中国鸢尾属花粉形态研究

本文借助光学显微镜和扫描电镜,对我国产鸢尾属Iris L．32种植物的花粉形态进行 了观察。该属植物的花粉为舟形或近球形。萌发孔可分为远极单沟、远极单沟-拟沟、二合 沟及无萌发孔等类型。外壁主要为网状纹饰,少数具瘤状或鼓槌状纹饰。本文依据花粉形态 和其它器官特征,对本属花粉外壁及萌发孔的演化趋势及某些种的分类地位进行了探讨。     

五味子科植物花粉形态及其系统学意义

用光镜和扫描电镜观察了五味子科Schisandraceae23种、6变种和1变型的91份花粉的形态。其中5种、4变种和1变型的花粉形态为首次报道。该科花粉为单花粉,异极,辐射对称,扁球形至超扁球形,其萌发沟的排列格局在被子植物中是独一无二的。若按萌发沟的数目划分,该科花粉可分为3沟型和6沟型两个类型。外壁为网状纹饰,网眼的大小和网脊的宽度与花的形态有一定相关性。研究结果不支持lowski对该科花粉用网眼大小来划分类型的作法,认为对他关于3长沟汇聚的一极即花粉的远极的结论应作进一步探讨;不支持一些学者认为南五味子属Kadsura比五味子属Schisandra原始的观点。根据研究结果可认为,南五味于属的总体演化水平高于五味子属,它们可能是源于共同祖先、沿两条不同的路线平行演化的两个近缘类群。     

中国芸苔属植物花粉形态的研究

本文对我国芸苔属Brassica Linn．36种(含变种、变型)植物的花粉形态首次作了系统报道。用光学显微镜进行观察,发现该属花粉有四种沟孔类型。即二、三、四沟;三沟;三、四沟,三、四孔沟。多数种类与以往的报道不完全相同。在扫描电镜下,纹饰为三种类型。拟脑纹-网状;网纹状;穴-网纹状。依据植物花粉形态和其它特征,对本属植物演变趋势和一些种,变种的分类处理进行了讨论。     

云南紫金牛属3种植物花粉粒形态特征

利用光学显微镜和电子显微镜对云南紫金牛属朱砂根、柳叶紫金牛和矮地茶的花粉进行了观察.其中,柳叶紫金牛属首次报道.结果表明:3种紫金牛属植物的花粉为单粒,三角状类圆球型;异极型,两侧对称;赤道面观为三面略凹的类圆球形;极面的顶面观为类三角形,具三孔(沟),为沟孔型,萌发沟为拟沟,多合成合沟,底面观为三面围合的深洞穴状.外壁多具穴状纹饰,表面光滑无附属物.云南紫金牛属花粉粒大小、形态、萌发沟和纹饰类型都较接近,属于单一型花粉.     

杜鹃属马银花亚属花粉形态的研究

首次报道了杜鹃属马银花亚属四组 2 0种 2变种植物的花粉形态。本亚属植物的花粉均为四合花粉 ,呈正四面体排列 ,四合体直径为 35 .85～ 6 0 .72 μm。单粒花粉球形或近球形 ,具三孔沟。在四合花粉上 ,相邻花粉粒上的沟相连 ,花粉粒表面或多或少具粘丝。在扫描电镜下 ,花粉粒呈现出粗糙、不明显聚颗粒状至致密的聚颗粒状等不同的纹饰 ,在不同的组间存在或多或少的差异 ,具有一定的分类学意义。对某些种的分类处理也能够提供某些孢粉学证据。     

侧金盏花属（Adonis L.）植物花粉形态研究

本文利用光学显微镜和扫描电镜对国产9种1变种及外国产8种侧金盏花属植物的花粉形态进行了研究,认为该属的花粉可以划分为2个大类型,这与根据外部形态分类划分的两个组是吻合的。另外根据本届花粉形态的变异,又将其中的1个大类型划分为4个亚类型。为进一步讨论该属的系统关系提供依据。 侧金盏花属植物是隶属于毛莨科毛莨族中的一个小属,约有30余种,分布于欧、亚大陆。我国有10种、1变种和2变型,分布于西南、西北、东北和山西等省区。本属植物的花粉形态过去在文献上曾有一些记载,如R.P.Wodhouse(1936)对本属的夏侧金盏花A.aestivalis)和A.vernalis进行了研究。《中国植物花粉形态》(1960)一书仅借助于光学显微镜描述了侧金盏花(A.amurensis)的花粉形态。T.Santisuk(1979)对本属12种(其中有4种产中国)的花粉形态进行了观察研究。但是,以上学者只是对本属植物的花粉形态作了轮廓性和描述和简单的讨论。他们报道该属的花粉为椭圆形或球形,具三沟、沟长而狭,轮廓不显著,沟膜具颗粒状雕纹;外壁分二层,外层厚,表面具刺状雕纹等。本文对国产的9种1变种以及外国的8种花粉形态分别利用了光学显微镜和扫描电镜进行了观察研究。     

豹子花属的花粉形态研究，兼论与百合属的界限问题

本文借助光学显微镜和扫描电镜,对豹子花属Nomocharis 6种植物和百合属Lilium 4 种植物的花粉形态与外部特征作了较系统的比较研究,其结果如下： 1．豹子花属植物花粉的 萌发孔均为单沟(远极)型,根据其外壁结构及表面纹饰的特点,可分为基柱网纹型和网纹 型,结合外部形态特征推断,可能存在由基柱网纹→网纹的进化趋势。 2．百合属植物花粉 的萌发孔多为单沟(远极)型,稀为2一3孔型,然而,其中外部形态极为相近的小百合集合群与 尖被百合在花粉形态上表现出较大的差异,这一事实为研究百合科花粉的演化提供了线索。豹 子花属与百合属花粉虽在表面纹饰上存在区别,但从外部形态上,该属的一些种类与百合属极 为相近,反映出二属之间存在着较为紧密的亲缘关系。     

中国茄科天仙子亚族的花粉形态研究

本文作者对国产茄科天仙子亚族6个属、12种植物的花粉,用光学显微镜、扫描电镜和 透射电镜观察了它们外壁雕纹、萌发孔的类型以及外壁层次的结构。 本亚族花粉以无萌发孔 和三孔沟类型为主,其次为三沟和拟沟类型。根据花粉资料,表明花粉形态特征对于论证该亚族内属的界限和属间系统发育的关系,可以提供重要的依据。     

中国栝楼属(Trichosanthes L.)花粉形态的研究

本文系统地研究了我国栝楼属30种及分布于日本的多裂栝楼的花粉形态,观察了各种花粉在光学显微镜及扫描电镜下的形态特征.同时通过花粉形态的研究,验证了在分类上本属所分各组的合理性。并观察了栝楼族另一属植物油瓜的花粉,探讨了二属之间的亲缘关系。由于本属植物多数为药用,而花粉形态特征为本属药材真伪的鉴别提供了依据。     

杜鹃属马银花亚属药花粉形态的研究

首次报道了杜鹃属马银花亚属四组20种2变种植物的花粉形态。本亚属植物的花粉均为四合花粉,呈正四面体排列,四合体直径为35．85－60．72μm。单粒花粉球形或近球形,具三孔沟。在四合花粉上,相邻花粉粒上的沟相连花粉粒表面或多或少具粘丝。在扫描电镜下,花粉粒呈现出粗糙、不明显聚颗粒状至致密的聚颗粒状等不同的纹饰,在不同的组间存在或多或少的差异,具有一定的分类学意义。对某些种的分类处理也能够提供某些孢粉学证据。     

POLLEN MORPHOLOGY AND SYSTEMATIC RELATIONSHIPS AMONG NEW WORLD SPECIES IN TRIBE ANTIRRHINEAE (SCROPHULARIACEAE)

The morphology of mature pollen grains among 12 New World genera in tribe Antirrhineae has been examined with light and scanning electron microscopy. Pollen from 29 American species have mean polar diam that range from 17 to 26 μm, have a tectate structure with perforate, microreticulate, or reticulate surface pattern, and are subspheroidal to prolate, and trizonocolporate with fusiform or narrowly oblong colpi that are free or occasionally fused at the poles. Among the genera, pollen size is positively associated with style length but not haploid chromosome number. Three major morphological categories are recognized based on grain shape, exine structural pattern, and colpus shape. Two of these morphotypes each characterize individual genera (Mohavea, Linaria). The other morphological category includes ten New World genera and has been divided into three subcategories based on variation in lumina diam and intermittent occurrence of fused colpi. Only Antirrhinum and Pseudorontium have species or populations with pollen in more than one subcategory. Concordance of morphological, anatomical, chromosomal, and palynological data suggests that Linaria and Mohavea are best placed in separate subtribes from other native American genera. Compared to Old World taxa in tribe Antirrhineae, the most common pollen type (subspheroidal, microreticulate, apocolpate, fusiform colpi) may be the most primitive. Pollen grains with fused colpi (Antirrhinum p.p., Pseudorontium) and perforate (Mohavea) or reticulate (Holmgrenanthe) structural patterns probably represent derived types.     

何首乌不同种质花粉形态及进化趋势研究

采用电镜扫描法,对48份何首乌种质的花粉形态进行了观察和分析。结果表明:何首乌花粉形状主要为椭球形,少量为长椭球形和近球形,部分种质花粉形状正处于椭球形向长椭球形进化的阶段;极面观主要为三裂圆形,部分种质的变异为半球状、四边形、凹陷状或平三角形;赤道面观主要为椭圆形,部分种质为三角形或四边形;萌发沟3条,狭长,几达两极,部分种质的1条或2条萌发沟中部或近极端处隆起,2条或3条萌发沟在极端处相交;表面纹饰为穴状,部分种质的穴中出现小孔。研究结果表明,何首乌物种正处于活跃进化阶段且因区域及生境的差异其进化速度不一致,低纬度地区的种质进化程度较高纬度地区的高,其最初的起源中心可能位于高纬度地区,在向低纬度地区迁移过程中其花粉形态发生了不同程度的变异。     

囊萼紫草属与滇紫草属花粉形态比较研究

本文借助光学显微镜和扫描电镜研究了囊萼紫草属3种和滇紫草属12种植物的花粉形态。囊萼紫草属的花粉为哑铃形或茧形,中等大小,P／E比为1．6一1．67,三孔沟,内孔横长;具小刺状纹饰。滇紫草属的花粉为近长球形或近卵球形,P／E为l—1．23;三孔沟或三合沟孔,内孔一般纵长,具皱波状纹饰,在皱波上具密集的小瘤或微颗粒。从花粉形态的角度,本文支持把囊萼紫草属从滇紫草属(广义)中分离出来的观点。值得注意的是,在滇紫草属的花粉中首次观察到了一种比较少见且特化的花粉即单极三合沟孔的花粉。     

矮牡丹小孢子母细胞减数分裂异常现象的观察

矮牡丹(Paeonia suffruticosa subsp. spontanea)(永济居群)存在多种结构杂合现象,减数分裂存在一些异常:如单价体、异形二价体、互锁四价体、六价体、后期I倒位桥、落后单价体、不均等分离、后期Ⅱ桥和微核等。统计了这些异常现象出现的频率,并对其形成的机制和对正常小孢子形成的影响进行了讨论。从细胞学水平上探讨了矮牡丹可能的濒危机制。同时结合前人的研究,对芍药属内3个组的结构杂合程度进行了比较。     

TAXONOMIC IMPLICATIONS OF EXTERNAL POLLEN MORPHOLOGY TO VERNONIA (COMPOSITAE) IN THE WEST INDIES

External pollen morphology of 39 species of West Indian Vernonias was examined by light and scanning electron microscopy in conjunction with a systematic revision of these species. There were three distinct types of pollen: Type A: subechinolophate, tricolporate grains with prominent spines; Type B: echinolophate, tricolporate with expanded germinal furrows and coincident polar muri; Type C: echinolophate, tricolporate grains with prominent polar lacunae. Pollen grains intermediate between the major types were found in several species. These same species had very distinct and atypical megamorphologies. In general, pollen types were found to correlate well with classification based on megamorphological characters, particularly at the infrageneric level, and to provide confirmation of subsectional assignments in the genus.     

Studies on the Pollen Morphology of Trapa from Zhejiang

In the present work, pollen grains of 9 species of Trapa L. from Zhejiang were examined under LM and SEM. They are subsphaeroidal or subprolate, obtuse-triangular in polar view, elliptic or subrounded in equatorial view, and 3-colpate. In the equatorial area, there are three ridge-shaped appendages which elongates along apertures toward two poles and ultimately combined, the ornamentation of other part of exine is minute-verrucate. The genus Trapa is uniform in shape of pollen grains, type and position of apertures and ornamentation of exine, while differentiation can be found in size of pollen grains and shape of ridge-shaped appendage. All of these provide valuable evidence for the classification of Trapa and the verification of their affinities. The validity of Trapaceae, the evolutionarytrends of pollen morphology and the affinities of some species are discussed in this paper.     

Division polarity,development and configuration of microtubule arrays in Bryophyte meiosis

Summary Immunofluorescence and TEM studies of meiosis in two mosses (Bryophyta) provide evidence that the prophasic tetrahedral system of microtubules contributes directly to the metaphase I spindle. Intense staining of tubulin, conspicuously absent around the nuclear envelope, is first seen associated with plastids. By mid-prophase, microtubules radiate from the plastids to the nuclear envelope and become organized into six bands that interconnect the four plastids, forming a tetrahedral cytoskeleton surrounding the nucleus. During transition of prophase to metaphase, the four poles of the tetrahedral microtubule system converge in pairs toward opposite cleavage furrows. Opposite furrows occupy mutually perpendicular planes and the pair of microtubule focal points straddling one furrow lies at right angles to the pair straddling the opposite furrow. Additional microtubules terminate in numerous small clusters in the concave polar regions arching over the cleavage furrows. By early anaphase, the microtubule focal points lie very close to the division axis. We conclude that microtubules recruited from the prophasic quadripolar system are incorporated into the mature metaphase I spindle and the two principal focal points at each pole are those derived from poles of the prophasic quadripolar system.     

Precocious cleavage furrows simultaneously move and ingress when kinetochore microtubules are depolymerized in <Emphasis Type="Italic">Mesostoma ehrenbergii</Emphasis> spermatocytes

A “precocious” cleavage furrow develops and ingresses during early prometaphase in Mesostoma ehrenbergii spermatocytes (Forer and Pickett-Heaps Eur J Cell Biol 89:607-618, 2010). In response to chromosome movements which regularly occur during prometaphase and that alter the balance of chromosomes in the two half-spindles, the precocious furrow shifts its position along the cell, moving 2–3 μm towards the half cell with fewer chromosomes (Ferraro-Gideon et al. Cell Biol Int 37:892-898, 2013). This process continues until proper segregation is achieved and the cell enters anaphase with the cleavage furrow again in the middle of the cell. At anaphase, the furrow recommences ingression. Spindle microtubules (MTs) are implicated in various furrow positioning models, and our experiments studied the responses of the precocious furrows to the absence of spindle MTs. We depolymerized spindle MTs during prometaphase using various concentrations of nocodazole (NOC) and colcemid. The expected result is that the furrow should regress and chromosomes remain in the midzone of the cell (Cassimeris et al. J Cell Sci 96:9-15, 1990). Instead, the furrows commenced ingression and all three bivalent chromosomes moved to one pole while the univalent chromosomes, that usually reside at the two poles, either remained at their poles or moved to the opposite pole along with the bivalents, as described elsewhere (Fegaras and Forer 2018). The microtubules were completely depolymerized by the drugs, as indicated by immunofluorescence staining of treated cells (Fegaras and Forer 2018), and in the absence of microtubules, the furrows often ingressed (in 33/61 cells) at a rate similar to normal anaphase ingression (~?1 μm/min), while often simultaneously moving toward one pole. Thus, these results indicate that in the absence of anaphase and of spindle microtubules, cleavage furrows resume ingression.     

Ultrastructure and germination of Vitis vinifera cv. Loureiro pollen

The cultivar Loureiro of Vitis vinifera is one of the most economically important, recommended in almost the totality of the Regi?o Demarcada dos Vinhos Verdes. In vineyards, the grape productivity of this cultivar is normal while in others it is extremely low. The aim of this work was to study the morphology and germination of Vitis vinifera cv. Loureiro pollen with high and low productivity. The pollen grain was examined under light, transmission and scanning electron microscopy. Typically V. vinifera pollen present three furrows but in the cultivar Loureiro we found tricolporated and acolporated (without furrows or pores) pollen grains. Both pollen types present generative and vegetative cells with the usual aspect and a dense cytoplasm rich in organelles. In the acolporated pollen a continuous exine layer and an irregular intine layer were observed. Differences were found in the starch accumulation, since only in tricolporated pollen abundant plastids filled with numerous starch granules were observed. To determine the causes of the low productivity of this cultivar we tested pollen viability by the fluorochromatic reaction and pollen germinability by in vitro assays. We observed that the acolporated pollen grain is viable, but no germination was recorded.     

Pollen evolution and systematics inAnnonaceae with special reference to the disulcate Australian endemic genera

All genera ofAnnonaceae endemic in Australia (Ancana, Fitzalania, Haplostichanthus) show almost exactly the same type of disulcate (disulculate) pollen with intact exine extending over the sulci. Tetrad stages inHaplostichanthus andAncana reveal a latudinal subequatiorial orientation of the two sulci at the proximal hemisphere. Sometimes they fuse into a ±zonosulcate aperture.Fissistigma pollen grains are ±globose and have a flattened pole with a central elevation and a concentric groove, covered by a somewhat reduced exine. This palynological characters give further support for separating the generaAncana andFissistigma. Germination was observed inHaplostichanthus where the pollen tube emerges at one of the two sulci and inFissistigma where the flattened part breaks up during germination. The aperture types described here are obviously transitional stages between aperturate and inaperturate pollen grains and are discussed in regard to pollen evolution.