Stand-scale transpiration estimates in a Moso bamboo forest: II. Comparison with coniferous forests     

Hikaru Komatsu  Yuka Onozawa  Tomonori Kume  Kenji Tsuruta  Tomo’omi Kumagai  Yoshinori Shinohara  Kyoichi Otsuki 《Forest Ecology and Management》2010

In western Japan, Moso bamboo (Phyllostachys pubescens) forests have been expanding by replacing surrounding vegetation such as coniferous plantation forests and natural broadleaved forests. It has been speculated that the replacement of surrounding vegetation by bamboo forests could alter the vegetation water cycle and available water resources. We quantified stand-scale transpiration (E) in a bamboo forest on the basis of sap-flux measurements and compared the E value with values for coniferous forests. The annual E was estimated to be 567 mm. Seasonal trends in E primarily corresponded to seasonal trends in the vapor pressure deficit. Annual E for the bamboo forest was higher than that for the coniferous forests by 12% of annual precipitation (P). This difference in annual E is comparable with the difference in annual interception evaporation (I) relative to P between bamboo and coniferous forests; previous studies reported lower I for bamboo forests by ∼10% of P. Thus, the sum of E and I was comparable for bamboo and coniferous forests. As this study is the first measuring E of bamboo forests, further studies are required to examine the generality of our results.  相似文献   

Biogeography of small odontocetes in relation to wide‐scale oceanographic structure in the North Pacific Ocean          下载免费PDF全文

Yu Kanaji  Makoto Okazaki  Hikaru Watanabe  Tomio Miyashita 《Fisheries Oceanography》2016,25(2):119-132

Information regarding the distributional patterns of top predators is undoubtedly important for the monitoring and management of marine ecosystems. Nevertheless, previous knowledge on the distributional patterns of cetacean species in relation to physical oceanography is usually limited to a small fraction of each species' range because of their vast distribution and infrequency of encountering many species. We carried out comprehensive analyzes on the distributions of small odontocetes covering almost the entire North Pacific Ocean. Using data from over 300 000 nautical miles (≈ 555 600 km) of dedicated sighting surveys and 7000 school sightings of 14 small odontocete species, which have accumulated for approximately a quarter of a century, we describe interspecific habitat differences in small odontocetes with respect to physical oceanography. Multivariate analyzes were used to discriminate the 14 species into four ecological groups: (i) Subtropical Domain species; (ii) Subarctic Boundary species; (iii) Transitional Domain species; and (iv) Subarctic Domain species. By comparing environmental variables in their habitats with variables indicative of water mass and frontal structures, the four species groups were further divided into several subgroups. Groups at higher latitudes comprised fewer species than those at lower latitudes, while species diversity was maximal at lower and intermediate latitudes. Our findings indicate that large‐scale oceanographic structures are important determinants for the present patterns in biogeography and species diversity of small odontocetes.  相似文献   

Allelopathic potential of indigenous Bangladeshi rice varieties          下载免费PDF全文

Sheikh M. Masum  Mohammad Amzad Hossain  Hikaru Akamine  Jun‐Ichi Sakagami  Prasanta C. Bhowmik 《Weed Biology and Management》2016,16(3):119-131

A series of experiments was conducted in the laboratory and greenhouse of the Subtropical Field Science Center, University of the Ryukyus, Japan, from April to October 2015 to assess the allelopathic potential of 50 indigenous Bangladeshi rice varieties by using the donor–receiver bioassay, equal compartment agar method (ECAM), plant residue extract method and pot culture method. Lettuce (Lactuca sativa L.), cress (Lepidium sativum L.), radish (Raphanus sativus L.), barnyard grass (Echinochloa crus‐galli L. Beauv.) and jungle rice (Echinochloa colona L.) were used as the test plants. The highest inhibition effect was given by Boterswar, while the stimulating effect was given by Kartikbalam and Panbira in the donor–receiver bioassay and ECAM tests. Boterswar, Goria, Biron and Kartiksail were selected as the highest allelopathic‐potential varieties by the donor–receiver bioassay and ECAM. In the methanol extract test, Boterswar gave the strongest inhibitory effect on both barnyard grass and jungle rice, while Kartiksail gave the highest inhibitory effect on the jungle rice shoot. The growth parameters and total dry matter of barnyard grass in the greenhouse pot experiment were significantly reduced as a result of the application of aqueous extracts of the selected rice varieties, which was similar to the results of the laboratory experiments. The varieties of Boterswar, Goria, Biron and Kartiksail were selected as the most allelopathic among the 50 indigenous Bangladeshi rice varieties. These rice varieties could be used for the isolation and identification of allelochemicals and to further develop new varieties that are tolerant to weeds.  相似文献   

Habitat and prey selection of common minke,sei, and Bryde’s whales in mesoscale during summer in the subarctic and transition regions of the western North Pacific     

Hikaru Watanabe  Makoto Okazaki  Tsutomu Tamura  Kenji Konishi  Denzo Inagake  Takeharu Bando  Hiroshi Kiwada  Tomio Miyashita 《Fisheries Science》2012,78(3):557-567

This study represents the first quantitative analysis of the characteristics of the distribution areas and stomach contents of common minke whale Balaenoptera acutorostrata, sei whale B. borealis, and Bryde’s whale B. edeni in relation to oceanographic and prey environments in mid summer in the western North Pacific. Common minke whales were distributed within subarctic regions and the northernmost region of the transitional domain, coinciding with the main habitat of their preferred prey, Pacific saury Cololabis saira. Sei whales were mainly found in the northernmost part of the transition zone and showed prey preference for Japanese anchovy Engraulis japonica, which was significantly more abundant in the main distribution area of the whale than in its adjacent areas. “Hot spots” of Bryde’s whales were found in several regions of the transition zone between the subarctic boundary and the Kuroshio front. This whale species preferred Japanese anchovy as prey, for which the distribution density was significantly higher in the main distribution area of the whale than in the adjacent areas. These results indicate that the summer distributions of Pacific saury and Japanese anchovy greatly influence the distributions of these whale species, suggesting that the whales’ habitat selection is closely related to their prey selection.  相似文献   

Ethylene Production in Fading Vanda Orchid Blossoms     

Akamine EK 《Science (New York, N.Y.)》1963,140(3572):1217-1218

The production of ethylene by fading blooms of Vanda Miss Agnes Joaquim, determined quantitatively by the perchlorate manometric procedure, was correlated with the degree of fading. A peak production of over 3400 microl per kilogram hour was obtained when 97 percent of the blooms were faded.  相似文献   

Seasonal changes of azimuthal,radial, and tree-to-tree variations in sap flux affect stand transpiration estimates in a <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> forest,central Taiwan     

Chen-Wei Chiu  Tomonori Kume  Hikaru Komatsu  Han Tseng  Tsong-Huei Wey  Kyoichi Otsuki 《Journal of Forest Research》2016,21(4):151-160

Stand transpiration (E) estimated using the sap flux methods is affected by the azimuthal, radial, and tree-to-tree variations of sap flux. Although several studies have examined the relative importance of the three variations in estimating E, the seasonality of the three variations remains unknown. In the current study, we attempted to clarify whether the relative importance of these three variations could show seasonal changes. Using sap flux data measured in a subtropical cloud forest from August 2010 to July 2011, we calculated the differences resulting from omitting the three variations in estimating E. The effects of the three variations in estimating E showed seasonality. The azimuthal and tree-to-tree variations were more pronounced during winter, whereas the radial variation was more pronounced during summer. However, the effect of tree-to-tree variation was consistently much larger than the other two variations throughout the study period. The tree-to-tree variation is more important in estimating E monthly, seasonally and annually than both the azimuthal and radial variations, although all three variations have shown seasonality. In addition, the sensor allocation for summer would be acceptable for the practical estimation of E if aiming at the long time scale.  相似文献   

Effects of wet–dry cycling on the mechanical properties of Arundo donax L. used for the vibrating reed in woodwind instruments     

Akahoshi  Hikaru  Obataya  Eiichi 《Wood Science and Technology》2015,49(6):1171-1183

Wood Science and Technology - The effects of wet–dry and moist–dry cycling on the mechanical properties of reed (Arundo donax L.) were investigated. Because water-soluble extractives...  相似文献   

Kid depletion in mouse oocytes associated with multinucleated blastomere formation and inferior embryo development          下载免费PDF全文

Akiyoshi Egashira  Nobuhiko Yamauchi  Md. Rashedul Islam  Kazuki Yamagami  Asami Tanaka  Hikaru Suyama  El‐Sharawy Mohamed El‐Sayed  Shoji Tabata  Takashi Kuramoto 《Animal Science Journal》2016,87(8):1048-1054

This study investigated the knockdown (KD) of Kid on maturation developmental competence and multinucleation of mouse germinal vesicle (GV) oocytes after parthenogenetic activation. Data revealed that Kid messenger RNA (mRNA) was expressed in GV and MII stage oocyte and 1‐ and 2‐cell embryos. Additionally, Kid mRNA expression in the Kid KD group decreased by nearly 46% compared to the control small interfering RNA (siRNA) groups. The rate of multinucleated embryos in the Kid KD group (52.4%) was significantly higher (P < 0.05) than the control siRNA group (4.7%). Finally, the developmental rates were significantly lower in the Kid siRNA group at > 4‐cell stage (28.6% vs. 53.5%) and the blastocyst stage (2.4% vs. 23.3%) compared to the control siRNA groups. Suppression of Kid using siRNA caused multinucleation in early embryos with high frequency and it may increase 2‐ to 4‐cell arrested embryos and reduce the developmental competence to blastocyst.  相似文献   

Effect of interleukin‐1β on occludin mRNA expression in the duodenal and colonic mucosa of dogs with inflammatory bowel disease          下载免费PDF全文

Misato Ogawa  Hironari Osada  Ayana Hasegawa  Hikaru Ohno  Nanako Yanuma  Kazuaki Sasaki  Minoru Shimoda  Junsuke Shirai  Hirotaka Kondo  Keitaro Ohmori 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2018,32(3):1019-1025

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Rainfall interception in a moso bamboo (Phyllostachys pubescens) forest   总被引：1，自引：0，他引：1  

Yuka Onozawa  Masaaki Chiwa  Hikaru Komatsu  Kyoichi Otsuki 《Journal of Forest Research》2009,14(2):111-116

In recent years, moso bamboo (Phyllostachys pubescens) forest areas in Japan have rapidly expanded, and bamboo is now invading nearby natural or plantation forests. To date, only one study has examined the rainfall interception of a moso bamboo forest. In that study, it was reported that the interception ratio (interception/rainfall) of the bamboo forest did not exceed the interception ratios of other natural and plantation forests (n = 4) in Japan. To expand the current state of knowledge about rainfall interception of bamboo forests, we measured throughfall and stemflow at another bamboo forest site. Annual rainfall (Rf), throughfall (Tf), and stemflow (Sf) during the measurement period were 2,105, 1,556, and 322 mm, respectively. Annual rainfall interception at the plot (I) was 228 mm. Tf/Rf, Sf/Rf, and I/Rf were 73.9, 15.3, 10.8%, respectively. I/Rf was less than 20% throughout the year except in October, the month with lowest rainfall. We also summarized rainfall interception data from 19 other natural and plantation forests. The I/Rf value of our site did not exceed the I/Rf values of these natural and plantation forests (n = 19). Our data will be useful for assessing changes in water resources that result from replacement of natural or plantation forests by bamboo forests.  相似文献