| 1. |
- Arnebrant, Kristina, et al.
(författare)
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Copper Tolerance of Microfungi Isolated from Polluted and Unpolluted Forest Soil
- 1987
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Ingår i: Mycologia. - : Informa UK Limited. - 0027-5514. ; 79:6, s. 890-895
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Tidskriftsartikel (refereegranskat)abstract
- Microfungi were isolated from unpolluted and copper polluted forest soils and their tolerance was tested on agar plates. Species from polluted sites were usually tolerant to Cu. The species were Paecilomyces farinosus, Beauveria bassiana, Verticillium spp. and Penicillium pactum. Sensitive species were found among Mortierella, Oidiodendron and Penicillium. usually rare in polluted sites. Little evidence for adaptation to Cu was found among isolates with short or long history of pollution.
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| 2. |
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| 3. |
- Nohrstedt, H.Ö., et al.
(författare)
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Changes in carbon content, respiration rate, atp content, and microbial biomass in nitrogen-fertilized pine forest soils in Sweden
- 1989
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Ingår i: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 1208-6037 .- 0045-5067. ; 19:3, s. 323-328
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Tidskriftsartikel (refereegranskat)abstract
- Carbon content and indices of microbial biomass and activity were determined in 1985 in different soil horizons of two nitrogen-fertilized pine forests in Sweden. The Kroksbo site was fertilized in 1974 with 150 and 600 kg N•ha−1 using NH4NO3 or urea, while the Nissafors site was fertilized in 1977 and 1984 with 150 kg NH4NO3-N•ha−1 The absolute amount of C per square metre of forest floor increased in fertilizer treatments compared with the control (by 10–26%, depending on the site or fertilizer treatment). Respiration rate, ATP content, and microbial biomass C, measured with the substrate-induced respiration technique, decreased in all horizons when expressed per gram of C. The decrease was most evident with NH4NO3, and at the highest level of fertilization. However, on an area basis there were no differences between fertilizer and control treatments. A calculated increase in litter fall in the fertilized plots could not explain all the increase in the amount of C per square metre compared with the control. Decreased microbial activity per gram of C therefore appeared to be an important factor in the increase in C content in fertilized plots.
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| 4. |
- Nordgren, Anders, et al.
(författare)
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Evaluation of soil respiration characteristics to assess heavy-metal effects on soil-microorganisms using glutamic-acid as a substrate
- 1988
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Ingår i: Soil Biology & Biochemistry. - 0038-0717. ; 20:6, s. 949-954
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Tidskriftsartikel (refereegranskat)abstract
- Computerized continuous monitoring of soil respiration rates before and during glutamic acid decomposition in heavy metal polluted soils was used to determine four microbial parameters: basal respiration rate, substrate induced respiration rate, lag time before the exponential increase of the soil respiration rate and the specific respiration increment during the exponential phase. Both smelter- and laboratory-contaminated soils were studied. Basal respiration rate was the parameter most inhibited (54–77%) by heavy metal contamination. Increased soil moisture resulted in increased basal respiration rate, irrespective of pollution level. The substrate-induced respiration rate after the addition of glutamic acid was strongly correlated with the basal respiration rate (r = 0.85−0.95). The change in specific respiration increment was not related to metal contamination but increased with increasing soil moisture, with an optimum at about 250% H2O based on soil organic matter (oven-dried). Lag time was the parameter best correlated with smelter-induced metal contamination (r = 0.64 and 0.75). Unlike the three other parameters, the lag time was unaffected by soil moisture, irrespective of contamination level.
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| 5. |
- Nordgren, Anders, et al.
(författare)
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Soil microbial activity, mycelial lengths and physiological groups of bacteria in a heavy-metal polluted area
- 1986
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Ingår i: Environmental Pollution. - 0269-7491. ; 41:1, s. 89-100
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Tidskriftsartikel (refereegranskat)abstract
- Effects of heavy metals and soil pH around a smelter detected, including decreased abundance of certain degradative capacities such as: acid formation from maltose, cellobiose, arabinose or xylose, or hydrolysation of starch, pectin, xylan, or cellulose. Soil respiration also decreased, but not phosphatase activity.
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| 6. |
- Nordgren, Anders, et al.
(författare)
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Soil microfungi in an area polluted by heavy-metals
- 1985
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Ingår i: Canadian Journal of Botany. - 0008-4026. ; 63:3, s. 448-455
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Tidskriftsartikel (refereegranskat)abstract
- The microfungal species composition was studied in coniferous forest soils surrounding a brass mill at Gusum in southeast Sweden. Both the Cu and Zn concentrations were ca. 20 000 μg/g dry soil close to the mill. Pb concentration was ca. 1000 μg/g dry soil and the pH about 2 units above the normal of 3.5–4. The microfungal species composition (determined by the dilution plate technique) was strongly affected by the heavy-metal contamination. Close to the mill there was a decrease in isolation frequency of fungi common in coniferous forest soils, e.g., Penicillium spinulosum, P. montanense, P. brevicompactum, Oidiodendron cf. tenuissimum, O. cf. echinulatum, and O. maius. Other less common or rare fungi increased, e.g., Paecilomyces farinosus, Geomyces pannorum, Chalara constricta, C. longipes, and sterile forms. Fungi of the genus Mortierella seemed affected little by the heavy-metal contamination. Multivariate statistical analyses showed that the heavy-metal pollution was the dominating influence along the metal gradient and that soil moisture and loss on ignition accounted for little of the variation in the fungal data.
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| 7. |
- Olsson, Stefan, et al.
(författare)
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Growth of Verticillium dahliae Kleb. hyphae and of bacteria along the roots of rape (Brassica napus L.) seedlings
- 1987
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Ingår i: Canadian Journal of Microbiology. - 0008-4166. ; 33:10, s. 916-919
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial density and the hyphal density of Verticillium dahliae were determined along the roots of sand-grown rape seedlings. Verticillium dahliae microsclerotia were trapped in nylon nets which were placed in front of the growing root tip. The growing hyphae on the nets were stained with fluorescein diacetate and rhodamine B isothiocyanate. Bacteria on the petri dish lids adjacent to the nets were stained with acridine orange. Both fungal and bacterial densities increased exponentially over a distance of 15–20 mm from the root tip. Further back along the root, the densities of microorganisms stabilized, but in some cases the fluorescein diacetate active hyphal density increased. The hyphal densities stopped increasing before bacterial densities, suggesting an increasing bacterial competition for root exudates as their population grew. The hyphal activity, measured as the proportion of flurescein diacetate to rhodamine B isothioicyanate stained hyphae, increased during the exponential growth phase of the bacteria, then decreased, and finally increased again as the lateral roots appeared.
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