Articles containing the keyword 'bacteria'

A ten-year old stand of hybrid aspen (Populus tremula x Populus tremuloides), growing in Southern Finland on about 1.5 ha of Oxalis-Myrtillus type (OMT) soil and affected by crown blight, was examined in 1971. The study revealed that almost all trees, both those removed by thinning and the remaining growing stock, were decayed. A number of bacteria, Fungi imperfecti species and ascomycetous fungi were isolated from the discoloured heartwood of the affected trees. No fungus of the Bacidiomycetes was found in the discoloured wood material.

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• Kallio, E-mail: tk@mm.unknown

During the summer and fall of 1966 changes brought about by urea, calcium ammonium nitrate, nitrate of lime, and ammonium sulphate were observed. Application of the fertilizers corresponded to 100 kg/N per hectare.

The effect of urea was immediate. The pH rose and the bacterial density increased to 20–30 times more than determined in the spring, while the microfungal density decreased to one third of the spring density. In the ammonium sulphate plot opposite changes occurred almost as rapidly as in the previous case. A gradually increasing biological activity observed after application of calcium ammonium nitrate and of lime fertilizers seemed almost the same for bacteria and microfungi. Both microbe groups displayed consistent quantitative growth. pH 4.3 was the limit of acidity below which the bacteria showed a tendency to decline and the microfungi to increase, while the opposite was true above this limit.

The PDF includes a summary in Finnish.

• Schalin, E-mail: is@mm.unknown

Quantitative investigation of bacteria in the humus is needed when the intensity of their function in decomposition in the soil is studied. In this study bacterial density of humus was measured using dilution plate method, which was subjected to thorough investigation. The method was chosen, despite its complexity, because it is quite consistent, each stage can be studied separately and the reliability can be tested. The aim of the study was to determine the best way to take samples so that the sample will represent the bacterial population as closely as possible, and to optimize homogenization and dilution of the sample and the assays.

On the basis of the results of the investigation, a procedure was developed for quantitative determination of aerobic bacteria in the humus by the dilution plate method. The paper recommends that subsamples are collected systematically from at least 25 different points. The moisture and temperature of the samples should remain similar to the natural environment until preparation of the dilution. The sample was homogenized with the Bühler homogenizer, which is constructed so that a certain degree of asepsis can be maintained and the speed of the apparatus can be regulated. The content of the mineral nutrients of the sample must be determined when choosing the way of homogenization to obtain the highest number of colonies per plate. The sample was diluted with either 0.1–0.01% peptone solution or 0.5% soil extract. The most advantageous degree of dilution was obtained by testing with the aid of Fisher’s dispersion index the probability of the Poisson distribution in the results.

• Schalin, E-mail: is@mm.unknown

The purpose of this investigation was to obtain a preliminary picture of the composition of the microbial population in some virgin soils on forest land in Finland. Four different forest types were studied, Oxalis-Myrtillus type birch (Betula sp.) stand, Oxalis-Myrtillus type Norway spruce (Picea abies (L.) Karst.) stand, Vaccinium type Scots pine (Pinus sylvestris L.) stand, and drained pine bog. In addition, a flood meadow was selected as a comparison.

The methods used captured only part of the fungi growing in the soil. Rapidly growing types, especially Mucor and Penicillium species, were mainly isolated. In addition, fungi showing activity of decomposition, such as Fusarium, Monosporium and Spicaria, as well as an ascomycete of the genius Ascobolus, were isolated. Autochthonous bacteria were most abundant in the soils of Oxalis-Myrtillus type forests and in the flood meadow. In the birch stand 90% of the autochthonous bacterial flora were gram-negative bacteria, in the Oxallis-Myrtillus spruce and Vaccinium type pine stand 60% were gram-negative, while the share was only 25% in the pine bog. Nitrogen-fixing bacteria of the type Clostridium pasteurianum were found in all soils. Actinomycetes were found in all sites. The numbers of protozoa were highest in the soils of Oxalis-Myrtillus type forests.

There were no big differences between the forest soils and the flood meadow. Some groups of micro-organisms seem to be absent from the forest soils, which is probably due to the more favourable pH in the meadow. The occurrence of myxobacteria is interesting since no earlier data exist of this organism in Finnish soils.

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• Gyllenberg, E-mail: hg@mm.unknown
• Hanioja, E-mail: ph@mm.unknown
• Vartiovaara, E-mail: uv@mm.unknown

Earlier studies show that different kind of biological processes occur in the soil of different forest types. These differences may be due differences in microbiology of those soils. This article studies these differences.

Soil samples from five different forest types were collected from the Ruotsinkylä research forest in three different seasons: in January, March and September.

The amount of bacteria in the samples is at the lowest in March and highest in September.   During the winter more anaerobic bacteria were found. The amount of denitrifying bacteria is higher in the soil than amount of nitrifying bacteria.

The results indicate that the species composition of soil varies between the forest types in the same manner than the vegetation composition above the soil. However, this study is only a preliminary and more knowledge is needed about the discipline before practical implications can be drawn.

The PDF contains a summary in Finnish.  

• Svinhufvud, E-mail: vs@mm.unknown

The aim of the study was to identify the microbes which reach the cut surface of Norway spruce (Picea abies (L.) Karst.) stumps during the first year after felling by means of air born spores, determine their occurrence frequency and the combinations in which they occur, investigate the colour changes in the wood caused by microbes and identify the microbial species isolated from the sap- and heart-wood.

The material consisted of 360 spruce stumps. 300 of the stumps were innoculated with five different fungi (Phlebia gigantea, Botrytis cinerea, Gliocladium deliquescens, Trichoderma viride, Verticicladiella procera) in order to inhibit air-born attack by Heterobasidion annosum. 60 stumps were left untreated as controls.

The cultural characteristics of the following fungi isolated from the stumps have been described e.g.: Ceraceomerulius serpens, Chondrostereum purpureum, Cylindrobasidium evolvens, Peniophora pithya, Phlebia gigantea (Phlebiopsis gigantea) , P. subserialis, Sistotrema brinhmannii, Bjerkandera adusta, Coriolellus serialis, Trametes zonata, Armillariella mellea, Panellus mitis, Nectria fucheliana (microconidial-stage), Ascocoryne cylichnium (conidial-stage), Leptographium lundbergii, Acremonium butyri, Gliocladium deliquescens, Verticicladiella procera.

The proportion of Basidiomycotina fungi out of the whole material was 53 %, Ascomycotina and Deuteromycotina fungi 37,6 % and bacteria 7,3 %.

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• Hallaksela, E-mail: ah@mm.unknown

Infection of living Norway spruce (Picea abies (L.) H. Karst.) trees by bacteria, and the properties of these bacteria were studied. Bacterial antagonism to three decay fungi was also studied in laboratory conditions.

Bacteria could be found in 26% of all spruce injuries. Bacterial infection was most frequent in injuries made in March–April and June, and least frequent in December–February. Bacteria infected most often sapwood injuries in roots above soil level, 55% of the bacterial colonies were isolated from these injuries. 27% of the colonies were isolated from injuries made by increment borer at breast height, extending to heartwood, 16% from sapwood injuries at breast height, and 2% from injuries at stump height. The main bacterial groups were gram-positive rods (55%) and gram-negative rods (29%).

In 65% of the bacteria the metabolism was fermentative, in 14% slowly fermentative, in 7% oxidative, in 8% slowly oxidative, and in 6% alkalizing. 19% utilized cellulose, 15% in the presence of organic, 3% in the presence of inorganic nitrogen.

One bacterial strain was the only micro-organism growing in the injury a year after the damage, although the injury had been infected with Peniophora gigantea (Phlebiopsis gigantea). In laboratory experiments, this rod bacterium, gram-negative strain proved to be antagonistic to Fomes annosus (Heterobasidion annosum), Stereum sanguinolentum and P. gigantea. It had no capacity for cellulose utilization.

The PDF includes a summary in Finnish.

• Kallio, E-mail: tk@mm.unknown

• Doi, AFE Building, School of Environment, Resources and Development, Asian Institute of Technology, Pathumthani 12120, Thailand E-mail: roird@aeiou.pt
• Ranamukhaarachchi, AFE Building, School of Environment, Resources and Development, Asian Institute of Technology, Pathumthani 12120, Thailand E-mail: slr@nn.th