农杆菌介导转化为目的的水稻组培体系的建立   总被引：2，自引：2，他引：2  

段承俐  萧凤回  Carl RathuS  Ian Godwin 《西南大学学报(自然科学版)》2001,23(6):527-531

高效可靠的组培再生体系是水稻农杆菌遗传转化的基础。该试验通过对培养基类型、光照条件和水稻基因型的研究,发现富含脯氨酸的N6D培养基能明显促进愈伤组织的生长,光照条件也可显著改善其生长。Calrose76和合系41号被证实为易于组培高效再生的粳稻品种,该高效组培体系的为云南栽培良种合系41号的进一步农杆菌转化体系的建立铺平了道路。  相似文献   

Quantum wonderland. Introduction to special issue     

Osborne I  Coontz R 《Science (New York, N.Y.)》2008,319(5867):1201

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Directionally controlled fluorescence emission in butterflies     

Vukusic P  Hooper I 《Science (New York, N.Y.)》2005,310(5751):1151

Recently developed, high-efficiency, light-emitting diodes use two-dimensional photonic crystals to enhance the extraction of otherwise internally trapped light and multilayer reflectors to control the direction of light emission. This work describes the characterization of a naturally evolved light-extraction system on the wing scales of a small group of Papilio butterflies. The efficient extraction of fluorescence from these scales is facilitated by a two-dimensional photonic crystal slab that uses a multilayer to help control emission direction. Its light-extraction function is analogous to that of the light-emitting diode.  相似文献   

Biodefense: 10 years after. Helping Hollywood create and battle a pandemic. Interview by Jon Cohen     

Lipkin I 《Science (New York, N.Y.)》2011,333(6047):1219

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Superconductivity. Happy 100th, superconductivity! Introduction     

Stajic J  Coontz R  Osborne I 《Science (New York, N.Y.)》2011,332(6026):189

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Ordering in a fluid inert gas confined by flat surfaces     

Donnelly SE  Birtcher RC  Allen CW  Morrison I  Furuya K  Song M  Mitsuishi K  Dahmen U 《Science (New York, N.Y.)》2002,296(5567):507-510

High-resolution transmission electron microscopy images of room-temperature fluid xenon in small faceted cavities in aluminum reveal the presence of three well-defined layers within the fluid at each facet. Such interfacial layering of simple liquids has been theoretically predicted, but observational evidence has been ambiguous. Molecular dynamics simulations indicate that the density variation induced by the layering will cause xenon, confined to an approximately cubic cavity of volume approximately 8 cubic nanometers, to condense into the body-centered cubic phase, differing from the face-centered cubic phase of both bulk solid xenon and solid xenon confined in somewhat larger (>/=20 cubic nanometer) tetradecahedral cavities in face-centered cubic metals. Layering at the liquid-solid interface plays an important role in determining physical properties as diverse as the rheological behavior of two-dimensionally confined liquids and the dynamics of crystal growth.  相似文献   

Reassessing research assessment in the UK     

Stewart I 《Science (New York, N.Y.)》2002,296(5574):1802-3; author reply 1802-3

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Orangutan cultures and the evolution of material culture     

van Schaik CP  Ancrenaz M  Borgen G  Galdikas B  Knott CD  Singleton I  Suzuki A  Utami SS  Merrill M 《Science (New York, N.Y.)》2003,299(5603):102-105

Geographic variation in some aspects of chimpanzee behavior has been interpreted as evidence for culture. Here we document similar geographic variation in orangutan behaviors. Moreover, as expected under a cultural interpretation, we find a correlation between geographic distance and cultural difference, a correlation between the abundance of opportunities for social learning and the size of the local cultural repertoire, and no effect of habitat on the content of culture. Hence, great-ape cultures exist, and may have done so for at least 14 million years.  相似文献   

Ice flow direction change in interior West Antarctica     

Siegert MJ  Welch B  Morse D  Vieli A  Blankenship DD  Joughin I  King EC  Vieli GJ  Payne AJ  Jacobel R 《Science (New York, N.Y.)》2004,305(5692):1948-1951

Upstream of Byrd Station (West Antarctica), ice-penetrating radar data reveal a distinctive fold structure within the ice, in which isochronous layers are unusually deep. The fold has an axis more than 50 kilometers long, which is aligned up to 45 degrees to the ice flow direction. Although explanations for the fold's formation under the present flow are problematic, it can be explained if flow was parallel to the fold axis approximately 1500 years ago. This flow change may be associated with ice stream alterations nearer the margin. If this is true, central West Antarctica may respond to future alterations more than previously thought.  相似文献   

Structure of the uncleaved human H1 hemagglutinin from the extinct 1918 influenza virus     

Stevens J  Corper AL  Basler CF  Taubenberger JK  Palese P  Wilson IA 《Science (New York, N.Y.)》2004,303(5665):1866-1870

The 1918 "Spanish" influenza pandemic represents the largest recorded outbreak of any infectious disease. The crystal structure of the uncleaved precursor of the major surface antigen of the extinct 1918 virus was determined at 3.0 angstrom resolution after reassembly of the hemagglutinin gene from viral RNA fragments preserved in 1918 formalin-fixed lung tissues. A narrow avian-like receptor-binding site, two previously unobserved histidine patches, and a less exposed surface loop at the cleavage site that activates viral membrane fusion reveal structural features primarily found in avian viruses, which may have contributed to the extraordinarily high infectivity and mortality rates observed during 1918.  相似文献