冠果草的性表达状态及其进化含义

通常认为雄花两性花同株是植物性表达两性花进化到雌雄异株的过渡类型之一。慈姑属仅冠果草（Ｓａｇｉｔｔａｒｉａ ｇｕｙａｎｅｎｓｉｓ Ｈ．Ｂ．Ｋ．ｓｕｂｓｐ．ｌａｐｐｕｌａ（Ｄ．Ｄｏｎ）Ｂｏｊｉｎ）的性表达为典型的雄花两性花同株,其他种为雌雄同株。对冠果草野外和实验居群的性配置进行了定量观察。东乡和武夷山居群雄花的比例分别为２．４８％０．９６％。实验表明,栽培条件影响冠果草的性表达：在营养较好的条件下     

冠果草种子萌发过程的组织化学动态

冠果草的种子中没有胚乳,营养物质贮藏在胚中,其成分主要是淀粉和蛋白质。胚各部分的物质积累情况差异较大,子叶和下胚轴细胞中的淀粉粒、蛋白体数目多、体积大,胚芽和胚根分生细胞中则只贮藏少量的淀粉粒、蛋白体。在种子萌发过程中,胚各部分的淀粉粒逐渐解体,至二叶幼苗期全部消失。蛋白体的降解有严格顺序,远离胚芽的细胞中蛋白体降解较早,胚芽附近细胞中的降解较晚,而且胚芽细胞中还有新的蛋白体形成。单个蛋白体的降解     

冠果草的胚胎学研究

冠果草花药壁的发育为单子口十型,绒毡层为周原质团型。小孢子母细胞减数分裂为连续型,四分体呈左右对称式排列,成熟花粉为三细胞型。双珠被,假厚珠心,倒生胚珠。胚囊发育为葱型,成熟胚囊的特点是两个极核分别位于中央细胞两端,不融合成次生核。受精过程中,一个精于与卵核融合形成合子,另一精子先与珠孔端极核融合,之后受精极核再移动到合点端与另一极核融合,形成初生胚乳核。胚的发育为石竹型。成熟胚呈马蹄形,具有2片真叶。胚乳发育为沼生目型。随着胚的发育,胚乳细胞逐渐解体,成熟种子中无胚乳。     

Breeding systems in Coriaria (Coriariaceae)

Species of Coriaria are wind-pollinated and self-compatible. Discrepancies in the literature regarding sex expression in the genus may be attributed to inter- and intra-floral dichogamy. The southern hemisphere species and the Himalayan C. terminalis are evergreen phanerophytes or high elevation hemicryptophytes, which flower on new wood. Their racemes are many-flowered and are produced singly (terminal) or more usually in pairs in the axils at each node, and contain protogynous, hermaphrodite flowers. The northern hemisphere species are deciduous phanerophytes, which flower on old wood. Their racemes are few-flowered but aggregated in axillary clusters of up to 12 per node; sex expression is andromonoecious or monoecious (depending on species), with inter-floral protandry and intra-floral protogyny. In this lineage of species the evolution of a deciduous habit, the presentation of an initial male phase (inter-floral protandry), and the aggregation of many, few-flowered racemes at each node are interpreted as responses to selection pressures in the seasonal climate of a northern, mixed woodland environment.     

Functional andromonoecy in Euphorbia (Euphorbiaceae)

The occurrence of cyathia containing staminate flowers but lacking a pistillate flower was studied in 17 species of Euphorbia. Male cyathia were found in the majority of species studied (88.2%) giving functional andromonoecy. In the male cyathia, the pistillate flower is generally totally absent, but sometimes a vestigial pistillate flower with a non-functional ovary is present. The proportion of male cyathia varied at both the population and species level. The position of male cyathia within the inflorescence showed a constant pattern among species: the proportion of male cyathia decreased from the first to the last levels of the pleiochasia. In general, perennial species had significantly higher proportions of male cyathia than annual species (mean 20 and 2.3%, respectively). In annual species there was a trend for production of male cyathia only in the first level of the inflorescence, whereas in perennials production up to the fourth level of the inflorescence was usual. Functional andromonoecy is common in Euphorbia and represents a new sex segregation in the genus. The selective forces causing this secondary sex segregation in Euphorbia, such as improved pollination or increased outcrossing, are discussed.     

冠果草的花部发育——兼论冠果草与近缘属的亲缘关系

利用扫描电镜首次对冠果草（Ｓａｇｉｔｔａｒｉａｇｕａｙａｎｅｎｓｉｓ,Ｈ．Ｂ．Ｋ．ｓｓｐ．ｌａｐｐｕｌａ（Ｄ．Ｄｏｎ）Ｄｏｇｉｎ）的花器官发生进行了观察,结果显示：萼片原基以螺旋状方式向心发生,花瓣原基以接近轮状方式近同时发生,并与萼片原基因相间交替排列,不存在花瓣－雄蕊复合原基;最外轮６枚雄蕊原基的发生与萼片原基和花瓣原基相交替,并倾向于两两对萼的形式发生,对萼雄蕊对和瓣雄蕊的对仅仅是这种相间交     

两株产生免疫抑制剂的小双孢菌分离株的鉴定

从江苏无锡土壤中分离到两株玫瑰小双孢菌SIPI226和SIPI207,经形态、化学分析、Ribotyping及16S rRNA分析,两菌株细胞壁含meso|DAP、磷酸类脂PIV、无枝菌酸,醌为MK9(H0,H2,H4),G+C mol%分别为683和694。经初步鉴定为玫瑰小双孢菌的两个新亚种：玫瑰小双孢菌无锡亚种(Microbispora rosea subsp. wuxiensis)和玫瑰小双孢菌鼋头渚亚种(Microbispora rosea subsp. yuantouzhuensis)。菌株SIPI226和SIPI207分别为玫瑰小双孢菌无锡亚种和玫瑰小双孢菌鼋头渚亚种的典型菌株。     

国产泽泻科植物特有种——腾冲慈姑

本文通过对腾冲慈姑Sagittaria tengtsungensis 模式产地的考察,并在查阅了所有馆藏标本的基础上对腾冲慈姑的形态描述进行了修订。有关形态特征的比较以及不同的地理分布区等研究结果均支持腾冲慈姑和小慈姑为两个中国特有种的观点。     

猪源马链球菌兽疫亚种表达的类M蛋白黏附抑制性单抗的获得

根据马链球菌兽疫亚种(Streptococcus equi subsp.zooepidemicus)猪源株ATCC35246株的类M蛋白基因序列,通过PCR技术,扩增出无信号肽的类M蛋白基因并定向克隆至表达载体pET-32a( )中。重组质粒经酶切鉴定和测序后,在大肠杆菌BL21中表达,获得60kDa产物,Western blot显示,其与ATCC35246株多克隆抗血清反应,抗原性良好。以His亲和层析柱纯化重组类M蛋白作为抗原免疫8周龄的BALB/c小鼠,采用淋巴细胞杂交瘤技术制备了12株稳定分泌抗类M蛋白单抗的细胞株,特异性检测显示其与A群链球菌、猪链球菌2型以及马链球菌马亚种等没有交叉反应。单抗亚类鉴定显示,其中6株为IgG1,3株为IgG2,另外3株为IgM。从腹水中纯化的单抗效价为2.56×104~1.01×105。黏附抑制实验显示,其中一株单抗能阻断类M蛋白黏附HEp-2细胞。     

雄全同株植物簇花芹花期性别分配与开花式样

簇花芹(Soranthus meyeri)是古尔班通古特沙漠中常见的、具雄全同株性系统的伞形科多年生早春短命植物。该文对簇花芹花期性比(两性花数/总花数)与植株大小的关系及其开花式样进行了研究, 重点对花期大小依赖的性别资源分配进行了讨论。结果表明: 2006-2008年簇花芹群体水平的性比分别为0.69 ± 0.03、0.62 ± 0.03和0.69 ± 0.02, 彼此间无显著差异( p > 0.05), 表明其性比是相对稳定的, 可能受遗传因素的控制。雄花生物量与花粉量均比两性花的小, 说明产生雄花比产生两性花所需资源少。一级复伞形花序比二级复伞形花序具有较多的两性花, 说明前者易从植株上获得资源用于增加雌性适合度; 而后者产生较多的雄花以避免在雌性功能上资源投入的浪费, 增大花展示以吸引更多传粉者来增加花粉输出总量, 提高其整体适合度。植株水平的性比与地上营养器官的生物量间呈正相关关系, 说明较大个体对雌性功能的投资较大, 雌性繁殖成功受资源限制。复伞形花序内各伞形花序几乎同时向心开放, 且所有两性花及花序均为雄性先熟, 雌雄阶段完全分离, 但一级复伞形花序比二级复伞形花序早开放约5天, 彼此开花重叠期约为1天。这些特征对于一级复伞形花序进行异株异花授粉以及植株内不同级别花序间的同株异花传粉、避免雌雄功能间的干扰具有重要意义。