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1.
We have shown previously that riboflavin is stored in chloragosomes of chloragocyte-derived earthworm eleocytes what may have an adaptive value for worms vulnerable to soil-derived pathogen invasion. Thus, it is important to determine whether riboflavin stores are also present in earthworm species with low eleocyte counts, especially in the chloragocytes of their chloragogen tissue that surrounds the coelomic site of the intestine, and find out its putative roles in earthworm immunity. Experiments were performed on adult worms from 6 species. Freely floating coelomocytes (consisting of amoebocytes plus species-specific numbers of eleocytes) were extruded by mild electric shock and then chloragocytes from the same anaesthetized worm were mechanically detached into buffer. Both cell suspensions were analyzed by spectrofluorometry for riboflavin content. It turned out that riboflavin is stored in species-specific quantities in all investigated species. Riboflavin storage predominates in free coelomocytes of eleocyte-rich species (Eisenia andrei, Dendrobaena veneta, Allolobophora chlorotica) while in chloragocytes of species with few eleocytes (Lumbricus terrestris, L. rubellus, and Aporrectodea caliginosa). Upon a massive microbial impact, the coelomocytes (both amoebocytes and eleocytes) are involved in the formation of multicellular bodies encapsulating soil-derived pathogens, what is connected with enhanced coelomocyte mobility. Thus the second aim of the present investigation was to check if riboflavin can participate in coelomocyte accumulations. Tests performed in a 48-well chemotaxis chamber revealed that riboflavin behave as chemoattractant for coelomocytes of all investigated earthworm species, which may be one of mechanisms underpinning its immunomodulatory functions.  相似文献   

2.
The riboflavin content in extruded coelomocyte lysates derived from Dendrodrilus rubidus may serve as a sensitive bioindicator of soil metal pollution: the vitamin (B2) content has previously been found to be high in worms from unpolluted soil but low in worms inhabiting Zn/Pb mine soils, aerially deposited Ni-contaminated soil, and in worms experimentally transferred from clean soil to the metalliferous field soils. The aim of the present work was to extend these observations by comparing the number and riboflavin composition of coelomocytes retrieved from three lumbricid species (Allolobophora chlorotica, Dendrobaena veneta, Eisenia andrei) after 4-week exposures to an unpolluted commercial soil, two geochemically contrasting unpolluted field soils, and two different Zn/Pb/Cd-polluted soils from the Bukowno district in South Poland. Whilst eco-physiologically contrasting, these three earthworm species share the trait of possessing relatively high numbers of eleocytes, a category of immune-competent coelomocyte rich in autofluorescent riboflavin. Spectroflurometric analysis indicated that coelomocyte riboflavin content in worms maintained in strongly metalliferous soils or in unpolluted sandy-clay and loamy-sand soils was increased in coleomocytes from epigeic D. veneta and E. andrei species, whilst was decreased in endogeic A. chlorotica. In conclusion, the riboflavin content of earthworm coelomocytes is affected in species-specific ways by edaphic variables, including organic matter and metal pollution.  相似文献   

3.
The principal aims of this study were to investigate the in vitro effects of copper (Cu), cadmium (Cd) and the polycyclic aromatic hydrocarbon (PAH) dimethylbenz[a]anthracene (DMBA) on reactive oxygen species (ROS) production and the effect of DMBA on immune function (phagocytosis) in coelomocyte samples isolated from the earthworm Eisenia hortensis. Using a fluorogenic indicator of ROS, dihydrorhodamine 123, we show that earthworm coelomocytes are induced to produce significant increases in ROS when exposed to Cu or Cd at 32–250 μM, an effect diminished by the chelator ethylenediaminetetraacetic acid (EDTA). DMBA also induced significant ROS production in the range of 20–400 μM compared to controls. Testing the effect of DMBA on cellular immune mechanisms, we used a phagocytosis assay to reveal an immunosuppressive effect of DMBA (50–200 μM) on the capacity of hyaline amoebocytes to ingest fluorescent Escherichia coli. These studies illustrate the relative ease and efficiency of these in vitro procedures for testing the toxicological effects of environmental pollutants, including heavy metals and PAHs, using earthworm coelomocytes as indicators of oxidative stress and immune response impairment.  相似文献   

4.
Earlier research with endogeic and epigeic earthworm species in loamy arable soil has shown that both earthworm groups can increase nitrous oxide (N2O) emissions, provided that crop residue placement matches the feeding strategy of the earthworm ecological group(s). However, it is not yet clear whether these effects also occur in sandy soils which typically contain less soil organic matter and have low soil aggregation levels. Here, we aimed to quantify N2O emissions as affected by endogeic and/or epigeic earthworm species, and to relate changes in N2O emissions to earthworm-induced changes in soil properties in a sandy soil. A 90 day mesocosm study was conducted with sandy soil and 15N-labeled radish (Raphanus sativus cv. Adagio L.) residue applied on top. Treatments included: (i) no earthworm addition, (ii) addition of the endogeic species Aporrectodea caliginosa (Savigny), (iii) addition of the epigeic species Lumbricus rubellus (Hoffmeister), and (iv) both species combined. An additional treatment was included without earthworms and with residue manually incorporated into the soil. L. rubellus significantly increased cumulative N2O emissions from 228 to 859 μg N2O–N kg?1 (F1,12 = 83.12, P < 0.001), whereas A. caliginosa did not affect N2O emissions. In contrast to earlier studies in loamy soil, no positive interaction between both species with regard to N2O emissions was found. This was probably related to high competition for organic resources in the relatively poor soil and a low potential for stable soil aggregate formation (and associated anaerobic microsites) by endogeic worms in sandy soil. 15N isotope analysis revealed that the activity of L. rubellus significantly increased (F1,12 = 6.20, P = 0.028) the recovery of 15N in the 250–8000 μm size fraction, indicating incorporation of crop residues into the mineral soil. When residues were manually incorporated, N2O emissions were significantly (P < 0.008) lower (509 μg N2O–N kg?1) than when incorporated by L. rubellus. The high N2O emissions in the presence of L. rubellus, when compared to manual mixing, suggest a stimulation of microbial activity and/or changes in the microbial community composition. Insights on the earthworm effects on N2O emission from such soils are discussed.  相似文献   

5.
A laboratory experiment was performed to assess the impact of ecologically different earthworm species on soil water characteristics, such as soil tension, water content, and water infiltration rate. Three earthworm species (Lumbricus rubellus, Aporrectodea caliginosa, Lumbricus terrestris) were exposed in soil columns (diameter 30 cm, height 50 cm) for 100 days with a total fresh earthworm biomass of 22.7 ± 0.4 g per column, each in duplicate. Each column was equipped with tensiometers at 10 and 40 cm and FD-probes at 10 cm depth, to continuously measure the temporal development of soil tension and soil moisture. Additionally, 30 g of sieved and rewetted horse manure was placed on the soil surface as a food source. Precipitation events (10 mm) were simulated at day 28 and day 64. At the end of the experiment the water infiltration rate and the runoff at 55 cm depth were determined.The results showed considerable evidence, that ecologically different earthworms modify soil water characteristics in different ways. The anecic L. terrestris and the endogeic A. caliginosa showed the tendency to enhance the drying of the topsoil and subsoil. Their intensive and deep burrowing activity might enhance the exchange of water vapor due to a better aeration in soil. In contrast, the epigeic L. rubellus tended to enhance the storage of soil moisture in the topsoil, which might be linked to lower rates of litter loss from soil surface and thus a thicker litter layer remaining. A. caliginosa led to considerable higher water infiltration rates and faster water discharges in the subsoil, relative to the other species, probably due to a high soil dwelling activity.  相似文献   

6.
To get a better understanding of earthworm’ responses towards flooding, three laboratory experiments were performed with the species Allolobophora chlorotica, Aporrectodea caliginosa and Lumbricus rubellus.Flooding response was determined in a pot experiment, in which the earthworms were incubated for 42 days in flooded or non-flooded soil, with or without heavy metal pollution. To determine moisture preference, earthworms were incubated for 9 days in aquaria with five compartments, containing soil with a moisture gradient (%, w/w), ranging from 35%, 45% (field capacity), 55%, 65% (saturated) to 65%+ (saturated and an extra water layer). Effects on earthworm health were studied by incubating earthworms of each species for 42 days in soil with the same range of moisture contents and determining the dry/wet weight ratio and dry weight gain as an indication of earthworm health.A. chlorotica was tolerant to water, although the worms tended to escape from flooded soil. Their health was significantly lower in the flooded soils (P<0.05). A. caliginosa showed little response to flooding. This species, however, was affected by the heavy metal pollution in the pot experiment. L. rubellus was sensitive towards flooding, with escape and avoidance behaviour being the main mechanism of survival. This species was able to survive when forced to stay in flooded soil for at least 42 days, but this significantly reduced its health (P<0.05).These results suggest that earthworms are able to survive in inundated soils, but there are large differences between species in response to flooding conditions.  相似文献   

7.
Earthworms can have a profound effect on a myriad of soil physical, chemical and microbial parameters. To better understand their role in the soil, they are often studied under controlled conditions. However, a persistent problem in such controlled experiments is the ability of earthworms to escape from experimental units with open tops (e.g. for plant growth). Here, we tested whether adhesive hook tape applied to the inside of mesocosms is effective in confining them to their experimental units. A mesocosm study was set up with hook tape treatments (control, one layer, two layers), mesocosm material (polyvinylchloride – PVC, polypropylene – PP) and earthworm species (Lumbricus rubellus (Hoffmeister), Aporrectodea caliginosa (Savigny), Lumbricus terrestris (L.) + Aporrectodea longa (Ude)) as different factors to study the escape of earthworms during 24 h. In the treatments without hook tape, individuals of L. rubellus and A. caliginosa escaped, with highest escape rates (80%) for L. rubellus from the PP mesocosms, and lowest escape rates (20%) for A. caliginosa from the PVC mesocosms. When hook tape was applied, in either one or two layers, no individuals of those species escaped. The two anecic earthworm species, L. terrestris and A. longa did not escape from any mesocosms, irrespective of the presence of hook tape. As not a single earthworm escaped from the hook tape treatments, we conclude that applying hook tape is a simple, inexpensive and effective method to keep earthworms confined to experimental units.  相似文献   

8.
Although the role of earthworms in soil functioning is often emphasised, many important aspects of earthworm behaviour are still poorly understood. In this study we propose a simple and cost-effective method for estimating burrow system area and continuity, as well as a new and often neglected parameter, the percentage of burrow refilling by the earthworms own casts. This novel parameter is likely to have a huge influence on the transfer properties of the burrow system. The method uses standard repacked soil cores in PVC cylinders and takes advantages of clay shrinkage and the fact that earthworms were previously shown to prefer to burrow at the PVC/soil interface. In this way, after removing the PVC cylinders off dry cores, the external section of the burrow system made by earthworms along the soil walls could be easily described. We applied this method to characterise the burrow systems of four earthworms species: two anecics (Aporrectodea caliginosa nocturna and Aporrectodea caliginosa meridionalis) and two endogeics (Aporrectodea caliginosa icaliginosa and Allolobophora chlorotica). After one month the burrow's area generated by both anecic species were much larger (about 40 cm2) than the endogeic burrow's area (about 15 cm2). A. nocturna burrow system continuity was higher than that of A. meridionalis and both anecic burrow systems were more continuous than those made by the endogeic earthworms. This was partly explained by the far larger proportion of the burrow area that was refilled with casts: approximately 40% and 50% for Al. chlorotica and A. caliginosa, respectively compared with approximately 20% for the anecic burrows. We discuss whether these estimates could be used in future models simulating the dynamics of earthworm burrow systems by taking into account both burrow creation and destruction by earthworms.  相似文献   

9.
Few earthworms are present in production agricultural fields in the semi-arid plains of Colorado, where earthworm populations may be constrained by limited water and/or organic matter resources. We conducted a 12-week laboratory incubation study to determine the potential of a non-native endogeic earthworm (Aporrectodea caliginosa) to survive in a low-organic matter Colorado soil (1.4% organic C content), supplemented with or without biosolids, and to determine the effects of A. caliginosa on soil microbial biomass and soil nutrient availability. A factorial design with three main effects of A. caliginosa, biosolids addition, and time was used. Data was collected through destructively sampling at one, two, four, eight, and twelve weeks. During the 12-week study, 97.5% of the worms in the soil survived, and the survival of the earthworms was not significantly affected by the addition of biosolids. The addition of biosolids, however, did significantly reduce the gain in mass of the earthworms (8% mass gain compared to 18% in soil without biosolids). The presence of A. caliginosa significantly increased soil NH4-N, and NO3-N concentrations by 31% and 4%, respectively, which was less than the six fold increases in both soil NH4-N, and NO3-N concentrations supplied from biosolids. Microbial biomass carbon was not affected by A. caliginosa, but microbial biomass N was affected by an earthworm × biosolids interaction at week 1 and 12. We concluded that A. caliginosa can survive in a low-organic matter Colorado soil under optimal moisture content and that once established, A. caliginosa can provide modest increases in inorganic N availability to crops Colorado agroecosystems.  相似文献   

10.
Wormcasts of Allolobophora caliginosa have been shown to have higher phosphatase activity than occurs in uningested soil, resulting in an increase in inorganic P released by mineralization of organic P. This paper describes similar observations on organic wastes which may be used for vermiculture. Besides A. caliginosa, three species which will feed on dung or other organic substrates were investigated, Eisenia foetida, Dendrobaena veneta and Lumbricus rubellus. When cow dung was used as a substrate, background phosphatase activity was too high for the effects of earthworm activity to be detected and a culture medium was therefore developed from sterilized paper waste sludge with added phytin. Phosphatase activity, assayed by a modified Hoffman method, was higher in the presence of all four earthworm species than in controls. It showed two peaks in relation to pH, at 3–5 and 9–10. The former is attributed to microbial activity and the latter to microbial activity or earthworm alkaline phosphatase. After 1 month, cultures of paper waste sludge with phytin contained about twice as much water soluble P when worms were present than in their absence.  相似文献   

11.
Laboratory toxicity tests are usually conducted under stable conditions, while exposures in the field occur under variable environmental conditions. Field studies are therefore more appropriate in understanding the effect of single or mixed pollutants in the environment. Short-term interactive effects of natural environmental factors (flooding and drought) and anthropogenic stressors (copper and salinity) on the earthworm Aporrectodea caliginosa were investigated using outdoor microcosm experiments. Specimens of the lumbricid earthworm A. caliginosa were exposed in microcosms loaded with soils with increasing salinity with electrical conductivity (EC) ranging from 0.08 to 1.05 dS m?1, with or without copper oxychloride spray treatments at recommended and elevated dosages. The experiment was conducted in August/September (end of winter) and repeated in November/December (end of spring) in the Stellenbosch area, South Africa to attain exposure under variable environmental conditions. In the soil, changes in Cu concentrations along the gradient of salinity were monitored using three methods: CaCl2, DTPA and nitric acid extraction. Survival, weight change, and cocoon production of worms and body Cu concentrations were used as indices of interaction. None of the three extraction methods could reveal interactive effects between salinity and Cu in both seasons either because concentrations of Cu were too low or below detection limits. Copper, on its own, did not have a significant effect on the measured worm parameters during both seasons. During the winter experiment, flooding of microcosms significantly reduced the survival and affected the weight change of worms, and probably caused leaching of chemicals. Interaction between salinity and Cu had no significant effects on the measured worm parameters in winter while salinity only had a significant negative effect on weight change of worms. During spring, significant synergistic interaction between salinity and Cu occurred but only at 0.3 dS m?1 by day 14 of the exposure period. At this and higher levels, salinity had a significant individual effect on survival and weight change of worms at days 14 and 28. The results indicate that higher toxicity of salinity could be expected during the dry spring periods than during the wet winter periods which are typical for southern temperate zones.  相似文献   

12.
Earthworms play an important role in many soil functions and are affected by soil tillage in agricultural soils. However, effects of tillage on earthworms are often studied without considering species and their interactions with soil properties. Furthermore, many field studies are based on one-time samplings that do not allow for characterisation of temporal variation. The current study monitored the short (up to 53 days) and medium term (up to 4 years) effects of soil tillage on earthworms in conventional and organic farming. Earthworm abundances decreased one and three weeks after mouldboard ploughing in both conventional and organic farming, suggesting direct and indirect mechanisms. However, the medium-term study revealed that earthworm populations in mouldboard ploughing systems recovered by spring. The endogeic species Aporrectodea caliginosa strongly dominated the earthworm community (76%), whereas anecic species remained <1% of all earthworms in all tillage and farming systems over the entire study. In conventional farming, mean total earthworm abundance was not significantly different in reduced tillage (153 m−2) than mouldboard ploughing (MP; 130 m−2). However, reduced tillage in conventional farming significantly increased the epigeic species Lumbricus rubellus from 0.1 m−2 in mouldboard ploughing to 9 m−2 averaged over 4 years. Contrastingly, in organic farming mean total earthworm abundance was 45% lower in reduced tillage (297 m−2) than MP (430 m−2), across all sampling dates over the medium-term study (significant at 3 of 6 sampling dates). Reduced tillage in organic farming decreased A. caliginosa from 304 m−2 in mouldboard ploughing to 169 m−2 averaged over 4 years (significant at all sampling dates). Multivariate analysis revealed clear separation between farming and tillage systems. Earthworm species abundances, soil moisture, and soil organic matter were positively correlated, whereas earthworm abundances and penetration resistance where negatively correlated. Variability demonstrated between sampling dates highlights the importance of multiple samplings in time to ascertain management effects on earthworms. Findings indicate that a reduction in tillage intensity in conventional farming affects earthworms differently than in organic farming. Differing earthworm species or ecological group response to interactions between soil tillage, crop, and organic matter management in conventional and organic farming has implications for management to maximise soil ecosystem functions.  相似文献   

13.
In traditional environmental risk assessment for soils, interactions between biota, contaminants and soil functioning are seldom taken into account. Also, single species toxicity tests are conducted with a fixed number of test animals. The objective of this study was to investigate effects of zinc (0–620 mg Zn kg?1 dry soil) on soil ecosystem processes at different densities of the earthworm Lumbricus rubellus. Experiments were conducted using 1-liter microcosms equipped with respirometers. The presence of L. rubellus stimulated relevant soil processes and parameters: litter fragmentation, leaf litter mass loss from the soil surface, soil organic matter (SOM) content and soil respiration. Zinc was not lethal to L. rubellus, but negatively impacted soil respiration at the highest concentrations. Litter mass loss from the soil surface was also decreased by zinc and there was a significant interaction with worm density. The results of the study demonstrate that the impact of zinc on soil processes depends on the presence and densities of key soil organisms such as earthworms that influence decomposition and SOM content. The outcome of this research can be used to make existing models for site-specific risk assessment more ecologically relevant, linking effects of contaminants on soil fauna populations with effects on ecosystem functioning.  相似文献   

14.
While many species of earthworms are globally distributed, very little is known about the genetic population dynamics of this diverse group. We present the characterization of novel simple sequence repeat (SSR) markers, including primer information, number of alleles, repeat motif, and approximate size ranges, to be used in population genetic analyses of the earthworm Lumbricus rubellus Hoffmeister 1843. Specifically, we designed and characterized 12 novel, polymorphic markers derived from published expressed sequence tags (EST) for amplification in L. rubellus. The mean number of alleles per locus was 6.25 ± 1.91, indicating these markers will be sufficiently polymorphic for population genetic studies of this species.  相似文献   

15.
This study aimed to evaluate short-term earthworm-induced changes in the availability of metals applied to soil directly (metal-spiked) or via an organic matrix (sludge-amended). A laboratory experiment was performed using destructive sampling of microcosms filled with agricultural soil. A concentration gradient of industrial sludge contaminated predominantly with Cr, Cu, Ni, and Zn, and a soil freshly spiked with the same metal concentrations were applied on top of the soil columns. Individuals of Dendrobaena veneta (mimicking a realistic density of 500 earthworms per m2) were introduced in half of the replicates of each treatment. Total and 0.01 M CaCl2 extractable metal concentrations were measured in soil after 0, 3, 6 and 12 weeks and metal concentrations in earthworms and percolates were measured after 3, 6, and 12 weeks. Earthworm activity did not affect metal availability of any treatment over time, but Ni and Cu concentrations in D. veneta were higher at the highest treatment levels. Earthworm Zn concentrations were similar in all treatments while Cr concentrations increased with increasing soil total metal content only for sludge treatments. Existing relationships of earthworm metal concentrations with total metal content in soil, taken from the literature, were not able to predict the metal levels measured in D. veneta. Results demonstrated that although over 12 weeks earthworm activity did not affect metal availability in soil, their burrowing activities did influence the metal concentrations of percolates over time.  相似文献   

16.
《Pedobiologia》2014,57(3):161-169
C mineralization and aggregate stability directly depend upon organic matter and clay content, and both processes are influenced by the activity of microorganisms and soil fauna. However, quantitative data are scarce. To achieve a gradient in C and clay content, a topsoil was mixed with a subsoil. Single soils and the soil mixture were amended with 1.0 mg maize litter C g soil−1 with and without endogeic earthworms (Aporrectodea caliginosa). The differently treated soils were incubated for 49 days at 15 °C and 40% water holding capacity. Cumulative C mineralization, microbial biomass, ergosterol content and aggregate fractions were investigated and litter derived C in bulk soil and aggregates were determined using isotope analyses. Results from the soil mixture were compared with the calculated mean values of the two single soils. Mixing of soil horizons differing in carbon and clay content stimulated C mineralization of added maize residues as well as of soil organic matter. Mixing also increased contents of macro-aggregate C and decreased contents of micro-aggregate C. Although A. caliginosa had a stimulating effect on C mineralization in all soils, decomposition of added litter by A. caliginosa was higher in the subsoil, whereas A. caliginosa decreased litter decomposition in the soil mixture and the topsoil. Litter derived C in macro-aggregates was higher with A. caliginosa than with litter only. In the C poor subsoil amended with litter, A. caliginosa stimulated the microbial community as indicated by the increase in microbial biomass. Furthermore, the decrease of ergosterol in the earthworm treated soils showed the influence of A. caliginosa on the microbial community, by reducing saprotrophic fungi. Overall, our data suggest both a decrease of saprotrophic fungi by selective grazing, burrowing and casting activity as well as a stimulation of the microbial community by A. caliginosa.  相似文献   

17.
Application of earthworm in soil re-cultivation and re-creation in post-industrial ecosystems make a big challenge for temporal applied zoology. The sediments of the Krakow Soda Works “Solvay” have undergone land reclamation in different ways: older sediments traps were left without any re-cultivation practices; meanwhile the newest ones were reclaimed using standard method (new soil cover planted with combination of grass and leguminous plants). The effect of different treatments on community and population structure of earthworm was estimated during consecutive years 1999–2000. Six localities differing in time of establishment, reclamation processes, vegetation type and soil properties were chosen. Nine species were recorded, among which Aporrectodea caliginosa occurred in all localities, being also the most abundant. Two other species, Lumbricus rubellus and Dendrobaena octaedra, which are epigeic species, become most important in forest assemblages and were characteristic for communities of older succession processes. Abundance of adult forms as well as total biomass were significantly affected by soil depth (r = 0.75, P < 0.05, r = 0.917, P < 0.001, respectively). Species richness however was connected with higher amount of macroelements and average plant height. Shannon diversity index and its evenness negatively correlated only with forestation (r = –0.67, P < 0.05, r = –0.68, P < 0.05, respectively). Niche overlap (α Pianka) for all analysed species extracted two groups differing in environmental requirements. First contained epigeic earthworms, closely related to plant succession (PCA results), the other one grouped endogeic and anecique species correlated significantly with soil depth and plant density. Community structure of earthworms do not reflects succession changes in post-industrial habitats, but is strongly affected by microhabitat factors in local scale (mainly soil depth and plant density).  相似文献   

18.
A soil microcosm experiment was performed to assess (1) the C- and N- turnover of residues from biogas plants in soils in the presence of three earthworm species (Lumbricus terrestris, Aporrectodea longa and Aporrectodea caliginosa) and (2) the resulting changes in soil chemical and microbiological properties when using these residues as fertilizer in comparison to conventional slurry. Earthworms were exposed in soils, fertilized with an equivalent amount of 120 kg of NH4-N ha?1 from: (1) conventional cattle slurry and (2) a fermented residue derived from cattle slurry, grass (silage) and maize. Additional treatments without slurry and earthworms were used as controls.There was considerable evidence that soils fertilized by fermented slurry comprised fewer amounts of readily available nutrients for microbial C and N turnover. We observed significant stimulation of microbial biomass, basal respiration and nitrification in treatments with conventional slurry, especially in the presence of earthworms. However, the stimulation of microbial activity by manure and earthworms were significantly lower in treatments with fermented slurry. Moreover, the results showed clear interactions between different earthworm species and manures. While the biomass of the anecic species (L. terrestris and A. longa) increased in both slurry treatments, the biomass of A. caliginosa (endogeic) decreased, with a significantly stronger biomass decline in treatments with fermented slurry. The metabolic quotients revealed microbial stress metabolism in fermented slurry treatments, predominantly in treatments with A. caliginosa. We conclude that particularly A. caliginosa and soil microorganisms competed for labile C sources in treatments with fermented slurry. An application of these residues as fertilizer might result in a reduction of microbial activity in agricultural soils and in a decline of endogeic earthworms.  相似文献   

19.
《Pedobiologia》2014,57(4-6):223-233
Mycorrhizal fungi and earthworms can individually or interactively influence plant growth and heavy metal uptake. The influence of earthworms and arbuscular mycorrhizal (AM) fungi either alone or in combination on maize (Zea mays L.) growth and cadmium (Cd) uptake was investigated in a calcareous soil artificially spiked with Cd. Soils were contaminated with Cd (10 and 20 mg Cd kg−1), inoculated or un-inoculated with the epigeic earthworm Lumbricus rubellus and two AM fungal species (Rhizophagus irregularis and Funneliformis mosseae) for two months of growth under greenhouse conditions. Generally, earthworms alone increased both shoot P uptake and biomass but decreased shoot Cd concentration and root Cd uptake. AM fungi individually often increased total maize P uptake, declined shoot Cd concentration, and consequently produced higher total biomass. However, R. irregularis enhanced shoot Cd uptake at low Cd level and root Cd uptake at high Cd level. In plants inoculated with F. mosseae species, earthworms increased shoot biomass and Cd uptake, decreased root biomass and Cd uptake at all Cd levels, and increased shoot Cd concentration at low Cd level. In plants colonized by R. irregularis species, however, earthworm addition decreased maize biomass only at high Cd level and root Cd concentration and total maize Cd uptake at both Cd levels. Earthworm activity decreased Cd transfer from the soil to maize roots at low Cd level, but this was counterbalanced in the presence of F. mosseae. Mycorrhizal symbiosis significantly reduced the transfer of Cd from roots to shoots, independence of earthworm effect. Overall, it is concluded that L. rubellus and AM fungi, in particular F. mosseae isolate, improved maize tolerance to Cd toxicity both individually and interactively by increasing plant growth and P nutrition, and restricting Cd transfer to the aboveground biomass. Consequently, the single and interactive effects of the two soil organisms might potentially be important not only in protecting maize plants against Cd toxicity, but also in Cd phytostabilization in soils polluted by this highly toxic metal.  相似文献   

20.
The river floodplain ‘Afferdense and Deestsche Waarden’ (ADW) in The Netherlands is diffusely contaminated with several heavy metals. It is, however, unclear whether this mixed contamination exerts any adverse ecotoxicological effects. In November 2000 and May 2001 a field survey was conducted in two areas in the ADW to collect a wide range of data concerning contamination levels, bioavailability, enchytraeids and earthworms and abiotic factors such as lutum and organic matter content, cation exchange capacity (CEC) and soil nutrient concentrations. Earthworms and enchytraeids were also analyzed for heavy metal content. At both sites arsenic and zinc were present in soil at relatively high concentrations (above the Dutch intervention value). In the two areas, both enchytraeids and earthworms accumulated metals. Fridericia ulrikae accumulated more cadmium than Enchytraeus buchholzi and Henlea perpusilla. The earthworm Lumbricus rubellus accumulated larger concentrations of Cr, Cu and Pb than Aporrectodea caliginosa and Allolobophora chlorotica. Dietary, physiological and behavioral characteristics may have contributed to these differences.  相似文献   

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