A Study on Pollen Morphology of Tribe Rhamneae (Rhamnaceae)in China

Pollen morphology of 25 Chinese species, representing 6 five genera in the tribe Rhamneae of Rhamnaceae, was examined under LM and SEM. Pollen grains are subspheroidal or suboblate, obtuse-triangular in polar view, 3-colporate, with the polar axis (P)10.4-28.7μm long and equatorial axis (E) 11.3-30.5μm long, P/E = 0.81-1.11. Colpi generally narrow and long, ora lalongate, with two ends connected with the thinned part of exine, forming a H-shape. Four thickenings were observed where colpi and ora cross, but sometimes the thickenings were indistinct or formed a ring. The stratification indistinct. The ornamentation of exine obscure or indistinctly reticulate under LM, but rugulose, short-striate, rugulose-foveolate or reticulate under SEM. The exine ultrastructure of Rhamnus ussuriensis was examined under TEM. It consists of imperforate tectum, granular layer, foot layer and endexine. The tectum is rather thick with uneven surface, while the granular layer is rather thin. A key to the genera based on pollen characteristics is provided and the general pollenmorphology of five genera, i.e. Sageretia, Rhamnus, Hovenia, Colubrina and Alphitonia, is described respectively. Based on pollen size, the four thickenings and the ornamentation, the five genera under study may be distinguished from each other. For example, pollen grains are smaller in Sageretia; the four thickenings are larger and distinct in Hovenia and Alphitonia. However, the ornamentation is short-striate under SEM in Hovenia and Alphitonia, while reticulate in the Colubrina and Rhamnus ( Subgen. Rhamnus) .Two different concepts of Rhamnus exist among taxonomists. Heppeler and Suessenguth divided Rhamnus into two subgenera (Subgen. Frangula and Subgen. Rhamnus), whereas Grubov separated Subgen. Frangula from Rhamnus as an independent genus. According to the pollen morphology, the separationis reasonable.     

太行菊属植物花粉形态研究

以采自河北、河南、山西太行菊属2种植物17个种群的花粉为实验材料,利用扫描电镜对其形态进行系统观察和比较,并进行聚类分析,探讨太行菊属植物的演化进程路线.结果显示:(1)太行菊属花粉为单粒花粉,球形或近球形,极面观三裂圆形,具3孔沟.(2)扫描电子显微镜下花粉外壁纹饰以刺-颗粒状复合纹饰为主,刺基部膨大,体积较小属小型...     

Studies on the Pollen Morphology and Seed Coat of the Genus Cistanche (Orobanchaceae) in China

In the present paper pollen grains of 5 species and seed coat of 4 species of the genus Cistanche (Orobanchaceae) from China were examined by scanning electron microscope As a result, two types of the pollen exine sculpture are distinguished: (1) tuberculate, C. salsa and C. lanzhouensis; (2) rugulate or fine reticulation formed by the fusion of rugae, C. sinensis, C. deserticola and C. tubulosa. Chinese Cistanche was classified into two sections based on the gross morphology by the present author (Zhang, 1984). C. lanzhouensis and C. sinensis were included in one section. This classification is in conflict with the pollen type, which indicates that the characters of pollen grains and external morphology in this genus have evolved at different rates. The differences in pollen morphology of Chinese Cistanche can serve as characters for delimitating species. According to our abservation, C. lanzhouenis Z. Y. Zhang differs from the other members of Cistanche not only in external morphology but also in pollen morphology. Pollen grains are subprolate in this species, while prolate in the other four species, and exine sculpture is tuberculate. The present study provides the establishment of this new species (Zhang, 1984) with palynological evidence. The seed coat sculpture in Chinese Cistanche are constantly alveolate, but there are some slight differences, by which the sculpture can be divided into two types: (1) testa cells have or have not thickenings on the inner anticlinal walls; cavernulous sculpture is present on outer periclinal wall of some cells: C. sinensis; (2) testa cells have striate thickenings on the inner anticlinal walls: C. salsa, C. deserticola and C. tubulosa. The characters of seed coatof some significance for the delimitation of species.     

两种山羊豆属植物花粉形态与花粉母细胞减数分裂行为观察

采用扫描电镜与1%醋酸洋红压片的方法,观察山羊豆属两种植物的花粉形态及花粉母细胞减数分裂行为,从而为山羊豆属的遗传学及分类学提供依据。两种山羊豆属植物立体形状为近球形或扁球形,均具三孔沟,穴—网状纹饰,极面观为近三角形,赤道面观为圆形。东方山羊豆的大小为:赤道轴×极轴=14.3（13.5～15.0）×12.6（12.1～13.7）μm,山羊豆的大小为：赤道轴×极轴=13.7（12.3～14.8）×12.4（10.6～13.0）μm.花粉母细胞减数分裂为同时型胞质分裂,终变期染色体构型为8Ⅱ,没有出现落后染色体及微核现象。小孢子四分体为四面体型。减数分裂过程有一定规律,与花蕾大小,颜色有密切关系。减数分裂进程存在一定差异,同一个花蕾中的不同花药花粉母细胞分裂速度基本相同,所处的时期及观察的分裂相一致,在同一个花药中的不同花粉母细胞中,可见各种不同时期的细胞。     

睡莲属植物花粉形态研究

为明确睡莲属植物花粉形态特征,研究利用扫描电镜对18种或品种睡莲属植物的花粉形态特征进行观察,并对花粉形态及其种间亲缘关系进行分析,同时利用离体萌发法对睡莲品种‘彼得’的花粉活力进行测定,为睡莲杂交育种亲本的选择提供依据。结果表明:(1)18种或品种睡莲属植物的花粉均为单粒花粉,形态均为近球体或扁球体,其中巨花睡莲花粉粒最大,体积指数为30.3;埃及白睡莲花粉粒最小,体积指数为19.2。(2)花粉外壁纹饰类型繁多,包括网纹状、小颗粒状、瘤状、小柱状、长条状、微波纹起伏状。(3)根据聚类分析可将18种或品种睡莲属植物分为4个类群,其中Nymphaea亚属与Brachyceras亚属间亲缘关系最近。(4)‘彼得’的花粉离体萌发率高,可达95%以上。研究认为,睡莲属植物的花粉形态特征,特别是花粉萌发沟类型、外壁纹饰等特征可作为睡莲属植物种间分类、亚属间以及种间亲缘关系、系统进化规律的关键证据。     

Studies on Pollen Morphology in Tiliaceae of China

Pollen morphology of 44 species representing 9 genera of Tiliaceae in China was examined under light microscope, 10 of them were observed with scanning electron microscope. Nine genera involved in this paper are: Colona. Corchoropsis, Corchorus, Excentrodendron, Grewia, Hainannia, Microcos, Tilia and Triumfetta The pollen grains of Tiliaceae are eurypalynous. Based on the aperture type and ornamentation, they may be grouped into four types: (1) The Grewia type, pollen grains tricolporate: Colona, Corchorus, Grewia, Microcos and Triumfetta, (2) The Tilia type, pollen grains brevitricolporate: Hainania and Tilia, (3) The Corchoropsis type, pollen grains triporate, spinate: Corchoropsis, and (4) The Excentrodendron type, pollen grains triporate, reticulate: Exce ntrodendron. The significance of pollen morphology in taxonomy of Tiliaceae is discussed. The palynological data seem to support the separation of Microcos from Grewia and the transfer of Corchoropsis to Sterculiaceae from Tiliaceae.     

A Study of Pollen Morphology of Sparganium from China

Pollen morphology of 8 species in genus Sparganium from China has been studied. All of them were examined under the light microscope and SEM. It may draw the following conclusions: The characteristics of pollen grains in genus Sparganium are very similar. They are spheroidal, subspheroidal or sometimes slightly angular in shape, 21.8–38.3μm in diameter, monoporate. Porus is slightly sunken, its margin distinct or indistinct, and some granules on the porus membrane. The thickness of exine is 1.7–2.6μ m. The sexine is about as thick as nexine, sometimes thinner than nexine. It is difficult to distinguish one another under the light microscope, but may be seperated under SEM on the basis of the shape or size of lumina and width or height of muff. In some species small excrescenses can be observed under SEM. Some taxonomists (Rendle, 1953) considered that Sparganium is closely related to Pandanus, but others (Hutchison 1934, Takhtajan 1969) to Typha. According to the data of pollen morphology, Sparganium is more close to Typhaceae than to Pandanaceae, thus we agree to put it into family Typhaceae.     

Studies on Pollen Morphology of Taxaceae of China

The present study deals with pollen morphology of 4 genera and l0 species of Taxaceae in gymnosperms. Pollen grains of the family are spheroidal or subspheroidal, 20.8μm in diameter and with laptoma or papilla in the distal face. Exine is two-layered, with sexine equal to nexine in thickness, but sometimes the stratification is indistinct. The surface is scabrous or slightly granular under LM. Coarse verrucae and fine tuberculae on pollen surface are observed under SEM. From thin section, endexine is shown to have lamellate structure, and ectexine is made of verrucate elements. In Amentotaxus argotaenia, some pollen grains show remnant saccate. According to pollen morphology, this family may be divided into two tribes: 1, Pseudotaxeae (including Pseudotaxus only), and 2, Taxeae (including Taxus and Torreya). Owirg to the special feature of pollen grains in Amentotaxus the present author suggests that the genus be separated from Taxaceae and raised to the level of family, Amentotaxaceae.     

Studies on Pollen Morphology of Podocarpaceae from China

The pollen morphology and ultrastructure of exine of Podocarpaceae in China were examined with light microscope, scanning electron microscope and transmission electron microscope. The pollen grains of Podocarpus have rather large and prominent sacs on both sides of body, and are 53.9-74.8 μm long in total, with their bodies 29.6-45.2 μm long and 19.1-31.3 μm wide. The sacs are smooth on outer surface with perforation, but reticulate inside. On distal view, they are obviously of radial muri from its base. The body is oblate or spheroidal, laddershaped on distal face. The exine of the capis tuberculate, but more distinctly on the margin than in the centre. The pollen grains of Dacrydium are of small and indistinct sacs around body, which are composed of many small bladders. The body is subcircular in outline. Both body and sacs are irrugulate tuberculate under SEM. Examination of thin sections of Podocarpus macrophyllus var. maki with TEM reveals that the exine includes ectexine and endexine. It is interesting to note that foot layer of ectexine possesses lamellar stru cture, but endexine is homogeneous in structure and lighter in colour. This character is specific in the gymnosperms. Based on informations of fossil pollen grains, Podocarpaceae is rather primitive and of ancient origin.     

The Pollen Morphology and Exine Ultrastructure of Paeonia L in China

The pollen morphology of 9 species of Paeonia L. has been investigated with both light microscope and scanning electron microscope. In addition, the exine structure of pollen grains of Paeonia suffruticosa and P. lactiflora was examined by transmission electron microscope. Tricolporoidate aperture is an important character of the pollen grains of the Paeonia. The surface of the exine is characterized by reticulate, foveolate and irregularly tuberculate-foveolate sculpture under the SEM. Thin sections of the pollen of this genus shows that the layers of exine are complete i.e. a perforate rectum to semitectum, columellae and foot layers. The endexine is continuous, considerably thickened in the aperture areas and relatively thin or indistinct in the mesocolpia. Paeonia has been placed in Ranunculaceae. But since the beginning of this century many authors have suggested to separating Paeonia from Ranunculaceae. Pollen marphology supports such separation. In Ranunculaceae most pollen grains are tricolpate or have other types of aperture, and exine with spinules and perforations between them. In electron microscopy, the ektexine contains a foot layer, columellae, and perforate rectum, the columellar layer with two types of columellae; the endexine is generally thin. However, the columellar layer of Paeonia has only monomorphic columellae. Some authors considered that there is a close relationship between Paeonia and the Dilleniaceae, but these also differ in the characters of the pollen grains. In Paeonia the constriction of the colpus in equator is in some degree similar to that of Theaceae (Camellia sasanqua Thunb.), Guttiferae (Hypericum L.), Actinidiaceae and Rosaceae. But in the other respects they are quite different. In sum, the pollen morphology of Paeonia is unique. So the palynological information supports Takhtajan's view that Paeonia should be elevated to a family (Paeoniaceae) or order (Paeoniales).     

中国紫草科破布木属花粉形态和外壁超微结构

为了深入探讨紫草科（Boraginaceae）的分类问题,用光学显微镜和扫描电子显微镜观察了该科破布木属（CordiaL.) 10种植物的花粉形态和外壁超微结构。发现该属花粉具三孔、三孔沟、三拟孔沟和三合沟4种萌发孔类型。外壁表面具微刺状纹饰、刺状纹饰、网状纹饰和不规则的条纹网状纹状。破布木属的花粉特征表明,该属花粉在紫草科中既是独特的分类群,又是比较原始的属种。     

Studies On the Pollen Morphology of the Genus Iris in China

In this paper, pollen grains of 32 species of the genus Iris in China were examined under light microscope and scanning elrctron microscope. Pollen grains in Iris of China are navicular or subspheroidal. According to the characters of aperture and shape, pollen grains may be divided into four types: (1) Monocolpate (distal): pollen grains navicular or subspheroidal, exine reticulate. (2) Monocolpate-colpoidal: pollen grains subspheroidal, exine pilate. (3) 2-syncolpate: polen grains subspheroidal or navicular, exine reticulate. (4) No aperture: pollen grains subspheroidal; exine verrucate. The evolutional trends of aperture and exine ornamentation are traced and systematic po-sitions of some species are discussed based on characteristics of pollen grains and other organs.     

广西野生毛葡萄雌雄株花粉形态学研究

通过电镜扫描,对原产于广西石山地区的野生毛葡萄雌、雄株花粉形态进行比较研究。结果表明,野生毛葡萄花粉粒为小型花粉粒,雌、雄株花粉粒形状及纹饰、萌发孔特征均有较大差异:雄株花粉粒萌发孔为三孔沟类型,长球形,花粉粒P/E=1.20(P极轴值,E赤道轴值);雌株花粉粒无萌发孔,近球形,花粉粒P/E=1.12。     

黄土高原蒿属植物花粉形态研究

运用光学显微镜和扫描电镜,观察了黄土高原32种蒿属植物的花粉形态,结果表明蒿属植物花粉形态具有高度一致性,支持传统的属级分类。根据花粉外壁纹饰,可将其分为5种类型。Ⅰ型:小刺密集,刺基部膨大,覆盖层有细小颗粒。Ⅱ型:小刺密集,刺基具显著膨大,几乎密集相连。Ⅲ型:小刺密集,刺基明显膨大状,覆盖层光滑。Ⅳ型:稀疏小刺,覆盖层光滑;轮廓线较光滑或微刺状。Ⅴ型:稀疏微刺,覆盖层有小颗粒;轮廓线较光滑,萌发沟细长,孔扁长。蒿属植物不同种花粉的大小、形状、萌发孔类型、外壁纹饰及边缘形态等方面均表现出一定的特异性,对蒿属植物种间鉴定分类及古植物孢粉鉴别均有一定的参考价值。     

中国西南地区当归属植物花粉形态及其系统进化分析

用光学显微镜和扫描电镜研究了分布于中国西南地区的当归属(Angelica L.)16种植物的花粉形态,其中有7种植物的花粉形态为首次报道。研究结果表明当归属植物花粉粒较大,分化明显,包含了伞形科花粉的原始、中等进化和进化的类型,其形态以菱形、椭圆形、近长方形、赤道收缩形为主,萌发孔为角孔或边孔,从花粉的这种多类型证明该地区的当归属植物既起源古老同时又在不断分化着。从孢粉学角度初步分析了当归属的属下系统,为该属植物种的划分及系统演化关系的探讨提供依据。     

Studies on the Pollen Morphology of the Genus Brassica (Cruciferae) in China

The present paper reports the pollen morphology of 36 species and varieties of Brassica L. in China mostly for the first time. They were examined both under LM and SEM. Pollen grains of Brassica L. in China are long-spheroidal, subspheroidal, spheriodal, oblate, rarely reniformis or subsquare. According to the aperture characters pollen grains may be divided into four types: 2,3,4-colpate, 3-colpate, 3,4-colpate, 3,4-colporate. The exine sculpture may also be divided into three types: 1, reticulate, 2, cerebroid-reticulate, 3, foveolatereticulate. Detailed characters of pollen grains for each taxon are presented in Table 1. The 2,3,4-colpate type of pollen grains may be considered as primitive one and the 3,4-colpate or 3,4-colporate type of pollen grains is the most advanced in Brassica. The tricolpate aperture and reticulate exine have been reported by the previous authors, whereas, 3,4-colporate and cerebroid-reticulate or foveolate-reticulate pollen grains are newly reported.     

中国15种变豆菜属植物的花粉形态及系统学分析

利用光学显微镜和扫描电子显微镜对变豆菜属15种植物的花粉形态进行观察。结果表明,变豆菜属15种植物的花粉大小为（28.51~54.29） μm~（12.23~28.98） μm,极轴与赤道轴比值（Polar axis/Equatorial axis）为1.48~2.46,具三孔沟。花粉粒赤道面观有近矩形、赤道收缩形、长椭圆形等类型,其中近矩形和赤道收缩形占多数;极面观为圆形或三角圆形。在扫描电镜下,其外壁表面纹饰为网状。我们研究结果支持在伞形科变豆菜亚科中,变豆菜属植物的花粉具有中等进化、比较进化的形态特征,花粉形态可为个别物种的分类处理提供孢粉学证据。     

Studies on Pollen Morphology of the Genus Corylopsis

The present paper describes the pollen morphology of 11 species of thc genus Corylopsis (Hamamelidaceae). The pollen grains were all examined with light microscope and scanning electron microscope. Pollen grains of the genus are prolate, spheroidal or subprolate. Three size types are recognized: (l) 18-23 μm, found in Corylopsis omeiensis Yang, C.gotoana Makino, C. himalayana Griff and C.platypetala Rehd. et Wils. (2) 24-32μm, found in C. sinensis Hemsl., C.willmottiae Rehd. et Wils., C.veitchiana Bean, C. brevistyla H.T.Chang, C.multiflora Hance, C.pauciflora Sieb. et Zucc. and C.spicata Sieb. Zucc. (3) 34-39μm, found in C. wilsonii Hemsl. and C. cordata Merrill. Pollen grains are 3-colpate and 4-colpate (only infrequently found in Corylopsis sinensis Hemsl.); the exine is 2-layered, 1.25-2.50μm thick, distinctly reticulate, sexine almost equal to nexine in thickness. From the pollen morphology the genus is considered as a natu-ral group.     

12种十字花科植物花粉形态研究

采用扫描电子显微镜对十字花科8属12种植物的花粉形态特征进行了观察分析.其中8种为首次报道.观察结果表明:4族8属12种十字花科植物花粉形态的一般特征为:花粉粒长球形至超长球形;极面观三裂圆形,少数四裂圆形;外壁纹饰为网状或细网状纹饰;三沟,偶四沟.12种植物的花粉可划分为5种类型:(1)花粉粒长球形,网状纹饰,三沟;(2)花粉粒超长球形,网状纹饰,三沟;(3)花粉粒长球形,细网状纹饰,三沟;(4)花粉粒超长球形,细网状纹饰,三沟;(5)花粉粒长球形,三或四沟,网状纹饰.十字花科花粉形态特征在不同族间、不同属间以及同属不同种间均没有明显规律,在十字花科分类过程中,不宜单独以花粉形态特征作为依据.     

A Study on the Pollen Morphology in Trochodendron,Tetracentron and Euptelea

Trochodendron, Tetracentron and Euptelea are considered as a small group of the primitive angiosperms. They are endemic to or mainly distributed in China. Their systematic position has long been debated. The purpose of the present work is to present palynological data both for systematic discussion and for the identification of fossil pollen. The three genera share a number of pollen characters, for example, being spheroid in shape, exine surface distinctly reticulate and lumina rather small and irregular in shape, etc. They are, however, obviously different in other respects of pollen morphology. The pollen grains of Euptelea are the largest of three (c. 30 μm in diameter), those of Tetracentron, the smallest (c. 15) and those of Trochodendron, intermediate (c. 20), 3-colpate in Trochodendron and Tetracentron, and those in Euptelea are 3-celpate but with transitional apertures in one species and 6-rugate, not 3-colpate, in the other. The ruga membranes are coarsely granular (rod-shaped elements under SEM). The lumina are the smallest in Euptelea. Muri in Tetracentron are distinctly striate. Thus, the establishment of three separate families is supported by pollen morphology. Since the pollen grains of Trochodendron and Tetracentron are 3-colpate and those of Magnoliaceae are 1-sulcate, it seems unreasonable to refer them to Magnoliaceae (or Magnoliales). If the rugae of pollen grains in Euptelea further shortened and their number increased, they would resemble those of Hamamelidaceae (such as Sycopsis). Pollen morphology, therefore, suggests that Euptelea is related to Hamamelidales, and supports Cronquist’s viewpoint. Hutchinson (1969) includes both Trochodendron and Euptelea in the same family (Trochodendraceae). However, these two genera are rather distinct in morphology and structure, the presence or absence of vessels and chromosome number, etc. Pollen morphology of two genera also disagrees with the Hutchinson’s viewpoint.