19个木莲属树种的花粉形态观察及其分类学意义

通过对19个木莲属树种的花粉进行扫描电子显微镜观察拍照,观察描述花粉的形态学特征,测量花粉极轴与赤道轴长度、花粉表面孔穴和突起的密度并据此进行聚类分析。扫描电子显微镜下形态学观察结果表明:木莲属19个种的花粉均为舟形,且具有长及两端的远极萌发单沟等一致特征,花粉表面孔穴、突起等特征在种内部比较稳定,不同种之间差异明显,具有一定的分类学意义,但作为属下分类依据需慎重。聚类分析结果表明:相同地区或分布地域相近的树种花粉特征更相近,证明的遗传分枝与地理分布有很强的相关性。     

四川雅安地区13种凤仙花属植物花粉形态及其分类学意义

采用扫描电镜观察了中国四川雅安地区13种凤仙花属植物的花粉形态,并对其花粉形态进行了主成分分析和聚类分析,基于孢粉学和SRAP聚类结果的比较,讨论不同孢粉学特征对分类结果的影响。结果显示:(1)雅安地区13种凤仙花属植物花粉粒均为中等大小,花粉粒形状从超扁到扁球形变化,花粉粒极面观形状从矩形和椭圆形到四边形、圆形、三角型变化,且只有湖北凤仙、峨眉凤仙和匙叶凤仙是三沟花粉粒,其余种均为四沟花粉粒;外壁纹饰仅扭萼凤仙和齿萼凤仙为细小网状,其余均为网状纹饰。(2)依据不同指标进行的孢粉学聚类均将13种凤仙花属植物划分为3个类群,而SRAP聚类结果则将13种凤仙花属植物划分为5个类群;不同孢粉学聚类结果的相似率只有30.77%。(3)孢粉学聚类并未与分子聚类显示严格的对应关系,以花粉大小和形状、外壁纹饰为指标进行的孢粉学分类与SRAP分类的相似率最高(69.23%)。研究认为,选择不同的花粉形态特征作指标对分类的准确性影响较大,花粉大小和形状、外壁纹饰这2个指标对凤仙花属植物分类具有意义,而萌发沟的特征则很难作为分类的依据,花粉形态特征在分类上有局限性;进行该属植物孢粉学分类需要选择有价值的分类指标,并结合形态学、分子生物学等综合研究。     

被子植物三种系发生论的孢粉学基础

花粉与孢子为形态学上的重要实体,它反映出植物进化的某些侧面与事实。在孢子外壁的各种特征中,萌发孔被认为是最保守的。菌藻类植物的孢子为原始型(其萌发孔不明显)颈卵器植物的孢粉为三型的(具三裂缝,单裂缝和无裂缝);而被子植物的花粉为多型的(具沟、沟孔、孔等等,且在数目与形状上有很多的变化)。三型孢粉为被子植物前身的颈卵器植物的特征,它在被子植物中的出现可能被看成是提供了一种表明该类中原始分类群的指示。面对这—背景,我们主张被子植物在其进化系列中是三种系发生的,有三条独立的系统发育主干,即单子叶植物主干、木兰类双子叶植物主干和毛茛类双子叶植物主干。     

中国东北牻牛儿苗科（Geraniaceae）花粉形态与系统分类学研究

本文对中国东北牛儿苗科Ｇｅｒａｎｉａｃｅａｅ老鹳草属Ｇｅｒａｎｉｕｍ和牛儿苗属Ｅｒｎｄｉｕｍ植物计２属,１４种,２变种及１变型的花粉形态进行了较系统的研究。并对本科花粉形态进行了分类处理,编制了花粉形态科种检索表。结果表明,本科花粉如按萌发孔类型、外壁雕纹式样可以分为二大类：即三孔沟,外壁雕纹瘤状（Ｇｅｒａｎｉｕｍ）三沟,外壁雕纹网状（Ｅｒｏｄｉｕｍ）。在老鹳草属种及种下等级的分类处理中,花粉粒大小、萌发沟长度、外壁覆盖层网眼均匀性、直径大小、网脊上纹饰及外壁雕纹瘤纹突起均匀性、大小及瘤上纹饰都具有较大的分类学意义。花粉形态分类与经典分类对本科分类群的处理意见相吻合。大大丰富了本科分类微形态的证据。     

眼齿鸟再分析显示其蜥蜴属性（英文）

最近在白垩纪晚期缅甸琥珀中报道了一件小型头骨化石,原论文作者将其鉴定为一蜂鸟大小的鸟翼类(Avialae)恐龙,并命名为宽娅眼齿鸟(Oculudentavis khaungraae)。基于这件标本,原论文提出了中生代恐龙(包括鸟翼类)体型演化和生态类型的种种假设。但原论文的插图和描述均显示这件头骨呈现出多个鳞龙类的典型形态学特征,这些特征很少在主龙类中出现。原论文先验地将标本鉴定为鸟翼类,继而进行仅包括鸟翼类作为内类群的系统发育分析。该分析的取样过于局限,不能对其系统位置归属提供有价值的参考。本文对宽娅眼齿鸟正型标本的计算机断层扫描原始数据重新进行了重建、渲染和分析,结果揭示了多个新的头骨形态学特征,包括侧生齿、开放的下颞孔以及头骨腭面着生有腭齿等,这些均为典型的鳞龙类/有鳞类特征,不支持其主龙类,遑论鸟翼类的系统位置归属。基于上述新的形态学发现,使用一双孔类(Diapsida)形态特征矩阵重新分析了眼齿鸟的系统演化位置。数据矩阵的分类单元涵盖了蜥蜴、鸟类和鳞龙形类与主龙形类中的主要支系。分析所得的严格合意树明确了眼齿鸟属于鳞龙形类中的有鳞类。因此,宽娅眼齿鸟的正型标本显示了足够丰富的形态学信息,完全能够指示眼齿鸟的系统分类位置应为有鳞类,而不是鸟翼类或非鸟恐龙。     

天仙子族(茄科)的花粉形态补充研究及其系统学意义

在扫描电镜下研究了茄科天仙子族7属及颠茄属、茄参属和枸杞属3属共10属23种植物的花粉形态学特征。结果表明:天仙子族的花粉粒形状为球形、近球形、扁球形和长球形;萌发孔类型有无萌发孔、不规则的拟孔、3沟、4沟、3～4沟、散沟和3孔沟;外壁纹饰为小刺状、瘤状、各式条纹状、条纹-穴状、条纹-网状、皱波状、细网状和网状。沟膜近光滑、具小颗粒、具小刺状突起或具瘤状突起。各属植物的花粉形态在萌发孔的有无、萌发孔的类型和外壁纹饰等方面有较大的差异,可以作为探讨属间分类和系统关系的重要依据。天仙子族植物花粉萌发孔的演化趋势为:无萌发孔→3、4沟→3孔沟。无萌发孔的山莨菪属是原始类群,三孔沟的马尿泡和天仙子等属是进化类群。还讨论了与前人研究结果不同之处和可能的原因。     

青藏高原东缘28种风毛菊属植物花粉形态研究

通过扫描电镜对青藏高原高寒草甸风毛菊属28种多年生草本植物的花粉进行了形态观察和比较,结果显示,该属植物花粉形态较为一致。花粉近球形或长球形,极面观三裂圆形,三孔沟,外壁表面具刺状突起。刺间纹饰可分为4种类型:穴状、颗粒状、网状—颗粒状和网状。花粉形态没有大的差异,但刺间表面纹饰、萌发沟的宽窄、刺的大小、分布密度和花粉大小在种间存在差异,可作为种的分类依据。花粉特征聚类分析结果表明,此28种风毛菊属植物花粉大致划分为明显的5个类群,所包含的种分别隶属于风毛菊属的四亚属:雪兔子亚属、雪莲亚属、附片亚属和风毛菊亚属。     

凤仙花属（Impatiens L.）10种植物花粉形态的扫描电镜观察

利用扫描电镜观察了10种凤仙花属（Impatiens L.）植物的花粉形态。结果表明：本属花粉为单粒花粉,呈长圆形至长矩圆形,大小为20.3～46.7 μm,具角萌发孔,网状纹饰,网眼明显;根据花粉网状纹饰中网眼内是否具颗粒状突起可将其分为2类：（1）网眼内无或近无颗粒状突起,黄金凤（I. siculifer）和婺源凤仙花（I. wuyuanensis）的花粉纹饰属于这一类型;（2）网眼内有明显颗粒状突起,其余8个种的花粉纹饰均属于该类型。研究表明,花粉特征,特别是花粉粒网状纹饰中网眼内有无颗粒状突起及颗粒状突起的形态等特征,在凤仙花属内常具种水平上的可见变异,因而可作为种类划分的依据,它们在分类学上的价值应予以关注。     

三种金花茶花粉形态的扫描电镜研究

金花茶分类系统尚未完善,金花茶又极具观赏价值,潜在价值极高,该研究应用扫描电镜观察三种金花茶花粉形态,即平果金花茶、直脉金花茶、金花茶,并运用数理统计和图片分析的方法对其花粉形态进行了探讨.结果表明:三种金花茶花粉均属于大花粉粒,花粉平均极轴在50μm以上,花粉极面观为钝凹三角形,萌发孔为三孔沟,即N3P4C5类型.平果金花茶与直脉金花茶花粉外壁纹饰为拟网状纹饰,平果金花茶网眼较密,网脊稍不平,直脉金花茶网脊稍隆起;金花茶为蠕虫状纹饰,短条状突起.花粉形态对其分类有重要意义,通过花粉外壁纹饰的类型可知金花茶与其二者亲缘关系较远,花粉形态各指标具有种间变异性,种内具有保守性,而平果金花茶和直脉金花茶花粉外壁纹饰相同但具体分类还需进一步研究.该研究结果为金花茶种质资源分类和利用提供了参考,在一定程度上促进了金花茶资源的开发和利用.     

两型豆花粉和叶表皮的扫描电镜观察

两型豆花粉和叶表皮在扫描电镜下的形态特征：花粉近球形至矩球形,三孔沟,外壁表面较粗糙,侧壁具疣状突起至块状突起,极面具粗网状纹饰,但两型豆祖山居群属于萌发沟不明显型,两型豆燕塞湖居群属于萌发沟明显型。叶表皮细胞不规则,排列紧密,叶脉表皮细胞长圆柱形,长轴与叶脉平行,角质膜薄,表皮毛均为单细胞非腺毛,气孔器仅分布在下表皮,属于平列型,偶见不规则型。表皮毛和气孔器在叶片上分布不均匀,两型豆祖山居群叶表皮毛和气孔器的平均密度大于两型豆燕塞湖居群叶表皮毛和气孔器的平均密度,自然生长的两型豆叶表皮毛和气孔器的平均密度大于遮光条件下的两型豆。     

Pseudointegricorpus clarireticulatum (Samoilovitch) Takahashi: morphology and ultrastructure

Dispersed tricolpate pollen of Pseudointegricorpus clarireticulatum (Samoil.) Takah. from the Upper Maastrichtian in Zeya-Bureya Basin, Amur (Heilongjiang) River area, Russian Far East/China has been studied with light and electron microscopy. Pollen size, pole outlines and the shape of equatorial projections show some variation within the species. The exine is striate-reticulate, semitectate and columellate. The species is characterised by highly complex structures that have harmomegathic function and include equatorial projections, endexinous thickenings, difference in the thickness of the infratectum, foot layer and endexine throughout the pollen grain, and equatorial furrows. Exine layers taper towards colpi regions while they break abruptly in furrow regions. The furrows could have helped to shed the exine quickly and enabled pollen germination. A non-extended region with a small cavity in the ectexine was observed in the equatorial region. We think that this region is characteristic of most Triprojectate species.     

A new elater-bearing Late Albian pollen species from offshore eastern Saudi Arabia

A new elater-bearing pollen referable to Elaterocolpites is described from Late Albian sediments of the Arabian Gulf, offshore eastern Saudi Arabia. This pollen has a main body consisting of five elater-like projections in the equatorial area and five colpi, one colpus at the base of each projection. The exine has three layers. The foot-layer forms the nexine whereas the other two layers, the baculate-layer and the tectum, form the sexine. The exine structure has an angiosperm affinity. The pollen occurs within the Middle Cretaceous phytogeoprovince characterized by its elater-bearing palynomorph occurrences.     

Genetic and environmental variation in anther,pollen and pistil dimensions in sesame

Measurements of anther (length, width, depth), pollen grain (percent fertility, polar diameter, equatorial diameter, polar diameter/equatorial diameter ratio, volume) and pistil (stigma length, style length, ovary length, total pistil length, stigma width, style width, ovary width) were taken on 12 diverse sesame (Sesamum indicum L.) genotypes on each of four collection dates in 1994. Highly significant differences among genotype means were obtained for all characters except polar diameter. Highly significant differences among environment (collection date) means were found for ten of the 15 characters measured. Highly significant genotype x environment interactions were obtained for all characters except anther length. For the anther characters measured, relatively high repeatability values were found, ranging from 99.8% for length to 87.6% for depth. For the pollen grain characters measured, the repeatability values ranged from 67.6% for percent fertility to 23.1% for polar diameter. For the pistil characters measured, the repeatability values ranged from 94.0% for style width to 49.6% for total pistil length. These results indicate that genotype and environment influence anther, pollen grain and pistil characters. Variation in some of these morphological aspects could influence the consistency and interpretation of male transmission studies on both the applied and evolutionary levels.     

Identification of species of Hyalomma asiaticum group (Ixodidae) in areas of their sympatry based on immature stages

Morphological characters of immature stages of three closely related tick species, Hyalomma asiaticum Schulze et Schlottke, 1929, H. dromedarii Koch, 1844 and H. schulzei Olenev, 1931, collected mainly in areas of their sympatry (Fig. 1) were investigated. The larvae and nymphs of these three species were collected in Egypt, Iran, Turkmenistan, Uzbekistan, Afghanistan and Tadjikistan: 159 larvae and 137 nymphs of H. asiaticum from 12 localities; 78 larvae and 167 nymphs of H. dromedarii from 5 localities; 30 larvae and 6 nymphs of H. schulzei from one locality. Both qualitative morphological features and measured character (in mkm) were used to discriminate these species. Main discriminant characters for larvae. H. asiaticum (Fig. 3). Scutum: length < 246, width < 389; base of capitulum: width < 158, dorsally hexagonal, apices of lateral projections directed forward; palpae (II and III segments): length < 106, width < 42; hypostome: length < 87, width < 25; the spur of coxa I small, equilateral triangular; patella: length < 154. H. dromedarii (Fig. 4). Scutum: length > 236, width > 379; base of capitulum: width > 158, dorsally almost triangular, apices of lateral projections directed laterally or backward; palpae: length > 110, width < 46; hypostome: length > 87, width < 26; the spur of coxa I large, isosceles triangular; patella: length > 115. H. schulzei (Fig. 5). Scutum: length > 249, width > 407; base of capitulum: width > 162, dorsally hexagonal, apices of lateral projections directed forward; palpae: length > 114, width > 44; hypostome: length > 89, width > 28; the spur of coxa I large, isosceles triangular; patella: length > 164. Main discriminant characters for nymphs: H. asiaticum (Fig. 3). Scutum: small, width < 650, length and width subequal, posterior margin widely rounded, lateral incisions weakly developed; spiracular plates with distinct, pointed dorsal projection, marginal row of perforations distant from the base of dorsal projection, submarginal row with a gap; base of capitulum: lateral projections situated in posterior half of capitulum; palpae (II segment) short and narrow; hypostome short and narrow, width < 69; pore of coxae I-III present. H. dromedarii (Fig. 4). Scutum: large, width > 650, length shorter than width, posterior margin widely rounded, lateral incisions moderately developed; spiracular plates: with distinct and wide dorsal projection, marginal row of perforations distant from the base of dorsal projection, submarginal row present, without gap; base of capitulum: lateral projections situated in the middle part of capitulum; palpae long and narrow; hypostome long and wide, width > 69; coxal pore lacking. H. schulzei (Fig. 5). Scutum: small, width < 630, length larger than width, posterior margin narrow rounded, lateral incisions weakly developed; spiracular plates: with weakly developed dorsal projections, marginal row of perforation situated just behind the base of dorsal projection, submarginal row with a gap; base capitulum: lateral projections situated in posterior half of capitulum; palpae short and wide; hypostome long and narrow, width < 73; coxal pore lacking.     

Striped projections of the outer membrane of the generative cell in Convallaria majalis pollen

In pollen grains of Convallaria majalis the outer membrane of the generative cell (GC) is the inner membrane of the vegetative cell (VC). Striped projections (SP) at the cytoplasmic face of the outer membrane of the GC were revealed by chemical fixation and also by a rapid freeze-fixation and freeze-substitution. The projections, located in groups on the protruding lobes of the GC, were arranged parallel to each other and were equally spaced (40 nm apart). The length of the SP, estimated from grazing sections of GC, was 400 nm. Each projection was composed of T-shaped elements, about 35 nm high, spaced at an average distance of 25 nm. SP were observed in mature, hydrated, activated and germinated pollen grains and seemed to be associated with microtubules and microfilaments of the VC. No evidence exists yet of SP on the sperm cell membrane. Immunogold labelling with anti-myosin antibodies showed many gold particles attached preferentially to the surface of the protruding lobes of the GC in the area of the projections. These results may suggest that the SP of Convallaria GC contain myosin-like protein and play an important role in the motility of the GC during pollen tube growth.     

兔眼越桔(杜鹃花科)花粉形态——兼谈用极坐标测量四合体花粉的一种新方法

扫描电镜下,兔眼越桔花粉为四合体,外形为准四面体,中等大小,表面具不规则皱波状纹饰,并有多处凹陷。萌发孔沟多为3对(顶分体3条,侧分体各对应1条),以四面体几何中轴为中心,中心对称分布于四面体的3个侧面。萌发孔沟的长度、宽度、孔盖长与宽、孔盖的形状、突起的程度等,在个体间有差异,尤其是一些具有多处凹陷的花粉粒,可能是导致花粉萌发率不同的生态类型。用极坐标法描述四合体花粉的新方法可以表现其饱满度,比较传统上用极轴、赤道轴的长短表现花粉平面大小的方法,更加准确而直观。     

Brachymesophalangia-V in five samples of children: A descriptive and methodological study

The occurrence of brachymesophalangia-V (BMP-V) in 2,012 individuals from five samples of children of different ethnic backgrounds was determined using two indices. Frequencies of BMP-V were analyzed for three variants: BMP-V alone, BMP-V with clinodactyly, and BMP-V with a cone-shaped epiphysis. The two indices used to identify BMP-V indicated highest relative frequencies among Mexican children, moderate frequencies among children of European ancestry (Pennsylvania White, Canadian, West German), and lower frequencies in Pennsylvania Black children. Index 1, based on the ratio of the width to the length of the fifth mid-phalanx, consistently produced higher frequencies than Index 2, based on the ratio of the length of the fifth to the length of the fourth midphalanges. Index 1 was also more selective of BMP-alone, while Index 2 selected primarily BMP-V with clinodactyly and/or cone-shaped epiphyses. The differences between indices were largely due to the fact that Index 1, which basically defines shape, selected both the shortest and/or widest mid-phalanges, while Index 2 related actual length differences. It is suggested that Index 2 provided a more suitable criterion of BMP-V in comparative studies, due to possible population differences in phalangeal shape.     

The topological organization of primary afferents in the terminal ganglion of crayfish,Procambarus clarkii

Summary The central projections of primary afferents in the terminal ganglion of the crayfish can be seen when an axonal filling with nickel chloride with subsequent silver intensification was used for identification. We describe here the topological relationships of the projections to the landmark structures of the neuropil.The terminal ganglion has five pairs of sensory nerves associated with the mechanosensory hairs and internal proprioceptors. The projection fields of the primary sensory neurons in the nerves Rl and R2 are almost entirely restricted to the ipsilateral half of the ganglion, whereas those of the nerves R3, R4 and R5 cross the midline to form three sensory commissures, A6SCI, A7SCI and A7SCII. The projection fields are segregated from each other, although all are restricted to the ventral neuropil which lies under the ventral intermediate tract (VIT). The intersegmental projections that ascend via the connective ipsilateral to their origins could be observed. This pattern of projection correlates well with the receptive fields exhibited by several mechanosensory interneurons on the body surface of the final segment.