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 st...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.展开更多
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...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.展开更多
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-...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.展开更多
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...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.展开更多
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 biolog...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.展开更多
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....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.展开更多
Screening was done for the isolation of effective lignin degraders from the forest soil samples, by providing lignin as a carbon source through the enrichment method, which leads to the isolation of 8 effective fungal...Screening was done for the isolation of effective lignin degraders from the forest soil samples, by providing lignin as a carbon source through the enrichment method, which leads to the isolation of 8 effective fungal isolates among 14 isolates. Submerged fermentation was done for the production of ligninolytic enzymes with the effective microorganisms by providing Guiaicol as a carbon source. The assay of laccase, lignin peroxidise activity and specific activity was done after the incubation intervals of 2, 4, 6, 7, 8, 10 and 12 days at 27±2℃ under shake culture condition. Partially purified protein content was estimated by using Lowry＇s method. Pleurotus sp. and Phanerochaetae chrysosporium are more effective at the 2nd and 7th days of incubation for the production of laccase and lignin peroxidases among the effective isolates.展开更多
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 ergo...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.展开更多
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 o...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.展开更多
Nitrogen(N)is one of the most limited nutrients of terrestrial ecosystems,whose losses are prevented in tightly coupled cycles in finely tuned systems.Global change-induced N enrichment through atmospheric deposition ...Nitrogen(N)is one of the most limited nutrients of terrestrial ecosystems,whose losses are prevented in tightly coupled cycles in finely tuned systems.Global change-induced N enrichment through atmospheric deposition and application of vast amounts of fertilizer are now challenging the terrestrial N cycle.Arbuscular mycorrhizal fungi(AMF)are known drivers of plant-soil nutrient fluxes,but a comprehensive assessment of AMF involvement in N cycling under global change is still lacking.Here,we simulated N enrichment by fertilization(low/high)in experimental grassland microcosms under greenhouse conditions in the presence or absence of AMF and continuously monitored different N pathways over nine months.We found that high N enrichment by fertilization decreased the relative abundance of legumes and the plant species dominating the plant community changed from grasses to forbs in the presence of AMF,based on aboveground biomass.The presence of AMF always maintained plant N:phosphorus(P)ratios between 14 and 16,no matter how the soil N availability changed.Shifts in plant N:P ratios due to the increased plant N and P uptake might thus be a primary pathway of AMF altering plant community composition.Furthermore,we constructed a comprehensive picture of AMF’s role in N cycling,highlighting that AMF reduced N losses primarily by mitigating N leaching,while N_(2)O emissions played a marginal role.Arbuscular mycorrhizal fungi reduced N_(2)O emissions directly through the promotion of N_(2)O-consuming denitrifiers.The underlying mechanism for reducing N leaching is mainly the AMF-mediated improved nutrient uptake and AMF-associated microbial immobilization.Our results indicate that synergies between AMF and other soil microorganisms cannot be ignored in N cycling and that the integral role of AMF in N cycling terrestrial ecosystems can buffer the upcoming global changes.展开更多
文摘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.
文摘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.
文摘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.
基金Supported by National Natural Science Foundation of China (30571264)Nation Key Technology Program (2006BAD07B03)
文摘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.
基金funded by the National Natural Science Foundation of China (51574253)the National High Technology Research and Development Program of China (2013AA102904)the Open Research Project of the State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology (Beijing) (SKLCRSM16KFA01)
文摘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.
文摘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.
文摘Screening was done for the isolation of effective lignin degraders from the forest soil samples, by providing lignin as a carbon source through the enrichment method, which leads to the isolation of 8 effective fungal isolates among 14 isolates. Submerged fermentation was done for the production of ligninolytic enzymes with the effective microorganisms by providing Guiaicol as a carbon source. The assay of laccase, lignin peroxidise activity and specific activity was done after the incubation intervals of 2, 4, 6, 7, 8, 10 and 12 days at 27±2℃ under shake culture condition. Partially purified protein content was estimated by using Lowry＇s method. Pleurotus sp. and Phanerochaetae chrysosporium are more effective at the 2nd and 7th days of incubation for the production of laccase and lignin peroxidases among the effective isolates.
基金The present work was supported by Foundation of State Key Basic Research and Development Project (G1998051100)
文摘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.
文摘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.
基金supported by the National Natural Science Foundation of China(Nos.32101304 and 32160281)the Key Laboratory Project,Xinjiang,China(No.2021D04006)+1 种基金China Postdoctoral Science Foundation(No.2021M692707)supported by the Swiss National Science Foundation(No.31003A-166079)。
文摘Nitrogen(N)is one of the most limited nutrients of terrestrial ecosystems,whose losses are prevented in tightly coupled cycles in finely tuned systems.Global change-induced N enrichment through atmospheric deposition and application of vast amounts of fertilizer are now challenging the terrestrial N cycle.Arbuscular mycorrhizal fungi(AMF)are known drivers of plant-soil nutrient fluxes,but a comprehensive assessment of AMF involvement in N cycling under global change is still lacking.Here,we simulated N enrichment by fertilization(low/high)in experimental grassland microcosms under greenhouse conditions in the presence or absence of AMF and continuously monitored different N pathways over nine months.We found that high N enrichment by fertilization decreased the relative abundance of legumes and the plant species dominating the plant community changed from grasses to forbs in the presence of AMF,based on aboveground biomass.The presence of AMF always maintained plant N:phosphorus(P)ratios between 14 and 16,no matter how the soil N availability changed.Shifts in plant N:P ratios due to the increased plant N and P uptake might thus be a primary pathway of AMF altering plant community composition.Furthermore,we constructed a comprehensive picture of AMF’s role in N cycling,highlighting that AMF reduced N losses primarily by mitigating N leaching,while N_(2)O emissions played a marginal role.Arbuscular mycorrhizal fungi reduced N_(2)O emissions directly through the promotion of N_(2)O-consuming denitrifiers.The underlying mechanism for reducing N leaching is mainly the AMF-mediated improved nutrient uptake and AMF-associated microbial immobilization.Our results indicate that synergies between AMF and other soil microorganisms cannot be ignored in N cycling and that the integral role of AMF in N cycling terrestrial ecosystems can buffer the upcoming global changes.
