Akita Prefectural University

About: Akita Prefectural University is a education organization based out in Akita, Japan. It is known for research contribution in the topics: Magnetic field & Starch. The organization has 1631 authors who have published 3107 publications receiving 45764 citations. The organization is also known as: Akita kenritsu daigaku.

Growth and wood quality of sugi ( Cryptomeria japonica ) planted in Akita prefecture (II). Juvenile/mature wood determination of aged trees

Abstract: Variations of certain anatomical and mechanical indices within tree stems of aged sugi (Cryptomeria japonica) trees planted in Akita prefecture were studied. The determination of the juvenile/mature wood boundary was also discussed, and the effects of wood structure on mechanical properties were investigated. On the basis of radial and vertical variation of the anatomical and mechanical indices, modulus of elasticity (MOE)/ shear modulus (G) was chosen as the index for determining the juvenile/mature wood boundary. The increase rates of MOE/G at the points of 1%, 2%, and 3% were discussed. It was found that for aged trees, all three points were thought to be effective for dividing juvenile and mature wood. However, for younger trees, the point of 2% was recommended, which was mostly consistent with the result obtained by the increase rate of 1% for tracheid length (TL). Among mechanical properties, the MOE showed more significant juvenile/mature wood differences than did modulus of rupture (MOR) and σ. By correlation analysis, it was suggested that microfibril angle largely contributed to the indices of MOE and G, and specific gravity largely contributed to the indices of MOR and σ.

Impact of Introduction of Arbuscular Mycorrhizal Fungi on the Root Microbial Community in Agricultural Fields.

Abstract: Arbuscular mycorrhizal (AM) fungi are important members of the root microbiome and may be used as biofertilizers for sustainable agriculture. To elucidate the impact of AM fungal inoculation on indigenous root microbial communities, we used high-throughput sequencing and an analytical pipeline providing fixed operational taxonomic units (OTUs) as an output to investigate the bacterial and fungal communities of roots treated with a commercial AM fungal inoculum in six agricultural fields. AM fungal inoculation significantly influenced the root microbial community structure in all fields. Inoculation changed the abundance of indigenous AM fungi and other fungal members in a field-dependent manner. Inoculation consistently enriched several bacterial OTUs by changing the abundance of indigenous bacteria and introducing new bacteria. Some inoculum-associated bacteria closely interacted with the introduced AM fungi, some of which belonged to the genera Burkholderia, Cellulomonas, Microbacterium, Sphingomonas, and Streptomyces and may be candidate mycorrhizospheric bacteria that contribute to the establishment and/or function of the introduced AM fungi. Inoculated AM fungi also co-occurred with several indigenous bacteria with putative beneficial traits, suggesting that inoculated AM fungi may recruit specific taxa to confer better plant performance. The bacterial families Methylobacteriaceae, Acetobacteraceae, Armatimonadaceae, and Alicyclobacillaceae were consistently reduced by the inoculation, possibly due to changes in the host plant status caused by the inoculum. To the best of our knowledge, this is the first large-scale study to investigate interactions between AM fungal inoculation and indigenous root microbial communities in agricultural fields.

Effects of microenvironmental heterogeneity on the seed-to-seedling process and tree coexistence in a riparian forest

Abstract: In a temperate riparian forest, the effects of substrate types, canopy gaps and conspecific seedfall density were investigated on the seed-to-seedling process for the five dominant species (Aesculus turbinata, Fagus crenata, Acer mono, Pterocarya rhoifolia and Cercidiphyllum japonicum). Densities of seedfall and subsequent seedling recruits were measured in the stand over a period of 6 years. A model assuming that local density of seedling recruits is proportional to seedfall density in the preceding year significantly explained a spatial variation in seedling recruits for all species. Several environmental factors were then added. Substrate composition had a positive effect on P. rhoifolia and C. japonicum. P. rhoifolia was favored by gravel substrate, which also explained the adult distribution of this species in this forest. C. japonicum appeared to be facilitated by a mineral-soil substrate. However, the distributions of this substrate and adults of C. japonicum did not follow each other closely. A. mono was negatively affected by gaps, and F. crenata was negatively affected by conspecific seedfall density. In contrast, A. turbinata was not significantly affected by any of the environmental factors tested. The microenvironmental heterogeneity in this forest explained species coexistence to a limited extent in the context of seed-to-seedling processes. Performances at later stages of the life-cycle and/or catastrophic disturbances (e.g. landslides) might have a stronger influence on species coexistence in this forest.