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741.
742.
Garden asparagus (Asparagus officinalis L.) is an economically important plant. This species is dioecious, and male plants are considered to be more desirable than females due to their higher yields. To reduce the time required for asparagus breeding, molecular marker techniques have been employed to identify sex-linked DNA markers. In the present study, we converted the male-specific random amplified polymorphic DNA marker T35R54-1600 into a sequence tagged site marker. We cloned a male-specific DNA fragment amplified with the T35R54 primer and determined the sequence of the fragment. The size of T35R54-1600 is 1,586 bp, and this fragment is not homologous to known sex-linked BAC sequences, indicating that this fragment is a new sex-linked region. Within this fragment, we designed the primer pair ‘MSSTS710’ to amplify a 710 bp region. This marker could be used to identify the sex of eight cultivars of A. officinalis: ‘Mary Washington 500W’, ‘UC157’, ‘Harumachi Green’, ‘Super Welcome’, ‘F4’, ‘Pacific 2000’, ‘F2’ and ‘Backlim’. We also analyzed the applicability of this marker to two dioecious Asparagus species, A. schoberioides and A. kiusianus, which are cross-compatible with A. officinalis. Although male-specific DNA fragments of two dioecious Asparagus species, A. schoberioides and A. kiusianus, were generated using the existing male-specific marker Asp1T7sp, no amplicon was obtained using the MSSTS710 marker. Since MSSTS710 can be employed for sex identification only in A. officinalis and not in closely related Asparagus species, the DNA region around the MSSTS710 marker must be variable among Asparagus species.  相似文献   
743.
744.
Taxonomy of the pen shell (genus Atrina) in East Asia has been confused because of the plasticity of the shell morphology and lack of unified morphological characteristics. We analyzed the mitochondrial cytochrome c oxidase subunit I (COI) sequence of the pen shell sampled from Ariake Bay and Seto Inland Sea, western Japan. All individuals were identified as the scaly form based on external morphology; however, their COI sequences were comprised of two distinct lineages. The sequence divergence between the two was 8.3%, indicating the high possibility that they are different species. The scaly form of the pen shell in Japan is one of the target species for resource enhancement, therefore COI lineage identification of broodstock individuals is critically important to avoid producing hybrid seed. We developed a loop-mediated isothermal amplification method that enables specific detection of the two lineages. This method can contribute to reducing the cost and time required for genotyping broodstock individuals prior to seed production.  相似文献   
745.
The pigmentation stages of Anguilla japonica were classified from the glass eel to yellow eel stage using 412 wild-caught eels from Hamana Lake and detailed developmental observations of 10 laboratory-reared eels. The sequential appearance of pigment was similar to that in A. anguilla, except for delayed pigment formation on the nerve cord of A. japonica. The general classification of pigmentation stages (VA–VIB) in A. anguilla was applicable to A. japonica, but the VB stage could be separated into two stages (VB1, VB2) in A. japonica. The completion of guanine deposition on the intra-abdominal membrane may be a trait to discriminate the yellow eel stage (VII) from the VIB stage. In natural conditions, wild-caught 0-age eels (n = 3,298) did not increase in size and retained a slender body form until VIA4, and then became thicker during VIB. The transition between body forms and growth may correspond to their ecological change from using passive transport in glass eels with tidal flow into rivers, to their settlement and further movements of elvers upstream. Considering this behavioral transition and pigmentation progression, it is proposed that the terms "glass eel" and "elver" could be defined as stages VA–VIA4 and VIB, respectively.  相似文献   
746.
Long-lived volcanism on the lunar farside revealed by SELENE Terrain Camera   总被引:2,自引:0,他引:2  
We determined model ages of mare deposits on the farside of the Moon on the basis of the crater frequency distributions in 10-meter-resolution images obtained by the Terrain Camera on SELENE (Selenological and Engineering Explorer) (Kaguya). Most mare volcanism that formed mare deposits on the lunar farside ceased at approximately 3.0 billion years ago, suggesting that mare volcanism on the Moon was markedly reduced globally during this period. However, several mare deposits at various locations on the lunar farside also show a much younger age, clustering at approximately 2.5 billion years ago. These young ages indicate that mare volcanism on the lunar farside lasted longer than was previously considered and may have occurred episodically.  相似文献   
747.
Cherry-harvesting robot   总被引:3,自引:0,他引:3  
A cherry-harvesting robot was manufactured for trial purposes and basic experiments were conducted. The main parts of the robot are a manipulator 4 degrees of freedom (DOF), a 3-D vision sensor, an end effector, a computer, and a traveling device. The 3-D vision sensor was equipped with red and infrared laser diodes. Both laser beams scan the object simultaneously. By processing the images from the 3-D vision sensor, the locations of the fruits and obstacles were recognized, and the trajectory of the end effector was determined. Fruits were picked by the end effector, while avoiding collisions with obstacles.  相似文献   
748.
This special issue deals with water and food as it applies to water resources and rice production in the Mekong River Basin. The range of papers reflects not only the broad interest but also the complexity of the topic. These reports are mainly based on the research carried out by the project, “Assessment of the Impact of Global-Scale Change in Water Cycles on Food Production and Alternative Policy Scenarios”. Hence the special issue gives a brief overview of the structure, goals, outcomes, and future direction of the above project. What we do in this paper are: (1) giving an overview of the project’s structure and goals, (2) stating the five common outcomes and several more specific results, and (3) looking forward to the future direction of the project. The aim of our research is to draw up scenarios for optimum water-resource distribution and to develop social guidelines, measures, and policies to help solving food and environmental problems by developing a world water–food model that emphasizes rice production in Monsoon Asia. We have integrated all of the data gathered and the research results into a food supply and demand model combined with a water-cycle analysis. We included operational factors, such as water-cycle change, water demand, water supply, and water distribution in the model. Emphasis is placed on the use of efficient resource-management technologies for proper use of water resources in agricultural and other sectors. The water–food model has been developed as a tool for evaluating technical decisions derived under various policy scenarios.  相似文献   
749.
Rice Metabolomics   总被引:1,自引:0,他引:1  
Metabolomics is a recently developed technology for comprehensive analysis of metabolites in organisms. Plant metabolites that are produced for the growth, development, and chemical defense of plants against climatic alterations or natural predators are also useful to us as nutrients or medicines; hence, it is important to comprehend the amounts and varieties of plant metabolites. Besides providing an understanding of the metabolic state in plants under various circumstances, metabolomic techniques are applicable to the clarification of the functions of unknown genes by using natural variants or mutants of the target plants. Furthermore, a metabolomic approach might be useful in the breeding of crops, since valuable plant traits such as taste and yield are closely related to metabolic conditions. Here, we describe the methodology of metabolomics including sample extraction and preparation, metabolite detection, and data processing and analysis, and introduce the application of metabolomic studies to rice.  相似文献   
750.
在日本北海道高位泥沼池,调查了远东红皮云杉(Piceaglehnii)、库页冷杉(Abies sachalinensis)和日本桤木(Alnusjaponica)树干茎流液的化学性质和泥炭孔隙水的化学性质,包括了横切和纵切面孔隙水化学性质。沼泽森林树干基部茎流对泥炭孔隙水化学性质有明显的作用,而且树基部的泥炭孔隙水化学性质具有物种特异性。远东红皮云杉茎流液和泥炭孔隙水中盐分含量最高,日本桤木则最低;盐分从茎基部向树冠形成浓度梯度。树冠下泥炭孔隙水化学受化学过程控制,孔隙水充沛条件下,控制作用减弱,因地势平缓(1°)茎流移动缓慢。事实上,泥炭孔隙水充足会使茎流化学物质浓度降低。微生物活动、优势树冠的营养再生介导的表面水和茎流对森林沼泽地微生境化学环境的空间异质性有贡献。图2表2参44。  相似文献   
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