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排序方式: 共有1061条查询结果,搜索用时 15 毫秒
971.
Naoyuki Yamashita Hiroyuki Sase Tsuyoshi Ohizumi Junichi Kurokawa Toshimasa Ohara Yu Morino Masatoshi Kuribayashi Seiichi Ohta Shinji Kaneko Kentaro Hayashi Haruo Fukuhara Tomoyuki Hakamata 《Journal of Forest Research》2016,21(3):115-124
Sensitivity maps of atmospheric acid deposition in Japan have not been updated in 20 years. Here, we propose new relative risk maps of surface water acidification in forests based on a weighted overlay of cumulative potential acid deposition (CPAD) simulated for a 25-year period (1981–2005), including the sensitivities of soil and bedrock to acidification. We assumed that relative acidification risk is high in areas that exhibit high sensitivities of soil and bedrock to acid and have received a large amount of cumulative acid deposition over the past several decades. We aggregated fine soil and bedrock maps into a 20-km mesh for overlay onto an 80-km mesh map of CPAD by considering their spatial structures in Japan. Allocation of the weights among CPAD and soil and bedrock sensitivities was performed based on observational trends in river pH over the past 30 years. The resulting risk map for surface water acidification showed that large areas of western Japan, as well as smaller areas of Hokkaido, Tohoku, Kanto, and Kyushu, are at high risk of surface water acidification. Seventy-seven percent of all rivers for which a declining trend in pH was observed from 2001 to 2009 were also high-risk areas. Acid deposition might be one factor controlling surface water acidification in areas with high bedrock sensitivity, in addition to high CPAD and soil sensitivity, although the risk of soil acidification remains unclear. 相似文献
972.
Tomohiro Osaki Koudai Kitahara Yoshiharu Okamoto Tomohiro Imagawa Takeshi Tsuka Yasunari Miki Hitoshi Kawamoto Hiroyuki Saimoto Saburo Minami 《Marine drugs》2012,10(11):2560-2570
We investigated the effect of fucoidan, a sulfated polysaccharide, on acceleration of healing of experimental cartilage injury in a rabbit model. An injured cartilage model was surgically created by introduction of three holes, one in the articular cartilage of the medial trochlea and two in the trochlear sulcus of the distal femur. Rabbits in three experimental groups (F groups) were orally administered fucoidan of seven different molecular weights (8, 50, 146, 239, 330, 400, or 1000 kD) for 3 weeks by screening. Control (C group) rabbits were provided water ad libitum. After the experimental period, macroscopic examination showed that the degree of filling in the fucoidan group was higher than that in the C group. Histologically, the holes were filled by collagen fiber and fibroblasts in the C group, and by chondroblasts and fibroblasts in the F groups. Image analysis of Alcian blue- and safranin O-stained F-group specimens showed increased production of glycosaminoglycans (GAGs) and proteoglycans (PGs), respectively. Some injured holes were well repaired both macroscopically and microscopically and were filled with cartilage tissues; cartilage matrices such as PGs and GAGs were produced in groups F 50, F 146, and F 239. Thus, fucoidan administration enhanced morphologically healing of cartilage injury. 相似文献
973.
Total sennosides concentration is a very important factor when rhubarb and senna will be used as crude drugs. However, one-step analytical technique for total sennosides has not been reported except HPLC. An enzyme-linked immunosorbent assay (ELISA) for total sennosides concentration by using the combination of anti-sennoside A (SA) and anti-sennoside B (SB) monoclonal antibodies (MAbs) in a single assay has been investigated. Total sennosides concentration in rhubarb and senna samples determined by newly developed assay system showed good agreement with those analyzed by ELISA using anti-SA MAb and anti-SB MAb, respectively. 相似文献
974.
Florigen and the Photoperiodic Control of Flowering in Rice 总被引:2,自引:0,他引:2
Flowering time is a key trait for geographical and seasonal adaptation of plants and is an important consideration for rice breeders. Recently identified genetic factors provide new insights into this complex trait. The list of genes involved in flowering and their functions tells us that the molecular basis of day-length measurement includes both of the evolution of unique factors and the regulatory adaptation of conserved factors in rice. This information helped identify rice florigen, a mobile flowering signal. Our current view of flowering time regulation incorporates the presence of complex layers of gene networks integrated with the synthesis of florigen protein and its subsequent transport and perception. 相似文献
975.
976.
Zhao Zhang Takehiko Fukushima Peijun Shi Fulu Tao Yuichi Onda Takashi Gomi Shigeru Mizugaki Yuko Asano Ken'ichirou Kosugi Shinya Hiramatsu Hikaru Kitahara Koichiro Kuraji Tomomi Terajima Kazuo Matsushige 《CATENA》2008
Understanding the seasonal and regional patterns of nitrogen (N) components in the headwaters of forested watersheds is important for forests management. Here, we investigated the NO3-N concentration and its seasonal variations in the baseflow headwaters in Japanese coniferous forests with different N saturation status in five regions (i.e., Nagano, Tokyo, Aichi, Kochi and Mie). We found that the ratios of NO3-N to DON were significantly higher in the N-saturated regions including Nagano (14.1 ± 2.2) and Tokyo (16.5 ± 4.1), compared with the regions, which didn't experience N saturation including Aichi (1.4 ± 0.2), Kochi (5.1 ± 1.8), and Mie (2.2 ± 0.5). In comparison with the regions without experiencing N saturation, the relatively higher NO3-N concentration, as well as its contrastive variation between growing season and dormant season, was also characteristic of the seasonal NO3-N concentration in the N-saturated regions. Our findings have indicated that NO3-N concentration, its seasonal variations, and the ratio of NO3-N to DON, are the better and applicable indicators for evaluating N saturation status in Japanese coniferous forests. 相似文献
977.
Masato Kamisako Hiroyuki Sase Taeko Matsui Hiroko Suzuki Akiomi Takahashi Takuji Oida Makoto Nakata Tsumugu Totsuka Hiromasa Ueda 《Water, air, and soil pollution》2008,195(1-4):51-61
Fluxes of major ions in rainfall (RF), throughfall plus stemflow (TF + SF), and stream water (SW) were measured for five water years in a small catchment of a Japanese cedar forest near the Sea of Japan. The fluxes of most ions in RF and in TF + SF, including the non-sea-salt constituents, increased from late autumn to midwinter owing to the seasonal westerly wind. The concentrations of most ions in SW showed no obvious seasonal trend during the study period, whereas ${\text{NO}}_3 ^ - $ concentrations were lowest in summer, with a small seasonality. The Ca2+ and Mg2+ outputs in SW were approximately 3.7 and 1.8 times the TF + SF inputs of these cations, respectively. The large net outputs of base cations in the catchment may indicate a decrease in the soil's acid-neutralizing capacity. Annual dissolved inorganic nitrogen inputs in RF and in TF + SF were 17.7 and 17.9 kg N ha?1 year?1, respectively, which exceeded previously published thresholds in Europe and the U.S. (i.e., the values at which these inputs increased ${\text{NO}}_3 ^ - $ levels in SW) and equaled the highest level of nitrogen deposition previously reported in Japan. The ${\text{NO}}_{\text{3}} ^{\text{ - }} $ concentrations in SW were relatively high even in summer. During high-precipitation events, ${\text{NO}}_{\text{3}} ^{\text{ - }} $ concentrations in SW increased with increasing water discharge, and the pH decreased simultaneously during several events. Nitrogen deposition may contribute to the high ${\text{NO}}_{\text{3}} ^{\text{ - }} $ concentrations in SW and the temporary acidification that occurred during the rain events. 相似文献
978.
Effect of high water temperature during vegetative growth on rice growth and yield under a cool climate 总被引:1,自引:0,他引:1
Global warming is likely to increase spring temperatures in regions with a cool climate. To examine the effects of this change on rice productivity, we exposed rice plants to a higher (by +2.7 to +2.8 °C) water temperature (Tw) during the vegetative growth period (for 35-50 days) under three levels of N fertilization. High Tw during vegetative growth made the heading stage occur 4-7 days earlier for all levels of N fertilization in both years. The crop growth rate during the treatment period was greatly enhanced by high Tw: by 51-82% in 2008 and by 49-62% in 2009. There was no Tw × N fertilizer interaction. This increased growth was associated with increased leaf expansion and increased canopy radiation capture rather than with increased radiation-use efficiency. However, the positive effect decreased during subsequent growth stages under all levels of N fertilization, leading to no significant differences in total biomass at maturity. High Tw during vegetative growth greatly reduced SPAD values during the grain-filling stage compared with SPAD values in the control Tw treatment, for all levels of N fertilization, and decreased leaf photosynthesis during the mid-grain filling stage. Grain yield was not significantly affected by high Tw at any N fertilizer level or in either year. 相似文献
979.
Kazuhiko Masaka Hajime Sato Hirokazu Kon Hiroyuki Torita 《Journal of Forest Research》2010,15(6):374-383
To assess and improve methods for the development of coastal forests in Hokkaido, northern Japan, this study examined the
factors affecting mortality of planted Pinus thunbergii Parlat. saplings in a region with seasonal soil frost. The needles of pine saplings at the study site turn red in late spring,
suggesting xylem embolism, which can lead to death. Sapling mortality was strongly correlated with the degree of cold just
after planting and with the occurrence of repeated severe winters. Volcanic ash soil had been supplied to improve the soil
nutrients, and the volcanic ash soil always thawed later than the original coastal sand. Saplings in volcanic ash were significantly
more damaged than those in original coastal sand. This suggests that hydraulic stress caused by cuticular transpiration under
frozen soil conditions during spring may also accelerate damage due to embolisms. Hence, volcanic ash soil should not be applied
to soils in regions with seasonal soil frost. A covering of woodchips can help prevent frost from reaching greater soil depths,
and, indeed, fewer saplings at the study site died in areas with such coverage. Planting location can also affect pine sapling
mortality. For example, shading caused by wood fencing may affect the soil freezing profile during winter; therefore, planting
close to a fence should also be avoided in regions with seasonal soil frost. These findings should be used to improve the
development of forests in regions with seasonal soil frost. 相似文献
980.
Takeuchi Y Iizuka H Kanemitsu H Fujino Y Nakashima K Uchida K Ohno K Nakayama H Tsujimoto H 《Journal of Feline Medicine and Surgery》2010,12(12):982-987
A 10-year-old American Shorthair cat with nasal discharge, anorexia, and weight loss was found to have pancytopenia and hyperproteinaemia. Bone marrow aspiration revealed atypical plasma cells that totalled 50% of the nucleated bone marrow cells. The number of atypical plasma cells progressively increased in the peripheral blood during the observation period of 64 days. The cat did not respond to treatments with melphalan, chlorambucil, and prednisolone, and died 71 days after the initial presentation. Clinical, cytological, histopathological, and immunohistochemical findings in this case supported the diagnosis of myeloma-related disorder (MRD) with leukaemic progression. 相似文献