两种生态型榕树的叶绿素含量、荧光特性和叶片气体交换日变化的比较研究

比较盆栽 生榕树和两栖型树的形态差异、叶片叶绿素含量、叶绿素荧光特性和气体交换的日变化。两栖型榕树具有较发达的气生根和水生不定根,叶片比陆生榕树宽,并有向中生性 倾向,陆生榕树的叶绿素含量比两栖榕树高,净光合速率略高于水培两栖型榕树,但明显高于土培两栖型榕树,蒸腾速率以水培两栖型树最高,陆生榕树次之,土培两栖型榕树最低,线性回归分析表明,三者的叶片气孔导度与净光合速率变化均呈正相关,气孔导度的变化     

重组BCG疫苗的研究进展

卡介苗（ＢＣＧ）由于其广泛应用的安全性和免疫佐剂作用,因而以ＢＣＧ为载体的重组疫苗研究日益被科学家们重视。本文就近年来细菌、病毒、寄生虫等的重组ＢＣＧ疫苗的研究进展作一简要概述。     

The New Flavonoids from Polygonum sphaerostachyum (Polygonaceae)

Two novel flavone glycosides, 3′-hydroxy-5,4′-dimethoxy-6,7-methylenedioxyflavone-3-O-［β-D-xylopyranosyl(1→6)］-β-D-glucopyranoside(1)and5,4′-dimethoxy-3′-isopropenylacetyl-6,7-methylenedioxyflavone-3-O-［β-D-xylopyranoxyl(1→6)］-β-D-glucopyranoside (2), were isolated from Polygonum sphaerostachyum Meisn., and their structures were deduced by spectral and chemical methods. This is the first report on the isolation of flavone glycosides from P. sphaerostachyum.     

Genetic Diversity of Gli-1, Gli-2 and Glu-1 Alleles in Sichuan Wheat Landraces

Genetic diversity at Gli-1, Gli-2 and Glu-1 loci was investigated in 89 Sichuan wheat ( Triticum aestivum L.) landraces by using acid polyacrylamide gel electrophoresis (APAGE) and SDS-PAGE. In these landraces, a total of 32 gliadin and 3 high-molecular-weight (HMW) glutenin patterns were observed. In total, 14, 15 and 5 alleles were identified at Gli-1, Gli-2 and Glu-1, respectively. At each locus, the alleles in higher frequency were Gli-A1a (89%), Gli-B1 h (46%), Gli-D1a (65%), Gli-A2a (64%), Gli-B2j (45%), Gli-D2 a (48%), Glu-A1c (99%), Glu-B1b (99%) and Glu-D1a (100%). The Nei's genetic variation index (H) of Sichuan wheat landraces was 0.3706, varying from 0 to 0.7087. The highest genetic diversity was found at Gli-B2 locus, while the lowest was found at Glu-D1 . The genetic diversity at Gli loci was higher than that of Glu-1 loci among these landraces, but it was much lower than that of modern wheat cultivars. These results indicated a narrow genetic base of Sichuan wheat landraces. In this study, “Chengdu-guangtou” had the identical gliadin and HMW-glutenin patterns with “Chinese Spring”, further supporting the proposal that “Chinese Spring” is a strain of “Chengdu-guangtou”.     

镉离子诱导BA/F3β细胞发生奇特的细胞凋亡

细胞凋亡一般都伴随有ＤＮＡ 片段化, 活性氧含量增加, 并能被过量的Ｂｃｌ２ 所抑制。以ＢＡ／Ｆ３β细胞为模型, 利用ＭＴＴ 检测、Ｈｏｃｈｅｓｔ 染色以及透射电镜检测等技术却发现, 镉离子虽然可以诱导该细胞凋亡, 但是这种凋亡没有ＤＮＡ 片段化, 也没有活性氧含量增加。此外, 过量Ｂｃｌ２ 对这种凋亡也没有保护作用。因此, 可以确认镉离子诱导ＢＡ／Ｆ３β细胞发生了奇特的细胞凋亡。     

Molecular phylogenetic systematics of twelve species of Acipenseriformes based on mtDNA ND4L -ND4 gene sequence analysis

Acipenseriformes is an endangered primitive fish group, which occupies a special place in the history of ideas concerning fish evolution, even in vertebrate evolution. However, the classification and evolution of the fishes have been debated. The mitochondrial DMA (mtDNA) ND4L and partial A7D4 genes were first sequenced in twelve species of the order Acipenseriformes, including endemic Chinese species. The following points were drawn from DNA sequences analysis: (i) the two species of Huso can be ascribed to Acipenser; (ii) A. dabryanus is the mostly closely related to A. sinensis, and most likely the landlocked form of A. sinensis; (iii) genus Acipenser in trans-Pacific region might have a common origin; (iv) mtDNA ND4L and ND4 genes are the ideal genetic markers for phylogenetic analysis of the order Acipenseriformes.     

满江红鱼腥藻遗传多样性的RAPD分析

共生在水生蕨类植物满江红(又称“红萍”:Azolla)叶腔中的固氮兰细菌曾被认为是一个种满江红鱼腥藻(Anabaena azollae Strasb.).但由于现存的满江红在分类学上有2个亚属,7个种1,对不同满江红叶腔中鱼腥藻的鉴别,多年来引起人们的重视.80年代,鱼腥藻的单克隆抗体和RFLP的研究,发现了它与宿主分类上一定程度的对应关系2,3.90年代以后,Van Coppenolle和Eskew分别以RAPD-PCR和DAF-PCR对从满江红共生体中提取的DNA进行了分析4,5,但后者发现了共生体中藻的DNA对整个PCR产物的干扰作用会影响满江红属本身系统分类.       

中国金鞘蛾属Goniodoma－新种记述(鳞翅目：鞘蛾科)

记述我国鞘蛾科一新种：中华金鞘蛾Goniodoma sinica sp. nov.。这是金鞘蛾属在我国的首次报道,对属征和世界名录进行了扼要介绍。     

热带森林的低密度种及其形成与维持机制

低密度种指在热带森林中存在的成年个体密度很低的物种,是热带森林中树种的主要存在形式。对低密度种的认识和保护是热带森林生物多样性保育的关键之一。与稀有种相比,低密度种的含义更为广阔,它还包括那些密度低、分布范围广和绝对个体数量大的物种。低密度种形成的主要原因是母树附近的幼苗和种子的存活率较低,密度制约和有限更新也是低密度种形成的重要原因。维持低密度种最重要的外部原因是昆虫较强的飞行能力和传粉能力,而其最重要的内部原因是低密度种的生殖特性。