Seasonal and interannual variation in net ecosystem production of an evergreen needleleaf forest in Japan     

Yasuko Mizoguchi  Yoshikazu Ohtani  Satoru Takanashi  Hiroki Iwata  Yukio Yasuda  Yuichiro Nakai 《Journal of Forest Research》2012,17(3):283-295

Carbon dioxide (CO₂) flux was measured above the forest at the Fujiyoshida site on the northern slope of Mount Fuji in Japan in 2000?C2008 using an eddy covariance technique. The forest mainly consists of Japanese red pine (Pinus densiflora) and Japanese holly (Ilex pedunculosa). The 9-year average of monthly mean net ecosystem production (NEP) ranged from ?0.1?g?C?m^?2?day^?1 in January to 2.5?g?C?m^?2?day^?1 in May. The maximum net uptake was observed in May, although gross primary production (GPP) was highest in July. Variation in the leaf amount did not notably affect seasonal variation in GPP. This site was characterized by carbon uptake even in winter, if the meteorological conditions were conducive for photosynthesis and a resulting long period of carbon uptake. The 9-year averages of annual NEP, GPP, and ecosystem respiration (RE) were 388, 1,802, and 1,413?g?C?m^?2?year^?1, respectively. The annual NEP was lowest in 2003 and highest in 2004 over the 9?years. Year-to-year variability of NEP mainly depended on air temperature and photosynthetically active radiation in summer, and the dependence of the deviation of annual NEP on that of GPP was greater than that of RE. Long-term observational data indicated that the carbon uptake ability at the study site was at a moderate level in comparison with other temperate humid evergreen forests around the world. These data also indicated that the site had a high carbon uptake ability compared with other deciduous forests in Japan because of the duration of carbon uptake.  相似文献   

Interannual variability of net ecosystem production for a broadleaf deciduous forest in Sapporo, northern Japan   总被引：1，自引：0，他引：1  

Kenzo Kitamura  Yuichiro Nakai  Satoru Suzuki  Yoshikazu Ohtani  Katsumi Yamanoi  Tomoki Sakamoto 《Journal of Forest Research》2012,17(3):323-332

To estimate net ecosystem production (NEP), ecosystem respiration (R _E), and gross primary production (GPP), and to elucidate the interannual variability of NEP in a cool temperate broadleaf deciduous forest in Sapporo, northern Japan, we measured net ecosystem exchange (NEE) using an eddy covariance technique with a closed-path infrared gas analyzer from 2000 to 2003. NEP, R _E, and GPP were derived from NEE, and data gaps were filled using empirical regression models with meteorological variables such as photosynthetic active radiation and soil temperature. In general, NEP was positive (CO₂ uptake) from May to September, either positive or negative in October, and negative (CO₂ release) from November to the following April. NEP rapidly increased during leaf expansion in May and reached its maximum in June or July. The four-year averages (±?standard deviation) of annual NEP, GPP, and R _E were 443?±?45, 1,374?±?39, and 931?±?11?g?C?m^?2?year^?1, respectively. The lower annual NEP and GPP in 2000 may have been caused by lower solar radiation in the foliated season. During the foliated season, monthly GPP varied from year to year more than monthly R _E. Variations in the amount of incoming solar radiation may have caused the interannual variations in the monthly GPP. Additionally, in May, the timing of leaf expansion had a large impact on GPP. Variations in GPP affected the interannual variation in NEP at our site. Thus, interannual variation in NEP was affected by the incoming solar radiation and the timing of leaf expansion.  相似文献   

Histopathological characteristics of hepatic lipogranulomas with portosystemic shunt in dogs     

Isobe K  Matsunaga S  Nakayama H  Uetsuka K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(2):133-138

In the canine liver with portosystemic shunts (PSS), focal lesions consisting of cells with cytoplasmic brown pigments and lipid vacuoles are often observed in the hepatic parenchyma. Termed lipogranulomas, their histopathological characteristics have been little studied. In the present study, we examined liver biopsy samples from 144 dogs (age: 3 months-16 years; 65 PSS and 79 non-PSS cases), and investigated the histopathological characteristics, incidence, and density of lipogranulomas. Lipogranulomas were detected histopathologically in 55.4% of PSS dogs. The lesions were then grouped into 3 types according to the amount of cytoplasmic lipid vacuoles and brown pigments. The pigments were positive for Berlin blue, PAS, and Sudan black B, but negative with the Hall method. The majority of the cells were immunohistochemically positive for macrophage scavenger receptor, class A (MSR-A), while no cells were positive for hepatocyte-antigen and albumin. The cytoplasmic pigments were recognized as electron-dense microgranular materials by electron microscopy. The incidence of lipogranulomas was significantly higher in the PSS group than non-PSS group when dogs less than 1 year old were excluded. The lipogranuloma density in the liver was significantly higher in the PSS group. It is concluded that lipogranulomas are frequently observed in liver biopsies of canine PSS especially in dogs more than 1 year old. The lesions consisted of Kupffer cells and/or macrophages, and the cytoplasmic brown pigments are ceroid and hemosiderin. The pathogenesis of lipogranuloma in PSS needs to be clarified.  相似文献   

Assessing sexual maturity of feminized Japanese eel Anguilla japonica by measuring eye size     

Akihiro Okamura  Hideo P. Oka  Noriyuki Horie  Tomoko Utoh  Yoshiaki Yamada  Naomi Mikawa  Satoru Tanaka  Katsumi Tsukamoto 《Aquaculture International》2009,17(1):91-99

For efficient production of Japanese eel Anguilla japonica eggs, knowledge of the status of the sexual maturity of potential broodstock females is important because this status directly influences the time required to produce mature eggs by successive hormone doses. Here we apply an eye index (relative eye size) to evaluate the gonadal status of feminized A. japonica, which were induced by administration of estradiol-17β. Examination of gonad somatic and eye indexes of 267 feminized eels, cultivated for 12–56 months, revealed a significant correlation between these two indexes. Artificial maturation of 35 feminized eels showed that the number of hormone injections administered before ovulation was significantly lower as the eye index score increased, indicating availability of this noninvasive method of predicting sexual maturity of feminized eel. There was no correlation between eye index and fertilization rate, hatching rate, or larval survival rate, suggesting that sexual maturity before hormonal treatment does not affect egg quality.  相似文献   

Species and lineage identification for yellowfin <Emphasis Type="Italic">Thunnus albacares</Emphasis> and bigeye <Emphasis Type="Italic">T. obesus</Emphasis> tunas using two independent multiplex PCR assays     

Ryouichi Higashi  Kay Sakuma  Satoru N. Chiba  Nobuaki Suzuki  Seinen Chow  Yasuko Semba  Hiroaki Okamoto  Kenji Nohara 《Fisheries Science》2016,82(6):897-904

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Mercury distribution in tephra soil layers in Hokkaido, Japan, with reference to 34,000-year stratification     

Satoru HOBARA  Naoharu MIZUNO  Yoji AMANO  Hiroshi YOKOTA  Hiroyuki TANIYAMA 《Soil Science and Plant Nutrition》2009,55(4):582-589

Tephra from volcanic eruptions contains only small amounts of mercury (Hg) right after the eruption because the high temperature at eruption evaporates Hg in volcanic ash. Thus, accumulation of Hg in tephra soil layers during the dormant periods of the volcano may reflect Hg deposition while the layer was exposed to the atmosphere. To estimate sequential changes in Hg deposition, we measured the Hg content and accumulation in tephra layers from 6 sites in Hokkaido known to have many tephra layers derived from volcanic eruptions over a 34,000-year period. Mercury content and accumulation rate in the soil profiles varied widely depending on the tephra. In each tephra layer, the Hg content and accumulation rates increased principally at the upper soil horizons and decreased at the lower depths. The Hg deposition rates calculated from the amount of Hg accumulated in the tephra layers were similar within the same tephra. These characteristics of Hg distribution indicate that Hg deposition accumulated on the surface of each tephra layer during the period the tephra layer was exposed to the atmosphere. Although physicochemical processes such as leaching out, wind erosion, and volatilization might lead to over- and/or underestimation of the deposition rates, our estimated amounts of Hg were markedly higher in the tephra soils after 1,600 year BP than before that time. The results of this study suggest that tephra layers in Hokkaido offer important implications for understanding of the historical changes in atmospheric Hg deposition.  相似文献   

Greater contribution of low-nutrient tolerance to sorghum and maize growth under combined stress conditions with high aluminum and low nutrients in solution culture simulating the nutrient status of tropical acid soils     

Afrin AKHTER  Md. Shahadat Hossain KHAN  Egashira HIROAKI  Keitarou TAWARAYA  Idupulapati M. RAO  Peter WENZL  Satoru ISHIKAWA  Tadao WAGATSUMA 《Soil Science and Plant Nutrition》2009,55(3):394-406

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Detection of Pythium aphanidermatum in tomato using loop-mediated isothermal amplification (LAMP) with species-specific primers     

Shiro Fukuta  Reiko Takahashi  Satoru Kuroyanagi  Noriyuki Miyake  Hirofumi Nagai  Hirofumi Suzuki  Fujio Hashizume  Tomoko Tsuji  Hiromi Taguchi  Hideki Watanabe  Koji Kageyama 《European journal of plant pathology / European Foundation for Plant Pathology》2013,136(4):689-701

A loop-mediated isothermal amplification (LAMP) reaction with a primer set designed from the rDNA ITS sequence of P. aphanidermatum was developed. Results of a specificity test using 57 strains of Pythium spp. indicated that the LAMP assay gave no cross reactions in other 39 Pythium species, 11 strains of Phytophthora spp. and eight other soil borne pathogens. The detection limit was 10 fg of genomic DNA, which was ten times the sensitivity of the polymerase chain reaction. The LAMP assay was applied to hydroponic solution samples from tomato fields, and the results were compared to those of the conventional plating method. LAMP was observed to be effective for the specific detection of P. aphanidermatum. Furthermore, P. aphanidermatum was detected directly in tomato roots infected with P. aphanidermatum without DNA extraction. The LAMP method established in this study is a simple, sensitive and rapid tool for the detection of P. aphanidermatum.  相似文献   

Stem canker and wilt of delphinium caused by Fusarium oxysporum f. sp. delphinii in Japan     

Toru Kondo  Eiichi Chu  Koji Kageyama  Satoru Sugiyama 《Journal of General Plant Pathology》2013,79(5):370-373

Stem canker and severe wilt were observed on delphinium plants (Delphinium elatum) in Aomori Prefecture, Japan, in 2008. The fungus isolated from the diseased crown was identified as Fusarium oxysporum f. sp. delphinii on the basis of morphological characteristics, nucleotide sequences, and host range. The isolate induced similar stem canker and wilt symptoms in inoculated delphinium plants. We propose the name “stem canker and wilt” for the disease.  相似文献   

Characterization of sulfonylurea-resistant Schoenoplectus juncoides having a target-site Asp₃₇₆Glu mutation in the acetolactate synthase     

Yoshinao Sada  Hajime Ikeda  Seiji Yamato  Satoru Kizawa 《Pesticide biochemistry and physiology》2013

Schoenoplectus juncoides, a noxious weed for paddy rice, is known to become resistant to sulfonylurea (SU) herbicides by a target-site mutation in either of the two acetolactate synthase (ALS) genes (ALS1 and ALS2). SU-resistant S. juncoides plants having an Asp₃₇₆Glu mutation in ALS2 were found from a paddy rice field in Japan, but their resistance profile has not been quantitatively investigated. In this study, dose–response of the SU-resistant accession was compared with that of a SU-susceptible accession at in vivo whole-plant level as well as at in vitro enzymatic level.  相似文献