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关键词： Arabidopsis Proteins   Binding Sites   Carbohydrate Conformation   Catalysis   Cell Membrane/metabolism   Cellulase   Cellulose/analogs & derivatives   Cellulose/biosynthesis   Cellulose/metabolism   Dextrins/metabolism   Glucans/biosynthesis   Glucans/metabolism   Glucose/metabolism   Glucosyltransferases/metabolism   Gossypium/enzymology   Gossypium/enzymology   Gossypium/metabolism   Gossypium/metabolism   Membrane Proteins/metabolism   Models, Biological   Organisms, Genetically Modified   Organisms, Genetically Modified   Plants/enzymology   Plants/genetics   Plants/metabolism   Sitosterols/metabolism   Uridine Diphosphate Glucose/metabolism   Yeasts/genetics   Yeasts/metabolism  

关键词： 生长素   植物向光性   横向光性   生长抑制物   侧生长   胚芽鞘   单侧光   植物生物学   抑制物质   生长素极性运输  

关键词： 植物凝集素   凝集活性   凝集效价   血凝反应   动物实验  

摘要： 通过血凝反应、凝集效价测定以及凝集素对淋巴细胞的凝集作用 ,探讨部分植物凝集素凝集作用及活性强弱。结果表明 :其中RCA、PHA、PSL、VFL对血红细胞及淋巴细胞均有凝集作用 ,且凝集活性强弱顺序依此为RCA >PHA >VFL >PSL。 6种凝集素中RCA与正常人血红细胞主要唾液酸糖蛋白的作用最强 ,而SBA和PNA与正常人血红细胞主要唾液酸糖蛋白可能无相互作用。小鼠胸腺和脾脏淋巴细胞有和RCA、PHA、PSL、VFL作用的对应受体 ,而无SBA受体和PNA受体 ,因此 ,RCA、PHA、PSL。

关键词： 宿根画眉草   鼠尾粟   生态生物学特性   坪用性状   草坪植物  

摘要： 通过 1 998～ 2 0 0 0年对野生宿根画眉草和鼠尾粟观察 ,对其形态特征和生物学特性进行了鉴定分析 ,从草坪和水土保持植物利用的角度对其进行建坪试验和水土保持试验 ,发现其具有优良坪用性状和水土保持效果。并对其特性作了综合性描述。

关键词： border cells   development   function   plant   stress  

摘要： Root border cells, previously referred to as sloughed root cap cells, is a special cell population which separates in large numbers from the periphery of the root cap and accumulates in the root tip. Recent evidence reveals that border cells, whose development is regulated by endogenous and exogenous signals, are biologically viable in the majority of higher plant species. As soon as border cells detach from root cap periphery, their metabolic activity dramatically increases in accordance with a differential gene expression from that in root cap cells. Recently, PsUGT1 and RCPME1, relevant to the early and late stage of border cell development, respectively, have been cloned and functionally identified. Border cells can synthesize specially and export a diverse array of chemicals including anthocyanins, antibiotics, special enzymes and other substances, that either inhibit or promote the growth of other entities in rhizosphere such as bacteria, fungi, viruses, and nematodes, and also antagonize some toxic chemicals around the root tip in soil such as aluminum toxicity. Therefore, there are multiple biological roles played by border cells during plant growth and development.

关键词： 药用植物   种子生物学特性   种子处理   休眠习性   种子寿命  

摘要： 中药产业是我国的传统产业,国家'十五'高新技术产业规划把推进现代中药产业化进程、加快技术进步列为重大专项.另外中药的价值也不断的被世人所认识,市场对中药的需求逐年增加,对药用植物野生资源的开发研究将取代原来的直接利用,人工栽培药用植物已成为必然.我国可供药用的植物已鉴定的约5000多种,常用的约500多种,需要量大、主要靠栽培的有250多种.建国以来,又有60多种贵重的和常用的药用植物由野生驯化为家种.由于药用植物种类较多,各种药材的生物学特性及其相应的栽培技术各不相同,影响了人工栽培药用植物在我国广大农村的推行.大部分药用植物都可利用种子繁殖,而且利用种子繁殖,繁殖量大,适合大面积的人工栽培.药用植物一般抗性较强,适应范围较广,相对而言,种子萌发是人工栽培中较困难的部分.本文将按照种子生物学特性的不同对常见的人工栽培的药用植物进行分类,并给出相应的种子处理技术以便生产中应用.这里所说的种子处理技术是相对于特殊的生物学特性而言的,并不是具体全面的种子萌发技术.

关键词： Viola pubescens   chasmogamy   cleistogamy   delayed selfing  

摘要： Plant response to variation in the surrounding biotic and abiotic environment often involves mechanisms that promote reproductive assurance. The goal of this study was to determine whether production of chasmogamous (CH) and cleistogamous (CL) flowers as well as delayed CH selfing in the perennial herb Viola pubescens enhances reproductive output in a heterogeneous environment. A central Ohio population was monitored for several years to study its reproductive biology and to measure selfing rates in CH flowers. A temporal switch from CH to CL flowers corresponded with a reduction in light availability as the forest canopy formed. Although similar numbers of CH and CL flowers were produced per plant, CH flowers were nearly twice as likely to disperse seeds as CL flowers. Both floral types had similar numbers of seeds with comparable mass, and there was no difference in emergence of CH and CL seedlings. In addition to outcrossing, CH flowers were capable of delayed selfing if left unvisited by insect pollinators. This was consistent with the rate of selfing over a 2-yr period (0.60, 0.07) measured with allozymes. Both CH and CL flowers contributed to reproduction in V. pubescens as well as delayed CH selfing, thereby creating a mating system that may be an adaptation to pollinator or resource unpredictability within the flowering season.

关键词： MANGROVE plants   NONFICTION  

摘要： Reviews the non-fiction book 'The Biology of Mangroves,' by Peter J. Hogarth.

关键词： 梅   鉴定   RAPD技术   分类  

摘要： 本研究对54个供试材料(其中包含27个花梅品种、19个果梅品种、8个李杏品种)形态部分的叶片、果核的性状特征进行分析，然后采用RAPD分子标记技术对其基因组DNA差异进行检测及聚类分析，结果表明： 李、杏、梅三者在叶片的形态特征上有较大差异。李类植物的叶形为长椭圆形，叶基楔形，叶面无毛，叶柄绿色且无毛;杏类植物叶面粗糙、有毛;梅类植物接近于杏类，与杏类植物有较近的亲缘关系，但又表现出丰富的种质特异性。从三者的果核特征来看，李类植物核表面较平滑，具皱纹;梅类植物核表面核点较多，表面粗糙;杏类植物核表面平滑，易于区分，但对于各类品种之间，却很难进行比较和分类。 选用改良CTAB法提取的梅及其近缘种的基因组DNA可直接用于PCR扩增分析，且效果良好。 从132个引物中筛选得到20个引物，共扩增出264个片段，扩增最多的引物是S44、S446和S456(17个片段)，最少的是引物S452(9个片段)，平均每个引物产生13.2个RAPD片段，片段长度多数集中在400-2500bp之间。 不同引物扩增出的带型完全不同，聚类分析结果表明，李属植物和杏属植物能完全被区分开，李、杏和梅之间表现出一定的亲缘关系，其中杏，梅之间的亲缘关系较近，各属品种之间都有不同的遗传距离，最小距离为0.1138，最大距离为0.7633，遗传距离的大小反映了材料间亲缘关系的远近，各属内品种的亲缘关系比较近，这一聚类结果从供试材料基因组DNA分子水平验证了传统的形态学分类观点。 从对供试材料进行的RAPD结果分析来看，梅类的果梅、花梅之间及各品种之间难以进行鉴别，而红叶李与其它李类及梅类、杏类各大类有较大区别，似可另列一类。 本研究验证了梅及其近缘种的形态学分类结果，但对于属以下的分类并不能完全提供佐证。从分析结果进一步证明RAPD技术可作为植物属间分类鉴定的依据。在选择引物得当，实验条件稳定的前提下，结果的重复性较好，也能够进行特定品种之间的鉴定。 文章还对RAPD技术对梅及其近缘种进行分类鉴定的可行性、在系统学研究中的问题及红叶李，桃形李的分类地位及进行了讨论。

关键词： Chemistry   Biochemistry  

摘要： Two component signal transduction systems, consisting of conserved histidine kinase and receiver domains, are present in over 30 genera of prokaryotic organisms. Recently, two-component systems have also been identified in plants, fungi, and slime mold. In Arabidopsis thaliana, the ethylene and cytokinin signaling pathways utilize the two-component ethylene receptor ETR1, and cytokinin receptor CKI1, respectively. While the transmembrane N-terminal domain of each protein binds to the signaling hormone, the cytoplasmic domains show significant sequence homology to the histidine kinase and receiver domains of archetypal two-component systems. Described herein is the first crystal structure of the plant receiver domain ETR1RD (residues 604–738 of ETR1), as well as the preliminary characterization of the receiver domain of CKI1, CKI1RD (residues 978–1122). The monomeric form of ETR1RD resembles the known structure of the bacterial receiver domain. ETR1RD forms a homodimer in solution and in the crystal, an interaction that has not been described previously. Dimerization is mediated by the carboxy terminus of the receiver domain, which forms an extended β sheet with the dimer-related β-strand core. Given that the dimer interface of ETR1RD coincides with the phosphorylation-dependent interfaces of characterized receiver domains, such as CheY, CheB, and FixJ, we suggest that the monomerization of ETR1RD is phosphorylation-dependent, too. Furthermore, the loop immediately following the active site adopts an exceptional conformation in ETR1RD. In the Mg2+-free form of ETR1RD, the γ-loop conformation does not allow a comparable interaction as observed in the active-site architectures of Mg 2+-bound CheY from Escherichia coli and Salmonella typhimurium. Preliminary characterization of the receiver domain of CKI1 illustrates its divergence from typical receiver domains. These structures will open the door to explore the structural biology of plant signaling pathways in general.