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.     

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.     

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 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.     

The time and duration of the premeiotic inteprhase in microsporocytes ofTrillium kamtschaticum

The time and duration of each phase of the premeiotic interphase were determined in microsporocytes of two clones (S and K clones) ofTrillium kamtschaticum. After collectionTrillium plants were stored at 3 C or 7 C prior to completion of premeiotic mitosis in archesporial cells. For autoradiography, cells were explanted in the presence of³H-thymidine to identify the interval of the premeiotic DNA synthesis. Approximate durations of the G₁, S and G₂ phases for the K clone stored at 3 C were estimated to be 12, 12 and 14 days, respectively. The interval of premeiotic development was markedly different between clones. A high degree of synchrony in meiotic development, which is usually observed within anthers up to late meiotic prophase, was confirmed at the S phase, suggesting that synchrony is established during the G₁ interval.     

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.     

Pollen morphology of certain species of the family Lamiaceae in Saudi Arabia

The intention of the present wok is to provide an account on the pollen morphological features of Lamiaceae in Saudi Arabia as a basis for future studies of Lamiaceae pollens in the region. Pollen morphology of 20 species belong to 16 genera of the Lamiaceae has been investigated using Light Microscope (LM) and Scanning Electron Microscope (SEM). The study revealed that the pollen grains were characterized by 3-zonocolpate or 6-zonocolpate. Size of the pollen is variable between the genera but not among the species of the same genus. The surface pattern of the exine varies from fine reticulate, rough reticulate, mega-reticulate, reticulate-perforate, bireticulate-perforate or granulate, leading to 6 types of pollen grains. These variations revealed by this study implies that pollen Morphology may be of significant value sharing in solving problems in the classification of Lamiaceae members. A Key to the species, based on the morphological features of pollen grains, is also provided.     

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 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.     

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...     

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 dimorphism in threeTeucrium species (Lamiaceae)

In the Iberian Peninsula and Balearic Islands pollen dimorphism was found inTeucrium fruticans L.,T. pseudochamaepitys L., andT. rotundifolium Schreber. Generally, this dimorphism shows two sizes of pollen grains, the smaller more or less collapsed. The percentage of pollen viability is calculated. Differences in size between viable and nonviable pollen grains are similar, being about 40% inT. fruticans andT. pseudochamaepitys, and about 26% inT. rotundifolium. With regard to pollen viability, the percentage of male sterility is higher inT. fruticans, in which from male sterile (ms) plants, 100% nonviable pollen was obtained from every flower observed. InT. pseudochamaepitys andT. rotundifolium with rare exceptions, the percentage of nonviable pollen does not seem to be significant.     

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 grain morphology ofCoris (Primulaceae)

Pollen grain morphology, sculpturing, and wall ultrastructure are investigated in two species ofCoris (Primulaceae),C. monspeliensis L. andC. hispanica Lange. The study includes both acetolysed and unacetolysed pollen. No evidence of any major palynological difference is recorded between these two species, apart from a somewhat larger pollen inC. monspeliensis. However,Coris can be distinguished from the remaining members of thePrimulaceae by the conjunction of relatively large pollen grains, prominent margo, and particular tectal pattern causing a reticulate surface with minute luminal perforations decreasing towards the colpi. From both these distinctive features, and others typically primulaceous, some evolutionary considerations are inferred. Finally, the higher proportion of irregular grains inC. hispanica is interpreted in light of environmental stress.     

Pollen morphology ofSonchus and related genera,and a general discussion

The pollen morphology of the taxa belonging to the generaAetheorhiza Cass.,Launaea Cass.,Reichardia Roth andSonchus L. in the Iberian Peninsula has been studied with light and electron microscopy. The pollen is 3(-4)-zonocolporate and echinolophate (without polar lacunae, but in general with prelacunae), with equatorial ridges and 15–20 lacunae: 3–4 poral, 6–8 abporal and 6–8 paraporal. Small to medium size, P × E = 19–36 × 23–42 µm; sometimes two different sizes have been found. Exine 3–9 µm thick and ornamentation microreticulate and echinate. The results clearly show the relationships between genera. Moreno-Socías, E., Mejías, J. A., Díez, M. J., 1994: Morfología polínica deLactuceae (Asteraceae) en la Península Ibérica, I.Lactuca y géneros relacionados. — Acta Bot. Malacitana.19: 103–113.     

Pollen irradiation and possible gene transfer in Nicotiana species

Summary Progeny from crosses of Nicotiana langsdorffii with gamma irradiated pollen of Nicotiana alata Crimson Bedder showed skewed segregation in the F₂ favoring the maternal parent. This is probably not gene transfer in a strict sense, rather just an extreme case of reduced transmission of irradiated chromosomes, leading to massive overrepresentation of maternal genes. Gene transfer or mutational loss may explain some anomalous F₁ plants. Segregation in the F₂ progeny showed the presence of several genes from the irradiated pollen. Crosses of Nicotiana sylvestris, N. plumbaginifolia N. paniculata, and Petunia parodii with irradiated pollen from N. alata and Petunia hybrida showed no evidence of gene transfer, nor did experiments with irradiated mentor pollen. This indicates that gene transfer with irradiated pollen between non-crossing species or between species giving sterile hybrids is probably a rare phenomenon.     

三倍体丹参杂交种的花粉形态研究

三倍体丹参是以二倍体丹参为父本、人工染色体加倍的四倍体白花丹参为母本杂交选育的杂交种。为深入了解三倍体丹参花粉的特性,以及为三倍体种质利用提供孢粉学依据,该文以二倍体丹参为对照,研究了三倍体丹参杂交种花粉的形态变异规律。利用光学显微镜和扫描电镜对二倍体和三倍体丹参的花粉萌发沟、外壁纹饰、花粉粒形状等特征进行了显微和超微形态观察,综合进行了花粉形态差异比较,并对花粉大小和形状数据进行了差异显著性分析和正态检验。结果表明:(1)二倍体丹参为6沟花粉,三倍体花粉萌发沟有6沟和8沟两种类型,沟内疣状颗粒分布不匀,出现畸形萌发沟。(2)二倍体和三倍体花粉外壁均为网状雕纹。二倍体花粉网眼内具多个多边形穿孔,穿孔大; 6沟和8沟两种类型的三倍体花粉网眼无穿孔或仅有几个小穿孔,6沟和8沟花粉的外壁雕纹相同。(3)三倍体花粉的极轴长(P)和赤道宽(E)均值显著小于二倍体花粉,花粉大小呈偏正态分布,P*E的差异系数大于二倍体花粉,且有极值存在。三倍体和二倍体丹参的萌发沟和雕纹存在差异,而花粉形状差异不显著。综上结果表明三倍体丹参花粉在倍性效应和杂合性的双重影响下发生了形态变异,且有多种形态变化。     

中国天南星科花粉形态的研究

利用扫描电镜对天南星科Araceae22属28种(除Arum maculatum产自德国外,其余均产自中国) 及菖蒲科Acoraceae 1属2种植物的花粉形态进行了观察。结果显示天南星科花粉形态在科内变异很 大。花粉粒形状从球形、近球形、椭球形到扁球形和橄榄形;萌发孔类型有散孔型、具薄壁区型、环沟型 或无萌发孔;外壁纹饰为小穴状、网状、肋条状、条纹状、疣状、具刺或光滑。主要依据花粉形态方面的证 据探讨了崖角藤属Rhaphidophora、麒麟叶属Epipremnam 、龟背竹属Monstera 3属的属间关系以及犁头尖属Typhonium属下分类中存在的一些问题。     

三种金花茶花粉形态的扫描电镜研究

金花茶分类系统尚未完善,金花茶又极具观赏价值,潜在价值极高,该研究应用扫描电镜观察三种金花茶花粉形态,即平果金花茶、直脉金花茶、金花茶,并运用数理统计和图片分析的方法对其花粉形态进行了探讨.结果表明:三种金花茶花粉均属于大花粉粒,花粉平均极轴在50μm以上,花粉极面观为钝凹三角形,萌发孔为三孔沟,即N3P4C5类型.平果金花茶与直脉金花茶花粉外壁纹饰为拟网状纹饰,平果金花茶网眼较密,网脊稍不平,直脉金花茶网脊稍隆起;金花茶为蠕虫状纹饰,短条状突起.花粉形态对其分类有重要意义,通过花粉外壁纹饰的类型可知金花茶与其二者亲缘关系较远,花粉形态各指标具有种间变异性,种内具有保守性,而平果金花茶和直脉金花茶花粉外壁纹饰相同但具体分类还需进一步研究.该研究结果为金花茶种质资源分类和利用提供了参考,在一定程度上促进了金花茶资源的开发和利用.