Arbuscular mycorrhizal symbioses in a cut-and-carry forage production system of legume tree Gliricidia sepium and fodder grass Dichanthium aristatum

Arbuscular mycorrhizal (AM) symbioses may alter the competitive abilities of plant species and facilitate positive interactions such as nutrient transfer between plants. They are therefore particularly interesting components in agroforestry systems. We studied spatial variation of AM colonisation on a cut-and-carry fodder production site (agroforestry plot) of the legume tree Gliricidia sepium and the fodder grass Dichanthium aristatum. Roots of the two plant species were sampled under the tree canopies and on the adjacent grass plot at 1 and 3.5 m from the first tree row where G. sepium roots also occur. Roots of D. aristatum were also sampled on a nearby grass monocrop. Colonisation of arbuscules, vesicles and hyphae in root samples was visually determined, and AM fungal species were identified by DNA sequencing. Colonisation and frequency of types of AM formations varied statistically significantly between the species and sampling points. Arbuscular colonisation in G. sepium roots was higher under the tree canopies than on the adjacent grass plot. Soil nutrient content, particularly P and N, and interspecies competition are the most probable explanations for the observed variation in AM colonisation. Both arbuscular colonisation and arbuscule:vesicle ratio in D. aristatum roots was lower on the D. aristatum monocrop than on the agroforestry plot under or near the tree canopies. Intercropping could stimulate AM symbiosis in D. aristatum. Both plant species formed symbiosis with Rhizophagus intraradices, indicating potential for interplant N transfer via common mycelial networks of AM-forming fungi.     

Towards interactive fish farming governance? a comparison of Finland and Sweden

The neighbouring countries, Finland and Sweden, compete in the same market with their aquaculture. Both countries have had, until recently, stringent environmental policies limiting production volumes. During recent years, however, Swedish fish farmers have been able to increase their production volume, and Finnish fish farmers have also redirected their investments to Sweden. Thus, the strict Finnish environmental permit policy has not benefited the Baltic Sea environment, but has moved the production volumes and employment opportunities to other locations in the Baltic Sea and its drainage basin. By comparing the Finnish and Swedish fish farming governance systems, we found that in Sweden, various types of formal and informal interaction and practice have enhanced the achievement of balanced decisions. This has only rarely been the case in Finland, which features a more authoritative decision-making culture. On the other hand, increased communication across the Finnish administrative sectors raises future prospects for more holistic fish farming governance, which balances economic, social and environmental goals.     

Enterotoxigenic Escherichia coli (ETEC) and Klebsiella pneumoniae isolated from dogs with diarrhoea

Faecal samples from 148 dogs with diarrhoea and from 15 healthy dogs were cultured for bacterial pathogens with enterotoxigenic properties. The aim of the study was to define the toxin profile (production of heat-labile [LT] and heat-stable [ST] toxins) and possible surface fimbrial antigens. Enterotoxigenic bacteria were isolated from 6 (4.1%) dogs with diarrhoea, four of these were Escherichia coli and two were Klebsiella pneumoniae. The E. coli strains and K. pneumoniae strains were producing both LT and ST toxins. The LT toxin from these strains was not neutralized by human anti-LT serum or anti-choleragen and did not cause coagglutination with Staphylococcus aureus coated with anti-human-LT. This suggests that the LT toxin produced by these canine isolates is non-identical to LT toxin from human strains.

Three of the ETEC strains were haemagglutinating and showed surface hydrophobic properties. Electron microscopy showed that canine ETEC isolates possessed fimbriae of two different types: thick (5–5.5 nm) and thin (2–3 nm).     

The effect of protein-feeding strategy during lactation on performance of primiparous dairy cows fed total mixed ration

Fifty primiparous Finnish Ayrshire cows were used in 2×2 factorial study. The factors were the protein-feeding strategy: constant (cCP) or variable (vCP) protein content in concentrate during lactation and the use of a commercial health product from 2 weeks pre- to 8 weeks postpartum. On treatment cCP, the CP content of the concentrate was 180 g/kg in dry matter (DM) throughout the lactation, and on vCP treatment, the CP content was 210, 180 and 150 g/kg DM during lactation days 0-100, 101-200 and 201-305, respectively. The concentrate blends included barley, oats, rapeseed meal, molassed sugar beet pulp and minerals and vitamins. Grass silage and ensiled wet sugar beet pulp (100 g/kg DM in TMR) were used as forage. The forage-to-concentrate ratio in TMR was 55:45 on both treatments. The experimental period was 305 days of the first lactation.The average daily milk yield (cCP: 26.3 kg/day vs. vCP: 27.5 kg/day) was higher (P<0.05) when feeding concentrate with decreasing protein content, but the effect was not seen in an energy-corrected milk (cCP: 28.1 kg/day vs. vCP: 29.0 kg/day). Milk composition was not affected by the protein-feeding strategy. Protein-feeding strategy had no effect on DM intake (cCP: 18.5 kg/day vs. vCP: 18.9 kg/day). The efficiency of CP utilization (milk protein/CP intake) was higher (0.327 vs. 0.301; P<0.05) on vCP treatment during the last 100 days of lactation, but during the first 200 days of lactation, no significant difference was found. The average efficiency of CP utilization throughout the lactation was 0.32 with no difference between treatments. The protein-feeding strategy had no effect on the development of body condition scores of the cows. In mid-lactation, the cows on cCP treatment gained more weight than the cows on vCP treatment. The health product had no significant effect on production or feed intake. The results suggest that only small benefits can be obtained from feeding TMR to primiparous cows differing in CP content at various stages of lactation.     

Landscape Position, Local Environmental Factors, and the Structure of Molluscan Assemblages of Lakes

Biotic communities are structured by both regional processes (e.g., dispersal) and local environmental conditions (e.g., stress). We examined the relative importance of landscape position (position within the hydrologic flow system and distance from other lakes) and local environmental factors in determining the assemblage structure of lake-dwelling snails and fingernail clams in a boreal landscape. Both landscape position and local environmental factors were highly influential in structuring the molluscan assemblages. In canonical correspondence analysis, 53.6% of snail and 48.2% of fingernail clam assemblage composition were accounted for by both sets of variables. The pure effects of landscape position were higher than those of environmental variables, and a considerable amount of variability was shared by the two sets of variables. In regression analysis, 95.5% of snail and 62.2% of fingernail clam species richness was accounted for by the explanatory variable groups, with most of the variability being related to shared effects, followed by landscape position. The effects of landscape position on species composition suggest that passive dispersal increases the similarity of molluscan assemblages in adjacent lakes. This process does not lead to an overall homogenisation of assemblage composition across the landscape, however, because local conditions set a strong environmental filter, excluding species that arrive at an unsuitable lake. These environmental filters may reflect either extinction probability (area, productivity) or species niche differences (calcium levels, abiotic stress). Landscape position may also be important in maintaining the species richness of lake-dwelling molluscan assemblages. By providing potential colonists, nearby source lakes are likely to be important in countering local extinctions. Our test of the relative importance of landscape position and local drivers of assemblage structure was partly confounded by their co-variation. Nevertheless, studying the relationship between landscape position and local variables is useful because it can tell us about the importance of local and regional processes in shaping lake communities.     

Length of cuttings in establishment and production of short-rotation plantations of Salix ‘Aquatica’

The effect of length of cuttings, 10 to 50 cm long, on establishment and productivity of short-rotation plantations was investigated in five trials, for periods of 2 to 9 years. The trials were established on abandoned agricultural fields planted with unrooted Salix Aquatica cuttings. The effect of cutting length was very similar in all five trials: the longer the cuttings (up to 30–50 cm), the better the survival and growth. In most trials the greatest difference in survival was between cutting lengths of 10 and 20 cm, especially in unfavorable growing conditions. In an annually harvested trial during the 9-year test period, a cutting length up to 30 cm affected biomass production per stool positively. In two trials grown with 5-year rotation, the longest cuttings produced 7 times the above-ground biomass of the shortest ones. Results of these trials also emphasize the importance of establishment for the future success of willow plantations.     

Developmental lignification and seasonal variation in beta-glucosidase and peroxidase activities in xylem of Scots pine,Norway spruce and silver birch

We examined the relationship between beta-glucosidase and peroxidase activities and xylem lignification in the stems of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and silver birch (Betula pendula Roth) during the 1999 growing season. Examination of stem cross sections stained with safranin and Alcian blue for lignin and cellulose, respectively, indicated that radial growth of pine and spruce xylem began in late May, whereas the growth of birch xylem was initiated 2 weeks later. Lignification began soon after thickening of the newly formed cell walls, i.e., upon deposition of cellulose. Hydrolysis of the synthetic beta-glucosidase substrate p-nitrophenyl-beta-O-D-glucopyranoside was correlated with radial growth and lignification in the xylem of both conifers, but the relationship between lignification and the hydrolysis of coniferin by beta-glucosidase was not obvious. Beta-glucosidase activities in the xylem of silver birch were low and did not correlate with growth or lignification with either substrate. An increase in peroxidase activity was detected at the initiation of growth and lignification in the conifers and during growth and lignification in silver birch, but high peroxidase activities were also measured outside the growth period during late autumn, winter and early spring.     

Silver birch (Betula pendula) plants with aux and rol genes show consistent changes in morphology,xylem structure and chemistry

The effects of Agrobacterium pRiA4 rol and aux genes, controlled by their endogenous promoters, on tree growth and wood anatomy and chemistry were studied in 5- and 7-year-old silver birch (Betula pendula Roth) plants. Southern hybridization confirmed the following rol and aux gene combinations: control plants (no genes transferred); plants with rolC and rolD genes; plants with rolA, rolB, rolC and rolD genes; and plants with rolA, rolB, rolC, rolD, aux1 and aux2 genes. Transgene mRNA was most abundant in phloem/cambium samples and in the developing xylem, whereas no expression was detected in leaves. Plants with rolC and rolD genes or with all the rol genes were significantly shorter and had smaller leaves and a more bushy growth habit than control plants or plants with both aux and rol genes. Morphological observations and wood chemistry analyses revealed that plants with rol genes produced less xylem and broke bud later than control plants or plants with both aux and rol genes. Tension wood was detected in both control and transgenic plants irrespective of their gene combination, probably as a result of greenhouse cultivation. Xylem fibers were shorter in transgenic plants than in control plants, and plants with all the rol genes were characterized by shorter vessels compared with the control plants and a smaller proportional area of vessels compared with the other groups. In addition, silver birch plants with all the rol genes had approximately a 3.3% lower concentration of total acid soluble carbohydrates than control plants. We conclude that the rolC and rolD genes induced the typical "rol-phenotype," and that this was emphasized by concomitant expression of the rolA and rolB genes and alleviated by the presence of aux1 and aux2 genes. We observed consistent phenotypic effects of rol and aux genes on the morphology, anatomy and cell wall chemistry of the plants.     

The challenge of information service development for private forest owners: The Estonia and Finland cases

This paper investigates forest ownership objectives and the need for information among Estonian and Finnish private forest owners based on two surveys. The motivation for the analysis is the fragmenting private forest ownership in Europe. The broad lines of ownership objectives are found to be similar in both countries, and can be described under the dimensions of economic objectives, intangible values, and products and activities provided by forests. In both countries, economic and intangible objectives are considered important at the same time. Thus forest owners can be described as multi-objective. The economic objectives are ranked as somewhat more important than non-economic objectives in Estonia, but not in Finland. Estonian forest owners most strongly emphasise information about legal and economic matters, including forest taxation and forest health issues, while Finnish forest owners emphasise information about wood markets and forest taxation. Differences between the two countries may be related to private ownership being relatively new in Estonia. Some generalisations may be drawn for European forest policy. Overall, private forest owners need both information about economic issues and personal advice on how to manage forests with regard to their individual and multiple objectives. Generally, personal advice may be concentrated on the complicated and most important themes, while information can mostly be provided via written or electronic channels. Particularly in countries where private forestry is new, there is a need for personal advice on legislative and economic matters. As a conclusion, it is suggested that efficient allocation of resources and development of information services require regular analysis of private forest ownership, and segmenting private forest owners according to their objectives and information needs.     

Untersuchungen über das Auftreten der Erreger der Holländischen Ulmenwelke in Österreich

Zusammenfassung Das Vorkommen der Erreger des Ulmensterbens in ?sterreich wurde in den neunziger Jahren des vorigen Jahrhunderts untersucht. Von insgesamt 174 Isolaten, die zwischen 1993 und 1997 in verschiedenen Teilen ?sterreichs gesammelt worden waren, konnten 150 aufgrund ihrer Wachstumsrate bei 20 °C und 33 °C sowie der Morphologie der Kultur auf Oxoid-Malzextraktagar der aggressiven ArtO. novo-ulmi zugeordnet werden. Die weniger aggressive ArtO. ulmi wurde kein einziges Mal nachgewiesen und kommt vermutlich in ?sterreich nicht mehr vor. Ein Isolat wies eine einzigartige Kulturmorphologie auf, die weder der vonO. ulmi noch jener vonO. novo-ulmi entsprach. Dieses Isolat ist m?glicherweise durch Hybridisierung vonO. ulmi undO. novo-ulmi entstanden. Ein Teil (<14 %) der Isolate ist aufgrund ungünstiger Bedingungen w?hrend der Stammhaltung degeneriert, zeigte untypisches Wachstum in Kultur und konnte daher nicht bestimmt werden.O. novo-ulmi konnte in den Bundesl?ndern Wien, Nieder- und Ober?sterreich, Burgenland, Steiermark, K?rnten und Tirol festgestellt werden und scheint in weiten Teilen des Verbreitungsgebietes der in ?sterreich heimischen Ulmenarten vorzukommen. Es ist damit zu rechnen, dassO. novo-ulmi weiterhin gro?e Sch?den in Mitteleuropa verursachen wird und früher oder sp?ter auch in Gebiete und Waldbest?nde vordringen wird, in denen bisher geringe oder keine Sch?den durch die Ulmenwelke aufgetreten sind.