. Observations of biochar particles colonized by hyphae from soil posed a range of difficulties including obstruction by the presence of soil particles on biochar surfaces and inside pores. Extensive hyphal colonization of the surface of the biochar in the soilless medium contrasted with limited hyphal colonization of pores within the biochar. Both visualization and quantification of hyphal colonization of surfaces and pores of biochar were restricted by two-dimensional imaging associated with uneven biochar surfaces and variable biochar pore structure. There was very little colonization ofbiochar from hyphae in the agricultural soil used in this study.

Biodiversity of arbuscular mycorrhizal fungi in different trees of madhupur forest, Bangladesh

Roots and rhizosphere soils of Acacia auriculiformis A. Cunn. ex Benth., A. mangium Wild., Artocarpus heterophyUus Lamk. C., Dalbergia sissoo Roxb. ex A. P. D., Eucalyptus camaldulensis Dehnn., Hevea brasiliensis （Wild. ex Juss） Muell. Arg., Swietenia macrophylla King. and Tectona grandis L. were collected from different locations of Madhupur forest area to study the biodiversity of Arbuscular Mycorrhizal （AM） fungal colonization and spore population. All the plants showed AM colonization. Out of eight selected plants, mycelial colonization was lowest in the roots of A. heterophyllus （22%） and the highest was in the roots of H. brasiliensis （78%）. Mycelial intensity was observed poor （25%-77%） and moderate （23%-57%） in all plants species and abundant （11%-40%） was in most of the plant species. Vesicular colonization was observed in five plant species. The lowest was recorded in E. camaldulensis （4%） and the highest was in H. brasiliensis （21%）. Poor （24%-56%）, moderate （16%-100%） and abundant （11%-40%） type of vesicular intensity were observed. Arbuscular colonization was observed in three plants. The highest was in A. mangium （72%） and the lowest was in S. macrophylla （17%）. Arbuscular intensity was recorded as poor （12%-44%）, moderate （22%-100%） and abundant （4%-47%）. The highest AM fungal spore population was in A. auriculiformis （714） and the lowest was in D. sissoo （102）. Five AM fungal genera were recorded. Glomus was found to be dominant. A few spores remained unidentified. Significant correlation was observed between percent coloniza- tion and spore population. The results of the present study indicate the occurrence of AM fungi and the mycotrophism of the plants of Madhupur forest area and the applicability of AM technology in the forest management of Madhupur forest.