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排序方式: 共有188条查询结果,搜索用时 31 毫秒
111.
Okamura Akihiro Yamada Yoshiaki Mikawa Naomi Horie Noriyuki Tsukamoto Katsumi 《Fisheries Science》2020,86(4):685-692
Fisheries Science - This study assessed the effects of diets supplemented with different types of chitin hydrolysate on larval growth of the Japanese eel Anguilla japonica. Larvae were reared for... 相似文献
112.
To study and model the interrill erosion process in an unmanaged Japanese cypress (Chamaecyparis obtusa) plantation, soil splash detachment rates were estimated based on the quantification of throughfall raindrop indices. Throughfall drops and soil splash detachment were simultaneously observed in the field, and observed data were compared with estimates produced by previous models. Observations took place over five months in 2005, during six observation periods. Raindrop indices of kinetic energy (KE), momentum (M), and momentum multiplied by the drop diameter (MD) were calculated from drop diameters and velocities. The median volume diameter of 1.99 mm for the overall observation period was well bounded by those from other Japanese cypress plantations. Throughfall consisted of large drops, generated as drips, exceeding 3 mm in diameter. The fall height was insufficient for the drops to attain terminal velocity, with 91% of the drops reaching less than 90% terminal velocity. The observed throughfall raindrop indices had strong correlation with throughfall rainfall intensity, even though throughfall raindrops occurred in seven rainfall events with different meteorological conditions. The values of observed KE and M were lower than previous model-derived estimations. Earlier models tended to overestimate throughfall KE and M, partly because the expected velocity was greater than that observed, and partly because they did not consider the effect of the splash water component during throughfall. The splash detachment rate in forests was weakly correlated with the total-amount raindrop indices but strongly correlated with the maximum value of raindrop indices over a short time scale such as 1 h. This result indicates that continuous and concentrated raindrop impacts over a short time duration cause splash detachment in the forest floor. Development of a comprehensive model of the process of forest floor soil surface erosion requires more detailed measurement of actual throughfall drops. 相似文献
113.
Analysis of yield attributes and crop physiological traits of Liangyoupeijiu,a hybrid rice recently bred in China 总被引:1,自引:0,他引:1
Crop physiological traits of Liangyoupeijiu, a “super” hybrid rice variety recently bred in China, were compared with those of Takanari and Nipponbare in 2003 and 2004 in Kyoto, Japan. Liangyoupeijiu showed a significantly higher grain yield than Nipponbare in both years, and achieved a grain yield of 11.8 t ha−1 in 2004, which is the highest yield observed under environmental conditions in Kyoto. Liangyoupeijiu had longer growth duration and larger leaf area duration (LAD) before heading, causing larger biomass accumulation before heading than the other two varieties. Liangyoupeijiu had a large number of grains and translocated a large amount of carbohydrates from the vegetative organ to the panicle during the grain filling period. The three yield components measured were panicle weight at heading (P0), the amount of carbohydrates translocated from the leaf and stem to the panicle during the grain filling period (ΔT), and the newly assimilated carbohydrates during grain filling (ΔW). It was found that the sum of P0 and ΔT were strongly correlated with grain yield when all the data (n = 8) were combined (r = 0.876**). However, there was no significant difference in the radiation use efficiency (RUE) of the whole growth period between Liangyoupeijiu and Nipponbare for both years. Even though the growth duration was shorter, Takanari, an indica/japonica cross-bred variety, showed a similar yield to Liangyoupeijiu in both years. The mean RUE of the whole growth period was significantly higher in Takanari, 1.60 and 1.64 g MJ−1 in 2003 and 2004, respectively, than in Liangyoupeijiu, which had a RUE of 1.46 and 1.52 g MJ−1 in 2003 and 2004, respectively. The high grain yield of Takanari was mainly due to its high RUE compared with Liangyoupeijiu and its large P0 and ΔT. Our result showed that the high grain yield of Liangyoupeijiu was due to its large biomass accumulation before heading, which resulted from its large LAD rather than its RUE. 相似文献
114.
Tomoko?UtohEmail author Noriyuki?Horie Naomi?Mikawa Akihiro?Okamura Yoshiaki?Yamada Atsushi?Akazawa Satoru?Tanaka Hideo?P?Oka 《Fisheries Science》2005,71(1):38-47
ABSTRACT: Annual changes in the gonadosomatic index (GSI), oocyte diameter, gonadal histology and plasma estradiol-17β (E2 ) levels were investigated in female common Japanese conger Conger myriaster in captivity. Juveniles were caught in September 1999 and reared in seawater at temperatures ranging from 10–20°C for 3 years. All fish were immature when captured in September 1999. GSI and oocyte diameter increased from October 2000, peaked between summer and autumn 2001, and bottomed-out in winter 2001. Plasma E2 level also increased from October 2000, but remained high. The ovarian developmental stage was at the peri-nucleolus stage or the oil droplet stage until September 2000. Vitellogenesis started in October 2000 and oocytes progressed to the tertiary yolk globule stage by summer 2001. However, vitellogenic oocytes regressed in all females after autumn 2001. The neogenetic oocytes began to increase after November 2001 and ovarian development progressed in 2002 as they did in 2001, although maximum GSI in 2002 was half its 2001 value. These data indicate that ovarian development in the common Japanese conger has an annual periodicity, and that these congers may be able to spawn in multiple years under rearing condition. 相似文献
115.
Soil salinity is an increasing threat to the productivity of glycophytic crops worldwide. The root plays vital roles under various stress conditions, including salinity, as well as has diverse functions in non-stress soil environments. In this review, we focus on the essential functions of roots such as in ion homeostasis mediated by several different membrane transporters and signaling molecules under salinity stress and describe recent advances in the impacts of quantitative trait loci (QTLs) or genetic loci (and their causal genes, if applicable) on salinity tolerance. Furthermore, we introduce important literature for the development of barriers against the apoplastic flow of ions, including Na+, as well as for understanding the functions and components of the barrier structure under salinity stress. 相似文献
116.
Harada K Asai T Kojima A Sameshima T Takahashi T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2006,68(10):1109-1111
We investigated the susceptibilities against 7 antimicrobial agents in Campylobacter jejuni and C. coli isolates from food-producing animals in 2004. In comparison with the results of past surveillance, no significant difference was observed in resistance rates against all of the antimicrobials tested in Campylobacter isolates. However, slight increase of erythromycin (EM) resistance was found in C. coli isolates from pigs. We examined the mutation of the 23S rRNA gene and their susceptibilities against azithromycin, tylosin, and lincomycin in 44 EM-resistant isolates and 28 susceptible isolates of porcine origin. All the EM-resistant isolates contained A2075G in the 23S rRNA gene and showed cross-resistance to azithromycin, tylosin, and lyncomycin. 相似文献
117.
Liangzi Cao Kazuki Hayashi Mayumi Tokui Masahiko Mori Hideho Miura Kazumitsu Onishi 《Breeding Science》2016,66(2):260-270
Pre-harvest sprouting (PHS) is one of the serious problems for wheat production, especially in rainy regions. Although seed dormancy is the most critical trait for PHS resistance, the control of heading time should also be considered to prevent seed maturation during unfavorable conditions. In addition, awning is known to enhance water absorption by the spike, causing PHS. In this study, we conducted QTL analysis for three PHS resistant related traits, seed dormancy, heading time and awn length, by using recombinant inbred lines from ‘Zenkouji-komugi’ (high PHS resistance) × ‘Chinese Spring’ (weak PHS resistance). QTLs for seed dormancy were detected on chromosomes 1B (QDor-1B) and 4A (QDor-4A), in addition to a QTL on chromosome 3A, which was recently cloned as TaMFT-3A. In addition, the accumulation of the QTLs and their epistatic interactions contributed significantly to a higher level of dormancy. QDor-4A is co-located with the Hooded locus for awn development. Furthermore, an effective QTL, which confers early heading by the Zenkouji-komugi allele, was detected on the short arm of chromosome 7B, where the Vrn-B3 locus is located. Understanding the genetic architecture of traits associated with PHS resistance will facilitate the marker assisted selection to breed new varieties with higher PHS resistance. 相似文献
118.
Tatsuya NAKANO Mizuki KONO Kazuki SEGAWA Satoshi KUROSAKA Yoshiharu NAKAOKA Yoshiharu MORIMOTO Tasuku MITANI 《The Journal of reproduction and development》2021,67(2):123
Methylglyoxal (MG) is a precursor for the generation of endogenous advanced glycation end-products involved in various diseases, including infertility. The present study evaluated the motility and developmental competence after in vitro fertilization of mouse sperm which were exposed to MG in the capacitation medium for 1.5 h. Sperm motility was analyzed using an SQA-V automated sperm quality analyzer. Intracellular reactive oxygen species (ROS), membrane integrity, mitochondrial membrane potential, and DNA damage were assessed using flow cytometry. The matured oocytes were inseminated with MG-exposed sperm, and subsequently, the fertilization and embryonic development in vitro were evaluated in vitro. The exposure of sperm to MG did not considerably affect the swim-up of sperm but resulted in a deteriorated sperm motility in a concentration-dependent manner, which was associated with a decreased mitochondrial activity. However, these effects was not accompanied by obvious ROS accumulation or DNA damage. Furthermore, MG diminished the fertilization rate and developmental competence, even after normal fertilization. Collectively, a short-term exposure to MG during sperm capacitation had a critical impact on sperm motility and subsequent embryonic development after fertilization. Considering that sperm would remain in vivo for up to 3 days until fertilization, our findings suggest that sperm can be affected by MG in the female reproductive organs, which may be associated with infertility. 相似文献
119.
Kazuki Komatsu Tsugumi Iwasaki Kosuke Murata Hideaki Yamashiro Valerie Swee Ting Goh Ryo Nakayama Yohei Fujishima Takumi Ono Yasushi Kino Yoshinaka Simizu Atsushi Takahashi Hisashi Shinoda Kentaro Ariyoshi Kosuke Kasai Masatoshi Suzuki Maria Grazia Palmerini Manuel Belli Guido Macchiarelli Toshitaka Oka Manabu Fukumoto Mitsuaki A. Yoshida Akifumi Nakata Tomisato Miura 《Reproduction in domestic animals》2021,56(3):484-497
Since the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, we have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of racoons from the ex-evacuation zone of the FDNPP accident. The radioactivity of caesium-137 (137Cs) was measured by gamma-ray spectrometry, and the measured radioactivity concentration was 300–6,630 Bq/kg in the Fukushima raccoons. Notably, normal spermatogenesis was observed in the seminiferous tubules of the testes, with the germinal epithelium composed of a spermatogenic cell lineage with no evident ultrastructural alterations; freeze-thawing sperm penetration ability was confirmed using the interspecific zona pellucida-free mouse oocytes IVF assays. This study revealed that the chronic and LDR radiation exposure associated with the FDNPP accident had no adverse effect on the reproductive characteristics and functions of male raccoons. 相似文献
120.
The mechanisms controlling the establishment of the embryonic-abembryonic (E-Ab) axis of the mammalian blastocyst are controversial. We used in vitro time-lapse imaging and in vivo lineage labeling to provide evidence that the E-Ab axis of the mouse blastocyst is generated independently of early cell lineage. Rather, both the boundary between two-cell blastomeres and the E-Ab axis of the blastocyst align relative to the ellipsoidal shape of the zona pellucida (ZP), an extraembryonic structure. Lack of correlation between cell lineage and the E-Ab axis can be explained by the rotation of the embryo within the ZP. 相似文献