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281.
Yo Toma Fumiaki Takakai Untung Darung Kanta Kuramochi Suwido H. Limin Salampak Dohong 《Soil Science and Plant Nutrition》2013,59(3):436-451
Our previous research showed large amounts of nitrous oxide (N2O) emission (>200?kg?N?ha?1?year?1) from agricultural peat soil. In this study, we investigated the factors influencing relatively large N2O fluxes and the source of nitrogen (N) substrate for N2O in a tropical peatland in central Kalimantan, Indonesia. Using a static chamber method, N2O and carbon dioxide (CO2) fluxes were measured in three conventionally cultivated croplands (conventional), an unplanted and unfertilized bare treatment (bare) in each cropland, and unfertilized grassland over a three-year period. Based on the difference in N2O emission from two treatments, contribution of the N source for N2O was calculated. Nitrous oxide concentrations at five depths (5–80?cm) were also measured for calculating net N2O production in soil. Annual N fertilizer application rates in the croplands ranged from 472 to 1607?kg?N?ha?1?year?1. There were no significant differences in between N2O fluxes in the two treatments at each site. Annual N2O emission in conventional and bare treatments varied from 10.9 to 698 and 6.55 to 858?kg?N?ha?1?year?1, respectively. However, there was also no significant difference between annual N2O emissions in the two treatments at each site. This suggests most of the emitted N2O was derived from the decomposition of peat. There were significant positive correlations between N2O and CO2 fluxes in bare treatment in two croplands where N2O flux was higher than at another cropland. Nitrous oxide concentration distribution in soil measured in the conventional treatment showed that N2O was mainly produced in the surface soil down to 15?cm in the soil. The logarithmic value of the ratio of N2O flux and nitrate concentration was positively correlated with water filled pore space (WEPS). These results suggest that large N2O emission in agricultural tropical peatland was caused by denitrification with high decomposition of peat. In addition, N2O was mainly produced by denitrification at high range of WFPS in surface soil. 相似文献
282.
Koichi Shoji Kazuyuki Itoh Fukiko Kawahara Yuumi Yoshida Yoshihisa Yamamoto Ken‐Ichi Sudo 《Weed Biology and Management》2013,13(2):45-52
Differences in local topography (micro‐elevation) within a paddy field that constitute a source of variability in agronomical indicators have not been considered thoroughly as a block factor in weed studies. This study investigated and evaluated the performance of weeding machines (weeders) in two herbicide‐free paddy fields that contained micro‐elevations. The plant density of Monochoria vaginalis, a typical and harmful paddy weed unless controlled with herbicides, was used as the indicator of the efficacy of the weeders. Among the three weeders that were tested, one suppressed M. vaginalis dramatically at low elevations and the others were less sensitive to micro‐elevation. For comparison across the fields, micro‐elevations at weed sampling locations were converted to the initial depth of water by using the records of hydrographs that had been set in each field. The relationship between the initial depth of water and the plant density of M. vaginalis was very clear with the use of the elevation‐sensitive weeder. Moreover, this relationship was valid, even with the less‐sensitive weeders. The finding that the greater the depth of water, the less the plant density was significant, even for M. vaginalis, a difficult aquatic paddy weed that was controlled with any of the weeders tested. Thus, micro‐elevation within a paddy field needs to be treated as a crucial block factor in weed‐sampling studies. A coarse survey of the level of a field and the installation of a hydrograph are recommended for a clear analysis of the background of weed control practices. 相似文献
283.
Masahiro Matsunaga Keiko Sakai Hiroshi Kamitakahara Kazuya Minato Fumiaki Nakatsubo 《Journal of Wood Science》2000,46(3):253-257
Heartwood of pernambuco (Guilandina echinata Spreng, synCaesalpinia echinata Lam.), which has been used as material for violin bows, was extracted by soaking in water, and the obtained extractives were analyzed. The main components of the extractives were identified to be protosappanin B and brazilin. In particular, protosappanin B occupied about 40% of the pernambuco extractives. The loss tangent (tan) of spruce wood impregnated with protosappanin B decreased markedly, the same as that of specimens impregnated with extractives before being purified. It is expected that protosappanin B can make a contribution to the decrease in tan due to impregnation with extractives.Part of this work was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998; and the 49th annual meeting of the Japan Wood Research Society, Tokyo, April 1999 相似文献
284.
Sanro Tachibana Etsuko Watanabe Junichiro Ueno Kiyoka Tokubuchi Kazutaka Itoh 《Journal of Wood Science》2005,51(2):176-180
From methanolic extracts of leaves of kyaraboku, Taxus cuspidata var. nana, phenylisoserine methyl ester (3) was isolated along with taxinine (1), taxol (2), sciadopitysin (4), ginkgetin (5), isorhamnetin (6), and quercetin (7). This is the first time that phenylisoserine methyl ester has been isolated from T. cuspidata var. nana. Compound 3 was also isolated from the ethanolic extracts of leaves of T. cuspidata var. nana. Furthermore, compound 3 was identified in methanolic extracts from the bark of this tree. 相似文献
285.
Masahiro Matsunaga Eiichi Obataya Kazuya Minato Fumiaki Nakatsubo 《Journal of Wood Science》2000,46(2):122-129
To clarify the lowering mechanism of loss tangen (tan) of sitka spruce (Picea sitchensis Carr.) wood impregnated with extractives of pernambuco (Guilandina echinata Spreng. synCaesalpinia echinata Lam.), we examined the vibrational properties of the impregnated wood in relation to the adsorbed water. The results obtained were as follows: (1) The equilibrium moisture content (EMC) of impregnated sitka spruce decreased to some extent compared with untreated wood. (2) Frequency dependencies of tan a about 400–8000Hz showed that impregnated wood has much lower tan than untreated wood at around 9% mois ture content (MC), except for the high-frequency region. At high relative humidity, impregnated wood has a minimum tan (at around 4000Hz); and at other frequency ranges the tan of impregnated wood did not differ considerably from that of untreated wood. (3) The apparent activation energy of the mechanical relaxation process (E) concerned with adsorbed water molecules was higher for impregnated specimens than for untreated ones at moderately high relative humidity, whereas at high relative humidity the difference was not observed. Based on these results, it is thought that the tan of impregnated wood decreased at low rela tive humidity because of the formation of direct hydrogen bonds between impregnated extractives and wood components. However, when the specimen is at higher relativePart of this work was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998 humidity, the formation of direct hydrogen bonds are disturbed by the existence of a large number of water molecules, and some extractives act as a plasticizer. 相似文献
286.
A. Itoh T. Yamakura S. Tan J. J. Kendawang H. S. Lee 《Journal of Forest Research》2003,8(2):0117-0121
Cuttings from older trees of the Dipterocarpaceae generally lose their ability to root. However, branches in a canopy of
adult dipterocarps are a possible source of cuttings because they show juvenile characteristics in architecture due to “adaptive
reiteration”, suggesting physiological rejuvenation. Effects of resource plant size on the rooting of cuttings and the possibility
of using cuttings from reiterated branches of adult trees were studied for Dryobalanops lanceolata, an emergent dipterocarp species. A cutting experiment with non-mist propagators was conducted for cuttings collected from
resource plants of four different size classes: <2 m, 2–5 m, 8–15 m, and 70 m in height. The smallest size class included
two different age classes: <2 and >2 years old. Cuttings from the tallest resource plant were collected from reiterated branches.
Rooting percentage was negatively correlated with resource plant size: 77–78% for resource plants <2 m, 63% for 2–5 m, 36%
for 8–15 m, and 0% for 70 m. Rooting percentages of cuttings collected from different individuals were not different for the
2–5 m tall class, while they were significantly different for the 8–15 m tall class. Resource plant size was negatively correlated
with the number of roots for rooted cuttings. No significant relationship was observed between resource plant size and mean
length of each root, total root length or total root dry weight for rooted cuttings. The results suggest the possibility of
collecting cuttings from relatively large resource plants up to 15 m tall and >20 years old if we chose good individuals for
resource plants. The results, however, show the difficulty in using reiterated branches of adult trees as a source of cuttings
for D. lanceolata.
Received: October 15, 2001 / Accepted: November 11, 2002
Acknowledgments We express our sincere thanks to Dr. S. Tamura, Dr. K. Ogino, and Mr. A.A. Hamid for their kind support. The tree tower was
constructed in a cooperative project between Japan and Sarawak supported by the Ministry of Education, Culture, Sports, Science
and Technology, Japan (Grant NP0201). The cutting experiment was partly funded by the Nippon Life Insurance Foundation and
the Japan Society for the Promotion of Science (JSPS-RFTF96R16001).
Correspondence to:A. Itoh 相似文献
287.
Reiichiro Sato Tetsuo Ito Tsunenori Suganuma Yumi Une Tomoo Kudo Hideki Kayanuma Eiichi Kanai Takehito Suzuki Hideharu Ochiai Nahoko Enomoto Seigo Itoh Ken Onda Yasunori Wada 《The Canadian veterinary journal. La revue veterinaire canadienne》2015,56(5):463-465
A male crossbred calf developed a limp and pain upon deep pressure on the right hind limb and the right forelimb. The radiographic findings of affected limbs and pathological findings of bone biopsy were similar to those observed in canine panosteitis. This is the first case of suspected panosteitis reported in cattle. 相似文献
288.
Masashi Yuki Hiroshi Itoh Katsuaki Takase 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2010,39(1):65-71
Background: α‐1‐acid glycoprotein (AGP) is an acute‐phase protein and a serum marker of inflammation and neoplasia in humans. AGP concentrations in diseased dogs and the potential effects of age, breed, and sex have not been elucidated. Objective: The purpose of this study was to examine differences in AGP concentration based on age, sex, and breed in a large population of clinically healthy dogs and to compare AGP concentrations in dogs with various diseases. Methods: Serum was obtained from clinically healthy puppies (n=74) and adults (n=172) of both sexes, and included mongrels (n=205) and Beagles (n=41). Serum also was obtained from 192 dogs with various diseases, including 8 with pyometra that were sampled before, and 1, 2, 3, and 10 days after surgery. AGP concentration was measured by single radial immunodiffusion. Statistical comparisons were made among age, sex, breed, and disease groups. Results: Serum AGP in healthy adult mongrels was 364±106 mg/L (reference interval, 152–576 mg/L). AGP was lowest in newborns (n=11, 122±54 mg/L) and gradually increased to adult levels by 3 months of age. Median AGP concentration was highest in dogs with parvovirus (n=17, 2100 mg/L), distemper (n=7, 1250 mg/L), and pyometra (n=18, 2480 mg/L) and was also significantly higher in dogs with acute filariasis, renal failure, urolithiasis, pancreatitis, hepatitis, trauma, hyperadrenocorticism, and immune‐mediated hemolytic anemia. Dogs with acute filariasis and acute hepatopathy had significantly higher AGP concentrations than dogs with chronic filariasis and chronic hepatopathy. Serum AGP concentration decreased gradually following surgery for pyometra but remained increased after 10 days (896±175 mg/L). Conclusions: Because of significantly lower AGP in puppies, the age of dogs should be considered when using AGP as a marker of disease. Serum AGP may be a useful marker of inflammatory disease in dogs and may help differentiate acute and chronic stages of disease. 相似文献
289.
Kohma Arai Hikaru Itakura Akihito Yoneta Tatsuki Yoshinaga Fumiaki Shirotori Kenzo Kaifu Shingo Kimura 《Fisheries Science》2017,83(5):735-742
To investigate the presence of non-native anguillid eels in Japanese waters, 141 eels were collected from seven sampling sites throughout the Tone River system. Genetic species identification showed an extraordinary dominance of the non-native European eel Anguilla anguilla in the uppermost site of the study area. Estimation of age from otoliths suggested that the European eels were introduced into the river in the 1990s, corresponding to previous reports from other Japanese water systems. Comparison of the von Bertalanffy growth curve parameters indicated that the European eels caught in the Tone River system appeared to have a similar or even higher growth rate than the same species in the original habitats in Europe. The long-term inhabitation and the normal development of European eels in Japanese waters suggest that regulations prohibiting the release of non-native eels and safeguards against accidental escape from culture ponds must be strictly maintained in order to ensure the conservation of the native Japanese eel. 相似文献
290.
Nobuaki Nanjo Tetsuya Takatsu Kazuo Imura Kingo Itoh Yuuhei Takeya Toyomi Takahashi 《Fisheries Science》2017,83(2):199-214
To clarify the recruitment process of sand lance Ammodytes sp., we investigated larval condition factor, relative gut fullness (%GF), prey abundance and oceanographic structure in Mutsu Bay, Japan, during 1999–2001. Ammodytes sp. larvae, which were collected by horizontal hauls of Motoda nets and a ring net at depths of 1, 10, 20, 30 and 40 m, were mainly distributed at 10–30 m. Larvae at the first feeding time until 12 mm in body length (BL) fed predominantly on copepod nauplii, whereas large larvae with BL of 12.1–14.0 mm fed on a mixture of copepod nauplii, copepodites and appendicularians from late February to April. A path analysis showed that difference in water density between 35- and 5-m depths negatively affected naupliar abundance at 10–30-m depth (standardised path coefficient β = ?0.71, p = 0.005 for 3.3–8.0-mm BL larvae and β = ?0.78, p < 0.001 for 8.1–12.0-mm BL larvae). Naupliar abundance positively affected the %GF of Ammodytes sp. larvae (β = 0.75, p < 0.001 for 3.3–8.0-mm BL larvae and β = 0.66, p < 0.001 for 8.1–12.0-mm BL larvae), whereas it was negatively affected by water temperature (β = ?0.45, p = 0.008 for 3.3–8.0-mm BL larvae and β = ?0.56, p = 0.002 for 8.1–12.0-mm BL larvae), and the temperature effect was weak compared with that of naupliar abundance. In turn, %GF positively affected larval somatic weight (β = 0.91, p < 0.001 for 6.0-mm BL larvae and β = 0.70, p = 0.005 for 10.0-mm BL larvae). The recruitment failure in 1999 was likely caused by a reduced condition factor, which resulted from low naupliar abundance. In contrast, the abundance of nauplii and Oithona similis copepodites was high in 2000 and 2001. It is possible that the higher recruitment success in 2001 was because of the higher water temperatures in Mutsu Bay, sustaining faster growth of the larvae than in 2000 under the high-prey abundance conditions. 相似文献