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.     

绣球属(Hydrangea L.)及近缘属花粉形态的研究

为深入研究绣球属植物花粉形态的分类学价值和系统学意义,厘清绣球属与近缘属之间的系统发育关系,该文利用扫描电子显微镜(SEM,scanning electron microscope)对国产绣球属及其近缘属41种绣球花科(Hydrangeaceae)植物的花粉形态以及表面纹饰进行了观察。结果表明:绣球属及其近缘属的花粉为三孔沟;形状多数为长圆体形或近球体形;赤道面观为椭圆形或圆形;极面观多为圆形,少数为三角形或圆三角形。花粉外壁纹饰可分为网状和孔穴状。网眼内的三级纹饰可分为光滑和具颗粒状突起。根据花粉形状和外壁纹饰类型将上述物种划分为4个组,即花粉的形状为长圆体形,表面纹饰为孔穴纹饰;花粉的形状为长圆体形,表面纹饰为网状纹饰;花粉的形状为近球体形,表面纹饰为孔穴纹饰;花粉的形状为近球体形,表面纹饰为网状纹饰。以上可进一步细分为8个类型。上述表明花粉形态证据可为绣球属及其近缘属的属下分类和种间界定提供重要佐证;但结合前人的系统发育重建分析该属植物花粉形态的系统学意义相对有限,如花粉形态证据对于该属及其近缘种属系统发育树上大支的界定难以提供有力的证据。     

Pollen morphology in Asiatic species ofTrillium

Pollen grains of five species and two interspecific hybrids ofTrillium from eastern Asia have been examined with scanning electron and transmission electron microscopy. All species from eastern Asia, excludingT. govanianum, are characterized by inaperturate pollen and an unstratified and granulated exine structure. Pollen of the Himalayan species,T. govanianum, is, however, monocolpate and intectate. The palynological evidence suggests that the Asiatic species, excludingT. govanianum, are closely related to each other and toT. erectum in North America, andT. govanianum is independent of the other species in the genus.     

Pollen morphology of Gyrostemonaceae,Bataceae andKoeberlinia

Pollen morphology of Gyrostemonaceae, Bataceae, andKoeberlinia, which have been affiliated with glucosinolate-producing taxa, was examined by field emission scanning and transmission electron microscopy. Pollen grains of Gyrostemonaceae are tricolpate with scabrate-spinulate surface and have a thick, unstratified exine, while those of Bataceae are tricolporoidate with granular surface and have a thin exine with a single, outermost granular layer. Gyrostemonaceae and Bataceae, which had often been considered sister taxa based on palynological similarity and now are considered more distantly related, have a similar spongy ektexine, but differences between them are evident.Koeberlinia, which is recently considered a sister group to Bataceae+Salvadoraceae (with no spongy ektexine), has tricolporoidate pollen composed of a plesiomorphic, stratified exine with columellae. The totality of evidence indicates that, contrary to earlier observations, pollen of Gyrostemonaceae and Bataceae does not closely resemble each other, and that the spongy ektexine, which looks to be similar in TEM sections, is a homoplasy that evolved independently in the two families. Dedicated to the late Prof. Emer. Kankichi Sohma (August 28, 1926–June 26, 1995), who supervised us for our M. Sc. and D. Sc. programs at Tohoku University, Sendai. He died after his 40 years career in palynology; his wide range of interests and enthusiasm for research, and his unfailing encouragement for students are greatly missed.     

Pollen morphology inLinum sect.Macrantholinum

Pollen of the two distylous species which make upLinum sect.Macrantholinum differs from that of other distylous species in the genus in being multiporate and in having much more modest differences in exine sculpturing between grains from long- and short-styled plants. Pollen morphology does not help in relating the two species to others in the genus but does support their retention in a separate section.     

Relationships among Cichorium species and related genera as determined by analysis of mitochondrial RFLPs

Mitochondrial DNA polymorphism was employed to assess cytoplasmic diversity among cytoypes of the genus Cichorium and related genera of the tribe Lactuceae (Asteraceae). Hybridization patterns of total DNA using six restriction enzymes and five heterologous mtDNA probes were examined. From estimates of mtDNA diversity, Cichorium spinosum appeared as an ecotype of C. intybus rather than a separate species. Interspecific mtDNA polymorphism in the genus Cichorium was higher than that observed in Cicerbita Crepis, Lactuca and Tragopogon. Molecular data seemed to indicate that Catananche is very distant from the other genera examined. Intergeneric comparisons allowed the clustering of Cicerbita, Lactuca and Cichorium, genera which belong to different subtribes. However, further molecular investigations on a larger number of genera are needed to clarify the relationships among genera within and between subtribes of the tribe Lactuceae.     

Pollen morphology ofPyrola and its taxonomic significance

Pollen from 152 collections representing 16Pyrola species was examined with LM, SEM and TEM. The genusPyrola is stenopalynous in having tetrads and 3-colporoidate grains. However, a continuous and serial variation in the exine sculpture and the tetrad diameter (D) was revealed within the genus. Křísa's system ofPyrola (1971) was re-examined in the light of these palynological characters which may have a taxonomic significance, as well as the external morphology. P. minor (only member of the subgenusAmelia), which is characterized by having small (D=30–35 μm) pollen tetrads with verrucate sculpture must best be placed near sectionPyrola of the subgenusPyrola. P. faurieana must be segregated from sectionChlorantha and together withP. media placed intermediate between the subgenusAmelia and sectionPyrola of the subgenusPyrola based on their larger (D=ca. 40 μm) pollen tetrads with verrucate sculpture. Two series of sectionChlorantha excludingP. faurieana are differentiated in the exine sculpture. Therefore, they are regarded as the distinct taxonomic groups. SectionScotophylla is characterized by having psilate sculptured pollen tetrads, which indicates that its sectional rank is sufficiently asserted. The evolutionary trend in the exine sculpture from verrucate through rugulate to psilate is suggested withinPyrola.     

Pollen morphology of JapaneseSymplocos (Symplocaceae)

The pollen morphology of all 23 Japanese species ofSymplocos (1 of subgenusEusymplocos, and 22 of subgenusHopea) was comprehensively studied using LM, SEM and TEM, and found to be classifiable into two types (Type I and II) primarily on the basis of wall structure. Type I, characterized by a thick tectum lacking a supratectal structure and reduced columellae, occurs in subgenusEusymplocos, while Type II, characterized by a thin tectum with a supratectal structure and generally distinct columellae, occurs in subgenusHopea. Resemblances in wall structure suggest a closer relationship of subgenusEusymplocos to subgenusMicrosymplocos as well as of subgenusHopea to subgenusEpigenia. This fact contradicts the earlier proposed infrageneric classification, and may require its revision. Within Type II, five subtypes are recognized primarily on the basis of sculpture combined with other pollen characters. Systematic value of sculpture (i.e., subtype), aperture morphology and “globules”, as well as certain species relationships based on those characters, are also discussed.     

Pollen morphology of the cypripedioid orchids

Pollen morphology of the four traditional genera (Paphiopedilum, Selenipedium, Cypripedium, Phragmipedium) comprising the cypripedioid orchids indicates that the monads are sulcate, more or less smooth-surfaced, and covered by a non-acetolysis resistant layer called elastoviscin. Evidence from ultrathin sections of pollen grains shows that typical exine layers are present only inSelenipedium, modified inPhragmipedium and absent inPaphiopedilum and most species ofCypripedium; that a small, inconspicuous portion of the grain surface is constructed as a sulcus; and that the pollen grain wall acts as a sponge in rapidly absorbing water. Several instances of parallelisms between non-related families and among different groups of orchids are reported and new ideas on the evolution of theCypripedioideae are presented.Dedicated to Prof. DrE. Tschermak-Woess on the occasion of her 70th birthday.Reprint requests toM. Hesse.     

Pollen morphology of the genera Polygonum s. str. and Polygonella (Polygoneae: Polygonaceae)

The pollen of 30 taxa (27 species, one subspecies and two varieties) in two genera, viz Polygonum s. str. and Polygonella was investigated with LM and SEM, and some selected taxa with TEM. In all genera investigated the pollen is prolate to spheroidal, and the aperture is mostly tricolporate, rarely panto-hexacolporate (especially Polygonum section Polygonum). The exine sculpturing pattern is the most variable feature. Three types of exine can be recognized. Type 1 (Avicularia-Type, sensu Hedberg) - All species of section Polygonum and section Tephis share the smooth tectate exine with spinules, sometimes the surface is more or less rough (Polygonum afromontanum in section Tephis). Type 2 (Pseudomollia-Type, sensu Hong) - Pollen of Polygonum molliaeforme (section Pseudomollia) has the exine, which is verrucose on both poles and nearby the mesocolpium, and mostly psilate around the ectoaperture. Type 3 (Duravia-Type, sensu Hedberg) - Pollen grains of Polygonum section Duravia and Polygonella have the exine which is semitectate-reticulate at the mesocolpium and the poles, and rugulate/reticulate or sometimes foveolate with microspinules around the ectoapertures. The pollen grains in four taxa (viz Polygonum section Pseudomollia, P. section Duravia and genus Polygonella) have a well-marked dimorphism of the ektexine, which is considered to be a synapomorphic condition. The differences of pollen grain between the genus Polygonella and Polygonum section Duravia are almost non existent and clearly interrelated. It is therefore postulated that the similarity in pollen of both taxa is not the result of convergency, but is interpreted as a homology. It is noteworthy that the pollen of Polygonum molliaeforme (section Pseudomollia) appears as intermediate between the Avicularia-type and the Duravia-type, and is well supported the value of separated section for its own. Additionally, in TEM, some exine ultrastructures (e.g. columellae, foot layer, endexine) appear to be valuable characters for comparison between/among taxa. The systematic potentialities of the pollen data of the studied taxa at various systematic levels are also discussed.     

Pollen morphology of Stachys (Lamiaceae) in Iran and its systematic implication

Pollen grains of 30 taxa of the genus Stachys (29 spp. and one subsp.), representing 9 of the currently recognized sections and 1 species of the closely related genus Sideritis (Si. montana) distributed in Iran were examined by light and scanning electron microscopy. Twenty-eight taxa are studied for the first time under aspects of pollen morphology. The basic shape of the pollen grains in most taxa studied is prolate-spheroidal, but subprolate, spheroidal and oblate-spheroidal pollen grains can also be found in few species. The grains are usually tricolpate (the amb triangular), but also tetracolpate (the amb circular to more or less square) in some species (S. iberica, S. atherocalyx and Si. montana). The surface is microreticulate (the frequent type), reticulate, perforate, foveolate-psilate or foveolate. The lumina are separated by smooth or sinuate muri which make them polygonal, more or less rounded and elongate. Major pollen morphological features of the taxa studied are compared and discussed on the basis of taxonomical concepts. In some cases, these characters are useful in delimitation of formerly introduced sections while they mostly provide further characters in separating related species from each other. For example, all members of S. sect. Aucheriana are characterized by elongated lumina. Based on the oblate-spheroidal shape of its pollen as well as tetracolpate aperture type, the results of the present study confirm sect. Pontostachys as including S. angustifolia, S. iberica, S. sparsipilosa as well as S. atherocalyx. Our results also suggest that although some species like S. fruticolosa and S. lavandulifolia are morphologically well characterized, they cannot be separated from other species of Stachys based on pollen morphology.     

Distinction of species in Aureobasidium and related genera by PCR-ribotyping

Taxonomic markers for differentiation of the anamorph genera Aureobasidium, Hormonema and Kabatiella were developed using PCR-ribotyping with the primers 5.8S-R and LR7 for amplification and the restriction enzymes Alul, DdeI, Hhal, MspI and RsaI for digestion. Aureobasidium and Hormonema are optimally differentiated with MspI; DdeI is particularly useful to distinguish aureobasidium, Kabatiella and Selenophoma. Relationships of the anamorph genera Aureobasidium, Hormoneng and Kabatiella with the teleomorph genera Pringsheimia and Dothiora are discussed.     

Pollen grain morphology supports the taxonomical discrimination of Mediterranean oaks (Quercus,Fagaceae)

The exine architecture and some quantitative parameters (polar and equatorial axes and their ratio) of pollen grains allow a clear discrimination between groups of Mediterranean oak species. For the differentiation of species within groups only the quoted parameters prove useful.     

10种金花茶组植物的花粉形态及分类学意义

金花茶组(Sect.Chrysantha)植物具有很高的观赏价值,但其分类存在争议.为探讨金花茶组植物花粉的形态特征和分类学意义,该研究用扫描电镜观察了10种金花茶的花粉形状、外壁纹饰以及穿孔特征,统计了极轴长、赤道轴长和萌发沟长,并进行聚类分析.结果表明:(1)10种供试金花茶植物花粉为中粒花粉,大部分花粉形状呈近球...     

Self-fertility and associated flower head traits in the Iberian taxa ofLactuca and related genera (Asteraceae: Lactuceae)

Sexual reproduction is the main reproduction mechanism among the 14 wild Iberian taxa ofLactuca, Prenanthes, Cicerbita, andMycelis. High levels of self-fertilization occur inLactuca, as well as facultative and obligate xenogamy. Xenogamy is strongly correlated with large capitula having blue or bright yellow colouration, high P/O ratios, and long anthesis, whereas self-fertilization is correlated with smaller capitula having pale yellow colouration, small P/O ratios, and short anthesis. Large variations occur in P/O index among taxa showing similar fertilization mechanism, probably in relation to the number of florets included in flower heads. Interesting differences in reproductive systems have been detected between subspecies ofLactuca viminea.     

Pollen morphology and pollen-wall proteins (localization and enzymatic activity) inSesamothamnus lugardii (Pedaliaceae)

The pollen grains ofSesamothamnus lugardii Stapf (Pedaliaceae of subdesert regions of SE tropical Africa) are associated in acalymmate tetrads (cross wall cohesion), with a tectate and perforate exine and 8–12 colpi. The pollen wall consists of an ectexine with a complete, perforate and ample tectum, columellated infratectum and clearly interrupted and fragmented foot layer. The endexine is built of scanty lamellae and granules. The intine is bistratificate, with a homogeneous, fibrillate layer (endintine or intine-2) and a heterogeneous, more lax and channeled layer (exintine or intine-1). Test for glycoprotein is particularly positive in the homogeneous internal intine and channels of external intine. On the other hand acid phosphatase has been localized in the exine and channeled external intine layers. These observations confirm the general interpretation of the distribution of wall compounds.     

Pollen morphology of Campanula (Campanulaceae) and allied genera in Iran with special focus on its systematic implication

Pollen grains of 47 taxa of Campanulaceae including 35 taxa of Campanula that represent its five subgenera and nine sections are investigated. Moreover, five species and three subspecies representing three sections in Asyneuma and one species of each genera Legousia, Michauxia, Zeugandra and Theodorovia were studied by light and scanning electron microscopy. The basic shape of the pollen grains was spheroidal. The apertures vary from tri- to hexa-porate. The sculpturing pattern of exine was rugulate-echinate, rugulate-microechinate or in few species rugulate-microreticulate and microechinate. The most valuable characters for subgeneric classification were the length and density of echini. The length of echini were significantly long (> 2 μm) in C. sclerotricha, Legousia falcata and Michauxia laevigata. Pollen grains show low variation in different species of subgen. Rapunculus, but were variable among different species of some groups, such as sect. Rupestres, probably indicating their non-monophyly despite homogeneity with respect to other morphological characters. Pollen morphology does not support recognition of Asyneuma, Legousia, Michauxia, Symphyandra, Theodorovia, and Zeugandra as separated from Campanula, since none of them exhibit any unique feature.     

A new pollen type,C-banded and fluorochrome counterstained chromosomes,and evolution inGuatteria and related genera (Annonaceae)

Guatteria, Guatteriopsis, Guatteriella andHeteropetalum share the same conspicuous pollen type which is new for theSpermatophyta. It is zonoaperturate with a folded aperture region and an extremely reduced exine. First chromosome counts and karyotype analyses forGuatteriopsis (4 species investigated) andGuatteriella (1 species) are identical with those ofGuatteria (19 species seen): 2n = 28. The genome is characterized by diploidization and partly telocentric chromosomes. Sequentially Giemsa C- and fluorochrome banded chromosomes and interphase nuclei are described. The cuticular folding pattern is distinct forHeteropetalum only. Growth forms and ecology are reported for many species. The evolutionary pattern of theGuatteria group is discussed and compared with other genera and families.     

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.