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关键词： Uca thayeri   population biology   reproductive biology   sex ratio   handedness  

摘要： Population and reproductive biology of Uca thayeri Rathbun, 1900 were studied for the first time in a tropical mangrove. Absolute density, sex ratio, population structure, handedness, breeding season and fecundity were investigated. Seven transects were delimited in a mangrove area of the Pacoti River, Northeast of Brazil (3 degrees 43' 02" S/38 degrees 32' 35" W). On each transect, ten 0.25 M-2 squares were sampled on a monthly basis during low tide periods from September 2003 to August 2004. A total of 483 crabs were obtained, of which 250 were males, 219 non-ovigerous females, and 14 ovigerous females. The U. thayeri population presented bi-modal size frequency distribution, with males and non-ovigerous females not differing significantly size-wise. Ovigerous females were larger than males and non-ovigerous females. The overall sex ratio (1:1.07) did not differ significantly from the expected 1:1 proportion. The major cheliped was the right one in 50% of the males. The observed density was of 8.5 individuals/M-2, with the specimens being found mostly in shaded areas. Ovigerous females were found in 5 months of the year, coinciding with the rainy season, suggesting that the population of U. thayeri presents seasonal reproductive events. juvenile crabs were more abundant during the dry period, while larger crabs were found mainly during the rainy period. The fecundity of the studied population was much smaller than that of subtropical populations of this species. The regression analysis shows that the number of eggs increases linearly with the increase of carapace width. (C) 2007 Elsevier Masson SAS. All rights reserved.

关键词： Animals   Arabidopsis/enzymology   Arabidopsis/enzymology   Arabidopsis/metabolism   Arabidopsis/metabolism   Arabidopsis Proteins/chemistry   Arabidopsis Proteins/metabolism   Crystallography, X-Ray   F-Box Proteins/chemistry   F-Box Proteins/metabolism   Indoleacetic Acids/chemistry   Indoleacetic Acids/metabolism   Phytic Acid/metabolism   Plant Growth Regulators/chemistry   Plant Growth Regulators/metabolism   Receptors, Cell Surface/chemistry   Receptors, Cell Surface/metabolism   Structure-Activity Relationship  

摘要： Auxin is one of the main agents that regulate plant growth and development. Intricate crystallographic studies reveal how this hormone acts as a "molecular glue" in mediating substrate-receptor interactions.

关键词： 植物   表皮蜡质   功能  

摘要： 蜡质是植物与外部环境的界面,对植物具有重要的生物学意义。本文综述了植物叶表皮蜡质的成分、蜡质形态的分类学意义及蜡质对植物保水、防辐射和防病虫害等方面的作用。

关键词： exotic invasive plants   Solidago canadensis   reproductive strategy   seed germination   clonal growth   caloric values  

摘要： Solidago canadensis,a perennial Compositae plant originating from North America,was introduced into China as a horticultural plant in *** natural condi-tions,*** allocates large amounts of energy to sexual reproduction and produces many seeds,which reflects an r-strategy with high seed number and small seed *** addition,naturalized populations have a great capacity to grow clonally with underground *** has become an invasive weed in eastern China,and has caused serious damages to agricultural production and ecosystems in several provinces in *** order to understand the reproductive characteristics of *** and effectively control its spread,we examined soil conditions,seed charac-teristics,seed germination and the capacity for asexual reproduction in different plant *** investigated the population dispersion of *** in fixed sites for three years,and analyzed the seasonal dynamics of the morphological parameters of the underground parts and the caloric values of different organs of *** also compared differences in the root systems of *** and composite exotic *** following results were obtained:1)Under natural conditions,the germination season of *** lasts from March to October,with a peak from April to *** growth and asexual reproduction are especially vigorous during summer due to high temperatures and soil drought *** the other hand,the rainy season proves suitable for seed *** *** flower between September and January,and fruit in late October.A mature plant can produce about 20000 *** mean weight of 1000 seeds ranges from 0.045 g to 0.050 g,and the mean seed moisture content ranges from 60%to 80%.The light-winged seeds disperse readily by air,water,vehicles,human activity or through livestock.2)*** seeds have a wide tolerance for different values of pH,salinity and soil *** mean percent germination of seeds

关键词： 黄酮类化合物   肺部疾病   抗氧化作用  

摘要： 黄酮类化合物是广泛存在于植物中的具有相似化学结构的生物活性成分。其生物活性包括抗炎、抗过敏、抗氧化、清除自由基、抗菌抗病毒及抗肿瘤等作用,虽然其作用机制还不完全清楚,但因其来源于植物,‘毒副作用小,故近年来国内外均在开展其药理作用的研究,并拟用于临床。呼吸系统疾病的发病率随环境污染的加重呈上升趋势,如慢性阻塞性肺疾病、哮喘、肺炎、肺癌等。研究显示,黄酮类化合物的生物作用对肺部疾病的预防和治疗可起到积极的影响,可能成为治疗肺部疾病的有效途径。

关键词： 植物病毒   病毒诱导的基因沉默   沉默信号   病毒载体的变化  

摘要： 主要从病毒诱导的基因沉默体系中植物与病毒的相互作用、VIGS涉及的信号分子和移动方式以及靶基因的沉默和病毒载体的复制关系介绍和分析植物病毒诱导的基因沉默效应的分子机制，并进一步分析此种体系在植物基因功能研究中应用的研究进展。

关键词： Plant   植物生物学   学术刊物   Cell   中国   植物分子遗传学   农业生物技术   生命科学  

摘要： 中国的植物生物学研究近年来发展迅速，研究的范围和层次逐步扩展和深入，已引起国际同行的高度关注．美国植物生物学家学会出版的生命科学领域著名学术刊物The Plant Cell（2006年18卷11期）发表了美国耶鲁大学分子与细胞发育生物学系教授、北大一耶鲁植物分子遗传学及农业生物技术联合中心主任、北京生命科学研究所所长邓兴旺博士等人的评述性文章“Plant biology research comes of age in China”．

关键词： 七子花   濒危   发育生物学  

摘要： 对濒危植物七子花(Heptacodium miconioides)的花、种子进行了形态解剖学研究。结果表明:七子花无花梗,由多轮呈头状的聚年花序组成顶生圆锥花序,多数花序开基轮与中轮。花药壁的内壁具纤维状增厚,绒毡层变形。成熟花粉为三细胞型。种子结实率较低。同时对七子花幼茎、根、叶与珊瑚树(同科)进行解剖比较,差异表现在:七子花根毛明显比珊瑚树少,根表皮角质层较厚。茎中维管柱形状也明显不同,七子花叶栅栏组织细胞较珊瑚树整齐。叶单位面积叶绿体数目要少。通过分析其各部分结构与查阅资料总结出导致其濒危的可能原因,提出保护其相应措施。

关键词： 《植物生物学》   实验   研究性教学   策略  

摘要： 研究性教学是高校培养适应社会主义市场经济发展所需要的具备较高专业知识素养和创新精神的人才,推动新一轮教育教学改革的重要教学模式。在全面把握研究性教学科学内涵与特征的基础上结合教学实际,从提高教师整体素质、实验研究性教学设计和实验研究性教学的评价等方面阐述了《植物生物学》实验研究性教学的策略,初步总结了近几年的教学实践成效并对今后的发展提出了合理化建议。

关键词： 表观遗传学   DNA甲基化   DNA甲基化抑制剂   5-氮杂胞嘧啶核苷(5-azaC)  

摘要： 本文综述了DNA甲基化抑制剂作用机理及其在植物发育生物学研究中的应用。DNA甲基化抑制剂使甲基基团不能转移到腺嘌呤或胞嘧啶,导致DNA甲基化反应受阻,从而使基因组甲基化水平降低。DNA甲基化抑制剂已被用于因DNA甲基化引起的植物表观遗传研究中,同时它可以代替低温促进植物提早开花,并可能在植物性状改良中得到进一步的研究和应用。