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11.
12.
The mass of a root is determined by two underlying morphogenetic factors: (1) the length of the main root axis (root axis length: RAL), and (2) the amount of lateral root development generated by a unit length of the axis (branching index: BI). The mass of a rice adventitious root was partitioned into these two factors at the quantitative trait locus (QTL) level, using ‘Akihikari’ (a lowland cultivar as a recurrent parent) × ‘IRAT 109’ (an upland cultivar) backcross inbred lines. Four QTLs were detected for the dry weight of individual adventitious roots (root dry weight: RDW), which were associated with a QTL for RAL (chromosomes 1 and 9) or a QTL for BI (chromosomes 6 and 11). For BI, an additional QTL was detected on chromosome 1. The absence of co‐located QTLs suggested that RAL and BI are under separate genetic control. Despite its small population size and few replications, this study suggests that the partitioning of root mass into these underlying components could be useful for understanding the complexity involved in the genetic control of root growth. 相似文献
13.
Summary Soybean DNA fingerprints were analyzed by digoxigenin-labeled oligonucleotide probes complementary to simple repetitive sequences. The clearest and most polymorphic patterns were obtained with (AAT)6 as a probe, with which all 47 soybean cultivars tested could be distinguished. However, DNA fingerprints of individuals within cultivars showed the same pattern. Using (CT)8, (GAA)5 or (AAGG)4 as probes, clear polymorphic patterns among cultivars and accessions in the subgenus Soja (Glycine max and Glycine soja) were not observed, while quite different patterns were found in accessions in the subgenus Glycine. The results suggest that G. max and G. soja are closer in their genome structure. DNA fingerprints of reciprocal crosses between cultivars and accessions in the subgenus Soja were similar, and contained bands of both parents. In an F2 population from these crosses, such bands segregated in a Mendelian fashion. 相似文献
14.
Zhengjun Xia Hiroko Sato Satoshi Watanabe Shiji Kawasaki Kyuya Harada 《Euphytica》2005,141(1-2):129-137
We have constructed a soybean (Glycine max (L.) Merrill) bacterial artificial chromosome (BAC) library from green leaf protoplasts of the cultivar, Misuzudaizu. The library contains 53,760 clones with an average insert size of 116 kb. About 2.9% chloroplast DNA origin was revealed by PCR and colony hybridization. Apart from 2.8% clones having no insert, this library represents 5.2 genome equivalents. With this genome coverage, the probability of having any DNA sequence represented in the library is higher than 99.5%. Three-dimensional pools of the BAC library in combination with the use of a high efficiency genome scanning (HEGS) electrophoresis facilitate rapid and efficient PCR-based screening. An average of five positive clones were identified after screening the BAC library with SSR and STS markers. BAC-end walking was performed for three SSR associated BACs. This library will provide a good resource for positional cloning of agronomically and biologically important QTL genes that Misuzudaizu possesses. 相似文献
15.
Naoki Harada Masaya Nishiyama Shigeto Otsuka Satoshi Matsumoto 《Soil Science and Plant Nutrition》2005,51(3):361-367
Phototrophic purple bacteria (PPB) are one group of dinitrogen (N2 )-fixing bacteria often found in the anoxic and photic zone of paddy soil. In the present study, the effects of inoculation of PPB on grain yield of rice and changes in their populations and nitrogenase activity were investigated with and without surface application of rice straw in a pot experiment. As an inoculant, Rhodopseudomonas palustris strain KN122 isolated from a paddy soil was selected, and the cell suspension was inoculated into the floodwater once or three times during the cultivation. As a result, the inoculation of PPB increased the grain yield of rice. Compared to the control, the grain yield was 9% higher in the inoculated plot without rice straw application. The treatment was more effective in combination with rice straw application. In the plots where PPB were inoculated with rice straw, grain yields were 21% (single inoculation) and 29% (triple inoculation) higher. Populations of PPB in the plots without rice straw application significantly increased by the inoculation, unlike those in the plots with rice straw application, except for the bulk soil. Phototrophic and heterotrophic nitrogenase activities (acetylene-reducing activity) associated with the soils or residues of the rice straw were not affected by PPB inoculation throughout the experiment. This indicates that the inoculation of PPB into floodwater may not be effective for enhancing N2 fixation in paddy soils and that the beneficial effect of PPB inoculation on the grain yield of rice may be due to unidentified functions of PPB other than biological N2 fixation. 相似文献
16.
Three strains—Nocardioides sp. MFC-A, Rhodococcus rhodochrous MFC-B, and Stenotrophomonas sp. MFC-C—were newly isolated from rice soil or bark compost as microorganisms capable of cometabolically degrading mefenacet (2-benzothiazol-2-yloxy-N-methyl-acetanilide). Several other species belonging to the genera Nocardioides, Rhodococcus, and Stenotrophomonas were also capable of degrading mefenacet, suggesting that the ability is not specific to these isolates, but common at least in these genera. N-methylaniline and 2-benzothiazoloxy acetic acid were identified as the metabolites by liquid chromatography-mass spectrometry. Besides mefenacet, the isolates could degrade one or more other amide pesticides, such as flutolanil, mepronil, metolachlor, and pretilachlor. These results indicate that the strains Nocardioides sp. MFC-A, Rhodococcus rhodochrous MFC-B, and Stenotrophomonas sp. MFC-C degrade mefenacet via hydrolysis of the amide bond, but their substrate specificities differ. 相似文献
17.
Infection of HTLV-III/LAV in HTLV-I-carrying cells MT-2 and MT-4 and application in a plaque assay 总被引:120,自引:0,他引:120
The human T-cell lines MT-2 and MT-4 carry the human T-cell leukemia virus type I (HTLV-I). When MT-2 and MT-4 were infected with HTLV-III, the probable etiologic agent of the acquired immune deficiency syndrome (AIDS), rapid cytopathogenic effects and cytotoxicity were observed that made it possible to titrate the biologically active virus in a plaque-forming assay. The cytopathogenic effects were preceded by the rapid induction and increase of HTLV-III antigens as revealed by immunofluorescence and immunoprecipitation. Activities of HTLV-III were neutralized by the human antibodies against the virus when immunofluorescence and plaque assays were used. Essentially the same results were obtained with the lymphadenopathy-associated virus (LAV1). 相似文献
18.
Oscillatory expression of the bHLH factor Hes1 regulated by a negative feedback loop 总被引:1,自引:0,他引:1
Hirata H Yoshiura S Ohtsuka T Bessho Y Harada T Yoshikawa K Kageyama R 《Science (New York, N.Y.)》2002,298(5594):840-843
19.
K Harada O Kamimura H Kasai T Matsuda A Tonomura VV Moshchalkov 《Science (New York, N.Y.)》1996,274(5290):1167-1170
The microscopic mechanism of the matching effect in a superconductor, which manifested itself as the production of peaks or cusps in the critical current at specific values of the applied magnetic field, was investigated with Lorentz microscopy to allow direct observation of the behavior of vortices in a niobium thin film having a regular array of artificial defects. Vortices were observed to form regular and consequently rigid lattices at the matching magnetic field, at its multiples, and at its fractions. The dynamic observation furthermore revealed that vortices were most difficult to move at the matching field, whereas excess vortices moved easily. 相似文献
20.
Naoki Harada Shigeto Otsuka Masaya Nishiyama Satoshi Matsumoto 《Biology and Fertility of Soils》2005,41(1):46-51
A pot experiment was conducted to investigate the influences of indigenous phototrophs on methane (CH4) emissions from a paddy soil where rice straw was incorporated or was surface-applied. During the cultivation, half of the pots were covered with aluminum foil, except for the minimum space for rice plants, to prevent ambient light reaching the floodwater or the soil surface. Growth of oxygen-producing phototrophs was hardly observed in the unilluminated plots, whereas intensive growth of algae, duckweed and hydrophytes was found in the illuminated ones. Plant growth was not affected by the different treatments. Seasonal changes in CH4 emission determined by a closed chamber method indicated that illumination had no or only minor effects on CH4 emissions when rice straw was incorporated or was not applied, but significantly reduced CH4 emissions when rice straw was surface-applied. Methanogenesis occurring in the soil-floodwater interface was further investigated in two lab-scale model experiments measuring methanogenic activity. As a result, more activated methanogenesis was found in the surface-applied rice straw and the soil around the straw compared with the soil incubated without rice straw. The magnitude of the methanogenic activity in the rice straw incubated under illuminated conditions was significantly lower than that incubated in the dark. Consequently, this study demonstrates that methanogenesis in paddy soil occurs even in the soil-floodwater interface if plant residues like rice straw exist, and such methanogenesis is likely to be suppressed by growth of indigenous phototrophs under illumination. 相似文献