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51.
Kazuya Iizuka Narumi Toya Jyunichi Ohshima Futoshi Ishiguri Naoko Miyamoto Mineaki Aizawa Tatsuhiro Ohkubo Chisato Takenaka Shinso Yokota 《Journal of Wood Science》2018,64(1):59-64
To utilize forest resources in areas affected by fallout from the Fukushima Daiichi Nuclear Power Plant accident, it is important to understand the mechanisms of 137Cs movement through the stem wood of contaminated trees. Understanding the mechanism of absorption and migration of 137Cs to stem wood is necessary for clues to the future prediction of the transition of 137Cs to xylem. In the present study, radial variations in 137Cs concentration were investigated in Japanese cedar (Cryptomeria japonica D. Don) trees collected 1 year and 10 months after the accident. Additionally, the relationship between 137Cs concentration and potassium (K) content was established. Trees with a higher moisture content and lower lightness value in heartwood tended to have a higher 137Cs concentration in the heartwood. In these trees, 137Cs concentration peaked at the heartwood–sapwood boundary and gradually decreased toward the pith. By contrast, K content within the heartwood remained nearly constant along the radial direction. The heartwood-to-sapwood ratio of 137Cs concentration was significantly positively correlated with that of K content. Based on these results, we suggest that 137Cs movement from sapwood to heartwood might be related to the K content ratio of heartwood and sapwood. 相似文献
52.
Winter nitrogen use in deciduous species is largely uncharacterized. We investigated nitrate uptake in the fine roots of a
deciduous oak (Quercus serrata Thunb. ex. Murray). We conducted a 15N-labeling experiment using saplings of Q. serrata in the winter. During three weeks of labeled nitrate application, the concentration of 15N in the fine roots increased significantly. The amount of nitrogen absorbed, as nitrate, was 1.16 ± 1.02 mg N g DW−1, equivalent to 7.6 ± 5.8% of the total nitrogen content. Our results indicate that Q. serrata saplings have significant potential for nitrate uptake in the fine roots in midwinter (i.e., in the absence of leaves). Although
a significant amount of nitrogen applied as nitrate was accumulated, nitrate concentration in the fine roots remained low
during the labeling period. Furthermore, significant nitrate reductase activity was detected. These data suggest that Q. serrata saplings can assimilate nitrate in the fine roots in midwinter. 相似文献
53.
Kenji Tsuruta Tomonori Kume Hikaru Komatsu Naoko Higashi Toshihiro Umebayashi Tomo’omi Kumagai Kyoichi Otsuki 《Journal of Forest Research》2010,15(6):398-403
Sap flow techniques are practical tools for estimating tree transpiration. Though many previous studies using sap flow techniques
did not consider azimuthal variations of sap flux density (F
d) on xylem trunk to estimate tree transpiration, a few studies reported that ignoring the azimuthal variations in F
d could cause large errors in tree transpiration estimates for some tree species. Therefore, examining azimuthal variations
in F
d for major plantation tree species is critical for estimating tree transpiration. Using the thermal dissipation method, we
examined azimuthal variations in F
d in six trees of Japanese cypress Chamaecyparis obtusa (Sieb. et Zucc.) Endl., which is one of the most common plantation tree species in Japan. We recorded considerable variations
among F
d at four different azimuthal directions. The F
d value for one aspect was more than 100% larger than those for the other aspects. We calculated differences between tree transpiration
estimates based on F
d for one to three azimuthal directions and those based on F
d for four aspects. The differences relative to tree transpiration estimates based on F
d for four aspects were typically 30, 20, and 10% in accordance with the F
d for one, two, and three measurement aspects, respectively. This finding indicates that ignoring azimuthal variations could
cause large errors in tree transpiration estimates for Japanese cypress. 相似文献
54.
Sawa S Cherrier M Lochner M Satoh-Takayama N Fehling HJ Langa F Di Santo JP Eberl G 《Science (New York, N.Y.)》2010,330(6004):665-669
Lymphoid tissue-inducer (LTi) cells initiate the development of lymphoid tissues through the activation of local stromal cells in a process similar to inflammation. LTi cells express the nuclear hormone receptor RORγt, which also directs the expression of the proinflammatory cytokine interleukin-17 in T cells. We show here that LTi cells are part of a larger family of proinflammatory RORγt(+) innate lymphoid cells (ILCs) that differentiate from distinct fetal liver RORγt(+) precursors. The fate of RORγt(+) ILCs is determined by mouse age, and after birth, favors the generation of cells involved in intestinal homeostasis and defense. Contrary to RORγt(+) T cells, however, RORγt(+) ILCs develop in the absence of microbiota. Our study indicates that RORγt(+) ILCs evolve to preempt intestinal colonization by microbial symbionts. 相似文献
55.
The increased mental stress of daily life and aging of the population are serious matters in Japan. There are many studies regarding the effects of human-animal interactions on mental and physical human health, whereas there are few studies examining the effects of visiting zoos. To determine the effect of visiting zoos on human health and quality of life, two different zoos were visited by 70 participants in Experiment 1 and 163 participants in Experiment 2. In this study we administered the WHO QOL-26 questionnaire in Japanese to assess the psychological scales of participants, and blood pressures and pulse rates were measured to assess their physical scales. We also used pedometers to count the number of steps taken during zoo visits. Both zoo visits decreased blood pressure and participants demonstrated more than 6000 steps during each visit. The quality of life sub-scale scores were improved after zoo visits. 相似文献
56.
Ogawa H Sanada Y Sanada N Kudo M Tuchiya K Kodama T Uetsuka K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(6):837-840
A 5-month-old female Citron-crested Cockatoo (Cacatua sulphurea citrinocristata) that was born and hand-reared in Japan died with suspected proventricular dilatation disease (PDD). Macroscopic and microscopic examinations of the bird revealed characteristic features of PDD, i.e., distention of the proventriculus and infiltration of lymphocytes and plasma cells in ganglia of various organs and in central and peripheral nerves. A linkage of this PDD case to infection with avian bornavirus (ABV) was documented by RT-PCR amplification of the virus genomes from the affected bird. Phylogenetic analysis revealed that the ABV identified in this study clustered into the genotype 2, which is one of the dominant ABV genotypes worldwide. To the best of our knowledge, this is the first report of a natural case of PDD associated with ABV infection in Japan. 相似文献
57.
Tomii R Ogawa B Imai N Handa Y Sasayama N Shirasu A Nagashima H 《The Journal of reproduction and development》2011,57(2):273-279
The aim of the present study was to optimize the conditions for in vitro development and postvitrification survival of somatic cell cloned feline embryos. To determine the effects of cell cycle synchronization of the nuclear donor cells, we cultured preadipocytes under serum starvation or conventional conditions. After two days in serum starvation culture, the proportion of synchronized donor cells at the G0/G1 phase was 91.6%. This was significantly higher than the proportion of non-synchronized cells in the proliferative phase (72.6%, P<0.05). The in vitro development of somatic cell nuclear transfer (SCNT) embryos reconstructed using donor cells treated under serum starvation conditions (normal cleavage rate of 65.7%, 46/70, and blastocyst formation rate of 20.0%, 14/70) was comparable to that of the serum supplemented group (52.5%, 31/59, and 20.3%, 12/59). Use of in vitro or in vivo matured oocytes as recipient cytoplasts equally supported development of the SCNT embryos to the blastocyst stage (11.9%, 5/42, vs. 9.5%, 2/21). SCNT-derived blastocysts were vitrified using the original minimum volume cooling (MVC) or the modified (stepwise) MVC method. Although none (n=10) of the SCNT blastocysts survived following vitrification by the original MVC method, the stepwise MVC method resulted in 100% survival after rewarming (n=11). In conclusion, we demonstrated that feline somatic cell cloned embryos with a high developmental ability can be produced irrespective of cell cycle synchronization of donor cells using either in vivo or in vitro matured oocytes. Furthermore, by utilizing a stepwise vitrification method, we showed that it is possible to cryopreserve cloned feline blastocysts. 相似文献
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