白杨细胞质遗传的细胞学机理(Ⅰ):生殖细胞和精细胞中细胞质DNA的存在状况

应用DAPI、DiOC荧光法与激光共聚焦电镜技术,观察白杨派树种毛白杨、毛新杨、银腺杨、中国山杨花粉发育中生殖细胞的细胞质DNA及其在精细胞形成过程中的动态。结果表明:不同发育时期的生殖细胞、精细胞中不存在具有DNA的细胞器,为白杨派树种具有母系遗传的潜能提供了细胞学证据;其中,线粒体在花粉发育过程中一直存在,但其DNA发生了降解,从而使父系线粒体DNA的传递中断,导致了线粒体的母系遗传。细胞学观察发现,银腺杨少数质体及其DNA被排除和降解的时期相对迟缓。本文还对被子植物线粒体遗传的机理进行了讨论。     

被子植物起源于买麻藤目的相关证据

综述了买麻藤目与被子植物关系的经典分类学、化学分类学、古植物学和现代分子生物学等方面的证据，结合买麻藤目与被子植物的基部类群中2类关键性成分:菧类和异喹啉类生物碱，对买麻藤目在被子植物演化中的地位进行了讨论，认同买麻藤目为被子植物姊妹群地位合理性，并认为被子植物应该起源于买麻藤目植物。     

被子植物小孢子发生中细胞质的分化(综述)

实验结果表明在被子植物小孢子发生过程中有明显的细胞质分化。这主要包括小孢子母细胞减数分裂过程中细胞质中核糖体数量迅速减少和恢复,以及质体和线粒体形态结构的脱分化和再分化的周期性变化。这些变化认为是消除孢子体时期一些细胞质因子,转向配子体发育的过程,而与减数分裂无关。     

被子植物小孢子发生中细胞质的分化（综述）

实验结果表明在被子植物小孢子发生过程中有明显的细胞质化。这主要包括小孢子母细胞减数分裂过程中细胞质中核糖体数量迅速减少和恢复，以及质体和线粒体形态结构的脱分化和再分化的周期性变化。这些变化认为是消除孢子体时期一些细胞质因，转向配子体发育的过程，而与减数分裂无关。     

河北菩提岛植物资源调查

对菩提岛被子植物进行了调查研究,结果表明,该区共有被子植物52科、145属、230种（含种下分类单位）,是河北省野生种子植物区系中物种多样性较为丰富的区域之一,区系植被分布概况分为疏林区、荒草区、盐生植物区。     

河北省临城县小天池林区被子植物区系研究

采用植物区系地理学的研究方法,对河北省临城县小天池林区被子植物区系的组成和地理成分进行了研究。结果表明,临城县小天池林区有被子植物88科,301属,555种(包括14变种);含10种以上的优势科有14科,305种;表征科有7科;中国特有属有5属6种。该植物区的被子植物主要以北温带成分为主(共计有98属,221种,分别占总属数和总种数的37.69%和46.9 2%),这表明小天池被子植物区系具有明显的温带性质。     

前沿

正我国被子植物发现新记录物种——海厚托桐近日,中国科学院华南植物园植物科学研究中心科研人员近期在珠海万山群岛发现了我国被子植物的一个新记录物种——海厚托桐。该植物隶属于大戟科厚托桐属,是近10年来在我国发现的第12个被子植物新记录属或新属,使我国被子植物属的数量增加至3112个。自2013年以来,在科技部、中科院以及广东省林业厅的支持下,研究人员对我国热带海岛和海岸带的重点保护野生植物和特有生物资源进行了大规模考察。考察结果发现,海洋岛屿的生物栖息地、岛屿群落物种组成和结构、岛屿生物资源的种类、岛屿植物对高温、高盐、干旱极端     

若干双子叶与单子叶植物细胞壁果胶结构单糖组成特征研究

为了系统研究被子植物初生壁果胶结构单糖的组成成分及其与被子植物两纲分类的关系,结合单糖单一环式的衍生化方法,采用GC/MS测定22种被子植物初生壁果胶中单糖组分及含量,并对测得的结果进行主成分、t检验和香农 威纳指数分析。结果表明:被子植物细胞壁果胶由木糖、鼠李糖、岩藻糖、阿拉伯糖、半乳糖、葡萄糖、甘露糖7种单糖组成,其中鼠李糖、阿拉伯糖和半乳糖含量较高;岩藻糖和甘露糖含量极少。主成分分析筛选出决定22种被子植物间糖含量差异的5种果胶单糖分别为:木糖、阿拉伯糖、半乳糖、鼠李糖和葡萄糖。主成分二维图和t检验结果显示:可通过果胶单糖含量实现被子植物中双子叶和单子叶两纲植物的区分,且木糖和半乳糖决定了两纲间的显著性差异（P＜0.01）。同时香农 威纳指数结果显示了被子植物两纲在单糖含量的多样性上也存在差异,且双子叶植物的单糖多样性显著高于单子叶植物（P＜0.01）。      

秦岭地区被子植物的特有现象研究

考订秦岭特有被子植物名录,并对其数量组成、生活型谱、水平和垂直分布进行了统计分析,同时总结了特有种所属科属的数量和分布区类型.结果表明,温带成分在秦岭被子植物特有类型中占显著优势,太白山是其集中分布的地区,同时可考虑将太白山国家级自然保护区向东延伸至户县.     

《植物学》教材中“花”章节教学内容分析

从6个方面分析了《植物学》教材中关于"花"的教学内容:花是适合于繁殖作用的变态枝;花是被子植物特有的器官;雌蕊是被子植物的标志性特征;真花学说是理解花的结构、起源和被子植物系统演化的理论基础;被子植物和裸子植物的区别主要体现在花及其受精以及受精后的产物上;被子植物花的结构与裸子植物和蕨类植物对应结构的比较。     

被子植物分类依据评述

评述了被子植物分类依据。形态学资料应用最广,是被子植物分类的基础,特别是生殖器官的形态特征,但形态分类并不能解决被子植物分类的一切问题。细胞学资料是植物分类的重要补充,它可以解决形态分类难以解决的遗留问题。化学资料可为某些属及属以上的类群演化提供重要线索。现代分子生物学资料能解决植物分类上一些长期争论的问题,特别是一些高级分类阶元的归属问题,对建立系统发育树有重要的帮助。微形态学也给被子植物分类提供有价值的资料。在应用这些资料时,一定要参考形态资料,综合考虑,才能建立一个真正能反映被子植物亲缘关系的分类系统。     

Reproductive and vegetative morphology of a cretaceous angiosperm

Recent collections from plant-bearing deposits of Cenomanian age in central Kansas have yielded angiosperm axes with helically arranged, seed-bearing, conduplicate carpels. Large leaves associated with these fruits are thought to represent parts of the same kind of plant because the leaves and fruits are the only plant fossils at this locality to have distinctive, morphologically identical, yellow bodies within their carbonaceous remains. These fossils provide a rare opportunity to study the morphology of an ancient angiosperm and illustrate the antiquity of certain features considered primitive by comparative angiosperm morphologists.     

An aptian plant with attached leaves and flowers: implications for angiosperm origin

Recent phylogenetic studies and fossil finds support a new view of the ancestral angiosperm. A diminutive fossil angiosperm from the Aptian of Australia has attached leaves, with intermediate pinnate-palmate, low-rank venation, and lateral axes bearing pistillate organs subtended by bracts and bracteoles that are the oldest direct evidence of flowers. A variety of data suggests a similar morphology for the ancestral angiosperm. This hypothesis explains similarities between rhizomatous to herbaceous Magnoliidae and basal monocots, scarcity of early agniosperm wood, and lack of recognition of earlier remains.     

Angiosperm diversification and paleolatitudinal gradients in cretaceous floristic diversity

The latitudinally diachronous appearance of angiosperm pollen during the Cretaceous is well documented, but the subsequent diversification and accompanying significant changes in floristic dominance have not been assessed quantitatively for a wide range of paleolatitudes. Trend surfaces fitted to within-palynoflora diversity data from 1125 pollen and spore assemblages show that angiosperms first become floristically prominent in low paleolatitude areas( approximately 20 degrees N to 20 degrees S). Non-magnoliid dicotyledons show a similar but slightly delayed pattern of increase and are the principal component of angiosperm diversity from all areas sampled. Monocotyledons and magnoliid dicotyledons are significant primarily in low to middle paleolatitude palynofloras( approximately 50 degrees N to 20 degrees S) during the latest Cretaceous. As angiosperms become increasingly prevalent the importance of most non-angiosperm taxa either decreases or remains unchanged. The only apparent exception is a striking increase in gnetalean diversity concurrent with the initial angiosperm diversification at low paleolatitudes.     

Winteraceous pollen in the lower cretaceous of Israel: early evidence of a magnolialean angiosperm family

Pollen of the primitive angiosperm family Winteraceae has been discovered in the Aptian-Albian of Israel, extending the fossil record of this phylogenetically important family of flowering plants from the uppermost Upper Cretaceous back some 40 million years to the upper Lower Cretaceous. This appears to represent the earliest known record of a magnolialean angiosperm family and is convincing evidence for the existence in the Early Cretaceous of an extant family of angiosperms.     

被子植物芽的类型

芽的特征在被子植物分类、生态等研究以及在农业和林业等行业生产实际中具有一定的意义。该研究归纳了被子植物芽的类型。类型划分的依据包括着生位置、形态特征、活动状态、季节性特征、发育阶段和状态以及生活型方面。类型包含不常见的隐芽等以及近些年提出的拟花芽。     

三峡库区消落带抢救植物中华蚊母群落伴生维管植物研究

中华蚊母原生境中维管植物以蕨类植物和被子植物为主,其中,蕨类植物7科9属13种,被子植物29科48属61种,具有从热带到温带的过渡性质.对中华蚊母原生境伴生种区系的研究,旨在保护好这一三峡库区抢救植物并为三峡库区及其他区域消落带建设提供参考.     

Eocene angiosperm flowers

Collections of well-preserved angiosperm flowers from the Middle Eocene of southeastern North America include a variety of morphological types. The first of these specimens to be studied extensively, a catkin, has yielded a great deal of structural information. Floral morphology, pollen morphology, and the nature of the peltate scales suggest that this catkin is allied with extant genera of the Juglandaceae. This confirms the antiquity of some of the diagnostic floral and pollen features found in extant genera of the Juglandaceae and the importance of structural information available from fossil angiosperm flowers.     

Torus-margo pits help conifers compete with angiosperms

The unicellular conifer tracheid should have greater flow resistance per length (resistivity) than the multicellular angiosperm vessel, because its high-resistance end-walls are closer together. However, tracheids and vessels had comparable resistivities for the same diameter, despite tracheids being over 10 times shorter. End-wall pits of tracheids averaged 59 times lower flow resistance on an area basis than vessel pits, owing to the unique torus-margo structure of the conifer pit membrane. The evolution of this membrane was as hydraulically important as that of vessels. Without their specialized pits, conifers would have 38 times the flow resistance, making conifer-dominated ecosystems improbable in an angiosperm world.