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Tsuda K.,Gifu Academy of Forest Science and Culture
Nihon Ringakkai Shi/Journal of the Japanese Forestry Society

The genus Iotonchium is one of the nematode groups utilizing fruiting bodies of basidiomycetous fungi. They have two ecological phases in their life cycles, i.e., mycetophagous phase living in mushrooms and insect-parasitic phase parasitizing mycetophilid gnats. In this genus, 11 species have been reported in the world, however, only 5 species, including 4 Japanese species, have been clarified the details of their life cycles. Iotonchium ungulatum, a pathogen of gill-knot disease of the oyster mushroom, is known to generate nematode-galls (knots) on the gills of fruiting bodies of Pleurotus fungi. Other Iotonchium species do not generate knots and inhabit the tissue of fruiting bodies of host fungi. Iotonchium nematodes are supposed to have close relationships with mycetophilid gnats. In the amber, their relative species has been discovered with the mycetophilid fossil. This review highlights the tripartite relationship of these organisms and discusses their evolutionary relationship and the future directions of research on this topic. Source

Kohara K.,Gifu Academy of Forest Science and Culture | Nomura T.,Tokai Rubber Industries Ltd. | Koumoto K.,NPO WOOD AC
Advanced Materials Research

Our research team developed a brace type and an angle brace type of the visco-elastic damper on seismic-response controlled structure for timber structure. We performed various dependence evaluations by the materials examination of the styrene olefin-based visco-elastic body which we developed newly. We made a structural model using the performance that loading tests in timber frame. We inspected the validity of the structural model. In addition, we built a technical support system for damper setting by the time history response analysis so that a general design architect was easy to use the damper. We could express dynamics properties of visco-elastic body properties by Voigt model, and the structural model almost accorded with an examination property value. We made a structural model of the whole frame system by Kb of installation rigidity obtained from loading tests in timber frame. Because a design level almost accorded with experimental value, the validity of the frame design on seismic-response controlled structure in consideration of the dependence (distortion, frequency, temperature) of the visco-elastic body was confirmed. This visco-elastic damper on seismic-response controlled structure acquired minister authorization of Ministry of Land, Infrastructure and Transport. In addition, this damper acquired the certification of the Japan Building Disaster Prevention Association. © (2013) Trans Tech Publicutions, Switzerland. Source

Tamaki I.,Gifu Academy of Forest Science and Culture | Setsuko S.,Japan Forestry and Forest Products Research Institute | Tomaru N.,Nagoya University
Conservation Genetics

Understanding the factors shaping rare species’ current genetic diversity and structure, particularly the impact of recent anthropogenic pressures, is important in order to develop appropriate conservation strategies based on robust predictions. Thus, we have genotyped all 585 surviving individuals of Magnolia stellata from six remnant populations and seven isolated tree sites in northern Mie Prefecture, Japan, using nuclear and chloroplast microsatellites. Three genetic clusters were detected by STRUCTURE analysis, with an oldest divergence time between pairs within 25 generations according to coalescent analysis. We attribute this recent divergence to recent anthropogenic environmental changes. Evidence of only one significant recent migration event between pairs of the six populations was detected, indicating that most of the remnant populations are isolated now. Their future genetic status was predicted using Monte Carlo simulations, under four scenarios. It declined more than twice as rapidly in a scenario assuming variations in fecundity among both female and male parents than in a scenario assuming no fecundity variations, but strongly improved in a scenario including promotion of migrations between adjacent pairs of populations. These predictions indicate that sexual reproduction of the species should be promoted by providing more suitable habitats and migration between populations should be enhanced by restoring remnant isolated tree sites and extinct populations. In addition, all the remnant populations should be conserved because they host current genetic variation that may be important for coping with future climate change, and they could provide important stepping-stones for gene flow. © 2016 Springer Science+Business Media Dordrecht Source

Matsumoto T.,Gifu Academy of Forest Science and Culture | Matsumoto T.,Tokyo University of Agriculture and Technology
Nihon Ringakkai Shi/Journal of the Japanese Forestry Society

The resistance force was measured as hung-up trees were passed through the crowns of remaining trees in a Chamaecyparis obtusa stand. The average resistance force was 1.0 kN. A large force was needed to remove manually a tree hung up between two standing trees in an overcrowded thinning stand. The size of a hung-up tree did not have an effect on the resistance force, while leaning angle at which the tree was hung-up influenced the resistance force strongly. The distance between the remaining trees affected the resistance force, which increased exponentially as the distance between the remaining trees decreased. Source

Muranishi S.,Nagoya University | Tamaki I.,Gifu Academy of Forest Science and Culture | Setsuko S.,Japan Forestry and Forest Products Research Institute | Tomaru N.,Nagoya University
Tree Genetics and Genomes

In order to understand the ongoing evolutionary relationships between species, it is important to elucidate patterns of natural hybridization. In the zone where two species are sympatrically distributed, we examined 274 individuals of Magnolia stellata, Magnolia salicifolia, and their putative hybrids by means of 16 nuclear and three chloroplast microsatellite markers. Hybrid classes of individuals were estimated by admixture analyses. Morphological traits were also investigated for 64 of the 274 individuals. Admixture analyses revealed that 66 of the 274 individuals were classified as hybrids, comprising 17 F1 and 19 F2 individuals, 27 backcrosses to M. salicifolia, and 3 individuals of unknown origin. Morphological data from the 64 individuals agreed well with their genetic admixture rates. Spatial locations of F1 and F2 hybrids at the study site were intermediate between the two purebred species, indicating that the site preferences of hybrids are intermediate. The occurrences of F2 and backcross hybrids indicate that F1 hybrids are fertile. The chloroplast DNA haplotypes of all F1 hybrids corresponded to those detected in M. salicifolia, so that maternal parents of the F1 hybrids were all M. salicifolia. Furthermore, no hybrid individuals derived from a backcross to M. stellata were detected. These results suggest that the direction of hybridization and the subsequent introgression have been quite asymmetric and that the introgression occurred from M. stellata into M. salicifolia. © 2013 Springer-Verlag Berlin Heidelberg. Source

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