Pollen morphology in thePortulacaceae (Centrospermae)

Pollen of 110 species from 18 genera in thePortulacaceae has been examined by light and scanning electron microscopy, and a representative number by transmission electron microscopy. Three basic pollen types were found: 3-colpate with thick tectum and foot layer with prominent unbranched columellae and an extremely thin endexine; pantoporate with thick tectum and foot layer with branched columellae enclosing pores and an endexine that is one to two layers thick; pantocolpate with thin tectum and foot layer with broad, short unbranched columellae and an inconspicuous endexine. All pollen types, however, have a spinulose and tubuliferous/punctate ektexine. Also, all the genera except three,Calandrinia H.B.K.,Montia L. andTalinum Adanson are stenopalynous. There is, however, no absolute correlation between pollen morphology and geographical distribution, although both the major centre of palynological diversity and the majority of all species with tricolpate grains occur in South America.     

Variation of pollen morphology, and its implications in the phylogeny of Clematis (Ranunculaceae)

Clematis s.l. (including Archiclematis and Naravelia) is a genus of approximately 300 species with cosmopolitan distribution. The diversity of its pollen was surveyed in 162 taxa belonging to all infrageneric groups of Clematis s.l. Pollen morphology was investigated by use of scanning electron microscopy to identify useful characters, test taxonomic and systematic hypotheses, and elucidate pollen character evolution on the basis of the molecular phylogeny. Clematis pollen is small to medium (14.8–32.1?μm?×?14.2–28.7?μm), oblate to prolate (P/E?=?0.9–1.4) in shape. The apertures may be tricolpate and pantoporate sometimes with 4-zonocolpate and pantocolpate pollen grains as transitional forms. The tricolpate pollen grains are predominant and occur in all the sections of the genus, whereas pantoporate pollen grains can be found in sect. Tubulosae, sect. Viorna, sect. Viticella, and Naravelia only. Phylogenetic mapping of aperture types reveals that the pantoporate pollen type may be the apomorphy in the genus and evolved several times. The surface ornamentation in all taxa studied is similar and characterized by microechinae evenly distributed on the microperforate tectum. The size and density of spinules on the tectum vary greatly but successive in the whole genus. According to the character syndromes of the ornamentation, separating sect. Brachiata from sect. Meclatis is supported. Though pollen morphology may contribute to investigation of problematic taxa, the taxonomic value of pollen morphology is limited at the species level.     

中国蓼属植物花粉形态的研究

本文用光学显微镜和扫描电镜对国产44种2变种蓼属植物的花粉形态进行了观察。除了前人报道的31种外,其中15种为首次报道。本属花粉形态多类型,有球形、近球形、近扁球形、近长球形及长球形;从萌发孔来看,有三沟型、三孔沟型、散沟型及散孔形：外壁纹饰有颗粒-穿孔、微刺-穿孔、微刺-凹穴、细网状、皱块状及粗网状。根据这些特征将花粉划分为10种类型,其中西伯利亚蓼型(Sibir-icum-type)为本文首次提出。文中对本属的分类问题进行了探讨,不支持Steward(1930)将本属划分为8个组的意见,而认为应将本属划分为11个组。     

POLLEN MORPHOLOGY OF THE DILLENIACEAE AND ACTINIDIACEAE

Pollen of 53 species of Dilleniaceae and Actinidiaceae was examined by light microscopy, scanning electron microscopy, and a selected group in transmission electron microscopy. Dilleniaceae pollen ranges from tricolpate, tricolporate, tetracolpate, and incipiently inaperturate. Tricolpate types occur only among the Old World subfamily Dillenioideae and the compound aperturate (3-colporate) condition is restricted to the subfamily Tetraceroideae. Within the Dilleniaceae the tricolpate pollen type with elongated apertures is considered primitive, having given rise to the 3-colporate and 4-colpate conditions. The striking pollen dimorphism in the Neotropical species of Tetracera, all of which are androdioecious, is documented; however, in contrast to previous reports, pollen from bisexual flowers appears to be incipiently inaperturate and not pantoporate. The inaperturate condition is interpretated as an early stage in the evolution of outcrossing. Pollen morphology does not support a close relationship between Dilleniaceae and Actinidiaceae. Pollen morphological differences that can be noted between these families are: tectum complete and predominantly psilate or psilate-granular in Actinidiaceae, tectum incomplete, punctate to reticulate in Dilleniaceae; an equatorial bridge of ektexine over the endoaperture usually present in Actinidiaceae, absent in Dilleniaceae; columellae reduced in Actinidiaceae, columellae usually well-developed in Dilleniaceae. Pollen morphology does not argue against a close relationship between Actinidiaceae and Theaceae.     

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).     

Pollen Morphology in the Order Centrospermae

Pollen of 190 species from 16 families has been examined by light and scanning electron microscopy. Three basic pollen types were found: 3-colpate, pantoporate, and pantocolpate, all with a spinulose and tubuliferous/punctate ektexine. The palynological data emphasize the close relationship of the betalain families, and support their association with the anthocyanin families. Caryophyllaceae and Molluginaceae. Pollen morphology reinforces the placement of the Cactaceae and Didiereaceae in the order, and would support the inclusion of Dysphania in the Chenopodiaceae. The pollen grains of the Achatocarpaceae, Bataceae, Gyrostemonaceae and Theligonaceae, none of which had the spinulose and tubuliferous/punctate ektexine, had no counterparts in the remaining taxa examined. Thus, the evidence from palynology does not support their inclusion in the Centrospermae and indicates that their placement should be re-examined.     

中国柽柳科植物花粉形态的研究

本文用光学显微镜和扫描电镜观察了分布于我国的4属30种柽柳科植物花粉形态。并用透射电镜研究了柽柳属的代表种, Tamarix elongata外壁内部的超微结构。本科花粉为三沟, 少数属种为三拟孔沟。根据扫描电镜观察, 柽柳属花粉外壁表面具粗网状纹饰和细网状纹饰, 以及界于这两个类型之间的过渡类型。水柏枝属外壁表面具粗网状纹饰, 细网状纹饰, 小穿孔以及小的蠕虫状突起。红沙属和枇杷柴属均为细网状纹饰。 本科柽柳属花粉与杨柳科中柳属的花粉特征较相似, 本文提出了它们之间的区别。     

北极Barrow地区几种冻原植物的花粉形态

根据中一美合作协议,研究北极巴罗地区2000年以来气候和环境变化史,张青松和唐领余于1998年5—6月到阿拉斯加巴罗地区进行了为期4周的野外考察。除湖泊打钻外,还在巴罗地区采集了表土花粉和植物标本。本文是研究北极巴罗(Barrow)地区12种冻原植物的花粉形态,它们的形状有球形、近球形、扁球形、茧形和四面体形,其萌发孔有三孔沟,三沟,二合沟以及散孔等类型。花粉具辐射对称和两侧对称两种类型。这些花粉的植物体是北极地区常见的植物,分属于10个科,除三种为小灌木外,大多数为多年生或一年生草本植物。这些冻原植物花粉形态的研究为恢复北极地区古植被和古气候的研究,提供了有价值的对比资料和依据。     

蓼科花粉外壁超微结构的研究

用扫描电镜和透射电镜对蓼科6属15种的花粉壁构造的特点进行了观察和研究。结果表明：(1)外壁纹饰有如下几种：颗粒-穿孔,微刺-穿孔,微刺-穿孔-光滑,颗粒-穿孔-光滑,细网状,粗网状,皱块状,鼓锤状;(2)外壁结构分化成两个明显的层次,即外壁外层以及外壁内层。其外壁外层由覆盖层、柱状层和基层组成。然而,由于每一部分发育状况的不同而导致外壁结构有各种变化,如无覆盖层或无外壁内层。     

大戟科叶下珠属花粉形态的研究

对叶下珠属Phyllanthus Linn.13种植物花粉进行了光学显微镜和扫描电镜的观察。研究表明,本属花粉虽然在大小、形状和外壁纹饰等方面有不同程度的差异,但差异最大的还是在于萌发孔类型上。可以把本属花粉分为3孔沟,4－5孔沟,多孔沟,散沟（沟短而纺锤形或近圆形）和散孔等类型。这些萌发孔类型虽然与李秉滔在中国植物志第44卷中所划分的组不很吻合,但或多或少有一定的相关性,并且对于属下的分类具有一定的意义。在外壁纹饰方面,均为网状纹饰,可分为具粗网眼,细网眼和中等网眼等几种类型。但纹饰类型在组间或种间的差异不大明显。     

中国酸模属植物花粉形态研究

利用光学显微镜、扫描电镜对１５种,透射电镜对２种国产酸模属植物的花粉进行观察与研究。本属花粉为球形或近球形,大小为１５～４０×１８～４０μｍ。具３孔沟、４斜孔沟、散孔沟、散沟等;沟或外沟狭长,几达两极,内陷或不内陷,内孔圆形、稍横长或纵长;表面具皱波状纹饰;外壁厚１．０～３．５μｍ,外层明显厚于内层。在透射电镜下,花粉外壁分３层：覆盖层最厚,具穴状或穿孔,颗粒状或刺状纹饰,内面均匀;柱状层明显,厚,小柱为钝圆锥体或圆柱状,基层和内层不分,最薄,但在萌发孔处明显增厚。根据花粉形态,本属花粉可以分成７个组,它们是：小酸模组、滨海酸模组、酸模组、土大黄组、荒地酸模组、巴天酸模组和钝叶酸模组。对萌发孔分布规律的研究,基本支持Ｗｏｄｅｈｏｕｓｅ（１９３１）的观点,同时据花粉萌发孔演化的规律,认为本属花粉可能是蓼科花粉由少数萌发孔向多数萌发孔演化的过渡类型。     

Transition within the exine of Nothofagus Blume

Pollen grains with bulged areas on their proximal and distal faces were observed in some species of Nothofagus Blume in the light and electron microscopes. Pollen grains sectioned meridionally are distinctly transitionary in character in the individual strata within the exine of one pollen grain. The tectum in the apocolpia is considerably thinner than in the mesocolpia, The thickness and the character of the bacular layer in the mesocolpia differ greatly from those of the apocolpia. The foot layer, thick and always present in the mesocolpia, is entirely lacking in the apocolpia. The significant difference in the structure and thickness of the bacular layer, as well as the partial absence of the foot layer in one pollen grain, influence the cohesion between the individual strata of the exine in the apocolpia. The cohesion between the tectum and underlying, globular stratum in the central part of the apocolpia is poor, which facilitates the separation of the tectum and its bulging at that area.     

Pollen Morphology and Generic Phylogenetic Relationships in Ophiopogonoideae (Liliaceae)

In the present work, pollen grains of 3 species of Liriope, 24 species of Ophiopogon and 2 species of Peliosanthes were examined under scanning electron microscope, Among them 4 species were also observed under transmission electron microscope. The observation (Table 3)shows that Liriope and Ophiopogon distinctly differ from Peliosanthes in the exine ornamentation and structure, They may be divided into two types: 1. Rugulate-perforate, ektexine with perforate tectum in Liriope and Ophiopogon. 2. Verrucate, Verracae unequal in size, ektexine intectate in Peliosanthes. Pollen morphology shows the close affinity between Liriope and Ophiopogon, but they are very far from Peliosanthes. The correlation between pollen and gross morphology in Liriope, Ophiopogon and Peliosanthes are stated and their evolutionaly trends are discussed in this paper. The pollen characters support the placement of Liriope and Ophiopogon in one tribe—Ophiopogoneae, and Peliosanthes in another tribe—Peliosantheae. Peliosanthes is more advancedthan Liriope and Ophiopogon.     

Pollen types in Southern New World Convolvulaceae and their taxonomic significance

Pollen morphology from 143 collections representing 11 genera and 75 species of native South American Convolvulaceae was analyzed with LM and SEM. Exine structure and sculpture allow to distinguish three main types, in two of these types some subtypes were recognized. 1) Tectate, microechinate-perforate exine, with ramified columellae. On the basis of apertures three subtypes were distinguished: tricolpate in Aniseia, Bonamia, Convolvulus, Cressa, Dichondra, Merremia and Jacquemontia blanchetii; penta-hexacolpate in Merremia umbellata; and pantoporate with elliptic and circular pores, in Calystegia. 2) Tectate, microechinate-perforate exine with microspines and single columellae in concordant pattern, relates pantocolpate pollen of Jacquemontia and Evolvulus. From pollen data generic status of J. blanchetii should be considered. 3) Semitectate, echinate or gemmate, microechinate-microreticulate exine with single columellae is exclusive of pantoporate pollen of Ipomoea. Four subtypes were recognized in this genera, which are discussed in relation to Austins infrageneric classification.     

滇南风吹楠花粉形态观察

采用光镜、扫描电镜和透射电镜对滇南风吹楠的花粉形态进行观察.滇南风吹楠的花粉粒呈单粒存在,远极面观为椭圆形,近极面观大体为三角形,为不等极,两侧对称.花粉粒具一条远极单萌发沟;花粉大小为(15)19.90(21) μm×(20)22.50(25) μm.花粉粒外壁纹饰为网状,网脊平均宽度为0.29 μm;网眼形状不规则...     

Erdtmanitheca portucalensis,a new pollen organ from the Early Cretaceous (Aptian–Albian) of Portugal with Eucommiidites-type pollen

A new lignitised, slightly compressed pollen organ, Erdtmanitheca portucalensis, with affinities to extinct Erdtmanithecales from the Early Cretaceous (Aptian–Albian) of Vale de Água (Lusitanian Basin, western Portugal), is described. The pollen organ is composed of loosely arranged microsporophylls radiating from a central core. The estimated number of microsporophylls is about 100–150. The microsporophylls are sessile and ellipsoidal to barrel-shaped with a flattened or slightly apically depression containing about ten narrow sporangia. The sporangia enclose abundant well-preserved pollen grains of Eucommiidites-type. Pollen grains found in situ are elliptical in equatorial outline, about 16.0–27.2 μm long and 11.9–16.4 μm wide. The main (distal) colpus is long with expanded rounded ends. It is flanked by two subsidiary colpi in an almost equatorial position. The surface of the pollen wall is psilate and occasionally punctate. The ektexine is composed of a distinct tectum, granular infratectal layer and a thin foot layer. The endexine is thick and laminar. The new Early Cretaceous Portuguese pollen-organ is similar in several respects to that of Erdtmanitheca texensis described from the Late Cretaceous of Texas, USA. The new fossil species further documents the importance of the Bennettitales-Erdtmanithecales-Gnetales group in the Early Cretaceous floras of Portugal extending the stratigraphic and geographical distribution of the genus with regard to systematic and phylogenetic significance of the Eucommiidites-producing plants that may have been co-occurring with the Early Cretaceous diversification of angiosperms. It is ascertained that perforate tectum occurs in pollen grains with a well-developed foot layer as well as in pollen grains in which a foot layer is poorly developed or lacking, and that pollen features do not support a separation of the Erdtmanithecales seeds and pollen organs.     

山茱萸科花粉形态研究

本文应用光学显微镜与扫描电子显微镜观察了山茱萸科Cornaceae4属(按照Wangerin1910年的概念)27种花粉形态,结果如下: 1.根据花粉特征,支持把青荚叶属Helwingia,桃叶珊瑚属Aucuba,鞘柄木属Torricellia三属分别独立成科的观点。 2.梾木属Cornus可明显区分为两种类型,即梾木型和四照花型;梾木型还可再分为三个亚类型.即灯台树亚型,长圆叶梾木亚型和梾木亚型。 5.支持四照花属应从梾木属中分出而独立成属;而在四照花属Dendronbenhamia下设立北美四照花亚属Subg. Apocarpea和四照花亚属Subg. Syncarpea;在梾木属下设立梾木亚属Subg. kraniopsis, 灯台树亚属Subg.Masomora等亚属的观点。 4.建立了—新亚属——长圆叶梾木亚属。     

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.     

Study on the Pollen Morphology of the Family Berberidaceae

The pollen grains of 33 species representing 11 genera of the family Berberidaceae, mostly from China, were examined with the light microscope and scanning electron microscope. Their characteritic details can be used for generic diagnosis. A pollen key to the genera based on these observations is presented. Based on the morphology, the pollen grains can be grouped into the following three types: 1. The tetrad pollen type found only in the genus Sinopodophyllum. 2. The spiraperturate pollen type found in the genera Berberis and Mahonia. 3. The tricolpate pollen type found in the genera Diphylleia, Jeffersonia, Nandina, Dysosma, Caulophyllum, Leontice and Epimedium. A diagnostic key to the pollen grains of genera in the Berberidaceae. 1. Pollen grains single 2. Pollen grains spiraperturate .................... Berberis L., Mahonia L. 2. Pollen grains tricolpate 3. Exine with spinose sculpture ........................ Diphylleia Michx. 3. Exine with non-spinose sculpture 4. Exine with striate or striate-reticulate sculpture ...... Jeffersonia Barton 4. Exine with reticulate sculpture 5. Exine around colpus with distinct thickening ........ Nandina Thunb. 5. Exine around colpus without thickening 6. Pollen grains larger (45—50)×(32.5—37.5)μ 7. Colpus with membrane ................ Dysosma R. E. Woodson 7. Colpus without membrane ................ Caulophyllum Michx. 6. Pollen grains smaller (25—550)×(20—527.5) μ 7. Pollen grains prolate-perprolate .................... Leontice L. 7. Pollen grains spheroidal-prolate...Epimedium L., Podophyllum L. 1. Pollen grains tetrad ............................ Sinopodophyllum Ying     

大风子科13个种的花粉形态

利用光镜和扫描电镜对大风子科 9属 1 3个种的花粉形态进行了观察。花粉形状长球形或圆球形 ,除大风子属 (Hydnocarpus)萌发孔为三拟孔沟 ,其余均为三孔沟 ;外壁纹饰在不同属、同属不同种间表现出明显的多样化 ,基本上可分为粗网状、细网状、穿孔状、穴状4种类型。研究认为花粉形态对于该科与近缘科以及属下的划分具有一定的意义