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从花发育研究的方法、花发育与被子植物花部结构的多样性、花发育与被子植物的系统发育以及 花发育的分子遗传学等四个方面对近年来被子植物系统学中花发育研究的主要进展作一综述,例举了 一些重要结果。同时,对该领域今后研究的方向和应注意的一些问题作了简要评论。作者认为植物的 形态结构可以看作是一个时空过程,在系统学研究中对花部性状的分析和认识应该树立动态的观点。 今后应该从动态的角度开展被子植物花的发生和发育以及性状在不同类群间的比较等方面的广泛研究,并加强对在被子植物花的起源和演化中起重要作用的花部同源异型现象的发育过程的观察。  相似文献
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Fruit sink strength or its ability to attract assimilates depends bothon sink activity and size. This study investigated one main component of sinksize, that is the number of fruit cells during tomato plant development. Plantswere grown in a controlled climate chamber under a limiting (LS, six fruits pertruss) and non-limiting (NLS, two fruits per truss and CO2enrichment) supply of carbon assimilates. Under NLS conditions, fruit cellnumber was homogeneous among successive trusses, and fruits contained onaverage1.2×106 more cells than under LS conditions,though differences were not significant on the first truss which underwent thelowest competition. Under LS conditions, an ontogenetic increase in cell numberwas observed in proximal fruits of the upper trusses attributed to theenlargement of the apical meristem during plant development. The decrease ofcell number from proximal to distal fruits within a truss, that was expectedfrom the literature, was generally observed in the LS experiment, with anaverage significant difference of about1.6×106cells between the first and fifth fruits. Nevertheless, whereas the gradient incell number from proximal to distal fruits was steep in the upper trusses, itwas not significant on the lower trusses indicating that this gradient largelydepended on the level of competition during floral development. Thus, under lowassimilate supply, cell division is a main limiting factor for fruit growth,although cell enlargement during further fruit development is also affected,butwas not measured in this work.  相似文献
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离体植物花芽和花器官的发育研究进展   总被引:5,自引:1,他引:4  
邵宏波  初立业 《广西植物》1993,13(3):275-288
在近二十几年,尤其是近十年由于离体培养技术的完善和进一步向精确的层次的发展,已使得许多种植物花序、花芽和单独花器官以及部分的花器官在体外成功地进行了培养和尝试,并且对花芽及花器官的离体发育有了更深入的认识。不同植物的花发育需要不同的植物生长调节剂以及它们的不同配比,并且不同植物在其花发育所需要的营养因子也存在着相当大的差异性。这种差异性又随植物器官及花发育的不同阶段而受到加大或缩小。通过对正常花及突变体花进行的离体培养实验研究已经对一些花器官发生过程中的调节程序有了新的了解。利用离体培养技术,包括刚发展起来的薄层细胞培养技术在阐明花发育的机理、形态建成的分子机制以及成花梯度的物质基础等问题上具有广阔的潜力。  相似文献
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Comparative floral anatomy and ontogeny in Magnoliaceae   总被引:4,自引:0,他引:4  
Floral anatomy and ontogeny are described in six species of Magnoliaceae, representing the two subfamilies Liriodendroideae (Liriodendron chinese and L. tulipifera) and Magnolioideae, including species with terminal flowers (Magnolia championi, M. delavayi, M. grandiflora, M. paenetalauma) and axillary flowers (Michelia crassipes). The sequence of initiation of floral organs is from proximal to distal. The three distinct outermost organs are initiated in sequence, but ultimately form a single whorl; thus their ontogeny is consistent with a tepal interpretation. Tepals are initiated in whorls, and the stamens and carpels are spirally arranged, though the androecium shows some intermediacy between a spiral and whorled arrangement. Carpels are entirely free from each other both at primordial stages and maturity. Ventral closure of the style ranges from open in Magnolia species examined to partially closed in Michelia crassipes and completely closed in Liriodendron, resulting in a reduced stigma surface. Thick-walled cells and tannins are present in all species except Michelia crassipes. Oil cells are normally present. Floral structure is relatively homogeneous in this family, although Liriodendron differs from other Magnoliaceae in that the carpels are entirely closed at maturity, resulting in a relatively small stigma, in contrast to the elongate stigma of most species of Magnolia. The flower of Magnolia does not terminate in an organ or organ whorl but achieves determinacy by gradual diminution.  相似文献
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桃PpMADS1基因启动子的克隆及功能分析   总被引:3,自引:0,他引:3       下载免费PDF全文
PpMADS1基因属于一类MADS box 基因,在植物的花发育调控中起着重要的作用。通过Genome Walking的方法从桃基因组中分离了长度为1 814bp的PpMADS1基因启动子片段,序列分析表明,在此启动子上不仅含有TATA box 和CAAT box基本元件,而且含有大量的与光调节有关的调控元件,如GT-1,Sp1和as-2-box,另外存在两个CArG-box元件、一个G-box元件和一个TGA-element,说明该启动子可能受光周期和激素的调控。将该启动子通过5′端缺失,分区段与GUS报告基因连接构建表达载体,并转化拟南芥。GUS组织化学染色分析结果表明,在-197到-454bp有促使GUS在花原基中表达的花原基特异性元件,在-454到-678bp之间存在促使GUS在萼片和花瓣表达的特异性元件,在-678到-978bp存在负调控作用元件,阻遏了GUS基因在花药中的表达。  相似文献
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Patterns of floral construction in ontogeny and phylogeny   总被引:2,自引:0,他引:2  
Among the flowering plants flowers are relatively closed systems of a considerable complexity and therefore more suitable for comparative developmental studies than other organs. They work with a few kinds of structural elements that occur in variable or fixed numbers and are arranged in patterns more or less constrained by developmental conditions. Diversity of floral structure occurs at different levels, with emphasis either on number and arrangement or on synorganization and form of the structural elements. The first level is shown here with examples of several representatives of the primitive subclasses Magnoliidae and Hamamelididae, the second with Asclepiadaceae representing the most advanced subclass of dicotyledons Asteridae. Although early ontogenetic patterns are fairly constant among larger groups, especially the sequence of initiation and position of the different classes of structural elements, there is no strict stability in any of the parameters studied.  相似文献
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Abstract.— Alternative ontogenetic pathways among heterostylous species of Rubiaceae may reflect differences in their evolutionary histories. In this study, measurements were taken at different developmental stages on a series of long-styled (LS) and short-styled (SS) buds of the heterostylous taxa Psychotria chiapensis, P. poeppigiana , and Bouvardia ternifolia (all Rubiaceae). Results indicated that modifications in growth rates of stamens relative to corollas in all three species led to differences in anther heights between LS and SS flowers. Distinct style heights for LS and SS flowers of P. chiapensis and P. poeppigiana originate in the earlier stages of bud development and are maintained as styles elongate at equal rates. This contrasts with B. ternifolia , which has differences in style heights resulting from unequal relative growth rates between floral morphs. The "approach herkogamous" floral morphology, defined by having stigmas positioned above anthers, has been proposed as a potential evolutionary precursor for heterostylous taxa. To examine this hypothesis, floral development of two species with approach herkogamous morphologies, Psychotria pittieri and P. brachiata , was compared to that of the three heterostylous taxa. Differences in the relative rates of style elongation for flowers of approach herkogamous versus heterostylous species predict additional steps in the original model for the evolution of heterostyly from an approach herkogamous ancestor. The diversity of heterostylous ontogenies found within Rubiaceae provides insight into potential evolutionary pathways for this sexual system in other angiosperm families.  相似文献
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