Exploring soil microbial communities and soil organic matter: Variability and interactions in arable soils under minimum tillage practice

This study describes an integrated approach (1) to monitor the quantity and quality of water extractable organic matter (WEOM) and size, structure and function of microbial communities in space (depth) and time, and (2) to explore the relationships among the measured properties. The study site was an arable field in Southern Germany under integrated farming management including reduced tillage. Samples of this Eutric Cambisol soil were taken in July 2001, October 2001, April 2002 and July 2002 and separated into three depths according to the soil profile (0–10 cm, 10–28 cm and 28–40 cm). For each sample, the quantity and quality (humification index, HIX) of water extractable organic matter (WEOM) were measured concomitantly with soil enzyme activities (alkaline phosphatase, β-glucosidase, protease) and microbial community size (C_mic). Furthermore, microbial community structure was characterised based on the fingerprints of nucleic acids (DNA) as well as phospholipid fatty acids (PLFA). We observed strong influences of sampling date and depth on the measured parameters, with depth accounting for more of the observed variability than date. Increasing depth resulted in decreases in all parameters, while seasonal effects differed among variants. Principal component (PC) analysis revealed that both DNA and PLFA fingerprints differentiated among microbial communities from different depths, and to a smaller extent, sampling dates. The majority of the 10 PLFAs contributing most to PC 1 were specific for anaerobes. Enzyme activities were strongly related to C_mic, which was depending on water extractable organic carbon and nitrogen (WEOC and WEON) but not to HIX. HIX and WEOM interact with the microbial community, illustrated by (1) the correlation with the number of PLFA peaks (community richness), and (2) the correlations with community PC analysis scores.     

Cd和Zn在滇池沉积物中的吸附-解吸特征

研究了Cd和Zn在滇池沉积物中的吸附-解吸特征并分析了影响其吸附的因素。结果表明滇池沉积物对Cd和Zn的等温吸附符合Langmuir模型,且Cd和Zn的最大吸附量很高,Cd为6443mg/kg,Zn为13889mg/kg,这表明滇池沉积物对重金属具有很大的吸附潜力。Cd和Zn的吸附和解吸过程都可以分成30min之前的快反应和60min之后的慢反应,且吸附率和解吸率与时间的关系都可以用乘幂函数拟和。沉积物对重金属的吸附受pH的影响,吸附量随着pH的增加而增加,当溶液pH为8.05时,Cd和Zn的吸附百分数都超过了97%。     

不同肥料长期施用下稻田镉、铅、铜、锌元素总量及有效态的变化

以中国科学院桃源农业生态实验站的长期田间定位试验为基础,研究了16年长期定量施肥对土壤Cd、Pb、Cu和Zn积累及其有效性的影响。结果表明:单施化肥可使土壤Cd含量降低、Pb含量增加,对Cu和Zn的积累无显著影响,水稻收获时的移出效应可能是Cd含量降低的主要原因;与单施化肥相比,有机物料循环可提高土壤Cd和Pb的积累,但对Cu和Zn的积累无显著影响。试验期内单施化肥对土壤Cd、Pb、Cu和Zn的有效性无显著影响;有机物料循环可显著提高Cd和Zn的有效性,这与有机物料循环引起的土壤有机质含量增加和pH降低有关。     

Functional resilience of soil microbial communities depends on both soil structure and microbial community composition

The effects of soil structure and microbial community composition on microbial resistance and resilience to stress were found to be interrelated in a series of experiments. The initial ability of Pseudomonas fluorescens to decompose added plant residues immediately after a copper or heat stress (resistance) depended significantly on which of 26 sterile soils it was inoculated into. Subsequent studies showed that both the resistance and subsequent recovery in the ability of P. fluorescens to decompose added plant residues over 28 days after stress (resilience) varied significantly between a sandy and a clay-loam soil. Sterile, sandy and clay-loam soil was then inoculated with a complex microbial community extracted from either of the soils. The resulting microbial community structure depended on soil type rather than the source of inoculum, whilst the resistance and resilience of decomposition was similarly governed by the soil and not the inoculum source. Resilience of the clay-loam soil to heat stress did not depend on the water content of the soil at the time of stress, although the physical condition of the soil when decomposition was measured did affect the outcome. We propose that soil functional resilience is governed by the physico-chemical structure of the soil through its effect on microbial community composition and microbial physiology.     

Effective alleviation of Cd stress to microbial communities in mining reclamation soils by thiourea-modified biochar amendment

Reclaimed soils in mining area usually display low fertility and present Cd stress. The amendment of modified biochar effectively fixes Cd in soils,enhances soil fertility, and reduces Cd stress in soil microorganisms. However, the effect of thiourea-modified biochar(TBC) on microbial adaptability to Cd stress in mining reclamation soils is still unclear. The present work studied the Cd immobilization and microbial community changes in a mining reclamation soil displaying extreme Cd contaminatio...     

几种铵盐对土壤吸附Cd2+和Zn2+的影响

采用平衡吸附法,研究了不同铵盐对潮褐土、红壤吸附Cd2+、Zn2+的影响。结果表明,土壤对Cd2+、Zn2+的吸附量随平衡溶液中Cd2+、Zn2+浓度的增加而增加;潮褐土和红壤对Cd2+、Zn2+的最大吸附量为:Zn2+ Cd2+,且潮褐土红壤;随NH4HCO3浓度的增加,两种土壤对Cd2+、Zn2+的吸附率显著提高,NH4Cl、NH4NO3和(NH4)2SO4抑制红壤对Cd2+、Zn2+的吸附及潮褐土对Cd2+的吸附,对潮褐土Zn2+的吸附率影响不显著;铵盐浓度相同时,红壤对Cd2+吸附率为:NH4HCO3NH4ClNH4NO3≈ (NH4)2SO4,红壤对Zn2+吸附率为:NH4HCO3NH4Cl NH4NO3(NH4)2SO4。     

土壤、蔬菜Cd污染相关性分析与土壤污染阈限值研究

为探求土壤重金属污染和蔬菜污染的相关性,为绿色蔬菜生产提供技术支持,该研究以郑州市常见的5种叶菜类蔬菜(油麦菜、荆芥、蕹菜、生菜、苋菜)为试验材料,采用温室盆栽土培试验方法研究了土壤不同浓度 Cd污染与蔬菜污染的相关性,并对绿色蔬菜生产要求的土壤污染阈限值进行了分析。研究结果表明：低浓度Cd污染的土壤对蔬菜生长、产量有促进作用;随着Cd浓度的增加,5种蔬菜中的Cd含量都呈现增加趋势。蔬菜中的Cd含量与土壤中的含量相关性较好;模拟得出土壤Cd阈限值为：油麦菜(0.3199±0.0349)mg/kg,荆芥(0.3335±0.01904)mg/kg,蕹菜(0.1952±0.1072)mg/kg,生菜(0.1554±0.0064)mg/kg,苋菜(0.2690±0.0532)mg/kg;对Cd富集能力由大到小排序为：生菜、蕹菜、苋菜、油麦菜、荆芥。     

The effect of electrokinetics on soil microbial communities

There is growing interest in the potential of applying an electric field to soil to move and stimulate the degradation of contaminants, but we know little of the impact of this approach on exposed microbial communities. The effect of electrokinetics (3.14 A m⁻²) on soil bacterial and fungal communities was studied using soil cartridge microcosms (13 cm×5.4 cm×5.9 cm). After 27 days of electrokinetics, a zone of low pH (<4) was detected close to the anode. Soil exposed to electrokinetics and immediately adjacent to the anode demonstrated an increase in carbon substrate utilisation potential (≤290%) and microbial respiration rates. The diversity and structure of the bacterial community showed little response to electrokinetics, with the exception of soil close to the anode. Here, an increase in the percentage of Gram-positive species isolated was identified, most notably of Bacillus megaterium. Overall, the only detectable response of the microbial community was observed in soil immediately adjacent to the anode. The results of this study provide evidence that the application of electrokinetics has no serious negative effect on ‘soil microbial health’, thus endorsing its validity as a viable soil remediation technology.     

镉、锌胁迫对番茄幼苗生长及其脯氨酸与谷胱甘肽含量的影响

试验研究重金属Cd、Zn胁迫对水培番茄种子萌发、幼苗生长及相关生理指标的影响结果表明,Cd、Zn明显抑制番茄种子的发芽势和根的伸长、幼苗株高和干物质积累,而对种子发芽率的影响则较小;番茄叶片叶绿素含量和a/b值减小,高浓度处理时茎和叶片中含水量明显降低,可溶性糖、脯氨酸和谷胱甘肽含量增加,且叶片含量均高于根系。     

Substrate utilization patterns of desert soil microbial communities in response to xeric and mesic conditions

The Negev Desert is characterized by low soil moisture and organic matter content and an unpredictable rainfall amount, dispersion, and intensity. Water and nutrient availability are, therefore, the major limiting factors of biological activity in arid and semi-arid ecosystems. Plants have developed different ecophysiological adaptations in order to cope with the harsh conditions in this xeric environment, e.g., excretion of salt (Reaumuria negevensis) and chemical compounds (Artemisia sieberi) through the leaves. Microorganisms constitute a major part of these ecosystems' total biomass, and are diverse members of the soil food web, being primarily responsible for breaking down complex organic compounds, which are then recycled. They are also known to be very sensitive to abiotic changes and can time their activity to the environmental conditions.Soil samples were collected monthly from a 0 to 10 cm depth, under the canopies of A. sieberi, Noaea mucronata, and R. negevensis. Samples collected from inter-shrub spaces served as control. CO₂ evolution, microbial biomass, microbial functional diversity, and the physiological profile of the community, were determined by MicroResp™ analysis. A significant difference was found between the two dry periods in most of the examined parameters. The values of water, organic matter content, and total soluble nitrogen were higher in soil samples collected in the vicinity of R. negevensis than in samples collected in the vicinity of N. mucronata, A. sieberi, and the open area. A similar trend was found in CO₂ evolution, microbial biomass, and H' values, in which soil samples collected beneath the canopies of N. mucronata and R. negevensis and from open area had higher values during the wet periods (which were characterized by a mesic environment) and in samples collected beneath the A. sieberi in the wet 2006 and dry 2007 periods.     

Adsorption density,mobility and limit values of Cd,Zn, Cu and Pb in acid forest soils

To investigate Cd, Zn, Cu and Pb adsorption in acidified forest soils, six soil samples of the aluminium buffer range were selected and analyzed for their physical and chemical properties. Determination of the specific surface area using ethylene glycol monoethyl ether (EGME) adsorption yielded a characteristic value of the solid phases, which can parameterize the major properties of the various soil constituents with sufficient accuracy.

Traditional adsorption isotherms reveal the relation between the amount of a heavy metal adsorbed and the heavy metal concentration in the soil solution only for the soil under study and can therefore not be applied to other soils. To meet the aim of modelling heavy metal adsorption and mobility also for soils differing greatly in their properties, it was attempted to establish a generalizing adsorption isotherm for soils of entirely different composition of the solid phase. The generalizing adsorption density isotherms introduced in the following provide a useful mathematical model for the quantity/intensity relation of heavy metals in soils that differ greatly in their specific surface area and their composition.

It is also shown that limit values which take into account the major quantities influencing heavy metal adsorption and mobility in acid soils can be established from the regression equation between the adsorption density of a heavy metal (ions/m² specific surface area) and its concentration in the soil solution. In particular in view of the groundwater contamination to be expected if acid rain and, as a result, soil acidification continues, these limit values seem to provide considerably more information than the European limit values, given in mg heavy metal /kg soil, which are presently valid for any soil condition and property.     

Changes in microbial community structure in soil as a result of different amounts of nitrogen fertilization

The changes in size, activity and structure of soil microbial community caused by N fertilization were studied in a laboratory incubation experiment. The rates of N fertiliser applied (KNO₃) were 0 (control), 100 and 2,000 μg N g⁻¹ soil. Despite no extra C sources added, a high percentage of N was immobilized. Whereas no significant increase of microbial C was revealed during incubation period, microbial growth kinetics as determined by the substrate-induced growth-response method demonstrated a significant decrease in the specific growth rate of microbial community in soil treated with 2,000 μg N g⁻¹ soil. Additionally, a shift in microbial community structure resulting in an increase in fungal biomarkers, mainly in the treatment with 2,000 μg N g⁻¹ soil was visible.     

Cattle grazing increases microbial biomass and alters soil nematode communities in subtropical pastures

This study focused on examining the impacts of cattle grazing on belowground communities and soil processes in humid grasslands. Multiple components in the soil communities were examined in heavily grazed and ungrazed areas of unimproved and improved bahiagrass (Paspalum notatum Flugge) pastures in south-central Florida. By using small (1-m×1-m) sampling plots, we were able to detect critical differences in nematode communities, microbial biomass, and mineralized C and N, resulting from the patchy grazing pattern of cattle. Soil samples were collected on three occasions between June 2002 and June 2003. Microbial C and N were greater (P?0.01) in grazed than in ungrazed plots on all sampling dates. Effects of grazing varied among nematode genera. Most genera of colonizer bacterivores were decreased (P?0.10) by grazing, but more persistent bacterivores such as Euteratocephalus and Prismatolaimus were increased, as were omnivores and predators. Higher numbers of persisters indicated that grazing resulted in a more structured nematode community. Some herbivores, particularly Criconematidae, were decreased by grazing. Abundance of omnivores, predators, and especially fungivores were strongly associated with C mineralization potential. Strong correlation of microbial C and N with nematode canonical variables composed of five trophic groups illustrates important links between nematode community structure and soil microbial resources. Including the analysis of nematode trophic groups with soil microbial responses reveals detection of grazing impact deeper into the hierarchy of the decomposition process in soil, and illustrates the complexity of responses to grazing in the soil foodweb. Although highly sensitive to grazing impacts, small-scale sampling could not be used to generalize the overall impact of cattle grazing in large-scale pastures, which might be determined by the intensity and grazing patterns of various stocking densities at the whole pasture level.     

Cd/Zn 及Cd /Zn/Ni复合污染对胡萝卜生长吸收特征的影响

利用盆栽试验对胡萝卜在不同浓度Cd/Zn及Cd/Zn/Ni复合作用下的重金属吸收效应进行了研究。结果表明,在Cd/Zn/Ni和Cd/Zn复合污染条件下,胡萝卜茎叶和块茎干重与对照土壤比较均受到显著影响（P＜0.05）,尤其是含Ni组合,在Ni浓度达到250 mg·kg-1后,胡萝卜块茎和茎叶生物量都锐降（P＜0.01）。对比不同剂量下两组合富集系数（EF）和转运系数（TF）的结果发现,含Ni组合中, Cd、Zn、Ni 3种重金属在不同迁移界面以及不同浓度水平时的活性不同：在土壤-胡萝卜块茎迁移界面,当土壤中Cd、Zn、Ni浓度分别在0.35～1.8、50～300 mg·kg-1以及60～250 mg·kg-1之间时,活性大小为Cd〉Zn〉Ni;当其浓度分别达到3.5 mg·kg-1（Cd）、600 mg·kg-1（Zn）以及500 mg·kg-1（Ni）时,活性大小变为 Zn〉 Ni 〉Cd ;而在胡萝卜块茎－茎叶界面,Cd的活性在任何浓度水平下始终最大,当Zn、Ni浓度分别在50～180 mg·kg-1以及 60～170 mg·kg-1之间时,活性大小为Zn＞Ni ,但在此浓度之后Ni的作用突显,活性大小变为Ni＞Zn。非含Ni组合中,在两迁移界面和不同浓度水平下,两种重金属的迁移能力始终为Cd＞Zn。此外,在碱性较高的绿洲灌淤土中,Cd、Zn、Ni之间的交互作用表     

Culture-based and culture-independent assessment of the impact of mixed and single plant treatments on rhizosphere microbial communities in hydrocarbon contaminated flare-pit soil

Phytoremediation is a novel treatment option for weathered, hydrocarbon contaminated, flare-pit soil in prairie ecosystems. The remediation potential of six different naturalized prairie plants was assessed by examining their impact on the degradation potential of indigenous bacterial communities. Culture-based and culture-independent microbiological methods were used to determine if mixed plant treatments stimulate different microbial communities and catabolic genotypes in comparison to individual plant species that comprise the mix. DGGE analysis of PCR-amplified 16S rRNA genes revealed that alfalfa (Medicago sativa) had a dominant effect on the structure of rhizosphere microbial communities in mixed plant treatments, stimulating relative increases in specific Bacteroidetes and Proteobacteria populations. Alfalfa and mixes containing alfalfa, while supporting 100 times more culturable PAH degraders than other treatments, exhibited only 10% TPH reduction, less than all planted treatments except perennial rye grass (Lolium perenne). Total petroleum hydrocarbon (TPH) reduction was greatest in single-species grass treatments, with creeping red fescue (Festuca rubra) reducing the TPH concentration by 50% after 4.5 months. Overall TPH reduction throughout the study was positively correlated (p<0.001) to culturable n-hexadecane degraders.     

Alteration of soil microbial communities and water quality in restored wetlands

Land usage is a strong determinant of soil microbial community composition and activity, which in turn determine organic matter decomposition rates and decomposition products in soils. Microbial communities in permanently flooded wetlands, such as those created by wetland restoration on Sacramento-San Joaquin Delta islands in California, function under restricted aeration conditions that result in increasing anaerobiosis with depth. It was hypothesized that the change from agricultural management to permanently flooded wetland would alter microbial community composition, increase the amount and reactivity of dissolved organic carbon (DOC) compounds in Delta waters; and have a predominant impact on microbial communities as compared with the effects of other environmental factors including soil type and agricultural management. Based on phospholipid fatty acid (PLFA) analysis, active microbial communities of the restored wetlands were changed significantly from those of the agricultural fields, and wetland microbial communities varied widely with soil depth. The relative abundance of monounsaturated fatty acids decreased with increasing soil depth in both wetland and agricultural profiles, whereas branched fatty acids were relatively more abundant at all soil depths in wetlands as compared to agricultural fields. Decomposition conditions were linked to DOC quantity and quality using fatty acid functional groups to conclude that restricted aeration conditions found in the wetlands were strongly related to production of reactive carbon compounds. But current vegetation may have had an equally important role in determining DOC quality in restored wetlands. In a larger scale analysis, that included data from wetland and agricultural sites on Delta islands and data from two previous studies from the Sacramento Valley, an aeration gradient was defined as the predominant determinant of active microbial communities across soil types and land usage.     

Effects of Cd,Zn, or both on soil microbial biomass and activity in a clay loam soil

We investigated Cd, Zn, and Cd + Zn toxicity to soil microbial biomass and activity, and indigenous Rhizobium leguminosarum biovar trifolii, in two near neutral pH clay loam soils, under long-term arable and grassland management, in a 6-month laboratory incubation, with a view to determining the causative metal. Both soils were amended with Cd- or Zn-enriched sewage sludge, to produce soils with total Cd concentrations at four times (12 mg Cd g⁻¹ soil), and total Zn concentrations (300 mg Zn kg⁻¹ soil) at the EU upper permitted limit. The additive effects of Cd plus Zn at these soil concentrations were also investigated. There were no significant differences in microbial biomass C (B _C), biomass ninhydrin N (B _N), ATP, or microbial respiration between the different treatments. Microbial metabolic quotient (defined as qCO₂ = units of CO₂–C evolved unit⁻¹ biomass C unit⁻¹ time) also did not differ significantly between treatments. However, the microbial maintenance energy (in this study defined as qCO₂-to-μ ratio value, where μ is the growth rate) indicated that more energy was required for microbial synthesis in metal-rich sludge-treated soils (especially Zn) than in control sludge-treated soils. Indigenous R. leguminosarum bv. trifolii numbers were not significantly different between untreated and sludge-treated grassland soils after 24 weeks regardless of metal or metal concentrations. However, rhizobial numbers in the arable soils treated with metal-contaminated sludges decreased significantly (P < 0.05) compared to the untreated control and uncontaminated sludge-treated soils after 24 weeks. The order of decreasing toxicity to rhizobia in the arable soils was Zn > Cd > Cd + Zn.     

Composition of the microbial communities in the mineral soil under different types of natural forest

Phospholipid fatty acid (PLFA) patterns were used to describe the composition of the soil microbial communities under 12 natural forest stands including oak and beech, spruce-fir-beech, floodplain and pine forests. In addition to the quantification of total PLFAs, soil microbial biomass was measured by substrate-induced respiration and chloroform fumigation-extraction. The forest stands possess natural vegetation, representing an expression of the natural site factors, and we hypothesised that each forest type would support a specific soil microbial community. Principal component analysis (PCA) of PLFA patterns revealed that the microbial communities were compositionally distinct in the floodplain and pine forests, comprising azonal forest types, and were more similar in the oak, beech and spruce-fir-beech forests, which represent the zonal vegetation types of the region. In the nutrient-rich floodplain forests, the fatty acids 16:1ω5, 17:0cy, a15:0 and a17:0 were the most prevalent and soil pH seemed to be responsible for the discrimination of the soil microbial communities against those of the zonal forest types. The pine forest soils were set apart from the other forest soils by a higher abundance of PLFA 18:2ω6,9, which is typical of fungi and may also indicate ectomycorrhizal fungi associated with pine trees, and high amounts of PLFA 10Me18:0, which is common in actinomycetes. These findings suggest that the occurrence of azonal forest types at sites with specific soil conditions is accompanied by the development of specific soil microbial communities. The study provides information on the microbial communities in undisturbed forest soils which may facilitate interpretation of data derived from managed or even damaged or degraded forests.     

玉米秸秆生物炭对褐土微生物功能多样性及 细菌群落的影响

生物炭施入土壤被认为是一种有效的固碳减排措施,可增加土壤有机碳及矿质养分含量,提高土壤的持水能力及保肥能力。为探明其施入土壤后对土壤微生物活性及多样性的影响,本文在盆栽试验条件下,采用Biolog与高通量测序相结合的方法,研究了CK(不施生物炭)和施用5 g·kg~(-1)、10 g·kg~(-1)、30 g·kg~(-1)、60 g·kg~(-1)玉米秸秆生物炭对土壤微生物碳源利用能力(AWCD)、功能多样性指数以及土壤细菌的丰度和多样性的影响。结果表明,随着生物炭施用量的增加,表征土壤微生物活性的AWCD值呈下降趋势,表现为:5 g·kg~(-1)处理≈CK10 g·kg~(-1)处理30 g·kg~(-1)处理60 g·kg~(-1)处理,其中CK和5 g·kg~(-1)处理间差异不显著(P0.05),而10 g·kg~(-1)、30 g·kg~(-1)和60 g·kg~(-1)处理在整个培养期间的AWCD值显著低于CK处理(P0.05);土壤微生物群落代谢功能多样性指数(H′)、碳源利用丰富度指数(S)均随生物炭施用量的增加而呈下降趋势,但均匀度指数(E)表现出相反趋势,5g·kg~(-1)、10 g·kg~(-1)、30 g·kg~(-1)、60 g·kg~(-1)各处理的H′较CK处理分别增加0.16%、-0.88%、-3.14%、-11.09%,S分别增加-2.82%、-11.27%、-18.31%、-47.89%,E分别增加1.14%、3.00%、3.73%和13.76%。主成分分析表明,与CK处理比较,5 g·kg~(-1)处理对土壤微生物群落碳源利用方式没有显著影响(P0.05),而10 g·kg~(-1)、30 g·kg~(-1)和60g·kg~(-1)处理对土壤微生物群落碳源利用方式影响显著(P0.05)。随着生物炭施用量的增加,土壤细菌OTU数目及丰富度指数(Chao1)呈增加趋势,5 g·kg~(-1)处理与CK处理差异不显著,而10 g·kg~(-1)、30 g·kg~(-1)、60 g·kg~(-1)处理的OTU数目较CK处理分别增加1.09%、5.26%、24.42%,Chao1分别增加5.73%、10.21%、37.68%。土壤中施用生物炭后土壤细菌变形菌门(Proteobacteria)的丰度在CK处理和5 g·kg~(-1)处理间差异不显著(P0.05),而10g·kg~(-1)、30 g·kg~(-1)、60 g·kg~(-1)处理较CK处理分别增加32.3%、21.1%、16.7%,拟杆菌门(Bacteroidetes)的丰度随着生物炭施用量的增加各处理较CK处理分别减少22.1%、55.3%、66.8%、50.5%。生物炭施入土壤后降低了土壤可培养微生物的活性,减少或改变了土壤微生物碳源利用的种类,使土壤原有微生物群落组分发生改变,生物炭也影响了土壤细菌各菌群在土壤中的丰度,使其分布的均匀性降低。为了不影响微生物群落结构和功能,石灰性褐土上生物炭一次还田量不能超过5 g·kg~(-1)(干土)。     

Cd Zn交互作用对金针菇富集重金属的影响

以金针菇为试验材料,在基质中分别单独添加和同时添加不同浓度的Cd、Zn,采用栽培袋接种培养法研究了食用菌富集Cd、Zn以及Cd、Zn交互作用对食用菌累积重金属的影响。结果表明,低浓度的Cd（〈1mg·kg^-1）、Zn（〈600mg·kg^-1）能够促进金针菇的生长,但是高浓度的Cd、Zn对金针菇生长会产生抑制作用。随着栽培基质中Cd、Zn处理浓度的增高,金针菇子实体中的Cd、Zn浓度也随之增加。Cd—Zn之间表现为互相拈抗作用,金针菇子实体内的Cd含量随着培养基质中Zn浓度的增加而显著降低（P〈0．05）,Cd浓度降低比例与Zn／Cd比值之间呈显著的正相关（P〈0．01）。在Zn处理浓度为600mg·kg^-1,Cd处理浓度分别为1mg·kg^-1和10时,与不加Zn相比,金针菇子实体Cd含量分别降低29％和11％。Cd对Zn也表现出一定的拮抗作用,但是除在Zn为0和Cd为10mg·kg^-1处理时拈抗作用显著（P〈0．05）外,其余处理没有达到显著水平。而在10mg·kg^-1 Cd和600mg·kg^-1 Zn处理条件下,金针菇生物量显著下降,可能是由于Cd—Zn协同作用,造成毒害作用的结果。