Factors affecting the dynamics of vegetation in the landscapes of shimokamagari Island,southwestern Japan     

Nobukazu Nakagoshi  Yoko Ohta 《Landscape Ecology》1992,7(2):111-119

On Shimokamagari, an island of the Seto Island Sea, patterns of vegetation in the landscape were studied using vegetation maps. Relationships between social and economic changes, site conditions and the vegetation were examined from a historical perspective. In the process of economic development, mandarin orange production became important on this island. However, over-production, a reduction in the price of mandarin oranges and low-temperature damage to orange trees caused large citrus orchards to be abandoned. A plant community dominated by kudzu appeared in the abandoned orchards and the pine forests, as well. These changes in orchards were connected with the natural site conditions, such as soil, geology, inclination, elevation, direction of slope, and also with artificial conditions, such as density of working paths. Another factor causing change was the replacement of the organic fertilizer of litter from forests by chemical fertilizer since the 1960's. As a result, medium and small forests of pine became tall forests and tall forests of pine changed into tall oak forests. In the human-dominated areas, the major factors affecting the process of vegetation were economic activities, and after the abandonment of the farm-lands, forest succession were controlled by natural site conditions. This paper was presented at the World-Congress of Landscape Ecology in Ottawa, 1991 Titles are tentative translations for original titles in Japanese by the authors.  相似文献   

Exploration of factors determining milk production by Holstein cows raised on a dairy farm in a temperate climate area     

Kino  Erina  Kawakami  Rui  Minamino  Tomoya  Mikurino  Yoko  Horii  Yoichiro  Honkawa  Kazuyuki  Sasaki  Yosuke 《Tropical animal health and production》2019,51(3):529-536

In this study, we examined factors that affected milk production by cows raised in a temperate climate area. We conducted this study on a large dairy farm containing approximately 2000 Holstein cows, located in a temperate climate area. We collected 7803 calving records for 4069 cows from 2012 to 2016. We then assessed the effect of hot weather on milk yield by examining three climate factors: season, maximum temperature (MAX), and the temperature and humidity index (THI). We found that increases in heat stress caused linear decreases in milk yield (P?<?0.05). Additionally, the effects of the three climate factors on milk yield varied depending on cow parity and days open (P?<?0.05). Thus, management procedures should consider cow parity and lactating stage to minimize the negative effects of heat stress on milk production. We also found that the lowest Akaike information criterion value was obtained in our model when using THI for 305-day milk yield. This suggests that THI is a more accurate variable for evaluating heat stress than MAX or season.

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Quantitative real‐time PCR monitoring of Escherichia coli and Clostridium perfringens with oral administration of Lactobacillus plantarum strain Lq80 to weaning piglets     

Shunsuke TAKAHASHI  Yoko YOSHIDA  Nobuo NAKANISHI  Takamitsu TSUKAHARA  Kazunari USHIDA 《Animal Science Journal》2008,79(6):737-744

Levels of fecal or intestinal lactobacilli, Escherichia coli and Clostridium perfringens, and the prevalence of clostridial alpha toxin gene and heat‐stable toxin (ST) gene of enterotoxigenic E. coli (ETEC) were monitored in weaned piglets before (day 0) and during (days 7, 14, and 21) the administration of Lactobacillus plantarum strain Lq80. Lactobacilli were enumerated in a culture‐dependent method. The remainders were determined by quantitative real‐time PCR. In this quantitative real‐time PCR method, the detection limit was proved to be as low as 10³ cells/g feces or intestinal contents. Number of lactobacilli increased from day 0 to day 7 (P < 0.05), to day 14 (P < 0.05), and to day 21 (P = 0.07) in the Lq80‐administered group. L. plantarum contributed to as low as 10% of the lactobacillal population in the Lq80‐administered group. The number of E. coli and C. perfringens, and the prevalence of alpha toxin gene in feces or intestinal contents of the Lq80‐administered group decreased, at least in the first week of the postweaning period. Oral administration of L. plantarum strain Lq80 can stimulate the growth of indigenous lactobacilli and decrease ST‐producing ETEC and C. perfringens in the intestine of postweaning piglets.  相似文献   

Meteorological factors affecting seroconversion of Akabane disease in sentinel calves in the subtropical Okinawa Islands of Japan     

Hayama  Yoko  Yanase  Tohru  Suzuki  Moemi  Unten  Kazuhiko  Tomochi  Hisayuki  Kakehi  Mayu  Shono  Yukina  Yamamoto  Takehisa  Kobayashi  Sota  Murai  Kiyokazu  Tsutsui  Toshiyuki 《Tropical animal health and production》2018,50(1):209-215

Tropical Animal Health and Production - Akabane virus, the pathogen-causing Akabane disease, is an arthropod-borne virus (arbovirus) transmitted by the Culicoides biting midge. A nationwide...  相似文献   

Microbial degradation of nonylphenol in some aquatic environments     

Katsuhiko Fujii  †  Naoto Urano  Shigeru Kimura  Yoko Nomura    Isao Karube 《Fisheries Science》2000,66(1):44-48

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Immunohistochemical localization of enzymes related to lignin biosynthesis in the primary xylem of hybrid aspen     

Yoshihiro Katayama  Yoko Mashino  Nobuyuki Nishikubo  Kaori Yoshitomi  Ryo Funada  Shinya Kajita 《Journal of Wood Science》2002,48(6):457-466

We have investigated the spatial regulation of the accumulation of enzymes involved in the biosynthesis of shikimate and lignin during differentiation of primary xylem from the apical meristem via procambium in hybrid aspen (Populus sieboldii x Populus grandidentata). Immuohistochemical staining revealed that, in the top part of shoots, lignification began in a single or just a few adjacent vessel elements and subsequently spread to neighboring cells. The spatial localization of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (DAHPS), which is one of the key enzymes in the shikimate pathway, was tightly correlated with the cell-specific deposition of lignin in the primary xylem. We also found that the spatial localization of enzymes in the general phenylpropanoid pathway and in the lignin-specific pathway was closely associated with the cell-specific deposition of lignin and the accumulation of DAHPS. Our data suggest that enzymes that act in the shikimate, general phenylpropanoid, and lignin-specific pathways are initially produced and function coordinately in a single or a few adjacent elements at the start of primary xylem development.  相似文献   

Predicting the humidity control capacity of material based on a linear excitation-response relationship     

Toshiro Morooka  Yoko Homma  Misato Norimoto 《Journal of Wood Science》2007,53(3):199-203

The Cb value is a useful parameter for estimating the humidity control capacity of materials. It is defined as the ratio of the range of variation of relative humidity in a steel box lined with the material of interest to that in an empty steel box, when sinusoidal temperature variation is applied. However, because it takes a long time to obtain the Cb values for materials at each temperature variation period, we developed an easier method based on a linear excitation-response theory to obtain the Cb values without measuring at each period. Japanese cedar was the material used in this study. The temperature excitation, a jump from a constant temperature to another constant temperature, was used to obtain the absolute humidity response. Under the assumption that the temperature excitation-humidity response relationship is linear, we were able to predict humidity variation to sinusoidal temperature variation at any period, and we obtained the Cb value for each temperature variation period. Predicted values agreed well with the experimental values. From this, it was found that the Cb value could be predicted without measuring the Cb value at each period over a long time. In addition, the peak time difference, which is closely related to the Cb value, could also be predicted in a similar manner.  相似文献   

Characterization of sp<Superscript>2</Superscript>- and sp<Superscript>3</Superscript>-bonded carbon in wood charcoal     

Kengo Ishimaru  Toshimitsu Hata  Paul Bronsveld  Takashi Nishizawa  Yuji Imamura 《Journal of Wood Science》2007,53(5):442-448

Japanese cedar (Cryptomeria japonica) preheated at 700°C was subsequently heated to 1800°C and characterized by electron microscopy, X-ray diffraction, and micro-Raman spectroscopy. The degree of disorder of carbon crystallites and the amount of amorphous phase decreased considerably with an increase in heat treatment temperature to 1400°C, while carbon crystallites clearly developed above this temperature, showing that the microstructure of carbonized wood undergoes drastic changes around 1400°C. Besides showing the bands for sp²-bonded carbon, the Raman spectra showed a shoulder near 1100 cm⁻¹ assigned to sp³-bonded carbon. With an increase of heat treatment temperature, the peak position of the Raman sp³ band shifted to a lower frequency from 1190 to 1120 cm⁻¹, which is due to the transformation of sp³-bonded carbon from an amorphous phase to a nanocrystalline phase. These data showed that the microstructure of carbonized wood from 700° to 1800°C consisted of the combination of sp²- and sp³-bonded carbon, which is probably due to the disordered microstructure of carbonized wood. It is suggested that the sp³-bonded carbon is transformed from an amorphous structure to a nanocrystalline structure with the growth of polyaromatic stacks at temperatures above 1400°C.  相似文献   

Influences of genetic and environmental factors on the concentration of the allergen Cry j 1 in sugi (Cryptomeria japonica) pollen     

Goto Y  Kondo T  Hayashi E  Kuramoto N  Takahashi M  Yasueda H 《Tree physiology》2004,24(4):409-414

Pollen from sugi (Japanese cedar, Cryptomeria japonica D. Don), a forest tree species that is widely grown in Japan, causes serious allergic disease. The major allergens from sugi pollen, Cry j 1 and Cry j 2, have been isolated and characterized. It has been reported that Cry j 1 concentration in pollen varies considerably among trees. If Cry j 1 concentration is genetically controlled, the planting of trees with low Cry j 1 concentrations would reduce pollinosis. We investigated genetic and environmental effects on Cry j 1 concentration in eight clones growing at four sites. Concentrations of Cry j 1 in pollen were measured with a monoclonal antibody-based Enzyme Linked Immunosorbent Assay (ELISA). The Cry j 1 concentrations differed significantly among clones and sites, but the site x clone interaction was not significant, suggesting that the Cry j 1 concentration is controlled primarily by genetic factors. We examined correlations between Cry j 1 concentration and temperature and precipitation from July through February. Temperature was not significantly related to Cry j 1 concentration, whereas cumulative precipitation during the 8 months and mean daily precipitation in September showed significant negative correlations with Cry j 1 concentration.  相似文献   

Carbon dioxide exchange of larch (Larix gmelinii) cones during development     

Wang W  Zu Y  Cui S  Hirano T  Watanabe Y  Koike T 《Tree physiology》2006,26(10):1363-1368

Larch (Larix gmelinii (Rupr.) Rupr.) cone scales are green, but little is known of their photosynthetic role in cone development or about how they differ in gas exchange characteristics from needle leaves. In contrast to leaf photosynthesis (Pleaf), we found that stomatal regulation of cone photosynthetic rate (Pcone) was marginal because the photosynthetic carbon came from internal recycling of respiratory carbon dioxide (CO2). Photosynthetic recycling of respired CO2 was confirmed by the finding that the intercellular CO2 concentration (Ci) in cone scales was much higher than ambient [CO2]; also, there was a positive correlation between Pcone and Ci, whereas Pleaf was almost constant as Ci varied. Low chlorophyll (Chl) concentration was a limiting factor for Pcone, but not for Pleaf, as indicated by the correlation between Pcone and chlorophyll concentration. Moreover, chlorophyll utilization efficiency (Psat/Chl a+b) for cone scales was lower than that for leaves. In both cones and leaves, nitrogen (N) was positively correlated with photosynthetic capacity (P), but the P/N value was much lower for cones than for leaves. For both organs, the ratio of respiration to N was broadly similar. Although mature cones have no photosynthetic capacity, Pcone of young cones was as high as 5.3 micromol m(-2) s(-1), about 1.26 times the value of Pleaf, and accounted for the refixation of 30-40% of the respiratory CO2 produced by cones, equivalent to the photosynthetic capacity of a bundle of short shoots near each cone. Thus, Pcone may be an important additional source of photosynthate for cones, given the weak assimilating capacity of leaves that are not fully expanded during cone development.  相似文献