Humus bacteria of Norway spruce stands: plant growth promoting properties and birch, red fescue and alder colonizing capacity.

We studied the potential of the humus layer of the Norway spruce stands to supply beneficial rhizobacteria to birch (Betula pendula), alder (Alnus incana) and fescue grass (Festuca rubra), representatives of pioneer vegetation after clear-cutting of the coniferous forest. Axenically grown seedlings of these species were inoculated with the acid spruce humus, pH 3.7-5.3. Actinorhizal propagules, capable of nodulating alder, were present in high density (10(3) g(-1)) in humus of long-term limed plots, whereas plots with nitrogen fertilization contained almost none (

Microbial activities related to C and N cycling and microbial community structure in the rhizospheres of Pinus sylvestris, Picea abies and Betula pendula seedlings in an organic and mineral soil.

The aim of this study was to determine whether Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and silver birch (Betula pendula Roth) seedlings have a selective influence on the soil microbial community structure and activity and whether this varies in different soils. Seedlings of pine, spruce and birch were planted into pots of two soil types: an organic soil and a mineral soil. Pots without seedlings were also included. After one growing season, microbial biomass C (C(mic)) and N (N(mic)), C mineralization, net ammonification, net nitrification, denitrification potential, phospholipid fatty acid (PLFA) patterns and community level physiological profiles (CLPPs) were measured in the rhizosphere soil of the seedlings. In the organic soil, C(mic) and N(mic) were higher in the birch rhizosphere than in pine and spruce rhizosphere. The C mineralization rate was not affected by tree species. Unplanted soil contained the highest amount of mineral N and birch rhizosphere the lowest, but rates of net N mineralization and net nitrification did not differ between treatments. The microbial community structure, measured by PLFAs, had changed in the rhizospheres of all tree species compared to the unplanted soil. Birch rhizosphere was most clearly separated from the others. There was more of the fungal specific fatty acid 18:2omega6,9 and more branched fatty acids, common in Gram-positive bacteria, in this soil. CLPPs, done with Biolog GN plates and 30 additional substrates, separated only birch rhizosphere from the others. In the mineral soil, roots of all tree species stimulated C mineralization in soil and prevented nitrification, but did not affect C(mic) and N(mic), PLFA patterns or CLPPs. The effects of different tree species did not vary in the mineral soil. Thus, in the mineral soil, the strongest effect on soil microbes was the presence of a plant, regardless of the tree species, but in the organic soil, different tree species varied in their influence on soil microbes.

Quantification of frankia strains and other root-associated bacteria in pure cultures and in the rhizosphere of axenic seedlings by high-performance liquid chromatography-based muramic Acid assay.

Application of a high-performance liquid chromatography-based muramic acid assay with precolumn fluorescence derivatization to quantification of root-associated bacteria was studied both in pure cultures and in the rhizosphere of axenic Festuca rubra seedlings. Quantities of muramic acid from acid-hydrolyzed cells of Frankia strains, Streptomyces griseoviridis, Enterobacter agglomerans, Klebsiella pneumoniae, Pseudomonas sp., and Bacillus polymyxa were mostly proportional to the respective cell protein and carbon quantities, but in some strains, culture age and particularly sporulation affected these ratios considerably. The muramic acid/cell protein ratio was generally 2 to 4 times higher in strains of the two actinomycete genera, Frankia and Streptomyces, than in the rest of the strains. Quantification of Frankia strains, S. griseoviridis, E. agglomerans, and Pseudomonas sp. was also attempted from the rhizosphere of F. rubra seedlings which had been inoculated with pure cultured bacteria and incubated briefly. It was possible to quantify Frankia cells by use of the muramic acid assay from both the root and the growth medium, whereas cells of the rest of the bacterial genera could only be detected in the medium. The detection limit for muramic acid was about 10 ng/ml hydrolysis volume, and from the Festuca rhizosphere, 28 to 63% of the muramic acid in the Frankia inoculum was recovered.

Use of lay opinion leaders to promote diffusion of health innovations in a community programme: lessons learned from the North Karelia project.

PIP: This article describes the systematic use of lay opinion leaders in the North Karelia project, a comprehensive community-based preventive cardiovascular program in Finland. Over 800 lay opinion leaders were trained to promote the reduction of heart disease risk factors and, after approximately 4 years, a survey was conducted to assess the long-term feasibility and self-reported effects. 267 of the 399 active lay workers surveyed were women; their median age was 52 years. The median age of the men was 50. 86% of the lay workers were married, and the majority lived in large villages. On the average they were members of 4 different associations or organizations and had acted as lay health workers for an average of 4 years. About 10% of these workers stated that they had had coronary heart disease themselves, and hypertension had been diagnosed in 19%. Only 2% were current smokers. The different types of milk they consumed was 1 indicator of their dietary habits: 14% too no milk at all, 23% skim milk/butter milk, 27% "low-fat" milk, 13% "consumption" milk (fatty milk), and 23% "full milk" (directly from the farm). 78% said they used butter on their bread. According to the lay workers' findings, 15% responded "very positively" and 60% "positively" in discussions about health matters; only 1% were reported as negative. There was little difference between the answers given by male and female lay workers. Discussions about physical activity were said to be the easiest, all other topics being only relatively easy. Although changes in health behavior were important, these workers saw clearly the difficulties in influencing people to accomplish these changes. Altogether 36% of the lay workers reported that at least 1 person had stopped smoking in association with their efforts, and 3% reported that as many as 6 or more persons had stopped smoking. This means that over 500 persons had over this period of time been influenced by the program to stop smoking. About 15-25% of the lay workers tried to promote action to restrict smoking in local bars, worksites, and at local meeting places. In bars this was rarely successful but in the other places some change often followed. The overall community impact of this volunteer lay worker activity cannot be assessed with certainty, but the overall evaluation of the project interventions in North Karelia from 1972-82 showed a major impact on behaviors and risk factors related to cardiovascular disease, i.e., a 28% reduction in smoking when adjusted for simultaneous changes in a matched reference area and a significant reduction in coronary mortality rates in contrast to the rest of the country.^ieng