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1.
Japanese pear (Pyrus pyrifolia) exhibits gametophytic self-incompatibility (GSI) controlled by a complex and multiallelic S locus. The pistil-part product of the S locus is the polymorphic ribonuclease, S-RNase. Information on S-genotypes is important for the production and breeding of Japanese pears. Molecular analyses of S-genotypes of Japanese pear have been conducted with the CAPS (cleaved amplified polymorphic sequence) system; PCR amplification of S-RNase fragments by a common primer pair followed by digestion with restriction enzymes each of which cleaves a specific S haplotype. Here, we show that the separation of S-RNase fragments by polyacrylamide gel electrophoresis (PAGE) distinguishes four out of nine S haplotypes of Japanese pear without restriction digestion. S3-, S5-, S6- and S8-RNases were identified as distinct bands by PAGE. S3- and S5-RNases were separated by PAGE despite their identical fragment sizes. Using this system, three Japanese pear lines with unknown S-genotypes were analyzed. The newly determined S-genotypes of the lines were confirmed by CAPS analysis.  相似文献   
2.
ABSTRACT:   The vertical distribution of jack mackerel Trachurus japonicus larvae was described based on discrete depth sampling using a MTD net system from the surface down to 100 m depth at 13 stations in the southern East China Sea between 27 February and 10 March 2002. Of the 20 782 fish larvae collected, T. japonicus larvae were most abundant, accounting for 37.0% of the total catch. The average abundance of the larvae was 419.0 individuals/10 m2, with the average (± standard deviation [SD]) body length of 2.6 ± 0.3 mm (range 1.8–7.5 mm). The larvae were concentrated in the mixed layer, with peak densities in the 10–30 m layer. The average (±SD) weighted mean depth was 21.5 ± 7.8 m. There was no evidence of either diel or ontogenetic vertical migration for the early larvae of <5 mm. More than 90% of the T. japonicus larvae were collected in the water temperature ranging from 21 to 23°C. Vertical profiles of the larval densities and chlorophyll a coincided with each other, which might reflect the abundance of their main prey organisms, copepod nauplii and copepodites, since copepod production is known to be closely related with the chlorophyll a concentration.  相似文献   
3.
Assemblages of vertical migratory mesopelagic fish are described for the nighttime upper 20 m layer of the transitional and adjacent waters in the western North Pacific. Twenty-three mesopelagic fish species belonging to six families and 16 genera were collected during June 1996. Family Myctophidae was most speciose, represented by 17 species, followed by Sternoptychidae (two spp.) and Bathylagidae (one spp.). Six assemblages are recognized based on their species composition: Subarctic, Northern Transition, Southern Transition, Subtropical, Slope Water and Seamount Assemblages. These assemblages are also characterized by size composition and biomass of the catches. The distributions of the Subarctic, Northern Transition, Southern Transition and Subtropical Assemblages are approximately defined by the Kuroshio and Oyashio fronts and the Subarctic Boundary. Slope Water and Seamount Assemblages are closely related to the slope water around the shelf edge off Japan and waters around the Shatsky Rise and the Emperor Seamount chain, respectively. The importance of the Southern Transition Assemblage area between the Kuroshio front and Subarctic Boundary as spawning and nursery grounds of many subarctic, transitional and subtropical fishes is elucidated, based on the geographical distribution patterns of their larvae and juveniles.  相似文献   
4.
Feline parvoviruses were isolated from frozen samples of intestines taken from a snow leopard (Uncia uncia) and a serval (Leptailurus serval) that died successively at Sapporo Maruyama Zoo in Hokkaido, Japan. Isolates possessed an antigenic epitope for both the feline panleukopenia virus (FPLV) and mink enteritis virus, identified with a hemagglutination inhibition test. Sequencing analyses of the VP2 region of the isolates revealed that the two isolates were identical and of the FPLV-type. These results suggested that FPLV was introduced from a feral cat which entered the zoo and transmitted the virus inside the zoo.  相似文献   
5.
As the fruits of loquat (Eriobotrya japonica, 2n = 2x = 34) carry large seeds, the breeding of seedless loquat has long been a goal. The recent creation of triploid cultivars (2n = 3x = 51) and the application of gibberellins allow commercial production of seedless loquat, but the possibility of seed formation in triploid loquats has not been carefully investigated. Through crossing experiments and cytological observations of meiosis and pollen tube growth, we found that the triploid line 3N-N28 was essentially self-sterile, but developed seeds on pollination with pollen from diploid cultivars at rates of up to 5.5%. Almost half of the seedlings survived to 5 months, and carried diploid (2n = 34), tetraploid (2n = 68), or aneuploid chromosome numbers. Our results suggest that triploid loquat cultivars might retain the risk of seed formation. Protection from pollination by diploid cultivars or the development of new triploid cultivars will be necessary to ensure the production of seedless loquat fruits.  相似文献   
6.
Genetic male sterility (GMS) has been a useful system for the production of hybrid varieties in self-pollinated plants. We obtained a GMS line developed from a spontaneous mutation in lettuce (Lactuca sativa L.). Genetic analysis in our previous study revealed that the sterility was controlled by a recessive gene which was named ms-S. For simple and quick screening of individuals showing male sterility, we attempted molecular mapping of the ms-S locus using an amplified fragment length polymorphism (AFLP) technique. From the examination of 4,096 AFLP primer combinations, 63 AFLP markers were found to be linked to the gene and nine of them were successfully converted into sequence characterized amplified region (SCAR) markers and cleaved amplified polymorphic sequence (CAPS) markers. Linkage analysis indicated that these nine markers were closely linked to the ms-S gene and all were located on the same side of the gene. The minimum genetic distance between the ms-S gene and a marker was 3.1 cM. These results provide additional information for map-based cloning of the ms-S gene and will be of great help for lettuce breeding using GMS to produce F1 hybrids.  相似文献   
7.
Methanol extractives from the red heartwood of Bengal catechu (Acacia catechu) contained (+)-catechin as a major component making up 0.3% of the wood. A new polyphenolic compound with a (+)-homo-iso-catechin structure and having catechol and phloroglucinol moieties constituted 0.005% of the wood, and probably its epimeric compound in trace amounts, were also found.This report was presented at the 49th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1999 and the 44th Lignin Symposium, Gifu, October 1999  相似文献   
8.
The effects of vitamin D (VD) deficiency on calcium (Ca) metabolism during pregnancy were evaluated in rats fed VD-repleted (VD-repleted rats) and VD-depleted (VD-depleted rats) diets. In the VD-depleted rats, the plasma concentrations of 1,25-dihydroxyvitamin D and Ca decreased severely, whereas the parathyroid hormone concentrations increased. The Ca contents of the feces of the VD-depleted rats were higher than those of the VD-repleted rats. The fetal Ca contents of the VD-repleted and VD-depleted rats increased continuously, but that of the VD-depleted rats was lower. These data reveal that VD deficiency during pregnancy induces severe hypocalcemia due to reduced intestinal absorption of Ca and elevated fetal demand for Ca.  相似文献   
9.
Grain size is an important yield component in rice, however, genes controlling the trait remain poorly understood. Previously, we have shown that an antagonistic pair of basic helix-loop-helix (bHLH) proteins, POSITIVE REGULATOR OF GRAIN LENGTH 1 (PGL1) and ANTAGONIST OF PGL1 (APG), is involved in controlling rice grain length. Here, we report the involvement of another atypical bHLH protein gene, POSITIVE REGULATOR OF GRAIN LENGTH 2 (PGL2), in the regulation of rice grain length. Over-expression of PGL2 in the lemma/palea increased grain length and weight in correlation with the level of transgene expression. Observation of the inner epidermal cells of lemma of PGL2-overexpressing lines revealed that the long grain size is caused by an increase in cell length. PGL2 interacts with a typical bHLH protein APG, a negative regulator of rice grain length and weight, in vitro and in vivo. It was reported that overexpression of BU1 (BRASSINOSTEROID UPREGULATED 1), the closest homolog of PGL2, caused an increase in grain length. However, we detected no interaction between BU1 and APG. These findings suggest that PGL2 and PGL1 redundantly suppress the function of APG by forming heterodimers to positively regulate the rice grain length, while the pathway through which BU1, the closest homolog of PGL2, controls grain length is independent of APG.  相似文献   
10.
The jack mackerel, Trachurus japonicus, has a prolonged spawning season and widely spread spawning grounds. The population in the coastal waters of Japan seems to be composed of several cohorts spawned seasonally from different waters. To understand its population structure along the Tsushima Warm Current, we analysed hatchdates and growth histories of fish from Kunda Bay, the southern, central and northern East China Sea (ECS), the southern Sea of Japan, and Maizuru Bay. Seven cohorts were detected from fish collected between June 2005 and June 2006 in Kunda Bay. Comparing hatchdate distributions and growth trajectories of the seven cohorts with those of the other five regional samples, we did not find that cohorts collected in Kunda Bay originated in the southern ECS. Therefore, these coastal waters of Japan appear to be significant spawning grounds for juvenile jack mackerel.  相似文献   
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