Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Sippen derOleaceae,Scrophulariaceae, Plantaginaceae undAsteraceae

Different members of the Angiosperm familiesOleaceae, Scrophulariaceae, Plantaginaceae andAsteraceae with variable modes of pollination were studied in relation to ultrastructure of pollenkitt and exine. In entomophilous representatives the mostly electron-dense and homogeneous pollenkitt is located on the outside layer of the exine, making the pollen sticky. In related anemophilous taxa the pollenkitt mostly is electrontransparent and inhomogeneous; it becomes inactive by remaining in the loculus or sinking to the bottom of the exine caves; this makes the pollen powdery. According to such criteria,Fraxinus ornus andRhinanthus serotinus are entomophilous, whileFraxinus excelsior is anemophilous. The pollen ofLathraea squamaria eventually becomes powdery and suited for wind dispersal. The broad transition field between entomo- and anemophily is demonstrated byPlantago andArtemisia. Plantago lanceolata is anemophilous, whilePl. serpentina andPl. media are amphiphilous.Artemisia nitida andA. mutellina are entomophilous,A. absinthium, A. pedemontana andA. gabriellae are amphiphilous, but tend towards entomo- (A. absinthium) or anemophily (A. gabriellae), whileA. chamaemelifolia and especiallyA. vulgaris are anemophilous.

     

湖北省泽泻科、水鳖科、眼子菜科及茨藻科植物花粉形态研究

本文利用光镜及扫描电镜对湖北省泽泻科、水鳖科、眼子菜科及茨藻科11属29种1变种1变型植物(另加采于湛江的软骨草)的花粉形态进行了研究,发现泽泻科植物花粉具多个圆形萌发孔,外壁表面为小刺状纹饰;茨藻科植物花粉具远极单槽,表面为绉波状纹饰;眼子菜科及本文研究的水鳖科植物花粉均无萌发孔,分别具网状和小刺状饰纹饰。1.茨藻科植物花粉最原始,泽泻科花粉较进化,眼子菜科花粉较水鳖科花粉进化;2.泽泻属与泽苔草属花粉较慈姑属花粉原始;3.鞘叶眼子菜亚屈花粉较眼子菜亚属的花粉处于更高演化阶段;4.多孔茨藻花粉在该科中最原始。本文工作尚对易变形水生植物花粉形态研究方法进行了尝试。     

茨藻科、角果藻科植物花粉形态的研究

在水生植物茨藻目中,茨藻科Najadaceae和角果藻科Zannichelliaceae植物由于其结构、尤其是花部结构的极度简化和趋同适应,系统关系仍不清楚。本文应用光学显微镜、扫描电镜和透射电镜对上述2科4属的10种代表植物的花粉形态进行了观察,系统描述了各属、种的花粉形态。结果表明角果藻科植物花粉均无萌发孔,外壁纹饰通常为拟网状至浅网状。花粉形态的研究结果支持将Vleisia作为角果藻属Zannichellia的近缘属处理的观点。茨藻科植物花粉外壁光滑、稍皱波状或为疣状,具颗粒状纹饰,萌发孔的有无在种间存在变异。花粉形态的研究结果表明角果藻科与眼子菜科Potamogetonaceae近缘,茨藻科可能与水蕹科Aponogetonaceae或水鳖科Hydrocharitaceae中具单沟花粉的类群有一定联系,而与角果藻科和眼子菜科则相去甚远。     

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.     

Ultrastruktur und Verteilung des Pollenkitts in der insekten- und windblütigen GattungAcer (Aceraceae)

Several insect- and wind-pollinated species of the genusAcer have been investigated and compared in regard to pollen stickiness. The considerable amount of very inhomogeneous pollenkitt inA. negundo remains on the loculus wall or is deposited inside the exine cavities; thus the pollen is powdery. The small amount of non-homogeneous, granular pollenkitt inA. campestre mostly disappears into the exine cavities; only small droplets appear on the tectum surface; the pollen stickiness therefore is only moderate. On the other hand,A. pseudoplatanus andA. opalus produce an average amount of granular pollenkitt, which is deposited partially inside the exine and partially as a slender film on the tectum surface; in both the pollen is sticky.A. platanoides contains a great deal of granular and homogeneous pollenkitt; it does not only fill up the exine cavities but also extends as a thick, ± homogeneous, non-granular layer of pollenkitt over the tectum surface; therefore, the pollen is very sticky.—The characteristics of pollen agglutination together with other aspects of floral biology illustrate the wide spectrum between unequivocal entomophily and anemophily within the genusAcer: WhileA. negundo is anemophilous andA. platanoides is entomophilous, the remaining species investigated have a pollination syndrome with entomophilous and anemophilous features and are thus amphiphilous. The evolution withinAcer is tending not only towards dioecy, but also towards anemophily.

Herrn Prof. Dr.L. Geitler zum 80. Geburtstag gewidmet.     

延龄草科四属花粉形态的研究

对延龄草科重楼属Paris L.延龄草属Trillium L.Medeola L.属和Scoliopus Torr.属以及百合科百合属Ｌilium L.和萱草属Ｈemerocallis L.花粉进行了光镜和电镜的观察和比较。结果表明,在延龄草科中,重楼属,Medeola属和Scoliopus属花粉具有较多的相似性：具单一远极沟,极面观椭圆形,外壁为网状纹饰或皱波－网状纹饰。而延龄草属花粉与它们的差异则较大,为圆形,无萌发孔,外壁非网状纹饰,而是颗粒状,疣状,芽孢状,星状和微刺状等纹饰。百合属中的Lilium michauxii和萱草属中的金针菜Hemerocallis citrina花粉均为单一远极沟,外壁表面为网状纹饰。但其网脊特别粗,具不规则突起并形成棱角（H.citina)或由许多排列成念珠状的、形状不一的分子组成（Lilium michauxii),结构特别复杂。就其萌发孔类型和纹饰特征看,它们与延龄草科中的重楼属,Medeola属和Scoliopus属花粉具有较多的性。花粉外壁的层次结构在延龄草科各属之间（延龄草属除外）,甚至在延龄草科与百合科之间均没有多大的差异。     

Phylogeny of the family hydrocharitaceae inferred fromrbcL andmatK gene sequence data

The family Hydrocharitaceae, with 15 genera and ca. 80 species, shows a remarkable morphological diversity which presumably developed as an adaptation to their aquatic habitat. This is particularly true in the case of the many different kinds of pollination mechanisms. To gather more basic information regarding the adaptive evolution of Hydrocharitaceae, we have carried out a phylogenetic analysis based on the sequences of therbcL andmatK. Our resulting neighbor-joining distance tree provides the following insights: (1) none of the previous classification systems were supported by molecular phylogenetic tree; (2) Najas (Najadaceae), which has never been included in Hydrocharitaceae except in Shaffer-Fehre's (1991) system based on seed coat structures, is an ingroup of Hydrocharitaceae; (3) Limnocharitaceae and Alismataceae are sister groups of Hydrocharitaceae; (4) the three marine genera,Halophila, Enhalus andThalassia, are monophyletic; and (5) a peculiar pollination mechanism specific to Hydrocharitaceae (Hydrocharitaceae-epihydrophily), underwent a parallel evolution.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Pollen morphology inParis and its related genera

Pollen grains ofParis, Medeola, andScoliopus have been examined with light, scanning electron, and transmission electron microscopies.P. quadrifolia L.,P. verticillata Bieb.,P. delavayi Franch. andP. polyphylla Smith have monosulcate pollen characterized by psilate, foveolate or reticulate exine sculpture. In contrast to the former species,P. japonica (Fr. et Sav.) Franch. andP. tetraphylla A. Gray have monosulcate pollen with gemmate (rarely rugulate) exine.Medeola has monosulcate pollen with reticulate exine that is distinct from that ofParis. Scoliopus has monosulcate pollen characterized by a peculiar reticulate exine pattern. The palynological evidence suggests thatParis andTrillium are closely related to each other, andMedeola andScoliopus should be separated fromParis andTrillium.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen:Ranunculaceae,Hamamelidaceae, Platanaceae undFagaceae

Transfer of fresh pollen either by wind or by insects is strongly related to the degree of its stickiness. The sticky substances involved should be understood as pollenkitt. Ultrastructural investigations indicate that the sticky pollen of entomophilous angiosperms (in this publicationHamamelis vernalis andH. virginiana, Corylopsis platypetala) results from the deposition of usually electron-dense, homogeneous pollenkitt mainly on the outside layer of the exine. In contrast, the pollen of anemophilous angiosperms (in this publicationParrotia persica, Platanus orientalis, Thalictrum flavum andQuercus robur), but also of some entomophilous angiosperms with special pollination ecology (e.g.Aquilegia vulgaris) is rather dry and powdery. In these cases the pollenkitt often is electron-transparent and inhomogeneous and is mainly removed into the cavities of the exine. Ultrastructure and deposition of pollen and pollenkitt in ambophilous angiosperms (in this publicationThalictrum minus, Castanea sativa) are ± intermediate.

     

POLLEN MORPHOLOGY IN THE GENUS ERYTHRONIUM (LILIACEAE) AND ITS SYSTEMATIC IMPLICATIONS

Pollen morphology was examined in 40 samples from 19 species in the genus Erythronium (Liliaceae) using scanning (SEM) and transmission electron microscopy (TEM). Pollen grains are monosulcate monads, except for a plant of E. oregonum which has dyad grains. North American and European species are characterized by reticulate exine sculpture composed of various degrees of wavy muri and variably-sized lumina. The most distinctive feature of exine sculpture in the genus is exhibited by the Asian species E. japonicum, which has a unique reticulate pattern composed of striate muri and a distinctive exine structure without columellae. The distinctness of E. japonicum pollen suggests that it has specialized in isolation from species in North America and Europe.     

水鳖科9属15种植物花粉形态的研究

应用光学显微镜、扫描电镜和透射电镜对水鳖科Hydrocharitaceae 9属15种植物的花粉形态进行 了观察。水鳖科植物花粉为圆球形至近椭球形,无萌发孔或偶为单沟萌发孔,外壁纹饰通常为小刺状纹 饰,刺密集或稀疏,花粉表面具瘤状、疣状、颗粒状、皱波状突起或光滑。外壁由覆盖层、柱状层和基层组 成。覆盖层厚或较薄,柱状层小柱发育不明显,基层薄。水鳖科植物在花粉大小、纹饰类型、刺的长短、 密度、形态、萌发孔的有无以及花粉壁的结构等方面表现出了较为明显的差异,这些特征对探讨类群间 关系具有较重要意义。由于黑藻属Hydrilla和Stratiotes属花粉较为特殊,支持将它们各自作为一个独立 的族处理。水鳖科植物花粉外壁纹饰和结构特点表明该科与水雍科Aponogetonaceae、泽泻科Alismataceae 和花蔺科Butomaceae等近缘,而该科植物花粉大多无萌发孔等则反应了该科与茨藻目Najadales植物有密切联系。     

POLLEN MORPHOLOGY AND ULTRASTRUCTURE OF THE CABOMBACEAE: CORRELATIONS WITH POLLINATION BIOLOGY

Of all species comprising the two genera of the Cabombaceae, only Brasenia schreberi J. F. Gmel. and Cabomba caroliniana Gray have been critically investigated with regard to their pollination biology. Brasenia schreberi has been shown to be anemophilous, while C. caroliniana has an entomophilous (myophilous) pollination syndrome. In the present paper, a number of pollen and pollen-related characters, including pollen size, shape, quantity, terminal settling velocity, pollen-ovule ratios, and overall exine architecture of B. schreberi and C. caroliniana are evaluated. Pollen from both species is elliptic, monosulcate, and has a tectate-columellate sporoderm with supratectal surface ornamentation. Grains of B. schreberi are small, produced in copious amounts, and settle relatively slowly. Flowers of this species have large pollen-ovule ratios. The exine of B. schreberi pollen is scabrate, relatively thin, has a uniformly thick sexine composed of a two-zoned (homogeneous/granular) tectum and distinct columellae, and a homogeneous nexine. Pollen of C. caroliniana is relatively large, produced in small quantities, and has a rapid terminal settling velocity. Flowers exhibit small pollen-ovule ratios. Exine organization of C. caroliniana pollen is typically two times thicker than that of B. schreberi; ornamentation is striate. Nonapertural sexine regions have a thick tectum and well-defined columellae, with both sexine components traversed by a dense system of channels. The nexine is relatively thin. All of the palynological characters examined correlate well with the anemophilous and entomophilous syndromes of B. schreberi and C. caroliniana, respectively. Moreover, several other parameters of exine ultrastructure from each species exhibit positive correlations with the respective pollination mechanisms, including: tectum thickness, columellae diameter, tectum-nexine ratios, and the consistency, distribution, and total amount of pollenkitt present. Overall exine ultrastructure is also discussed from a historical perspective as well as with respect to its phylogenetic significance.     

甘薯属10种植物花粉形态扫描电镜观察

对用于育种研究的甘薯属(Ipomoea)10种植物花粉形态进行扫描电镜观察研究,以补充该属植物花粉形态学信息. 结果表明,甘薯属植物花粉粒的形状均为近球形,体积较大;花粉萌发孔多为散孔,少数萌发孔不明显;表面纹饰有3种:刺状类型、网状带刺类型和网状类型.根据花粉粒大小、刺的长短、萌发孔特征和表面纹饰类型等可以把这10种植物区分开来,同时发现I.wrightii与已有报道存在较大差异.     

蜘蛛抱蛋亚族的花粉形态

本文研究并报道了百合科蜘蛛抱蛋亚族的花粉形态,主要结论如下：1．开口箭属含两种花粉类型即：(1)单槽、椭圆形;(2)无萌发孔、球形。具单槽、椭圆形花粉的种类含单型性核型,花形较小,柱头小而花柱短,雄蕊高于柱头;无萌发孔、球形花粉的种类则为单型性核型,花形较大,柱头常高度膨大,雄蕊常着生在花被筒基部。2．万年青属花粉为椭圆形,具单槽;蜘蛛抱蛋属花粉则为球形,无萌发孔;开口箭属花粉一部分与万年青属相似,另一部分则与蜘蛛抱蛋属雷同。3．蜘蛛抱蛋亚族中最原始的花粉类型为单槽椭圆形,具孔状或网状外壁纹饰。球形,无萌发孔,外壁具皱波状、瘤状或芽孢状纹饰的花粉为派生类型。4．蜘蛛抱蛋亚族种下花粉形状、萌发孔类型和外壁纹饰基本稳定,可作为分种特征。     

Le Infezioni Con “Stubborn” Ottenute per Trauma E Il Grado di Recettività dei Tipi di Grano

Abstract

Dioecy ensures cross pollination but pollen must travel from male to female plants, sometimes covering long distances. The present study concerns the reproductive strategy of two Italian dioecious plants: Mercurialis annua L. and Bryonia dioica L. The former is anemophilous and the latter is entomophilous; the latter has nectar and pollen as rewards. The distribution of pollen grains on the stigma is very different in the two species, reflecting the different types of pollination. In both species there is a number-dependent mechanism of pollen germination on the stigma. This mechanism could enhance male gametophytic competition.     

Allergenicity of Acroptilon repens and Juglans regia pollen in rats

Pollen proteins that are located in the cytoplasm or on the surface of the exine can function as allergens and evoke immune system responses in sensitive patients, leading to allergic rhinitis and asthma. In this research, the pollen allergenicity and ability to induce IgE response of the pollen of two plant species were studied in rats. Acroptilon repens is an herbaceous, invasive plant with entomophilous pollen, while Juglans regia which is a tree crop produces anemophilous pollen. Immunoblot analysis using sera of sensitised rats revealed IgE reactivity to three protein bands including the 70, 41 and 25.12 kDa bands present in the A. repens pollen extract, while only one single immunogenic band of 11 kDa was detected in J. regia pollen extract. Both pollen extracts increased the eosinophil content and caused some clinical signs of allergy in treated rats. The results showed that both entomophilous and anemophilous pollen can be allergenic.     

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。     

Pollen Morphology in the Subtribe Aspidistrinae (Liliaceae s. l.)

Pollen morphology in the subtribe Aspidistrinae is reported and the main viewpoints are summarized as follows: (1) Two major types of pollen grains, i.e., monosulcate,ellipsoidal pollen and inaperturate, spheroidal pollen, are identified in the genus Tupistra. The species with monosulcate, ellipsoidal pollen usually have monomodal karyotypes, brightcolored flower, smaller stigma, and stamens inserted at upper or middle part of perianth tube, while the inaperturate and spheroidal pollen is always found in the species with bimodal karyotypes, dingy-colored flower, swollen stigma and stamens inserted at the base of perianth tube. (2) Pollen grains in the genus Rhodea are monosulcate and ellipsoidal, while those in the genus Aspidistra are inaperturate and spheroidal, correspondingly similar to the second type of pollen grains in the genus Tupistra. (3) The most primitive pollen in the subtribe Aspidistinae is regarded as monosulcate and ellipsoidal, having perforate or reticulate exine sculpture. The inaperturate, spheroidal pollen with verrucate, gemmate or rugulate exine sculpture is considered derived; (4) Unlike those reported in other groups of the family Liliaceae, the infraspecific pollen shape, aperture type and exine sculpture in Aspidistrinae are basically stable and may serve as a taxonomic character.     

POLLEN MORPHOLOGY IN NORTH AMERICAN SPECIES OF TRILLIUM

The pollen morphology and tapetal membranes of 17 species of Trillium from North America have been examined by scanning and transmission electron microscopy. The pollen grains of the genus are consistently spherical and inaperturate. The exine is unstratified and ultra-thin. Five types of exine structure are recognized, namely, echinate-, corrugate-, granulate-, verrucate- and spinulate-type, based on the variations in the components of the exine. The granulate-type is the most common and is divided into six subtypes. The features of tapetal membranes also vary in relation with the variation of the exine structures. This study demonstrates the potential of palynological evidence in assessment of taxonomic relationships within the genus.