Gross nitrification rates in four Japanese forest soils: heterotrophic versus autotrophic and the regulation factors for the nitrification     

Megumi Kuroiwa  Keisuke Koba  Kazuo Isobe  Ryunosuke Tateno  Asami Nakanishi  Yoshiyuki Inagaki  Hiroto Toda  Shigeto Otsuka  Keishi Senoo  Yuichi Suwa  Muneoki Yoh  Rieko Urakawa  Hideaki Shibata 《Journal of Forest Research》2011,16(5):363-373

Measurements of gross NH ₄ ⁺ and NO ₃ ^? production in forest soils were conducted using the ¹⁵N pool dilution method. Mineral topsoils (0?C10?cm depth) were collected from four forests from northern to southern Japan with a natural climate gradient to elucidate the mechanisms regulating gross nitrification rates in forest soils. Additionally, we attempted to evaluate the relative importance of heterotrophic nitrification in gross total nitrification using acetylene as a specific inhibitor of autotrophic nitrification. Distinct differences were found among sites in the gross rates of NH ₄ ⁺ production (3.1?C11.4?mg?N?kg^?1?day^?1) and gross total nitrification (0.0?C6.1?mg?N?kg^?1?day^?1). The rates of gross heterotrophic nitrification were low in this study, indicating that heterotrophic nitrification is of minor importance in most forest mineral topsoils in Japan. Significant relations were found between gross autotrophic nitrification and gross NH ₄ ⁺ production, soil N, and soil C concentrations, but none was found between gross autotrophic nitrification and soil pH. We determined the critical value of the gross NH ₄ ⁺ production rates for gross autotrophic nitrification under which no gross autotrophic nitrification occurred, as well as the critical soil C/N ratio above which gross autotrophic nitrification ceased. Results show that tight coupling of production and consumption of NH ₄ ⁺ prevents autotrophic nitrifiers from utilizing NH ₄ ⁺ as long as NH ₄ ⁺ availability is low.  相似文献   

Splay fault branching along the Nankai subduction zone   总被引：3，自引：0，他引：3  

Park JO  Tsuru T  Kodaira S  Cummins PR  Kaneda Y 《Science (New York, N.Y.)》2002,297(5584):1157-1160

Seismic reflection profiles reveal steeply landward-dipping splay faults in the rupture area of the magnitude (M) 8.1 Tonankai earthquake in the Nankai subduction zone. These splay faults branch upward from the plate-boundary interface (that is, the subduction zone) at a depth of approximately 10 kilometers, approximately 50 to 55 kilometers landward of the trough axis, breaking through the upper crustal plate. Slip on the active splay fault may be an important mechanism that accommodates the elastic strain caused by relative plate motion.  相似文献   

Comparison of water stress effects on growth,leaf water status,and nitrogen fixation activity in tropical pasture legumes siratro and desmodium with soybean     

Yoshiyuki Ohashi  Hirofumi Saneoka  Katsushi Matsumoto  Shoitsu Ogata  Gnanasiri S. Premachandra  Kounosuke Fujita 《Soil Science and Plant Nutrition》2013,59(4):795-802

Siratro (Macroptilium atropurpureum), desmodium (Desmodium intortum), and soybean (Glycine max) were grown in pots with or without irrigation for 20 d at the vegetative growth stage in order to examine the effects of water stress on the leaf water potential, stomatal conductance, biomass production, biological nitrogen fixation, and nitrogen accumulation. Whole plant weight decreased under water stress conditions and the decrease was less pronounced in siratro than in desmodium and soybean. Decrease in total leaf area was the largest and dry matter partition to stem and petioles was the highest in siratro. Decrease in leaf water potential was lower in desmodium and soybean than in siratro. Although water stress decreased biological nitrogen fixation in all the species, the decrease was relatively less pronounced in siratro than in desmodium and soybean. Whole plant nitrogen concentration was higher in siratro than in soybean and desmodium. The results indicated that siratro is more tolerant to water stress than soybean and desmodium. This could be partially attributed to the maintenance of a higher water potential and higher biological nitrogen fixation by siratro under water stress conditions.  相似文献   

Effect of slope on surface drainage in converted rice paddy     

Yoshiyuki Shinogi  Yutaka Kanri  Yuichi Hirose  Kaneto Inoue 《Paddy and Water Environment》2005,3(3):165-170

Due to the recent regulation of rice production in Japan, it has become necessary to convert rice paddy to other field crops production. To achieve this, drainage conditions, especially for surface drainage, must be improved. We propose the introduction of a slight slope to improve surface drainage, but the optimal slope must be determined in order to prevent soil erosion caused by excessive slope, as well as increased cost. In Japan, a 0.1% slope has recently come into widespread use and, therefore, the impact on surface drainage must be quantified. In this report, observations were carried out to quantify the impact of a 0.1% slope for converted rice paddy and the following results were obtained: (1) An approximate 0.1% slope enables improvement of 46% of the soil surface saturation area as compared to flat conditions about 10 h after inundation; and (2) Inundated water remains on a flat field, while it moves downward toward the end on a sloped field. These results give a basis for determining a slope on a rice paddy in terms of surface drainage improvement. However, the optimal slope should be decided from various perspectives including engineering, agronomy, and economics etc.  相似文献   

Comparative Effect of Carperitide and Furosemide on Left Atrial Pressure in Dogs with Experimentally Induced Mitral Valve Regurgitation     

S. Suzuki  R. Fukushima  Y. Yamamoto  T. Ishikawa  L. Hamabe  S. Kim  R. Yoshiyuki  T. Fukayama  N. Machida  R. Tanaka 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2013,27(5):1097-1104

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Removal of heavy metals in aqueous solution using Antarctic krill chitosan/hydroxyapatite composite     

Hang Qi  Xiao Jiang  Dayong Zhou  Beiwei Zhu  Lei Qin  Chun Ma  Yihang Ong  Yoshiyuki Murata 《Fibers and Polymers》2013,14(7):1134-1140

Discarded Antarctic krill shells can be used to prepare chitosan and adsorption materials in an attempt to save resource and protect environment. The optimal conditions of composite materials preparation were as follows: mass ratio of CS and HA was 2:1 at 40 °C, pH 10–10.5, volume ratio of chitosan and Ca(NO₃)₂ was 2:1 over a period of 1 day. Under these conditions, the Cr (VI) removal rate was about 75±8 %. SEM, TEM, XRD, FTIR, DT-TGA analysis indicated that CS/HA composite was made up of CS and HA and it possessed good mechanical strength and thermal stability. The ability to remove Cd (II), Cr (III) and Cu (II) in aqueous was high, and the optimal conditions were as follows: a contact time of 60 min at 35 °C and pH 6–7. The removal rates of all three heavy metals were above 90 %.  相似文献   

Genetic polymorphism and virulence of Colletotrichum gloeosporioides isolated from strawberry (Fragaria × ananassa Duchesne)     

Takeshi Suzuki  Chika Tanaka-Miwa  Yoshiyuki Ebihara  Yasuyuki Ito  Seiji Uematsu 《Journal of General Plant Pathology》2010,76(4):247-253

To analyze genetic relationships among Colletotrichum gloeosporioides isolates; 34 isolates were collected from strawberries all over Japan, but primarily from Chiba Prefecture, and 20 were isolated from hosts other than strawberry. These isolates were assayed for virulence on strawberries and subjected to a fingerprint (FP) analysis by repetitive extragenic palindromic-PCR. Most of the isolates that were highly virulent to strawberries had relatively similar FPs even though they were isolated from various host plants (strawberry, cyclamen, nipplefruit and Japanese pear) in different regions. A cluster analysis revealed that the highly virulent and the weakly virulent isolates tended to form individual clusters, indicating that the highly virulent strains of C. gloeosporioides, which were genetically close to isolates with similar FPs and distinguishable from the weakly virulent strains, were responsible for strawberry anthracnose in Japan.  相似文献   

Evaluation of the Subchronic Toxicity of Dietary Administered Equisetum arvense in F344 Rats     

Tago Y  Wei M  Ishii N  Kakehashi A  Wanibuchi H 《Journal of toxicologic pathology》2010,23(4):245-251

Equisetum arvense, commonly known as the field horsetail, has potential as a new functional food ingredient. However, little information is available on its side effects, and the general toxicity of Equisetum arvense has yet to be examined in detail. In the present study, we evaluated the influence of administration in diet at doses of 0, 0.3, 1 and 3% for 13 weeks in male and female F344 rats. No toxicity was detected with reference to clinical signs, body weight, urinalysis, hematology and serum biochemistry data and organ weights. Microscopic examination revealed no histopathological lesions associated with treatment. In conclusion, the no-observed-adverse-effect level (NOAEL) for Equisetum arvense was determined to be greater than 3% in both sexes of F344 rat (males and females: >1.79 g/kg BW/day and >1.85 g/kg BW/day, respectively) under the conditions of the present study.  相似文献   

Anti-Obesity effects of protopanaxdiol types of Ginsenosides isolated from the leaves of American ginseng (Panax quinquefolius L.) in mice fed with a high-fat diet     

Rui Liu  JingZhao Zhang  WenCong Liu  Yoshiyuki Kimura  YiNan Zheng   《Fitoterapia》2010,81(8):1079-1087

Effects of protopanaxdiol (PDG) and protopanaxatriol (PTG) types of ginsenosides isolated from the leaves of American ginseng on porcine pancreatic lipase activity were determined in vitro. PDG inhibited the pancreatic lipase activity in a dose-dependent manner at the concentrations of 0.25–1 mg/ml. It inhibited hydrolysis of about 83.2% of triolein at about 1 mg/ml of PDG. However, PTG showed no inhibitory activity. Therefore, anti-obesity activity of PDG was evaluated in mice fed a high-fat diet. The results demonstrated that PDG was effective in preventing and healing obesity, fatty liver and hypertriglyceridemia in mice fed with a high-fat diet.  相似文献   

Nondestructive evaluation of egg-to-adult development and feeding behavior of the bamboo powderpost beetle <Emphasis Type="Italic">Dinoderus minutus</Emphasis> using X-ray computed tomography     

Hiroki Watanabe  Yoshiyuki Yanase  Yoshihisa Fujii 《Journal of Wood Science》2017,63(5):506-513

The life history and feeding biology of the bamboo powderpost beetle Dinoderus minutus remain poorly understood because the beetles’ oviposition, development, and feeding take place inside bamboo culms. In this study, X-ray computed tomography (CT) was employed to nondestructively quantify the progression of larval body size and tunnel size from the first instar to pupation. Eggs of D. minutus laid between laminates of nutrient-containing filter paper were easily collected. The newly hatched larvae were inoculated singly into pieces of internodes of madake (Phyllostachys bambusoides). The pieces were scanned using a microfocus X-ray CT system every 3–5 days to visualize the beetles’ bodies and tunnels with resolutions of 18–60 μm/voxel. CT scans were continued after adult eclosion to analyze pre-mating adult feeding. The collected eggs were 0.84 ± 0.06 mm (mean ± SD) in length and the egg duration lasted 5.0 ± 0.8 days. Based on CT images, the larvae grew to 3.53 ± 0.23 mm in body length and turned into pupae of 3.42 ± 0.09 mm. The larvae bored tunnels with a length of 80.2 ± 4.8 mm and a volume of 68.0 ± 7.0 mm³ over the larval period of 61 ± 11 days. Newly emerged adults remained in the bamboo pieces to feed before making exit holes in 8 ± 1 days after adult eclosion. During this period, they bored tunnels at rates of 2.64 ± 0.58 mm/day in length and 4.87 ± 1.10 mm³/day in volume.  相似文献