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151.
Yukio Nezu Masahiro Miyazaki Kazuhiko Sugiyama Ikuo Kajiwara 《Pest management science》1996,47(2):103-113
A number of 6-(4-phenoxyphenoxy)pyrimidines and triazines were synthesized and their herbicidal activity was measured. Compounds with the methoxy groups at the 2- and 4-positions on the pyrimidine and triazine rings exhibited high herbicidal activity. Introduction of a substituent into the 5-position of the pyrimidine ring diminished the activity. In the phenoxyphenoxy substructure at the 6-position, the central ether bond can be replaced by a methylene group without loss of activity. The optimum substituent on the terminal phenyl ring was 3-trifluoromethyl. The compounds showed a strong Hill reaction inhibition, but unfortunately showed poor selectivity between weeds and crops. 相似文献
152.
Katsuhisa Tanaka Yukio Hanamura Ving Ching Chong Satoshi Watanabe Alias Man Faizul Mohd Kassim Masashi Kodama Tadafumi Ichikawa 《Fisheries Science》2011,77(5):809-816
Stable carbon (δ13C) and nitrogen (δ15N) isotope ratios were measured to investigate the migration of John’s snapper Lutjanus johnii and its dependence on the food resources provided within the large Matang Mangrove Forest Reserve (40,151 ha), Malaysia.
John’s snapper, and its main prey food such as penaeids, Acetes shrimps and mysids, showed generally depleted δ13C values in the inner mangrove area but more enriched values in the river mouth and coastal area. Some juveniles migrated
into the inner mangrove areas, although they were also distributed near the river mouth areas. Isotopic signatures of snapper
fish and prey reveal the ontogenetic migration of the youngest juvenile fish (<5 cm in total length) from the coastal area
into the mangrove area, shifting their dependence from the coastal food web to the inner mangrove food web with their growth.
The study shows the importance of the complex interconnected mangrove waterways and associated prey animals present in the
large mangrove system to juvenile John’s snapper. 相似文献
153.
154.
Masafumi SHIMIZU Yoshiko NAKAGAWA Yukio SATO Tamotsu FURUMAI Yasuhiro IGARASHI Hiroyasu ONAKA Ryuji YOSHIDA Hitoshi KUNOH 《Journal of General Plant Pathology》2000,66(4):360-366
To survey endophytic actinomycetes as potential biocontrol agents against fungal diseases of rhododendron, young plants of
rhododendron were surface-sterilized for use as an isolation source. Nine, six and two isolates, with distinguishing characteristics
based on the macroscopic appearance of colonies, were obtained from roots, stems and leaves, respectively, suggesting that
various species of actinomycetes grow in the respective organs of this plant as symbionts or parasites. On an agar medium,
only isolate R-5 commonly formed a clear growth-inhibition zone against two major fungal pathogens of rhododendron, Phytophthora cinnamomi and Pestalotiopsis sydowiana, indicating that this isolate can produce antifungal material(s). Acetone extracts of a liquid culture of R-5 had a broad antimicrobial
spectrum against Gram-positive bacteria, yeast and filamentous fungi. Isolate R-5 was identified as a Streptomyces sp. based on morphological, physiological and chemotaxonomical characteristics. The present results indicate that isolate
R-5 is a suitable candidate for the biocontrol of diseases of rhododendron.
Received 25 March 2000/ Accepted in revised form 18 May 2000 相似文献
155.
Optimal carbamate treatment conditions were studied for flower induction in seedlings of an asparagus cultivar ‘Mary Washington
500 W’. Flower induction was most accelerated by soaking seeds in 50 mg l−1 carbamate solution for 12 days at 25 °C under the fluorescent light. Longer exposure to carbamate over a 12 day period induced a higher percentage of seedlings
to flower. A higher percentage of flowering seedlings were male. Flower induction frequency among seven cultivars through
carbamate treatment widely ranged from 13 to 67%. ‘Geynlim’, ‘Mary Washington 500 W’ and ‘Welcome’ exhibited a high percentage
of flowering seedlings, while ‘Larac’ and ‘Vulkan’ showed low values. Only male flowers were induced in all-male cultivars.
Variation in pollen germination was found within all cultivars. ‘Geynlim’, ‘Cito’ and ‘Mary Washington 500 W’ showed high
values of average pollen germination. Application of carbamate compound to induce flower production can rapidly produce homogenic
cultivars which include both sexes. This is necessary for genetic studies and breeding purposes.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
156.
157.
Yasuo Nakamura Tadashi Nakano Tatsuya Yurimoto Yukio Maeno Takayoshi Koizumi Akio Tamaki 《Fisheries Science》2010,76(6):931-941
We assessed the reproductive cycle of the venerid clam Meretrix lusoria by histological analysis of the gonads. Individuals for study were collected from natural populations on the Shirakawa tidal
flat, Ariake Sound, and from populations that had been transplanted from the Shirakawa flat to the Oi flat in Tokyo Bay. In
both study areas, the reproductive cycle was synchronized between sexes. Gonads of the clam started to develop in early spring
and matured during the summer. Mass spawning occurred in the late summer/early fall. The clam matured at a shell length of
17–20 mm, which is much smaller than previously considered. While trophic conditions and salinity differed considerably in
the two study areas, water temperatures showed similar seasonal changes (12°C during the winter and around 30°C during the
summer). Thus, temperature probably controlled gonadal development. The coincidence of the period of spawning with the period
of frequent intrusion of hypoxic waters into the tidal flats in Tokyo Bay suggests that such hypoxic events interfere with
clam recruitment and are at least partly responsible for the disappearance of the natural population at this location. 相似文献
158.
159.
Nobuhide Fujitake Atsuko Kusumoto Mayuko Tsukamoto Yukio Noda Takeshi Suzuki Hiroo Otsuka 《Soil Science and Plant Nutrition》2013,59(2):349-358
Abstract Humic acids (HAs) obtained from four different soils by sequential extraction with pyrophosphate solutions at different pH values (i.e. at pH 3, 5, 7, 9, 11, and 13), were examined by ultraviolet and visible (UV-VIS) spectroscopy and elemental analysis. UV-VIS spectra from 230 to 700 nm were measured, and absorbance coefficients of 1% humic acid solutions at 600 nm (E 1% 600) and Δlog K were calculated. The shape of the spectra of humic acids depended on the soil types rather than on the pH values. The (E 1% 600) values were higher in the neutral region, and lower in the alkaline region, for each pH value they decreased in the following order: buried Andosol > Andosol > Histosol ≧ Cambisol. The Δlog K values for each pH value were higher in the following order: Histosol> Cambisol > buried Andosol≧Andosol. Although the linear correlation was found to be significant between the E 1% 600 and Δlog K values, the relation between these optical properties and pH values differed among the soil types. However, in the neutral region, the higher E 1% 600 values of humic acids from buried Andosol and Andosol and the lower Δlog K values of humic acids from Cambisol and Histosol suggest that the humification degree was higher in the neutral region. Data of elemental composition and atomic ratios were obtained for each humic acid. The H/C ratios in the four soils increased gradually with increasing pH values from 5 to 13, and those for each pH value were commonly higher in the following order: Cambisol> Histosol> Andosol> buried Andosol. The O/C and OIH ratios decreased with increasing pH values. The results of the H/C versus O/C diagram suggested that decarboxylated humic acids were extracted at the higher pH values. A highly significant correlation coefficient was obtained between the H/C and OIH ratios (r= ?0.891***). Results showing that the decrease of the pH values corresponded to the order of the humic acids in the correlation curve in the H/C versus O/H diagram suggest that the humic acids with a higher content of unsaturated bonds and a higher degree of oxidation were extracted at the lower pH values within the range from 5 to 13. 相似文献
160.
Plexins are cell surface receptors for semaphorin molecules, and their interaction governs cell adhesion and migration in a variety of tissues. We report that the Semaphorin 4D (Sema4D) receptor Plexin-B1 directly stimulates the intrinsic guanosine triphosphatase (GTPase) activity of R-Ras, a member of the Ras superfamily of small GTP-binding proteins that has been implicated in promoting cell adhesion and neurite outgrowth. This activity required the interaction of Plexin-B1 with Rnd1, a small GTP-binding protein of the Rho family. Down-regulation of R-Ras activity by the Plexin-B1-Rnd1 complex was essential for the Sema4D-induced growth cone collapse in hippocampal neurons. Thus, Plexin-B1 mediates Sema4D-induced repulsive axon guidance signaling by acting as a GTPase activating protein for R-Ras. 相似文献